Visual Psychophysics / Physiological Optics 106 Retinal

Transcription

ARVO 2015 Annual Meeting Abstracts by Scientific Section/Group - Visual Psychophysics / Physiological Optics
106 Retinal Alterations In Aging and Disease
Sunday, May 03, 2015 8:30 AM–10:15 AM
Exhibit Hall Poster Session
Program #/Board # Range: 87–94/A0247–A0254
Organizing Section: Visual Psychophysics / Physiological Optics
Contributing Section(s): Low Vision, Multidisciplinary Ophthalmic
Imaging
Program Number: 87 Poster Board Number: A0247
Presentation Time: 8:30 AM–10:15 AM
Characterization of Human Photoreceptor Packing Arrangement
as a Function of Retinal Eccentricity using an Adaptive Optics
Scanning Laser Ophthalmoscope (AO-SLO)
Elaine M. Wells-Gray1, Susanna C. Finn3, Cherry Greiner2, Stacey S.
Choi1, Nathan Doble1. 1College of Optometry, Ohio State University,
Columbus, OH; 2InfraredX, Burlington, MA; 3University of
Massachusetts Lowell, Lowell, MA.
Purpose: The human photoreceptor mosaic has been well
characterized through histological measurements from excised retina.
In vivo measurements of cone photoreceptor packing have been
reported by several research groups out to retinal eccentricities of
15°. Reports of rod properties in vivo are not so common. The aim of
this study was to examine the packing arrangement of cone and rod
photoreceptors in vivo at greater eccentricities than have currently
been reported.
Methods: An adaptive optics scanning laser ophthalmoscope (AOSLO) was used to image two human control subjects at the foveal
center and 4 temporal retinal (TR) eccentricities extending out to
25°. Both subjects had low refractive error without any history of
retinal disease and were imaged over a dilated pupil diameter of 7.2
mm. The AO system employed a Shack-Hartmann wavefront sensor
and a 97 actuator deformable mirror to measure and correct for the
ocular aberrations. The imaging wavelength was 680 nm with a field
of view of 0.9° x 1° on the retina. The frame acquisition rate was 30
Hz and the confocal pinhole diameter was set to 1 Airy disk. In the
subsequent post-processing, individual frames underwent strip-wise
registration to remove eye motion and were then averaged to increase
the signal-to-noise ratio. At each retinal location, the cone and rod
spacing were measured.
Results: The cone mosaic was clearly imaged at the fovea, 4, 8,
and 13° TR in both subjects, and at 25° TR in subject 2. Mean
cone spacing was 3.43 ± 0.44 mm, 9.01 ± 0.62 mm, 14.1 ± 1.86 mm,
18.1 ± 0.50 mm, and 19.7 mm, for fovea, 4°, 8°, 13°, and 25° TR
respectively. The spacing increased sharply when moving out from
the fovea, but then tapered beyond 8° TR. Rod photoreceptors were
clearly visible at 4, 8, and 13° TR in both subjects, with mean spacing
of 3.18 ± 0.03 mm, 3.31 ± 0.25 mm, and 3.82 ± 0.06 mm respectively.
The visibility of the rod mosaic especially at the higher eccentricities
was found to be highly sensitive to the plane of focus.
Conclusions: Results for both cone and rod photoreceptor spacing
as a function of retinal eccentricity show good agreement with
known distributions established by histology. This data can serve as a
benchmark against which diseased retinas (e.g., age-related macular
degeneration and retinitis pigmentosa) can be compared.
Commercial Relationships: Elaine M. Wells-Gray, None; Susanna
C. Finn, None; Cherry Greiner, None; Stacey S. Choi, None;
Nathan Doble, None
Support: NIH Grant EY020901, Department of Defense (DoD)
Telemedicine and Advanced Technology Research Center (TATRC)
W81XWH-10-1-0738
Assessing cone mosaic disruption in patients with X-linked cone
dysfunction
Emily J. Patterson1, James Tee2, 6, Jay Neitz3, Christopher S.
Langlo4, Alfredo Dubra5, 1, Maureen Neitz3, Adam M. Dubis2, 6,
Alison J. Hardcastle2, Michel Michaelides2, 6, Joseph Carroll1, 4.
1
Ophthalmology, Medical College of Wisconsin, Milwaukee, WI;
2
Institute of Ophthalmology, University College London, London,
United Kingdom; 3Department of Ophthalmology, University of
Washington, Seattle, WA; 4Cell Biology, Neurobiology, and Anatomy,
Medical College of Wisconsin, Milwaukee, WI; 5Biophysics, Medical
College of Wisconsin, Milwaukee, WI; 6Moorfields Eye Hospital,
London, United Kingdom.
Purpose: Cone dysfunction syndromes are typically associated
with reduced color vision and have been linked to the OPN1LW and
OPN1MW genes on the X chromosome. How mutations in these
genes affect cone photoreceptor integrity remains an important
question as we seek to elucidate a deeper understanding of the
genotype-phenotype relationship in these conditions. Here we
used adaptive optics scanning light ophthalmoscopy (AOSLO)
to characterize cone structure in subjects with mutations in the
OPN1LW and OPN1MW genes.
Methods: Six males (aged 11-37 years) with OPN1LW and
OPN1MW mutations were recruited. All subjects were dichromatic
(5 protanopic, 1 deuteranopic). Images of the cone mosaic were
obtained using AOSLO (both confocal and non-confocal splitdetection). Cone density was measured at parafoveal regions of
interest (ROIs) using semi-automated cone-counting software and
compared to published normative data. In five subjects, we compared
cone density across the confocal and non-confocal split-detection
modalities. Confocal cone density was assessed over time for two
subjects (follow up = 2 or 4 years).
Results: Three subjects had the previously reported LIAVA haplotype
encoded by either the OPN1LW or OPN1MW gene, while two others
had an insertion in exon 2 of the OPN1LW gene resulting in a 32bp
repeat. The final subject had no OPN1LW gene, and one of his two
OPN1MW genes encoded either the LIAVA or MIAVA haplotype.
Subjects showed variable reduction in cone density compared to
normal observers using both confocal (range = 26-90%) and split
detection (range = 7-87%) images. In most ROIs, we observed
greater cone density using split-detection rather than confocal images
(p = .70), indicating that the low cone density in confocal images was
due partly to altered cone reflectivity, rather than complete loss of
cones. No change in cone density was observed for the two subjects
for whom serial images were acquired (p = .30 and .42).
Conclusions: There is striking variability in the cone mosaic
phenotype in individuals with OPN1LW and OPN1MW mutations.
The combined use of confocal and split-detection AOSLO imaging
allows for a more thorough assessment of residual cone structure in
these patients. It remains to be seen whether the variable degree of
cone loss observed here correlates with variable functional deficits.
Commercial Relationships: Emily J. Patterson, None; James Tee,
None; Jay Neitz, None; Christopher S. Langlo, None; Alfredo
Dubra, Canon USA Inc (P); Maureen Neitz, None; Adam M.
Dubis, None; Alison J. Hardcastle, None; Michel Michaelides,
None; Joseph Carroll, None
Support: NIH (P30EY001931, R01EY017607, P30EY001730,
R01EY009303), National Institute for Health Research Biomedical
Research Centre at Moorfields Eye Hospital, Fight For Sight (UK),
Moorfields Eye Hospital Special Trustees (UK), Moorfields Eye
Charity (UK), Foundation Fighting Blindness (USA), The Wellcome
Trust. MM is supported by an FFB Career Development Award.
©2015, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
to reproduce any abstract, contact the ARVO Office at pubs@arvo.org.
Recovery of cone photoreceptors at the macula after concussion
of the retina
Atsushi Hayashi, Mitsuya Otsuka, Masaaki Ishida, Toshihiko Oiwake.
Ophthalmology, University of Toyama, Toyama, Japan.
Purpose: To examine changes in cone photoreceptors at the macula
after concussion of the retina with an adaptive optics (AO) fundus
camera.
Methods: Two patients after blunt injury who visited Toyama
University Hospital were included in this study. Patient#1 was
16 years old female and patient#2 was 27 years old male. They
were followed more than 3 months and underwent comprehensive
ophthalmic examinations and AO fundus camera (rtx1™, Imagine
Eyes, France) examination during the follow-up. Cone densities at
500 mm and 1000mm from the foveal center of the injured eyes were
obtained with AOdetect software. OCT images were compared to the
AO images.
Results: Cone densities of the patient#1were increased from 3984
/mm2 to 16317 /mm2 at 500mm, and 3803 /mm2 to 9766 /mm2 at
1000mm during 6 months after the injury. Cone densities of the
patient #2 were also increased from 4044/mm2 to 9533 /mm2 at
500mm, and 1285 /mm2 to 6686 /mm2 at 1000mm during 3 months
after the injury. Visual acuity was improved to 1.0 at 3 months in both
patients. OCT images showed irregular inner segment ellipsoid line
and cone outer segment tip line at the macula.
Conclusions: This is the first report to show the recovery of cone
densities after concussion of the retina. Even though visual acuity
and OCT images recovered with time, cone densities at the macula
remained reduced.
Commercial Relationships: Atsushi Hayashi, None; Mitsuya
Otsuka, None; Masaaki Ishida, None; Toshihiko Oiwake, None
Cone density loss on adaptive optics in early macular
telangiectasia type 2
Julie Jacob1, Valérie Krivosic2, Michel Paques3, Ramin Tadayoni2,
Alain Gaudric2. 1Ophthalmology, University Hospitals Leuven,
Leuven, Belgium; 2Ophtalmologie, Hôpital Lariboisière, Paris,
France; 3Imaging, Hôpital des Quinze-Vingts, Paris, France.
Purpose: To study whether cone photoreceptors are early impaired in
the progression of Macular telangiectasia type 2 (MacTel 2) disease.
MacTel2 is a macular neurodegenerative disease characterized by
progressive loss of Müller cells, intraretinal capillary proliferation
and ultimately loss of central photoreceptors. Early dysfunction or
loss of cone photoreceptors in the course of MacTel2 is debated. We
studied cone density, using flood illumination adaptive optics (AO) in
early-stage MacTel2.
Methods: Design: Eight patients with early signs of MacTel2 and 8
healthy volunteers underwent multimodal retinal imaging including
infrared reflectance scanning laser ophthalmoscopy, OCT, fluorescein
angiography and flood-illumination AO (rtx 1, Imagine Eyes,
France). Cone mosaic was studied in 5 sampling windows ranging
from 2° to 7° from the foveal center.
Main Outcome Measure: Structural appearance of cones; cone
density, spacing and hexagonal arrangement.
Results: Cone density values in the 10 MacTel2 eyes were inferior
to normal at all eccentricities from 2° to 7° (p<0.0001). Mean
cone spacing values were larger than normal at all eccentricities
(p<0.0001) and mean percentage of hexagonally organized
cone photoreceptors was lower at all eccentricities from 2° to 7°
(p<0.0001). This difference was more pronounced on the temporal
side of the fovea (p<0.0001) but also significant in nasal and was not
limited to the area of capillary anomalies. AO images in MacTel2
patients showed an irregular patchy disturbance of the cone mosaic
corresponding to some fragmentation of the Cone Outer Segment
Tips (COST) line (or Interdigitation zone) on OCT. The Inner/outer
segment (IS/OS) line (or ellipsoid zone) remained intact.
Conclusions: Adaptive optics showed that in early MacTel2 the cone
mosaic is altered in the macular area. The cone density was inferior
to normal even outside the telangiectasia, although the IS/OS line
remained intact on OCT. However OCT showed fragmentation of
the COST line, which correlated with decreased cone density. These
findings do not indicate that the loss of cone density is causative of
the disease but that it might be secondary to Müller’s cell and rod loss
in this area. However cone density assessment could become a useful
parameter to follow the progression of the disease.
Cone density values in the 10 Mac Tel eyes were significantly inferior
to normal values at all eccentricities from 2° to 7° (p<0.0001).
Commercial Relationships: Julie Jacob, Bayer (R), Novartis (R);
Valérie Krivosic, None; Michel Paques, Imagine Eyes (C), The
Agence Nationale de la Recherche (F); Ramin Tadayoni, None;
Alain Gaudric, None
Clinical Trial: NCT01546181
Visual function and retinal structure in suspected carriers of
choroideremia
Erle Hortense Veim, Rigmor C. Baraas, Stuart J. Gilson. Optometry
and Visual Science, Buskerud and Vestfold University College,
Kongsberg, Norway.
Purpose: To investigate visual function and retinal structure in
suspected carriers of choroideremia using clinical methods, and highresolution imaging techniques.
Methods: Three symptomatic suspected carriers of choroideremia
from one family aged 24, 59 and 62 yo and nine healthy age-matched
controls with normal logMAR letter acuity and no observed ocular
abnormalities, were included in the study. The youngest carrier was
examined two-years ago and re-examined this year. Visual field
and dark adaptation were examined with standard Humphrey VFA.
Images of retinal layers and the cone mosaic of the fovea, para- and
perifoveal regions were obtained with the Heidelberg Spectralis OCT
and the Kongsberg Adaptive Optics Ophthalmoscope II, respectively.
The subject’s eye was dilated and accommodation suspended with
Cyclopentolate 1% prior to imaging.
Results: All the carriers had normal logMAR letter acuity. A ringshaped visual field loss and poorer rod dark adaptation was observed
in all three carriers (mean deviation >12.02 dB difference and >0.4
log units difference, respectively, as compared with age-matched
controls). OCT showed intact retinal layers in the central 5 deg of the
24 yo and the central 2–3 deg of the 59 yo and 62 yo carrier. Beyond
this point the layers of outer and inner segments, external limiting
membrane and outer nuclear layer merged in to one. Foveal retinal
thinning was observed in the 24 yo and 59 yo as compared with
age-matched controls, but not in the 62 yo. All three have patches
of pigmentary abnormalities in the periphery. The 24 yo showed
a marked change over a two-year periode. The region of intact
retinal layers was 1 deg smaller and foveal and parafoveal retinal
layers were nearly 20 um thinner than two years ago. Her patches
of pigmentary abnormalities seemed unchanged. Visual sensitivity
(mean deviation) was reduced by 2 dB. AO images revealed reduced
cone density as compared with normal controls and loss of reflective
cones beyond the central parts corresponding with findings on OCT
images.
Conclusions: Changes in retinal structure in female carriers of
choroideremia progress over time and are clearly visible both in OCT
and AO images. Loss of sensitivity is seen both with standard visual
field testing and dark adaptation. The latter indicates a greater loss of
rods in peripheral parts.
Commercial Relationships: Erle Hortense Veim, None; Rigmor C.
Baraas, None; Stuart J. Gilson, None
mm2 (range 4670-8775 cells/mm2) for healthy controls. This gives a
mean cone:GC ratio of 2.15:1 for glaucoma patients and 1.15:1 for
healthy controls. PGRA, but not cone density, was reduced in the
scan locations of the maximum visual field loss in glaucoma patients
(mean cone:GC ratio 4.59:1).
Conclusions: The number of cones does not differ in glaucoma
patients compared to age-matched normal controls, despite large
differences in ganglion cell density. Since large inter-individual
differences in GC density exist even in normal subjects [2], cone:GC
ratio may prove to be a useful indicator of GC loss from baseline in
glaucoma.
References:
1. Drasdo N, Fowler CW. Non-linear projection of the retinal image
in a wide-angle schematic eye. Br J Ophthalmol 1974;58:709-714.
2. Curcio CA, Allen KA. Topography of ganglion cells in human
retina. J Comp Neurol 1990;300:5-25.
Determining the cone:ganglion cell ratio in glaucoma using
psychophysical measures of retinal ganglion cell density and in
vivo imaging of the retinal cone mosaic by a modified Heidelberg
Retina Angiograph (HRA2)
Juliane Matlach1, Padraig Mulholland1, Marketa Cilkova1, Reena
Chopra1, Nilpa Shah1, Tony Redmond2, Steven C. Dakin3, David F.
Garway-Heath1, Roger S. Anderson4, 1. 1NIHR Biomedical Research
Centre, Moorfields Eye Hospital & UCL Institute of Ophthalmology,
London, United Kingdom; 2Optometry and Vision Sciences, Cardiff
University, Cardiff, United Kingdom; 3School of Optometry,
University of Auckland, Auckland, New Zealand; 4Vision Science
Research Group, University of Ulster, Coleraine, United Kingdom.
Purpose: To determine the parafoveal cone:ganglion cell (GC)
density ratio in glaucoma patients compared to age-matched normal
controls using a modified Heidelberg Retina Angiograph (HRA2)
to image cones and localized measurements of peripheral grating
resolution acuity (PGRA) to estimate GC density.
Methods: A group of glaucoma patients with early to moderate
visual field loss and healthy age-matched controls underwent in
vivo cone imaging at 4 retinal locations at 6° eccentricity using a
modified HRA2 (scan angle of 3°). Retinal cones were identified and
counted using custom software. PGRA measurement was performed
at the same retinal locations and converted to GC density. PGRA
values were converted to minimum angle of resolution (MAR) and
GC density was calculated using the equation MAR = 0.93/√D. A
conversion factor [1] was used to calculate the number of ganglion
cells per square millimetre of the retina.
Results: The mean cone count within the 3° window was 4545
(6678 cells/mm2, range 6235-7287 cells/mm2) for glaucoma patients
and 4808 (7064 cells/mm2, range 6601-8007 cells/mm2) for healthy
controls. Mean ganglion cell density was 3110 cells/mm2 (range
420-5634 cells/mm2) for glaucoma patients compared to 6139 cells/
Figure shows the location of the cone images with a retinal
eccentricity of approximately 6 degrees.
Figure is an example of an image of the retinal cone mosaic of a
glaucoma patient using the modified HRA2.
Commercial Relationships: Juliane Matlach, None; Padraig
Mulholland, None; Marketa Cilkova, None; Reena Chopra,
None; Nilpa Shah, None; Tony Redmond, Heidelberg Engineering
(F); Steven C. Dakin, None; David F. Garway-Heath, Carl Zeiss
Meditec (C), Carl Zeiss Meditec (F), Heidelberg Engineering
(F), OptoVue (F), Topcon (F); Roger S. Anderson, Heidelberg
Engineering (F)
Support: Supported by Hirsch Award from Fight for Sight UK,
Technical assistance Heidelberg Engineering GmbH, Dr. Werner
Jackstädt-Stiftung (J Matlach),
Age related changes of longitudinal chromatic aberration on
Color Visual Acuity
Yoshiki Tanaka1, Sho Yokoyama2, Hideki Nakamura2, Kazuo
Ichikawa1, Shoko Tanabe1, Kato Yukihito3, Rie Horai3, Kiyoshi
Tanaka4. 1Vision Laboratory, Chukyo Eye Clinic, Nagoya, Japan;
2
JCHO Chukyo Hospital, Nagoya, Japan; 3Chukyo Eye Clinic,
Nagoya, Japan; 4Shinshu University, Nagano, Japan.
Purpose: To study the age related changes of longitudinal chromatic
aberration (LCA) on color visual acuity (CVA).
Methods: Eight normal eyes of 8 subjects were enrolled in this
study. All the subjects had no ocular disease or color anomaly. The
mean age was 34.3±6.3 years old (27~47). The mean spherical
equivalent was -2.28±2.33D. They had best corrected visual acuity
of 20/13 or above. We utilized a laptop personal computer and a
Liquid Crystal Display (ColorEdge CG245W, EIZO Corp., Ishikawa,
JPN) to display the Ladnolt rings. The Landolt rings were colored
with four colors (R: Red, GY: Green-Yellow, BG: Blue-Green, BP:
Blue-Purple) in the 15 colors (Chroma 6) of NEW COLOR TEST
(Lanthony). The dominant-wavelength values were R: 607 [nm], GY:
566 [nm], BG: 488[nm], BP: 440[nm]. The background was colored
with white point D65 (achromatic color). The luminance of the
background and the Landolt ring color was equiluminance (30 [cd/
m2]) based on colorimetry. The CVAs of four colors were measured
by 0.5D increments using addition lenses from +1.0 to -2.0D with
the best correction. The visual distance was 3 [m]. This experiment
was conducted in a dark room. The LCA was the delta between the
R (long-wavelength) and BP (short-wavelength) with the use of the
addition lens with which was obtained best visual acuity.
Results: Figure 1 shows the results of CVA for each addition lens.
The addition lens which obtained the best CVA were R: 0D (best
correction), GY, BG, BP: -0.5D. Figure 2 shows the results of agerelated changes of LCA. The LCA and age showed the significant
positive correlation (r=0.766, p=0.0310).
Conclusions: Our study shows that LCA can be evaluated by CVA
numerically and subjectively. We expect that LCA evaluated by CVA
can be useful data to attain best corrected visual acuity in infant,
because the LCA was high in young subjects.
Figure 1. CVA for each addition lens (+1.0 ~-2.0) in four colors (R:
Red, GY: Green-Yellow, BG: Blue-Green, GY: Green-Yellow, BP:
Blue-Purple).
Figure 2. Age-related changes of chromatic aberration. The chromatic
aberration means the delta of the addition lens which obtains best
visual acuity by the most positive side of the lens between the visual
acuity of Red and Blue-Purple.
Commercial Relationships: Yoshiki Tanaka, None; Sho
Yokoyama, None; Hideki Nakamura, None; Kazuo Ichikawa,
None; Shoko Tanabe, None; Kato Yukihito, None; Rie Horai,
None; Kiyoshi Tanaka, None
Cone-weighted chromatic pupillometry as an outcome measure
for clinical trials in Usher syndrome patients
Ieva Sliesoraityte1, Saddek Mohand-Said1, Konstantin E.
Kotliar3, Ana Fakin2, Jose A. Sahel1. 1Centre Hospitalier National
dïOphtalmologie, Paris, France; 2UCL Institute of Ophthalmology,
Ocular Biology, Moorfields Eye Hospital, London, United Kingdom;
3
FH Aachen University of Applied Sciences, Juelich, Germany.
Purpose: Progressive dysfunction of photoreceptors, particularly
cones, leads to severe visual impairment in Usher syndrome patients.
Reliable cone functional estimates are of key importance for
measuring safety and efficacy outcomes in clinical trials. The aim of
this study was to evaluate the cone-weighted chromatic pupillometry
potential to be used as a standard outcome measure in Usher
syndrome patient clinical trials.
Methods: The prospective case series study enrolled 50 Usher
syndrome patients. All patients underwent in-depth phenotypic
examination and were found to carry at least one mutation.
Monocular pupil diameter was recorded (Neurolight®, IDMed,
Marseilles, France) in response to red (640 nm) light stimuli for
varied intensity levels (ranging from 1000 cd/m2 to 0.001cd/m2).
Raw data were exported and analyzed off-line using MATLAB
software. Data were fitted using the sigmoid Naka-Rushton function.
Repeatability and reproducibility was evaluated. Mean response
amplitudes were analyzed and compared to the clinical phenotype.
Results: The mean cone-weighted response amplitude was 75±20μm
in Usher syndrome patients. Lower cone-weighted responses
were related to the reduced b-wave amplitude in full field scotopic
electroretinogram (ERG) (r=0,49;p<0.001) and decreased P1N1
peaks in mfERG (r=0.60;p<0.001). Cone-weighted responses were
measurable in all cases, even with non-recordable scotopic ERG and
mfERG. Higher cone-weighted responses were positively associated
with preserved kinetic visual field area (r=0,63;p<0.001), although
they were not correlated with best- corrected visual acuity. Higher
cone-weighted response amplitudes were observed in cases with
a preserved inner/outer segment in optical coherence tomography
(r=0,54;p<0.001) and increased cone density in adaptive optics
(r=0,56;p<0.001). Repeatability and reducibility were 98% and 95%,
respectively.
Conclusions: Cone-weighted chromatic pupillometry responses are
repeatable and reproducible, with a significant correlation potential
for cone-related phenotype measures in Usher syndrome patients.
Cone-weighted chromatic pupillometry could be used as a standard
outcome measure to assess safety and efficacy in clinical trials,
particularly in advanced Usher syndrome cases.
Commercial Relationships: Ieva Sliesoraityte, None; Saddek
Mohand-Said, None; Konstantin E. Kotliar, None; Ana Fakin,
None; Jose A. Sahel, None
Support: ERAREl N°58: Eur-USH
135 Binocular vision, refraction and development
Sunday, May 03, 2015 1:30 PM–3:15 PM
Contributing Section(s): Anatomy/Pathology, Clinical/
Epidemiologic Research, Eye Movements/Strabismus/Amblyopia/
Neuro-Ophthalmology, Multidisciplinary Ophthalmic Imaging
Presentation Time: 1:30 PM–3:15 PM
Effects of mercury exposure on the visual functions of children
from Amazonian riverine villages
Joyce D. Freitas1, Eliza Lacerda1, Dario Rodrigues1, Daniela Bonci3,
Maria Izabel Côrtez4, Tereza Cristina Corvelo1, 2, Dora F. Ventura3,
Luiz Carlos L. Silveira1, 2, Maria da Conceição Pinheiro1, Givago
S. Souza1, 2. 1Núcleo de Medicina Tropical, Universidade Federal do
Pará, Belém, Brazil; 2Instituto de Ciências Biológicas, Universidade
Federal do Pará, Belém, Brazil; 3Instituto de Psicologia, Universidade
de São Paulo, São Paulo, Brazil; 4Programa de Pós-Graduação em
Ciências da Saúde, Universidade Federal do Amapá, Macapá, Brazil.
Purpose: The purpose of the present study was to investigate the
color vision of children living in riverine communities located in
the Tapajós river basin, in order to evaluate the impacts of mercury
exposure earlier in the developing nervous system. We compared the
results with those from children living in the Tocantins river basin,
considered to be a region without mercury exposure.
Methods: One hundred and seventy eight children, 7-14 years old,
were studied. They lived in three riverine communities from two
different river basins of the Brazilian Amazon: Barreiras and São
Luiz do Tapajós from the Tapajós river, and Limoeiro do Ajuru from
the Tocantins river. We quantified their mercury hair concentration
using atomic absorption spectrophotometry and evaluated their color
vision using the Lanthony D-15 desaturated test (D-15d). We applied
the Vingrys and King-Smith (1988) vector analysis to estimate the
angle and magnitude of the hue ordering error (C-Index). KruskalWallis test and Dunn post-hoc test was applied to compare the data
from each children population.
Results: Children from Tapajós river basin had 10 times higher
mercury exposure than children Tocantins river basin (p < 0.05).
Most of children from Tocantins river basin showed Lanthony D-15d
C-index between 1 and 4 and error angle between +45o and +900
(normal trichromats), while a few of them had error angle between
-750 and -900 (blue-yellow color deficiency). In Barreiras, there
was a large cluster of children with C-index between 1 and 3, error
angle between +45o and +900, and two smaller clusters, one with
radius between 1 and 4 and angle between +150 and -300 (red-green
color deficiency) and another with radius between 1 and 3 and angle
between -750 and -90). In São Luiz do Tapajós, there were three well
distinct groups with C-index between 1-4: error angle between +450
and +900, +150 and -300, and -750 and -90o. In São Luiz do Tapajós,
the results of color vision defects were associated to mercury hair
concentration higher than 1.15 ppm.
Conclusions: We found that in the village with higher mercury
exposure, the color vision deficits were associated with the level of
mercury exposure. Continuous monitoring of children performance
in color vision tests can be important to understand the effects of
long term, low levels of mercury exposure in the developing visual
nervous system.
Commercial Relationships: Joyce D. Freitas, None; Eliza
Lacerda, None; Dario Rodrigues, None; Daniela Bonci, None;
Maria Izabel Côrtez, None; Tereza Cristina Corvelo, None;
Dora F. Ventura, None; Luiz Carlos L. Silveira, None; Maria da
Conceição Pinheiro, None; Givago S. Souza, None
Support: CAPES, CNPq, FINEP IBN-Net. DFV, LCLS, and MCNP
are CNPq research fellows.
Small Fluctuations in Limbal Thickness are Associated with
Blood Glucose Values in Young Healthy Subjects
Wendy W. Harrison, Vladimir Yevseyenkov, Catherine Dee, Kristen
Davison, Robert Cook, M. Brayden Lundquist, Todd Albrecht, Brady
Haslam, Julie Welch. Optometry, Midwestern Univ Arizona Coll of
Optometry, Glendale, AZ.
Purpose: Previously our group has reported in cross sectional data
that limbal thickness (LT) values are positively associated with
blood glucose (BG) measures in low myope controls (under-5.50D).
This association is absent in patients with diabetes of the same Rx
range and higher myopes with thinner scleras. The timeline of these
structural changes and the mechanism behind this remains unclear.
Here we follow up with a longitudinal pilot study. It seeks to both
confirm that these short term fluctuations in LT with BG changes
occur within individuals and to learn more about the scale of these
differences.
Methods: Eighteen 24-32 years old were recruited for this portion of
the study. There were 2 high myopes, 9 low myopes, and 6 essential
emmetropes. OCT of the temporal sclera at the limbus was performed
(Heidelberg Spectralis SD-OCT AS module lens) and LT was
measured on the more myopic eye. BG was taken directly before.
Two measurements of LT and BG were taken at different times of
day but within the same week. The differences between the measures
were evaluated.
Results: Within individuals, short term differences in BG were
positively associated with differences in LT (p<0.03), 78% of patients
exhibited this trend. Of the 4 who did not; 2 are the high myopes and
a third is a -5D myope. This furthers the data that high myopes may
not experience these same fluctuations in LT with BG changes due to
scleral differences. This new data is in-line with the cross sectional
results previously gathered. The scale of the LT fluctuations was
highly variable between subjects but typically small, 7 ± 30 microns.
Conclusions: These results confirm short term structural changes
at the limbus, which are tied to systemic BG values and measurable
with AS-OCT in low myopes. Evaluation of these changes in vascular
conditions such as diabetes as well as higher myopia is warranted as
a follow up to this work. It appears that higher myopes with thinner
scleras may not exhibit this trend. Further investigation into the
mechanism at a more detailed level would aid in this analysis.
Commercial Relationships: Wendy W. Harrison, None; Vladimir
Yevseyenkov, None; Catherine Dee, None; Kristen Davison,
None; Robert Cook, None; M. Brayden Lundquist, None; Todd
Albrecht, None; Brady Haslam, None; Julie Welch, None
The effect of a cycloplegic agent on the objectively and
subjectively determined refraction
Arne Ohlendorf, Alexander Leube, Siegfried Wahl. Ophthalmic
Research Institute, ZEISS Vision Science Lab, Tuebingen, Germany.
Purpose: To study changes in subjective and objective refraction due
to relaxed accommodation caused by an cycloplegic agent in myopes
and non-myopes.
Methods: 18 subjects with a mean age of 27.1 ± 3.5 years
participated in the study. Refractive errors of their right eye were
measured subjectively and objectively before and after a cycloplegic
agent (three times one drop of 1% cycloplentolat with 10 minutes
between application) was administered. Subjective refraction was
performed by the same investigator, using a trial frame, trial lenses
and a 4mm artificial pupil. Objective refraction was measured with
the i.Profiler plus (ZEISS, Germany) before and after cycloplegia and
data were analyzed for a pupil diameter of 4mm.
Results: Objectively and subjectively determined refractions were
analyzed for changes in the power vectors M, J0, J45 and the blur
strength B (difference in power matrix between post- and precycloplegic refraction). Using the objective refraction method, more
hyperopic refractions were observed for M and B in myopes (n=10;
delta M 0.44D ± 0.38D, p<0.01 and B 0.49 ± 0.34D, p<0.01) and
non-myopes (n=8; delta M 1.12D ± 0.62D, p<0.01 and B 1.14 0.61,
p<0.01). Changes in objectively determined J0 and J45 were minor
and lacked statistical significance, in both groups. Also, subjectively
measured refraction showed a significant shift towards more
hyperopia in non-myopes (delta M 0.84D ± 0.68D, p<0.05 and B
0.89 ± 0.62, p<0.001), while J0 and J45 were unaffected. In myopes,
blur strength B showed significant changes, again towards hyperopia
(0.36 ± 0.24, p<0.01), while changes in power vectors M, J0 and J45
lacked statistical significance.
Conclusions: Mean spherical equivalent and blur strength
shifted positively after cycloplegia when refraction was assessed
subjectively and objectively for the same pupil size. The cycloplegic
effect of the drug should be taken into account when interpreting
refraction measurements for the prescription of spectacles, planning
a wavefront-guided laser ablation or cataract surgery. Possible
influence of changes in axial length or choroidal thickness may
account for the observed differences but were not investigated in the
current course of the study.
Commercial Relationships: Arne Ohlendorf, ZEISS Vision
International GmbH (E); Alexander Leube, None; Siegfried Wahl,
ZEISS Vision International GmbH (E)
Factors affecting the calibration of white light eccentric
photorefraction
Yun Chen, Frank Schaeffel. Institute for Opthalmic Research,
University Hospital Tubingen, Tubingen, Germany.
Purpose: Infrared eccentric photorefraction is widely used to
measure refractive errors in animal models and humans(Schaeffel
et al. 1993).If photorefraction is performed by a flash of white light
LEDs,a separate analysis of the R G and B channel of the video
camera could provide longitudinal chromatic aberration.It is unknown
how variations in fundal reflectance due to macular pigment,as well
as higher order aberrations affect the calibration of photorefraction.
Methods: Calibration of white light photorefraction was done
simultaneously in the R G and B by trial lenses (-4D~+4D) in 12
eyes of young Caucasian subjects.Pupil size was controlled (5mm).
Calibration occured under 3 conditions:1)in the fovea, 2)10 degrees
off-axis in the temporal retina,3) in the fovea but after 10mins of
previous exposure to bright light.The luminance to pixel response
of the video camera was determined in white light.Higher order
aberrations were measured with WASCA wavefront Analyzer (Carl
Zeiss Meditec AG,Germany).MPOD was measured by the MPOD
Tinsley(UK).Ocular parameters were correlated with the calibration
factors (converting the brightness slope in the pupil into refractive
error;Schaeffel et al 1993).Paired t-tests were used to comparing
differences in calibration factors.
Results: The luminance to pixel response function of the video
system could not explain the interocular variance of the conversion
factors.As previously found,calibration factors were highly
variable among subjects and even much more variable than what
is typical in infrared light, from 3.8 to 13.8 in condtion1, 2.38.0 in 2, and 7.6-16.0 in 3. There were a number of significant
correlations:calibration factors fovea to temporal retina,calibration
factors to spherical aberration,and even to the foveal refractive error.
Furthermore,calibration factors were highly correlated to MPOD in G
and B in the fovea but not at 10 degree temporal retina. Exposure to
bright light increase conversion factors.
Conclusions: The following ocular parameters determined the
calibration of white light photorefraction:MPOD, refractive error,
previous history of light exposure and spherical aberration. While
the effect of the first 3 correlations may ultimately trace back to
variations in fundal reflectance, the correlation to spherical aberration
is unexpected and requires further studies. These factors have to
be controlled before polychromatic photorefraction can be used to
measure LCA.
Commercial Relationships: Yun Chen, None; Frank Schaeffel,
None
Variability in autorefraction for subjects with and without Down
syndrome
Jason D. Marsack, Julia Benoit, Heather A. Anderson. Optometry,
University of Houston, Houston, TX.
Purpose: Patients with Down syndrome (DS) have a high incidence
of refractive error and corneal distortion, and a relationship between
DS and keratoconus is reported in the literature. Objective measures
of refractive error, such as autorefraction, provide a starting point
for subjective refraction and may more heavily influence prescribing
decisions for this group given the difficulty of performing subjective
refraction. This study compares variability in repeated measures of
autorefraction in patients with and without DS.
Methods: Grand Seiko autorefraction was performed binocularly on
140 DS subjects (age range: 8 to 55, mean: 25±9 yrs) and 138 control
subjects (age range: 7 to 59, mean: 25±10 yrs). Subjects where at
least 3 repeated measures were recorded in both eyes (DS: 112 and
control: 136) were included in further analysis. Each refraction was
converted to power vector notation (M J0 J45). The dioptric distance
between each refraction pairing for each eye of each subject was
calculated for the total (square root of the sum of the squares of ΔM,
ΔJ0 and ΔJ45) and astigmatic (square root of the sum of the squares
of ΔJ0 and ΔJ45) components of the refraction. The mean total and
astigmatic variability in refraction for each eye was calculated as
the mean dioptric distance between all 3 comparisons. Right and left
eyes were pooled and the mean total and astigmatic variability was
calculated within each group.
Results: DS eyes exhibited a significantly greater mean total dioptric
distance in refraction (+0.66D ± 0.67D) than control eyes (+0.20D
± 0.17D)(t=10.07, p<.001) with 96.7% of control eyes ≤ 0.50D,
compared to only 59.4% of DS eyes. No control eye had mean total
dioptric distance over 1.50D, whereas 8.9% of DS eyes exceeded
that benchmark. When only the astigmatic component is considered,
DS eyes exhibited a significantly greater mean astigmatic dioptric
distance in refraction (+0.41D ± 0.40D) than control eyes (+0.13D
± 0.13D)(t=9.97, p<.001), with 98.16% of control eyes ≤ 0.50D,
compared to 77.7% of DS eyes. No control eye had mean astigmatic
dioptric distance over 1.27D, whereas 6.25% of DS eyes exceeded
that benchmark.
Conclusions: Refractive variability with autorefraction in DS was
3.3x (total) and 3.15x (astigmatic) the levels observed in controls,
indicating greater potential uncertainty in the starting point for
subjective refraction for this population.
Commercial Relationships: Jason D. Marsack, None; Julia
Benoit, None; Heather A. Anderson, None
Support: NIH EY024590
Variability of simulated keratometry measures in subjects with
and without Down syndrome
Ayeswarya Ravikumar, Jason D. Marsack, Heather A. Anderson.
College of Optometry, University of Houston, Houston, TX.
Purpose: Individuals with Down syndrome (DS) are known to
have steeper corneas and greater astigmatism as compared to the
general population. In addition, their corneas demonstrate distortion
characteristics similar to keratoconus which could result in increased
variability in clinical measurements. This study investigates the
variability of corneal astigmatism magnitude, steep keratometry (K)
power and the flat K orientation of subjects with and without DS
obtained with the Zeiss Atlas corneal topographer.
Methods: Corneal topography was obtained on 140 DS subjects and
138 controls (age range=7 to 59 years). Subjects with three corneal
topography measures per eye were analyzed for this study (DS:
n=108 (216 eyes), controls: n=133 (266 eyes)). Corneal astigmatism
(calculated as the difference between steep and flat keratometry
powers), steep K power and the flat K orientation was obtained.
Variability of each parameter for the DS and control groups was
defined as the group mean standard deviation of the three measures.
For flat K orientation comparisons, only eyes with >0.50 DC of
astigmatism were included (201 and 220 for DS and control eyes
respectively). T-tests were performed to compare the mean standard
deviations between DS and control eyes for each parameter.
Results: Average variability in corneal astigmatism magnitude in
DS eyes (0.30 ± 0.39DC, range 0 to 2.83 DC with 65.3% ≤ 0.25
DC and 87.0% ≤ 0.50 DC) was significantly greater (p <0.001) than
control eyes (0.09 ± 0.06 DC, range 0 to 0.50 DC (100%)). Average
variability in steep K power in DS eyes (0.33 ± 0.43D, range 0 to
3.75D with 60.65% ≤ 0.25 D and 83.80% ≤ 0.50 D) was significantly
greater (p <0.001) than control eyes (0.09 ± 0.09 D, range 0 to 1.00D
with 99.25% ≤ 0.50D). Average variability in flat K orientation in DS
eyes (5.62 ± 5.89 degrees, range 0 to 60 degrees with 86.07% ≤ 10.00
degrees) was significantly greater (p <0.001) than control eyes (3.16
± 3.01 degrees, range 0 to 30 degrees and 96.82% ≤ 10 degrees).
Conclusions: DS eyes showed more variability compared to controls
for all parameters. Although differences were statistically significant,
on average 86% of DS eyes had variability of astigmatism magnitude
and steep K power ≤ 0.50 D and variability of flat K orientation ≤ 10
degrees, indicating tolerable clinical variability for the majority of the
group.
Commercial Relationships: Ayeswarya Ravikumar, None; Jason
D. Marsack, None; Heather A. Anderson, None
Support: NIHEY024590
Binocularity mitigates the impact of night myopia
Emmanuel Chirre1, Christina Schwarz2, Pedro M. Prieto1, Pablo
Artal1. 1Laboratorio de Optica, Universidad de Murcia, Murcia,
Spain; 2Center for Visual Science, University of Rochester,
Rochester, NY.
Purpose: Night myopia, the myopic shift occurring at low
luminance, has been studied during decades. In most cases, the
experiments were performed monocularly with scarce data available
under natural binocular viewing conditions. We used a new openview binocular sensor to study binocular accommodation responses
under natural viewing conditions to evaluate the effect of binocularity
on night myopia.
Methods: The instrument is a Hartmann-Shack based sensor to
measure refraction, aberrations, pupil diameter and the relative
position of both eyes simultaneously in real time (25Hz) with an
invisible infrared (1050nm) beam. Subjects unobtrusively observe a
1.3 degree high-contrast black Snellen E letter on white background
displayed on an LCD monitor at 2.75 meters. Seven young subjects
participated in the study: age 28.7±2.69 years; spherical refractive
error was -0.11±0.32 D and -0.24±0.33 D, and astigmatism was
-0.46±0.19 D and -0.31±0.14 D for the left and right eye respectively.
Accommodation error, high-order aberrations, inter-pupillary
distance and pupil size were measured simultaneously in both eyes
at 7 different luminance levels ranging from 180 to 0.0005 cd/m2.
Measurements were performed both monocularly (with the fellow
eye covered) and binocularly.
Results: The average values of myopic shift when measured
monocularly were -0.51±0.57 D and -0.47±0.55 D for each eye.
In binocular vision, these values were reduced to -0.27±0.32 D
and -0.26±0.32 D for the left and right eyes respectively. Both the
magnitude and variability of the defocus shift were larger in the
monocular cases. The average pupil size was smaller in the binocular
case for most luminances. A shorter relative inter-pupillary distance
in monocular viewing revealed the presence of dark-vergence that is
correlated to the myopic shifts.
Conclusions: Myopic shifts occurring at low luminance are smaller
under binocular conditions than when measured monocularly. Darkvergence occurred under monocular conditions and may have a larger
impact on vision. Natural binocular viewing reduces myopic shifts at
low luminance and can mitigate the visual impact of night myopia.
Commercial Relationships: Emmanuel Chirre, None; Christina
Schwarz, None; Pedro M. Prieto, None; Pablo Artal, None
Support: Spain grants FIS2013-41237-R & FIS2010-14926
Binocular Vision, Reading Ability and Associated Symptoms in
School Children
Ida Henrysson, Baskar Theagarayan. Department of Medicine and
Optometry, Linnaeus University, Bergen, Norway.
Purpose: The purpose of this study was to investigate relationship
between binocular vision, reading ability and any associated
symptoms in School Children.
Methods: The study was conducted in a School in western Sweden.
A sample of 54 Children aged between 10 and 12 years were
invited to participate in this study. A consent form and a letter with
information was sent to their parents. Children with at least 20/25 and
N6 visual acuity and good Stereopsis were included. After receiving
consent forms, 27 Children participated in all the measurements.
Amplitude of accommodation was measured using push-up method
both monocularly and binocularly. Accommodative facility was
measured using ± 2.00 D flippers at 40 cm both monocularly and
binocularly. Near point of convergence was measured using a
Royal Air Force (RAF) ruler and both break and recovery points
were documented. All the Children performed a group of reading
ability tests to detect whether they have any reading difficulties.
A questionnaire called “The College of Optometrists in Vision
Development Quality of Life (COVD-QOL)” was filled by their
parents together with their Children. A score of 20 or more is
considered as symptomatic.
Results: Mean amplitude of accommodation was OD 10.8 ± 4.0 D,
OS 11.8 ± 4.1 D and OU 14.2 ± 3.7 D. Amplitude of accommodation
was low in terms of Hofstetter’s formula. Based on age, 59% of
the Children were below expected value. The accommodative
facility was lower than expected, with mean values of OD 5.5 ±
4.0 cpm, OS 5.5 ± 4.0 cpm and OU 5.0 ± 3.5 cpm. Mean near point
of convergence was 6.0 ± 5.4 cm for break and 6.6 ± 5.9 cm for
recovery. In the reading ability tests all the Children had normal
values. Three Children received ≥ 20 points on the symptom
questionnaire COVD-QOL, which is considered to be high. All of
these three Children had values below normal limits for the amplitude
of accommodation and/or the accommodative facility. Regression
analysis showed no significant correlation between binocular vision
tests, reading ability and symptom score (r < 0.6; p > 0.05).
Conclusions: Amplitude of accommodation and accommodative
facility was lower than expected values for their age. Near point of
convergence values reached the expected normal level. There was no
significant correlation between binocular vision tests, reading ability
and associated symptoms in this sample of Swedish Children.
Commercial Relationships: Ida Henrysson, None; Baskar
Theagarayan, None
The evidence base underlying symptoms of ocular discomfort in
emmetropic school children
Barbara M. Junghans1, 2, Serap Azizoglu2, Ayla Barutchu2, Sheila
G. Crewther2. 1School of Optometry and Vision Science, Univ
of New South Wales, UNSW Sydney, NSW, Australia; 2School
of Psychological Science, La Trobe University, Melbourne, VIC,
Australia.
Purpose: To examine whether reports of ocular discomfort by
school children with emmetropic refractions are primarily related
to binocular vision anomaly(s) (BVA). Also, to investigate whether
the Convergence Insufficiency Symptom Survey (CISS) can be
utilized to identify suspect BVA and separate accommodative and/or
convergence anomalies.
Methods: Children aged 8 to 16 years in grades 3 to year 10, were
recruited from a private school in Melbourne, Australia for a basic
vision screening. Tests included visual acuity for distance and near,
non cycloplegic retinoscopy and subjective refraction, stereopsis
and cover test. Those children classified as emmetropic and without
ametropia, astigmatism, anisometropia, amblyopia, strabismus,
ADHD or learning difficulties, also underwent a further detailed
binocular vision assessment including a battery of accommodation
and convergence tests and completed the CISS.
Results: Of the 247 primary and middle school students screened
(participation 72.6% of all enrolled, mean age 11.5 ± 2.2), 74.5%
(n=184) emmetropes were included for binocular vision assessment.
In those who had their binocular vision assessed, 54.3% (n=100)
had normal binocular vision (NBV) and the remainder (45.7%,
n=84) were suspected on standard clinical tests of having a BVA
(35.7% convergence anomaly, 10.7% accommodation anomaly and
53.6% mixed anomaly). BVA groups including accommodative
dysfunction had significantly higher symptom survey scores (p<0.01)
compared to the NBV group. Results of the 15 question survey
revealed 4 redundant questions. The remaining 11 questions were
further analysed using factor analysis, whereby two major factors
were extracted from the CISS variance, one associated with ocular
discomfort and the other relating to cognitive consequences.
Conclusions: This study suggests that it is common in a nonselected group of emmetropic school children to find children with
suspected BVA who warrant referral based on binocular vision signs
and symptoms. Also, this study suggests that the CISS is useful in
identifying BVA, and is sensitive to convergence and accommodation
anomalies.
Commercial Relationships: Barbara M. Junghans, None; Serap
Azizoglu, None; Ayla Barutchu, None; Sheila G. Crewther, None
The Relation Between Convergence Insufficiency and
Astigmatism
Amy Davis, John D. Twelker, Joseph M. Miller, Erin M. Harvey.
Ophthalmology and Vision Science, University of Arizona, Tucson,
AZ.
Purpose: To determine if children with moderate/high astigmatism
have an increased rate of convergence insufficiency compared to
children with no/low astigmatism.
Methods: Subjects were 3rd-8th grade Tohono O’odham students
who have a high prevalence of astigmatism. An eye examination
including subjective refinement of Retinomax (Nikon, Inc.)
cycloplegic autorefraction was performed on each student. Spectacle
correction was prescribed for students with a significant refractive
error (>1D myopia, >1D astigmatism, >2.5D hyperopia, >1.5D
anisometropia). Hyperopic correction was reduced by 1/3 or by
1.00D whichever was greater. Cover testing at distance and near, near
point of convergence, positive and negative fusional vergence at near
(fusional convergence and divergence amplitudes), accommodative
amplitude (Donder’s pushup method), and symptoms (Convergence
Insufficiency Symptom Survey (CISS)) testing was conducted while
students wore spectacle correction (if prescribed). Students with an
exodeviation at near at least 4∆ greater than at far, a receded NPC
(6 cm or greater), and insufficient positive fusional vergence at near
(PFV) (convergence amplitudes) (i.e., failing Sheard’s criterion
(PFV less than twice the near phoria) or minimum PFV of < 15∆
base-out blur or break), and a CISS score of > 16 were classified as
having convergence insufficiency. Astigmatism was categorized by
magnitude in the most astigmatic eye (<1D, 1 to <3D, ≥3D). Chisquare analysis was conducted to determine the relation between
convergence insufficiency and astigmatism magnitude.
Results: The final sample included 484 Tohono Oodham students
ages 8.26 to 15.87 years. Prevalence of convergence insufficiency
was 6.2% (30/484). Astigmatism <1.00D was present in 43.8%
(212/484), >1D to <3D was present in 26.0% (126/484) and > 3D
was present in 30.2% (146/484). There was no significant relation
between presence of convergence insufficiency and magnitude of
astigmatism (p=0.30, see Table and Graph).
Conclusions: The prevalence of convergence insufficiency is
consistent with reports from other samples, although this finding
should be interpreted with caution as the present sample was not
population-based. The results suggest that children with moderate
to high astigmatism are not at an increased risk for convergence
insufficiency.
Commercial Relationships: Amy Davis, None; John D. Twelker,
None; Joseph M. Miller, None; Erin M. Harvey, None
Support: NIH EY13153, Research to Prevent Blindness
Comparison of best-corrected vs uncorrected performance on the
Beery VMI Developmental Test of Visual Perception in astigmatic
children
Tina K. Green1, Amy Davis1, Mabel Crescioni1, Irene Campus1,
Kathleen Mohan1, John D. Twelker1, Joseph M. Miller1, 2, Erin
M. Harvey1, 2. 1Ophthalmology and Vision Science, University of
Arizona, Tucson, AZ; 2College of Public Health, Tucson, AZ.
Purpose: To compare performance of astigmatic students on the
Beery VMI Developmental Test of Visual Perception while wearing
best correction and while uncorrected.
Methods: Subjects were third through eighth grade Tohono
O’odham students, who have a high prevalence of astigmatism. An
eye examination which included measurement of refractive error
(subjectively refined cycloplegic autorefraction) was performed
on each student. The Beery VMI Developmental Test of Visual
Perception was administered on two separate dates once with best
correction and once uncorrected. Order of testing was randomly
selected. Testing was conducted binocularly. Standardized testing
forms were used and administration and scoring was conducted per
the BEERY VMI Manual. Raw scores were converted to age based
standardized score (mean = 100, SD = 10). Students were categorized
as having moderate (1 to < 3D) or high (>/= 3D) astigmatism based
on astigmatism magnitude in their least astigmatic eye. Repeated
measures analysis of variance compared performance with correction
vs. without correction across astigmatism groups while controlling
for test order.
Results: The final sample included 195 students (109 moderate
astigmats, 86 high astigmats). There was a significant effect of
correction, with students scoring better with than without the
spectacles (97.82 (SD 12.2) vs 95.01 (SD 14.25), p = 0.006). There
was no significant effect of astigmatism magnitude. However, there
was a significant interaction between correction and testing order.
For students who completed the test with their correction first, there
was no significant difference between performance when corrected
and when uncorrected (98.75 (SD 11.12) vs. 99.09, (SD 12.14)).
For students who completed the test uncorrected first, performance
when corrected (97.00, SD 12.74) was significantly better than when
uncorrected (91.43, SD 15.04, p < 0.001).
Conclusions: The results indicate that uncorrected refractive error,
particularly astigmatism, may significantly reduce scores on the
BEERY VMI Developmental Test of Visual Perception. However,
when correction was worn, average scores in the astigmatic sample
approached the standardized score mean of 100. Strategies students
developed while performing the test first with their best-correction
may have improved performance when uncorrected.
Commercial Relationships: Tina K. Green, None; Amy Davis,
None; Mabel Crescioni, None; Irene Campus, None; Kathleen
Mohan, None; John D. Twelker, None; Joseph M. Miller, None;
Erin M. Harvey, None
Support: NIH/NEI Grant EY13153 (EH) and funds from Research to
Prevent Blindness
A research based novel method for vergence rehabilitation
Zoi Kapoula1, Aurelien Morize1, François Daniel1, Fabienne Jonqua1,
Christophe Orssaud2, Dominique Bremond-Gignac3. 1CNRS, Paris,
France; 2HEGP, Paris, France; 3Université de Picardie, Paris, France.
Purpose: About 30% of population may experience problems of
binocular vision related to vergence insufficiency. Rehabilitation of
vergence is mostly based on push-up exercises or use of prisms. We
have developed a real space visual-acoustic rehabilitation device
(patent US 8851669). We aim to validate its clinical efficiency.
Methods: Nineteen students (20 to 27 years old) underwent
ophthalmologic and orthoptic examination; 8 of them were diagnosed
for vergence disorders (high CISS scores, see CITT study 2009).
All subjects performed a vergence test with video-oculography (Eyee
See Cam). Subjects with vergence disorders performed 5 sessions of
vergence rehabilitation 30 min each, over 5 weeks. The vergence test
was repeated 1 month after the rehabilitation.
Subjects were seated in front of the trapezoid tablet composed of
LEDs along the median plane.
Vergence test: twenty convergence and twenty divergence eye
movements were randomly interleaved starting always from an LED
at 40 cm and going to an LED at 20cm or 150 cm.
Vergence rehabilitation protocol: convergence trials always started
by fixating (for 1000 – 1600 ms) an LED at 150 cm; the target LED
was presented at 90cm or 23 cm for 1300 ms after stepping for 200
ms at a distance 20% shorter (double step paradigm); the two types of
trials were randomly interleaved. Subjects performed a total of 2200
movements.
Results: In healthy latency was 194 vs 203ms for convergence vs
divergence; the gain was 0.97 vs 0.76, and mean velocity 26°/s vs
16°/s. Subjects with vergence disorders showed lower gain (0.71
vs 0.54), significantly higher variability for convergence gain,
and significantly lower mean velocity (22°/s vs 13°/s). After the
5 sessions of rehabilitation we observed: significant reduction
of latency (dropping to 155ms vs 181ms for convergence and
divergence); the gain increased significantly for convergence (1.0)
and to a less extent for divergence (0.85). Moreover, variability of
latency, gain and mean velocity decreased significantly, to values
even lower than those from healthy subjects. The CISS decreased
significantly.
Conclusions: This research based device allows objective evaluation
of vergence disorders and efficient rehabilitation, leading to
normalization of vergence. The efficiency is due to regular and
frequent timing of vergence trials with a double step paradigm, a
widely established method for saccade adaptation in research that we
now extend for clinical use in patients.
Commercial Relationships: Zoi Kapoula, None; Aurelien Morize,
None; François Daniel, None; Fabienne Jonqua, None; Christophe
Orssaud, None; Dominique Bremond-Gignac, None
Adaptation of phoria and accommodation in the presence of
prism in young children
Yifei Wu1, Vidhyapriya Sreenivasan1, Erin Babinsky2, T R.
Candy1. 1School of Optometry, Indiana University Bloomington,
Bloomington, IN; 2Universitat Pompeu Fabra, Barcelona, Spain.
Purpose: Young children have reduced interpupillary distance
and hyperopic refraction relative to adults, leading to decreased
convergence and increased accommodation demands. Children with
typical amounts of hyperopia accommodate to achieve clear retinal
images, at the same time generating convergence through neural
coupling. It is known that adults demonstrate vergence adaptation to
a variety of visual stimuli. Henson and North (1980) reported adults
showing average adaptation of 72% to a 6pd demand after 3.5 mins.
Do young children also show adaptation to their immature demands?
Methods: Purkinje image tracking and eccentric photorefraction
were used to record eye alignment and accommodation in adults
and young children (3.25 - 5 yrs). Participants viewed a naturalistic
target at 95cm binocularly (bi) for 15 secs, followed by 15 secs
of monocular (mo) viewing. Each heterophoria was derived from
the difference between these two alignments. Additional vergence
demand was introduced by holding a 2 MA base out prism (10pd
in adults; 6pd in kids) in front of one eye for an extended period of
time (~2.5-3.5 mins). The heterophoria measurements were repeated
during this period. Adaptation was defined as the percentage of the
additional prism that was compensated for by changes in phoria
position.
Results: 90% of adults maintained fusion when viewing through
prisms and on average adapted to 52% of the additional demand
(range 39%- 72%). 86% of young children also fused and on average
adapted to 55% of the additional demand (range 38% - 67%).
When comparing accommodation during the adaptation period with
baseline, accommodation was somewhat increased in the beginning
of the adaptation (0.25±0.13D bi, 0.02±0.09D mo in adults;
0.28±0.18D bi, 0.25±0.18D mo in kids) and greater still at the end of
adaptation (0.31±0.19D bi, 0.14±0.27D mo in adults; 0.33±0.13D bi,
0.15±0.14D mo in kids).
Conclusions: Young children and adults showed heterophoria
adaptation to a 2 MA demand at a 95cm distance. Changes in
accommodation responses during the adaptation were significantly
smaller than the changes in phoria. In typically developing children
who experience changing visual demands, this adaptation might help
maintain eye alignment. Its role in clinical abnormalities is yet to be
determined.
Commercial Relationships: Yifei Wu, None; Vidhyapriya
Sreenivasan, None; Erin Babinsky, None; T R. Candy, None
Support: NIH Grant R01EY014660, P30EY019008, Fight for Sight
for VS
Relationship between working distance and lag of
accommodation in myopic and emmetropic children
Bjorn Drobe1, 2, Xinjie Mao3, 2, Yuwen Wang3, 2, Zuopao Zhou3, 2,
Xianling Yang3, 2, Hao Chen3, 2. 1R&D Optics, Essilor International,
Wenzhou, China; 2WEIRC, WMU-Essilor International Research
Centre, Wenzhou, China; 3School of Optometry and Ophthalmology,
Wenzhou Medical University, Wenzhou, China.
Purpose: To evaluate the relationship between habitual working
distance and lag of accommodation in young myopic and emmetropic
Chinese children.
Methods: Working distance and lag of accommodation were
measured in 24 emmetropic (E: +0.16±0.24 D) and 66 myopic
(M: -1.93±0.83 D) Chinese children aged from 7 to 11 (E: 9.6±0.9
y.o., M: 8.6±0.6 y.o.). Myopes were equipped with their best
distance correction in spectacles. Near vision posture was recorded
continuously at 10 Hz during one reading and one writing task on
a desk by means of a Fastrack (Polhemus, USA) electromagnetic
motion tracking system. Working distance was defined as the distance
between the base of the nose and the center of each line and averaged
for the whole duration of the task. Before posture measurements,
accommodative response was measured at 33 cm using a Grand
Seiko WAM-5500 (Grand Seiko, Hiroshima, Japan) openfield
autorefractor and lag of accommodation calculated based on the
average of three consecutive readings.
Results: Emmetropic children were reading at closer distance than
myopic children (E: 263±56 mm, M: 291±57 mm, p=0.04) while
both groups were writing at similar distances (E: 223±66 mm, M:
228±61 mm, p=0.79). Adjusting data for height did not change those
results. Lags of accommodation were of similar amount in both
groups (E: 1.19±0.32 D, M: 1.36±0.46 D, p=0.12). In emmetropic
children, working distance was positively correlated with lag of
accommodation for both reading (r=0.50, p=0.02) and writing
(r=0.54, p=0.01) tasks. In myopic children however, those parameters
were not correlated for any of the two tasks (p>0.10).
Conclusions: Emmetropic children with higher lags of
accommodation had greater working distances compared to children
with lower lags. This relationship was not observed in myopic
children. As lag increases with decreasing distance, it is possible that
emmetropic children adjust their posture to keep an acceptable level
of retinal blur depending on their initial lag of accommodation while
in myopes decreased blur sensitivity may disrupt this relationship.
Commercial Relationships: Bjorn Drobe, Essilor Int, (E); Xinjie
Mao, Essilor Int. (F); Yuwen Wang, Essilor Int. (F); Zuopao Zhou,
Essilor Int. (F); Xianling Yang, Essilor Int. (F); Hao Chen, Essilor
Int. (F)
Support: International S&T Cooperation Program of China (Grant
No. 2014DFA30940)
Myopes’ ability to discriminate and detect blur
Fuensanta A. Vera-Diaz1, Guido Maiello4, 3, Kristen L. Kerber1,
Frank Thorn2, Peter Bex3. 1Primary Care, New England College of
Optometry, Boston, MA; 2Vision Science, New England College of
Optometry, Boston, MA; 3Psychology, North Eastern University,
Boston, MA; 4UCL Department of Ophthalmology, University
College London, London, United Kingdom.
Purpose: Animal studies show that retinal defocus causes abnormal
eye growth and myopia. Although some studies indicate larger
blur detection thresholds in myopes, this finding is not consistent.
We hypothesize that it is an impaired ability to discriminate blur
(difficulty interpreting small changes in blur) and greater variability
in their response to blur that is associated with myopia.
Methods: Continuous images (16deg diameter @ 40cm) of “dead
leaves” stimuli were presented in four quadrants, each with a
different level of Gaussian blur. Using a spatial 4AFC psychophysical
paradigm, observers were required to decide which quadrant of
the image was blurriest. For the blur discrimination condition, six
different blur levels were used: 0.4, 0.8, 1.6, 3.4, 6.8 and 13.6 arc
min.
Thirty-seven young (22-31yrs) healthy adults participated, reliable
psychophysical data was obtained for n=35 (n=21 myopes). Subjects
had best corrected VA 0.0 LogMAR (20/20) or better in each eye and
no binocular or accommodative dysfunction. Refractive error was
determined by binocular subjective refraction that followed a vision
screening and objective refraction. Subjects were classified into:
Emmetropes (SE OU +0.50 to -0.25D); Myopes (SE -0.50 to -9.00D);
or Hyperopes (SE +0.75 to +6.00D).
Results: No differences were found in the blur detection task
between refractive groups (p=0.5) and there was no correlation
between amount of refractive error and blur detection thresholds
(R2=0.1, p=0.8). Blur discrimination thresholds were lower for
myopes than emmetropes at discriminating for higher (≥1.6 arc min)
levels of pedestal blur (p<0.05). There was a correlation between blur
discrimination thresholds and amount of refractive error for those
higher levels of pedestal blur (R2=0.32, p=0.05).
Conclusions: Contrary to our hypothesis, myopes were better than
emmetropes at discriminating blur, and no different at detecting
blur. These data suggests that myopes learn to discriminate blur
and even when corrected their perception of blur is different than in
emmetropes.
Commercial Relationships: Fuensanta A. Vera-Diaz, None; Guido
Maiello, None; Kristen L. Kerber, None; Frank Thorn, None;
Peter Bex, None
Myopes’ ability to accurately accommodate to blur cues in virtual
3D images
Kristen Kerber1, Guido Maiello3, 2, Frank Thorn1, Peter J. Bex2,
Fuensanta A. Vera-Diaz1. 1The New England College of Optometry,
Boston, MA; 2Psychology, Northeastern University, Boston, MA;
3
UCL Institute of Ophthalmology, University College London,
London, United Kingdom.
Purpose: Defocus blur affects refractive error development. Various
human studies report decreased ability to accurately accommodate in
myopic adults and children compared to emmetropes, however other
studies have found no differences. We hypothesize that myopes have
a decreased ability to accurately accommodate, but only when certain
3D cues to accommodation are not available to them.
Methods: Binocular accommodative responses were measured using
a PowerRefractor while subjects wore shutter glasses and viewed
naturalistic images on a 3D display. Stimuli were “dead leaves”
images that capture the spatial characteristics of real world images.
Subjects viewed five types of images, each randomly presented five
times at 40cm for 5 sec, with various cues to accommodation: (1) flat
[2D], (2) blur gradient, (3) disparity gradient, (4) size gradient, (5) all
cues. Subjects were instructed to fixate on a central green dot at all
times.
Thirty-eight young (22 to 31 years) healthy adults participated;
reliable data was obtained for 21 (n=10 myopes). Refractive error
was determined by binocular subjective refraction that followed a
vision screening and objective refraction.
Results: Myopes show less stable accommodation responses than
emmetropes, which are significantly more variable when viewing 2D
flat images (Wilcoxon, p=0.01), but become as stable as emmetropes’
responses when 3D and blur cues are available.
Accommodation response latencies appear larger in myopes for all
conditions, particularly for the “size” and “disparity” conditions.
A positive correlation was found between amount of myopia and
accommodation response latency when size and/or disparity cues
were available (R2>0.4).
The amplitude of accommodation was not significantly different
between the refractive groups for any condition, although myopes
appear to accommodate more (smaller lags) for all conditions.
Conclusions: Our results indicate larger variability in
accommodation responses in myopes when viewing flat images. Only
when additional cues are added (disparity, blur, size), do myopes’
accommodation responses stabilize. In addition, the time lag to
achieve adequate accommodation is larger for myopes. Inaccuracies
of accommodation when viewing 2D images (typical of indoor
activities) may cause long-term blur on the retina, which may impede
precise emmetropization.
Commercial Relationships: Kristen Kerber, None; Guido
Maiello, None; Frank Thorn, None; Peter J. Bex, None; Fuensanta
A. Vera-Diaz, None
Approximating Spectacle Wear Time Through the Use of a
Temperature Sensor
Matthew J. Lentsch, Jason D. Marsack, Heather A. Anderson.
College of Optometry, University of Houston, Houston, TX.
Purpose: This study aims to determine if temperature sensors
mounted on spectacles can accurately indicate wear time.
Methods: Fifty adults wore a temperature sensor on their spectacle
temple for at least 10 hours for one week. Sensors were mounted
with adhesive or custom silicone sleeves (randomized) and recorded
temperatures every five minutes. Subjects documented wear time
on log sheets. Mean temperatures indicating spectacle wear were
determined by comparing subject logs to temperature recordings.
Wear time was then approximated based on temperature data alone
by two strategies: 1) filtering for each individual’s mean (± 1.5 sd)
ON temperatures and 2) filtering for the group’s mean (± 3.4°C)
ON temperature. Wear time was also approximated by two masked
examiners independently analyzing temperature vs time plots with
data viewing software. Approximated wear time was compared to
subject reported wear time and percent error calculated for each
approximation method.
Results: ON/OFF temperatures differed significantly (p < .0001)
and varied with gender (p=0.04), but not mount type (p = 0.18)
(repeated measures ANOVA). Wear time approximations were within
80% agreement of subject reported wear time in 82-86% of subjects
for the two examiners and in 76-82% of subjects for temperature
filtering strategies. For subjects with <80% agreement, the magnitude
of errors were smaller for examiners than temperature filtering
strategies.
Conclusions: Wear time was better approximated by examiners
than current temperature filtering strategies and demonstrated good
ability of sensors to quantify spectacle wear time. Analytical software
will be developed, incorporating examiner criteria, to automate
calculation of wear time from temperature plots.
Commercial Relationships: Matthew J. Lentsch, None; Jason D.
Marsack, None; Heather A. Anderson, None
Support: NIH Grant EY024590, NIH EY0070088, NIH EY07551
The long-term changes in axial length and refraction and
the characteristics of Fourier domain-OCT in children with
syndrome of myelinated retinal nerve fibers, axial myopia and
amblyopia
Yang Shen, Ling Sun, Peijun Yao, Jooyeon Son, Mi Tian, Xingtao
Zhou. Ophthalmology, Eye and ENT Hospital, Fudan University,
Shanghai, China.
Purpose: To investigate the long-term changes in axial length and
refraction and the characteristics of Fourier domain-optical coherence
tomography in children with syndrome of myelinated retinal nerve
fibers (MRFN), axial myopia and amblyopia.
Methods: Ten children (4.40±2.22 years, 4 boys and 6 girls) with
the syndrome of MRNF, axial myopia and amblyopia were recruited
in this prospective self-controlled study. Each eye underwent
routine ophthalmic examinations, including axial length (AL),
cycloplegic refraction, best-corrected distance visual acuity (BDVA),
simultaneous perception, cover test, corneal curvature, anterior
segment and fundus examinations. Spectacles or rigid gas permeable
contact lenses (RGP) were used for refractive correction. Part-time
occlusion therapy (6-8 hours per day) was employed for amblyopia.
Lesion areas and macular thicknesses were examined only on the
final visit. Statistical analysis was performed using SPSS 19 software.
Cut-off P values were 0.05.
Results: The follow-up periods ranged from 1.17 to 9.75 years (mean
4.00±2.40 years). No one dropped out. Two affected eyes had a final
BDVA of 20/25; four had 20/60 or better; eight were better than
20/200 and one was worse than 20/200. Nine fellow eyes were 20/25
or better. Six children had normal simultaneous perception. AL and
spherical equivalent were both significantly different over time and
between groups (P<0.0001), but no time*group interaction effect
(P>0.05) was observed. The differences in the corneal curvature,
annual mean rate of axial elongation (AMR-AE), annual mean rate
of refractive growth (AMR-RG), foveal thickness and parafoveal
thickness between the two groups were not significant (P>0.05).
The mean perifoveal thickness in the affected eyes was significantly
higher than that of the control eyes (P=0.047). In the treatment group,
the occlusion dose correlated positively with final BDVA (R=0.764,
P=0.016) but did not correlate with the AMR-AE, or AMR-RG
(P>0.05).
Conclusions: The affected eyes and the fellow eyes show similar
developmental processes in AL and refraction. Part-time occlusion
therapy may have no effect on axial elongation or refractive growth
but may have positive effect on visual improvement.
The color fundus photographs on the last visit
The affected area revealed by the FD-OCT and the Fundus camera
Commercial Relationships: Yang Shen, None; Ling Sun, None;
Peijun Yao, None; Jooyeon Son, None; Mi Tian, None; Xingtao
Zhou, None
Short-term monocular patching boosts the cortical response to
the patched eye
Jiawei Zhou1, Daniel Baker3, Mathieu Simard2, Dave SaintAmour2, Robert F. Hess1. 1McGill Vision Research, Department
of Ophthalmology, McGill University, Montreal, QC, Canada;
2
Department of Psychology, Université du Québec à Montréal,
Montreal, QC, Canada; 3Department of Psychology, University of
York, Heslington, United Kingdom.
Purpose: Ocular dominance is an extensively studied form of neural
plasticity. Several recent studies have demonstrated that a degree of
eye dominance plasticity occurs in adults after one eye is patched for
as little as 2.5 hours. Over these timescales, the patched eye, rather
than the unpatched eye, becomes stronger in subsequent binocular
viewing. However, little is known about the site and nature of the
underlying processes. In this study, we examine the mechanisms
underlying this eye dominance plasticity in adults by measuring
steady-state visual evoked potentials (SSVEPs) as an index of the
neural contrast response in early visual areas.
Methods: The experiment consisted of three consecutive stages:
a pre-patching EEG recording (14 minutes), a monocular patching
stage (2.5 hours) and a post-patching EEG recording (14 minutes;
started immediately after the removal of the patch). During the
patching stage, a transparent patch (i.e. a diffuser, which transmits
light but not pattern) was placed in front of one randomly selected
eye. During the EEG recording stage, we measured contrast
response functions for each eye to obtain an estimate of the contrastdependence of the patching-induced changes.
Results: We found that patching one eye with a diffuser for 2.5
hours in adult humans increased the neural response to stimuli in the
patched eye, whilst the responses from the unpatched eye remained
the same. Such phenomena occurred under both monocular and
dichoptic viewing conditions.
Conclusions: We interpret this eye dominance plasticity in adult
human visual cortex as homeostatic intrinsic plasticity regulated by
an increase of contrast-gain in the patched eye.
Commercial Relationships: Jiawei Zhou, None; Daniel Baker,
None; Mathieu Simard, None; Dave Saint-Amour, None; Robert
F. Hess, None
Support: NSERC-46528, CCI-125686 and CIHR-53346 to RFH,
a RI-MUHC Postdoctoral award to JZ, and FRSQ Visual Heath
Research Network awards to DSA and RFH
Preventing visuocotical bilirubin induced neurological
dysfunction
William V. Good1, Chuan Hou1, Vinod Bhutani2, Anthony Norcia3,
Ronald Wong2, Kathleen Lewis4, Terri Slagel4. 1Smith-Kettlewell Eye
Research Institute, San Francisco, CA; 2Department of Neonatal and
Developmental Medicine, Stanford University School of Medicine,
Stanford, CA; 3Department of Psychology, Stanford University,
Stanford, CA; 4California Pacific Medical Center, San Francisco, CA.
Purpose: Controversy exists regarding the spectrum of bilirubininduced neurologic dysfunction (BIND) in neonates, and at what
level of bilirubin an infant should be treated to reduce the chances
of developing BIND. The goal of this study was to compare sweep
visual evoked potential (sVEP) thresholds for 3 measures of vision:
contrast sensitivity (CS), vernier acuity (VA), and grating acuity
(GA), to an algorithm that predicts risk of BIND based on the
hour-specific bilirubin Bhutani nomogram. We hypothesized that
infants at higher risk on the algorithm would show worse acuity
thresholds.
Methods: 90 full-term infants were recruited at birth from the well
baby nursery. None had any clinical evidence for hemolysis or other
risk factors for developing jaundice. Bilirubin levels were determined
by measurements of transcutaneous bilirubin (TcB), total plasma
bilirubin (TB), and “free” or unbound bilirubin (UB) levels. At 6
and 12 mos of age, VA, GA, and CS thresholds were measured by
a masked observer using the sVEP technique. Neonatal history was
tracked prospectively for predischarge TB, use of phototherapy,
exposure to anesthesia (none), heart disease (excluded), and thyroid
dysfunction. Infants were divided into 4 quartiles, based on their
hour-specific TB level. Infants in each quartile were compared to
their average acuity thresholds at 6 and 12 mos of age.
Results: TB levels ranged from 0.5–21.6 mg/dL (median 7.9). CS
and VA (p<0.05 for 6 and 12 mos) were significantly correlated to
TB levels overall, but the effect was most pronounced in infants in
the top quartile at both 6 and 12 mo of age; i.e., those who have the
highest for BIND. GA was not affected by TB level.
Conclusions: A reduction in visual sensitivity occurs at 6 mos and
persists to 12 mos of age, and correlates with the level of TB in the
newborn period for CS and VA measures. Infants whose TB levels
were in the highest (4th) quartile on the Bhutani nomogram were
significantly more likely to have reductions in visual sensitivity
compared to infants in the lower 3 quartiles. These findings suggest
that a strategy for managing neonatal jaundice, and for potentially
preventing BIND, at least in regards to the visual cortex and related
functions.
Commercial Relationships: William V. Good, None; Chuan Hou,
None; Vinod Bhutani, None; Anthony Norcia, None; Ronald
Wong, None; Kathleen Lewis, None; Terri Slagel, None
Support: R21EY019996-02
216 IOL optics and visual performance
Monday, May 04, 2015 8:30 AM–10:15 AM
702/704/706 Paper Session
Program #/Board # Range: 1353–1359
Program Number: 1353
In-vitro assessment of dysphotopsia in IOLs
Huawei Zhao1, Mihai State2, Luuk Franssen2, Marrie Van der
Mooren2, Henk A. Weeber2, Patricia A. Piers2. 1Abbott Medical
Optics Inc., Santa Ana, CA; 2AMO Groningen BV, Groningen,
Netherlands.
Purpose: Negative dysphotopsia (ND) remains a clinical
phenomenon whose understanding is not to date materialized in an
ameliorated intraocular lens (IOL) design. In this context, the current
study describes the development and initial results of an in-vitro
method for measuring dysphotopsia.
Methods: For the theoretical evaluation of the photic events, a
Zemax Non-Sequential model eye (OpticStudio 14, Zemax LLC)
was developed in which the IOL was implemented as a 3D CAD
object with a complete geometry (optics, edges, haptic system). The
irradiance was mapped on the entire image plane as a function of
object angle (0 – 85o), pupil size (3, 6 mm), wavelength and IOL
effective position and orientation. Additionally, the image heights of
the glare secondary images were computed. For the measurements,
an off-axis MTF bench with a 12-bit CCD camera was used (Image
Master HR, Trioptics). An anatomical physical eye model with a
population average cornea was designed and manufactured. The
measurements were performed in photopic light. The measurements
output were image frames which were processed off-line by the
means of a Matlab script (R2013, The MathWorks Inc.). The figures
of merit were frames, average intensities as well as areas under the
intensity curves. For benchmarking, both silicone and PMMA IOLs
with unfrosted and frosted edges respectively were measured. Finally,
IOLs designed to reduce negative dysphotopsia were tested.
Results: Both positive dysphotopsia (PD) and ND were captured
by simulation and measurement results. All IOLs produced different
levels of PD and ND under the conditions tested in this study. PD
was observed more for small to medium light incident angles for
IOLs without edge frosting and was more visible when the pupil
was larger. ND was observed and measured at larger light incident
angles and more obvious for smaller pupil sizes. Objective measures
show the potential for dysphotopsia occurrences for varying types of
lenses. IOLs with optimized geometries were proposed and shown to
reduce the incidence of dysphotopsia.
Conclusions: The study proposed a dysphotopsia measurement
method based on a combined theoretical and experimental approach.
This enables a quantitative mapping in order to better understand the
origins of the IOL dysphotopsia including how these relate to a given
IOL geometry and implantation position.
Commercial Relationships: Huawei Zhao, Abbott Medical Optics
Inc (E); Mihai State, AMO Groningen BV (E); Luuk Franssen,
AMO Groningen BV (E); Marrie Van der Mooren, AMO
Groningen BV (E); Henk A. Weeber, AMO Groningen BV (E);
Patricia A. Piers, AMO Groningen BV (E)
Intraocular lens doublet for full ocular aberrations correction
Enrique-Josua Fernandez, Pablo Artal. Physics, Universidad de
Murcia, Murcia, Spain.
Purpose: Current intraocular lenses (IOLs) are usually based
in a single lens design. A proper selection of the lens’ surfaces
characteristics allows for adequate defocus, astigmatism and
spherical aberration correction. However, with a single lens, perfect
image quality cannot be achieved. We explored the potential of an
intraocular lens doublet for a more complete correction of the optical
aberrations in pseudophakic eyes.
Methods: Ray-tracing techniques were used to optimize the optical
performance of different configurations of IOL doublets within an
eye model. The analysis was performed in white light to consider
chromatic aberration correction. The model incorporated chromatic
dispersion data from the ocular media and IOL standard materials
as acrylics and silicone. Iterative optimization algorithms were
applied to design the different doublet configurations to correct for
longitudinal chromatic aberration, spherical aberration and peripheral
aberrations within 10 degrees of retinal field.
Results: Full aberration correction was achieved by combining
two materials in one doublet IOL, including off-axis aberrations.
Chromatic aberration was typically reduced as much as 95 %
compared to the value present phakic eyes. The use of aspheric
surfaces permitted to obtain near diffraction-limited image quality
on an extended range around the optical axis of 10 degrees. Lateral
color and sphero-chromatic aberration were also largely reduced
as compared with the phakic normal eye, and also compared with
the pseudophakic eye implanted with a standard IOL. A tolerance
analysis of the impact of biometrical parameters after surgery was
also performed. The benefits in optical quality of the doublet IOL
were maintained within a reasonable range of values of decentering
and tilt.
Conclusions: The potential of an IOL doublet to provide full
aberration correction after cataract surgery has been analyzed. By
using two materials within an IOL and combining with proper
aspheric surfaces, chromatic and peripheral aberrations can be
corrected. While an improvement in image quality should provide
patients with a better quality of vision, the practical application of
doublets IOL should be further explored in terms of manufacturing
and surgical limitations.
Commercial Relationships: Enrique-Josua Fernandez, None;
Pablo Artal, None
Support: Programa Jóvenes Líderes en Investigación, Fundación
Séneca-Agencia de Ciencia y Tecnología de la Región de Murcia
(Spain), (grant 18964/JLI/13); SEIDI, Spain (grant FIS201341237-R);
Contrast sensitivity in patients with aspheric profiles in lightadjustable intraocular lenses
Eloy A. Villegas1, Lucia Hervella1, José Caballero2, Matthew Haller3,
Antonio Benito1, Jose María Marín2, Pablo Artal1. 1Laboratorio
de Óptica, Universidad de Murcia, Murcia, Spain; 2Servicio de
Oftalmología, Hospital Virgen de la Arrixaca, Murcia, Spain;
3
Calhoun Vision, Inc., Pasadena, CA.
Purpose: To assess contrast sensitivity (CS) both with and without
the presence of glare, in patients implanted bilaterally with lightadjustable intraocular lenses (LALs).Patients were treated to have
one eye set to emmetropia and the contralateral with induced negative
spherical aberration (SA) to increase the depth of focus.
Methods: Twenty cataract patients were implanted bilaterally with
LALs (Calhoun Vision, Pasadena, USA). Two weeks after surgery,
the implanted lenses were irradiated with appropriate spatial light
intensity profiles to correct for defocus and astigmatism in both
eyes and to induce a pre-defined amount of negativeSA in the nondominant eye. After the adjustment procedures, two photo-lockin
treatments were performed to ensure the LALs were fixed. Refraction
and ocular SA were measured during the entire adjustment process
using an adaptive optics instrument (AOneye, Voptica SL, Spain).
Visual acuity (VA) and CS were measured both monocularly (each
eye separately) and binocularly with and without a glare source
surrounding the gratings patch.
Results: In the eyes treated with aspheric treatments, the final
negative SA ranged between -0.05 and -0.23 microns (for a 4-mm
pupil diameter). Mean values of binocular uncorrected decimal VA
was around 1.00 at far and intermediate (60 cm) distances and ranged
between 1.00 and 0.80 at 40 cm depending on the particular SA. As
expected, uncorrected monocular contrast sensitivity was better in
the emmetropic eyes than in aspheric eyes at all spatial frequency.
Binocular summation improved the CS with respect to the monocular
case with emmetropic eyes. Glare had not a measurable impact in the
binocular CS.
Conclusions: Patients implanted with LALs bilaterally with induced
asphericity in one eye showed normal binocular contrast sensitivity.
There were not significant differences between the binocular contrast
sensitivity measured with and without glare.
Commercial Relationships: Eloy A. Villegas, Calhoun Vision,
Inc. (F); Lucia Hervella, Calhoun Vision, Inc. (F); José Caballero,
Calhoun Vision, Inc. (F); Matthew Haller, Calhoun Vision, Inc.
(E); Antonio Benito, Calhoun Vision, Inc. (F); Jose María Marín,
Calhoun Vision, Inc. (F); Pablo Artal, Calhoun Vision, Inc. (C),
Calhoun Vision, Inc. (F)
Support: Supported by the SEIDI, Spain (grants FIS2013-41237-R)
& Calhoun Vision
New Parameter for Predicting the Postoperative IOL Position:
Preoperative Lens Equator Depth measured By ThreeDimentional Anterior Segment Optical Coherence Tomography
Kyu-yeon Hwang1, Young-Sik Yoo1, Choun-Ki Joo1, Geunyoung
Yoon2. 1ophthalmology, the Catholic university of korea, Seoul,
Korea (the Republic of); 2Advanced phisiological Optics laboratory,
University of Rochester, Rochester, NY.
Purpose: We tested the hypothesis that the preoperative crystalline
lens equator depth (pre-LED) measured by three-dimensional
anterior segment optical coherence tomography (OCT) is an effective
predictor of the postoperative anterior chamber depth (post-ACD).
Methods: Thirty-nine eyes that underwent phacoemulsification and
implantation of a one-piece, plate-haptic Intraocular lens between
December 2013 and June 2014 were examined to develop the new
algorithm for predicting the post-ACD. The pre-LED was defined
as the depth from the back surface of central cornea to the line
connecting the intersecting points between the anterior and posterior
capsule intraoperatively using 3-D OCT in Catalys (Abbott Medical
Optics). The post-ACD was measured by Pentacam (Oculus) in
each case at 2 months postoperatively and was analyzed by multiple
linear regression for covariance with preoperatively defined variables
including the pre-LED, lens thickness, lens vaulting measured by the
OCT and the preoperative ACD (pre-ACD) measured by the OCT
and Pentacam.
Results: The mean pre-ACD, pre-LED, AL, lens thickness and
lens vaulting was 2.74±0.50 mm (range, 1.75-3.36); 4.14±0.35 mm
(range, 3.36-5.91); 23.97±1.37 mm (range, 21.89-27.63), 4.23±0.46
mm (range, 3.01-5.12) and 1.42±0.27 mm (range, 0.82-1.89).
Single regression analysis showed significant correlations between
the post-ACD and pre-LED, R2 = 0.468, P<0.001; pre-ACD, R2 =
0.379, P<0.001) Using a new regression formula with the two most
significant variables (pre-LED and pre-ACD), the post-ACD can be
predicted with an accuracy of 47.3% . In the prospective study, the
postoperative ACD was predicted with a correlation coefficient of
0.696.
Conclusions: The crystalline lens equator depth may be a promising
preoperative parameter to predict the postoperative IOL position.
Commercial Relationships: Kyu-yeon Hwang, None; Young-Sik
Yoo, None; Choun-Ki Joo, None; Geunyoung Yoon, None
Clinical results in 30 eyes with a purkinje based ocular biometer
for IOL power calculation
Michael C. Mrochen1, 2, Diana Bogusevschi2, Andrew Nolan2, Maria
Galligan2, Arthur Cummings2. 1IROC Science, Zurich, Switzerland;
2
R&D, ClearSight Innovations Ltd, Dublin, Ireland.
Purpose: Feasibility study on IOL power calculation based on
ocular parameters measured by means of a novel Purkinje imaging
technique combined with an optical coherence method.
Methods: Thirty eyes scheduled for cataract surgery were enrolled
into this prospective feasibility study. The study was approved by the
local ethic committee and the Irish Medicine Board. Patients were
consented in writing before enrolled into the clinical investigation.
All eyes underwent pupil dilation to at least 5 mm pupil diameter
before the eyes were measured with a standard of care (SOC) corneal
tomography (Oculyzer, WaveLight, Erlangen, Germany) and ocular
biometry (Biograph, WaveLight, Erlangen, Germany). After that
the eyes were measured by means of a prototype ocular biometry
device that consists of a Purkinje imaging technique combined with
an optical coherence method (ClearSight Innovation Ltd, Dublin,
Ireland). The Purkinje imaging technique allows measurements
of the corneal anterior and posterior surfaces as well as the lens
anterior and poster surfaces. The optical coherence method provides
measurements of corneal thickness, anterior chamber depth, lens
thickness and axial length. The obtained ocular parameters from each
were statistically compared by means of regression analysis, bland
altman plots and paired descriptive statistics, where applicable.
Results: All correlation coefficients (r) for the ocular parameter:
anterior radius of curvatures, posterior radius of curvatures, anterior
chamber depth, lens thickness, axial length were found to be r >
0.9 compared with the SOC devices. No significant differences
for all mean values were found between the new device and the
SOC devices. The SOC ocular biometry device did not provide any
measurements of the posterior corneal surface, and anterior and
posterior lens. The SOC ocular tomography device provided only
anterior and posterior corneal surface measurements and corneal
thickness.
Conclusions: The results of this initial prospective study demonstrate
the feasibility of the new ocular biometry system to provide
comparable ocular parameters with SOC devices. However, SOC
devices do not provide information about the lens geometry. In
contrast, the combined measurements of the new device allow a
complete reconstruction of the eye parameter suitable for optical ray
tracing to calculate intraocular lens power.
Commercial Relationships: Michael C. Mrochen, ClearSight
Innovations (I), IROC Science (I); Diana Bogusevschi, ClearSight
Innovations (I); Andrew Nolan, ClearSight Innovations (I); Maria
Galligan, ClearSight Innovations (I); Arthur Cummings, ClearSight
Innovations (I)
Clinical Trial: CIV-IE-13-12-011775
Testing vision with radial and angularly segmented multifocal
patterns using adaptive optics
Maria Vinas, Carlos Dorronsoro, Veronica Gonzalez, Daniel Cortes,
Susana Marcos. Visual Optics & Biophotonics Lab, Instituto de
Optica, CSIC, Madrid, Spain.
Purpose: Multifocal vision corrections are increasingly used
solutions to correct for presbyopia, by producing different foci
for different distances. We will evaluate the effect of multi-zone
multifocal designs (angular & radial, 2-4 zones) on vision, in the
presence and absence of natural aberrations.
Methods: Perceived visual quality was tested on 8 subjects
(age:29±2; spherical error:-1.32±1.00D) with 6 segmented multifocal
designs simulated by a phase-only reflective spatial light modulator.
A custom-developed Adaptive Optics (AO) system, including
a Hartmann-Shack sensor and an electromagnetic deformable
mirror, was used to measure and correct the eye’s aberrations
(HOA). Light source from a supercontinuum laser was used for
wavefront sensing (827nm) and to back-illuminate (555nm) a static
natural visual stimulus. The multifocal phase designs had 2 to 4
zones of progressive power (0 to +3D) in either radial or angular
configurations. In a psychophysical paradigm the subject judged
the better perceived image (first or second) from pairs of images
viewed through different multifocal patterns (a total of 240 pairs,
randomly presented), providing a weighted response (±10, 5 & 1).
The experiment was performed under natural HOA and under AOcorrection. Patterns were graded according to the weighted perceived
visual quality responses for far vision. The optical quality of each eye
(with/without HOA) with each multifocal pattern was calculated in
terms of Visual Strehl (VS).
Results: 85.76% of the perceptual responses were statistically
significant (p<0.05; i.e. higher than chance). On average, radial
profiles provided better perceived quality (495±59) than angular
profiles (-468±61). However, in the presence of HOA, 2 subjects
consistently scored higher the angular patterns, a trend that
disappeared upon HOA correction. With HOA correction there was a
statistically significant correlation (p<0.05) between optical quality
(VS) and perceived quality (scores) in 6/8 subjects. There was a trend
for 2-zone patterns to provide better quality (perceived & optical)
than 3 and 4 zones, which was statistically significant (p<0.05) with
HOA correction.
Conclusions: Visual simulation with AO allows identifying the
optimal multifocal correction for a patient and the effects of
interactions of the natural aberrations. Aberrations play a significant
role in perceived visual quality across different multifocal patterns.
Commercial Relationships: Maria Vinas, None; Carlos
Dorronsoro, None; Veronica Gonzalez, None; Daniel Cortes,
None; Susana Marcos, None
Support: Spanish Government FIS2011-25637, and FPU Programs;
European Research Council ERC-2011-AdG-294099; CSIC JAE
Predoctoral Program;
Extending depth of focus with a 1 ring diffractive technology
Patricia A. Piers1, Carmen Canovas1, Aixa Alarcon1, Henk A.
Weeber1, Silvestre Manzanera2, Pablo Artal2. 1Research and
Development, Abbott Medical Optics Groningen, Groningen,
Netherlands; 2Universidad de Murcia, Laboratorio de Optica, Murcia,
Spain.
Purpose: To describe a new design to extend depth of focus in the
pseudophakic eye and to compare the optical and visual performance
provided by this design to that of a monofocal IOL.
Methods: The new design consists of an aspheric anterior optic
to compensate corneal spherical aberration and a single diffractive
ring on the posterior optic. Optical properties of this design and a
monofocal lens that compensates for corneal spherical aberration
were evaluated in different pre-clinical settings. Through focus MTF
for different spatial frequencies and USAF pictures for a 3mm pupil
in white light were measured using an optical bench. In addition,
best focus contrast sensitivity (CS) was measured in white light
in five subjects using a binocular adaptive optics visual simulator
(BAOVS) when the phase profile corresponding to each IOL design
was induced bilaterally. CS was measured using the q-CSF procedure
with a 4.5mm pupil under mesopic conditions, and evaluated at 1.5,
3, 6 and 12 cpd.
Results: USAF pictures showed that the new lens design extends
depth of focus up to -1.5D in the spectacle plane and that it provides
a good image quality over a larger range of defocus than the
monofocal design. The area under the MTF (MTFa) integrated up
to 50cpmm increased by 26% with respect to the monofocal lens
at -1.5D and decreased by 18% for distance vision. However, CS
for far was not statistically different between both models for any
of the spatial frequencies evaluated, except for the highest spatial
frequency evaluated (12cpd was 1.18±0.10 vs 1.06±0.04logCS for
the monofocal and new design, respectively).
Conclusions: The optical quality and visual performance provided
by a new diffractive IOL designed to extend the depth of focus were
compared with a monofocal IOL that corrects corneal spherical
aberration. Binocular visual simulation and preclinical data showed
that the new design improved visual performance at intermediate and
provides similar CS to a monofocal IOL at distance.
Commercial Relationships: Patricia A. Piers, Abbott Medical
Optics (E); Carmen Canovas, Abbott Medical Optics (E); Aixa
Alarcon, Abbott Medical Optics (E); Henk A. Weeber, Abbott
Medical Optics (E); Silvestre Manzanera, Abbott Medical Optics
(F); Pablo Artal, Abbott Medical Optics (C)
Support: Eureka Grant for Clear Multifocal Vision
239 Refractive errors and optical aberrations
Monday, May 04, 2015 11:00 AM–12:45 PM
Heritability of ocular, corneal and lens optical aberrations
Juan Tabernero1, Lucia Hervella1, Antonio Benito1, Lucia ColodroConde2, Juan Ramón Ordoñana2, Marcos Ruiz-Sánchez3, Jose María
Marín3, Pablo Artal1. 1Laboratorio de Optica, Universidad de Murcia,
Murcia, Spain; 2Murcia Twin Registry, Area of Psychobiology,
Universidad de Murcia, Murcia, Spain; 3Servicio de Oftalmología,
Hospital Universitario Arrixaca, Murcia, Spain.
Purpose: To estimate the relative contribution of genetic and
environmental factors to the variance of ocular, corneal and lens
higher order optical aberrations of a population.
Methods: Optical aberrations were measured in 116 eyes
corresponding to 58 twins; 27 monozygotic (MZ) and 31 dyzogotic
(DZ) pairs (age 54 years, SD 6 years). Corneal aberrations
were estimated from the elevation data measured with a corneal
topographer and using our own developed ray-tracing procedure
to express aberrations in Zernike coefficients. Ocular aberrations
were measured using a Hartmann-Shack sensort (AOnEye; Voptica
SL, Murcia, Spain). Both procedures used the center of the pupil
as a reference so that internal aberrations could be estimated by
subtraction of corneal to ocular Zernike coefficients. Intraclass
Correlation Coefficients (ICC) were used to estimate how strongly
aberrations of twins resemble each other and genetic models were
fitted to quantify heritability in the selected phenotypes.
Results: Spherical Aberration (SA) presented the highest value of the
ICC in MZ twins (0.71 right eyes; 0.74 left eyes) while for DZ twins
correlations were much lower (0.09 right eyes; 0.15 left eyes). The
strong difference between MZ and DZ twins suggested a dominant
genetic contribution to the variance of the SA. Corneal SA was
also highly correlated in MZ twins (0.64 right eyes; 0.71 left eyes)
compared to DZ twins (0.03 right eyes; 0.34 left eyes) and nearly at
the same level as the crystalline (internal) SA (0.66 and 0.65 for right
and left MZ; 0.14 and 0.41 for right and left DZ). In general, other
higher order aberrations presented lower correlations than those of
SA for both groups of twins but still the ICC of ocular higher order
RMS in MZ twins were systematically higher than in DZ (0.36 and
0.40 for right and left MZ; 0.01 and 0.30 for right and left DZ).
Model fitting results yielded heritability estimations for SA ranging
between .5 and .7.
Conclusions: Variability in the optical aberrations of the components
of the eye is far from being randomly generated. Heritability plays
an important role to explain a large part of this variance. This is
specially the case for SA, while for other aberration terms there was
an increase in the contribution of unique random errors and relatively
less genetic influence. Whether this genetic basis of the eye’s
aberrations is linked or independent to refractive diseases should be
subject of further research.
Commercial Relationships: Juan Tabernero, None; Lucia
Hervella, None; Antonio Benito, None; Lucia Colodro-Conde,
None; Juan Ramón Ordoñana, None; Marcos Ruiz-Sánchez,
None; Jose María Marín, None; Pablo Artal, None
Support: European Research Council Advanced Grant ERC-2013AdG-339228 (SEECAT) & SEIDI, Spain (grant FIS2013-41237-R).
Measurements of peripheral ocular aberrations under natural
viewing conditions
Hae Won Jung1, Atanu Ghosh2, Geunyoung Yoon1, 2. 1Optics,
University of Rochester, Rochester, NY; 2Flaum Eye Institute,
Rochester, NY.
Purpose: Previous studies have measured peripheral optics of the
human eye with eccentric fixation using commercial devices. These
devices required subjects to turn their eyes to measure peripheral
aberrations. The goal of the study is to measure wavefront aberrations
at peripheral retina with accommodation using a custom built
peripheral wavefront sensor which does not require eccentric fixation.
Methods: The open view peripheral wavefront sensor can rotate
about the pupil center while subjects maintain their natural foveal
fixation. Accommodation can be stimulated naturally without visual
distraction as wavefront sensing light source is totally invisible
(λ=980nm). Wavefront aberrations measured in four myopic subjects
(aged from 22 to 28, refractive error: -1 .00 to -4.50D) with their
natural pupils at fovea ( 0°) and peripheral retina ( 10° and 20°)
with distance (0D) and near target vergence (3D and 5D). During
these measurements, subjects were fixating on a high contrast
free space target (i.e. Maltese cross) displayed on a micro display.
Zernike polynomials up to 10th radial order were fit to the wavefront
measurements for a fixed 4 mm pupil.
Results: Subjects became more myopic in the periphery with
accommodation compared to fovea (mean difference: 0.33 ± 0.54
D and 0.27 ± 0.74 D for 3D stimulus at 10° and 20° eccentricity,
respectively; 1.1 ± 0.58 D and 0.83 ± 0.61 D for 5D stimulus at 10°
and 20° eccentricity, respectively). Of the higher order aberrations,
horizontal coma C (3, 1) had a greater change at 20° eccentricity
compared to fovea (mean difference 0.03±01 mm, p=0.02) with
accommodation. Accommodation caused greater changes in primary
spherical aberration C(4,0) at periphery compared to fovea (mean
change: -0.02±0.01 mm, -0.02±0.01 mm and -0.03±0.02 mm at 0°,
10° and 20°, respectively). Higher order RMS increased from fovea
to peripheral retina with distance accommodation (mean change:
0.03±0.01mm at 10°, p=0.09 and 0.07±0.01mm at 20°, p=0.01),
however there was no significant change in HORMS in periphery
with accommodation.
Conclusions: Significant myopic shifts observed in the periphery
with accommodation compared to fovea that might be associated
with biomechanical factors; e.g., changes in retinal curvature or axial
elongation during accommodation. Accommodation might have little
impact on higher order aberrations in periphery.
Commercial Relationships: Hae Won Jung, None; Atanu Ghosh,
None; Geunyoung Yoon, None
Retinal shape modeled from discrete ocular length
measurements, biometry and refractive error in healthy
Norwegian males
Jon B. Gjelle, Elisabeth Bratlie Finstad, Siri Bjørnetun Jacobsen,
Stuart J. Gilson, Rigmor C. Baraas. Department of Optometry
and Visual Science, Buskerud and Vestfold University College,
Kongsberg, Norway.
Purpose: Prolate retinal shape as formed by equatorial expansion
has been suggested to be a determinant for myopia development. We
investigated parameters of retinal shape through modeling of discrete
ocular length (OL) measurements by partial coherence interferometry
(PCI) and its correlation with spherical equivalent refraction (SER).
Methods: Twenty-three healthy males aged 21–38 years, with
normal logMAR letter acuity, color vision and no observed ocular
abnormalities, were included in the study. In addition to standard
biometry, OLs were measured at 22 deg sagittal and transverse of
the fovea in the subject’s dominant eye (Zeiss IOLMaster). SER
was determined by autorefraction (Nidek AR-1000). The subject’s
eye was dilated and accommodation suspended with Cyclopentolate
1% prior to examination. Vitreous depth (VD) and retinal curvature
coordinates were determined from individual schematic eye models
based on biometry of each subject. 3D retinal models were calculated
from retinal curvature coordinates by shape fitting ellipsoids using
custom software following a Nelder-Mead simplex algorithm.
Results: Ten were emmetropes (EMM, SER: -0.50 to +0.75 D), 7
hyperopes (HYP) and 6 myopes (MYO), 92% being of Caucasian
descent. Axial lengths (AL) ranged from 22.60–25.18; VD: 15.65–
19.68, corneal radii (CR): 7.35–8.30 mm and SER: -4.50 – +1.92 D.
MYO had significantly larger ALs than both EMM (p=0.004) and
HYP (p=0.008) with larger AL/CR ratios than both EMM (p=0.008)
and HYP (p<0.001). EMM and HYP showed no significant difference
in AL (p=0.587), but EMM had larger AL/CR ratios than HYP
(p=0.009). There was no difference in VD between refractive groups
(p=0.235). The fitted models revealed an oblate retinal shape for all
subjects, with vertical and horizontal asphericity significantly larger
than 0 (both p≤0.001). There was no difference in horizontal or
vertical asphericity between refractive groups (p=0.305 and p=0.461).
Conclusions: A novel 3D model of retinal shape based on discrete
OLs from PCI reveal an oblate retinal shape regardless of refractive
status. Furthermore, VD did not vary between refractive groups.
The results indicate oblate retinal shape as formed by a global
expansion, rather than prolate as formed by equatorial expansion,
to be associated with myopia for the population studied here. The
technique has potential as a clinical method for estimating retinal
shape.
Commercial Relationships: Jon B. Gjelle, None; Elisabeth Bratlie
Finstad, None; Siri Bjørnetun Jacobsen, None; Stuart J. Gilson,
None; Rigmor C. Baraas, None
Presentation Time: 11:45 AM–12:00 PM
Impact of refractive error on the meridional effect in peripheral
vision
Len Zheleznyak, Atanu Ghosh, Antoine Barbot, Geunyoung Yoon.
Flaum Eye Institute, University of Rochester, Rochester, NY.
Purpose: Optical blur in the peripheral retina is known to be
highly anisotropic due to astigmatic wavefront aberrations and may
play a role in emmetropization. In addition, peripheral vision is
characterized by the meridional effect, a neural mechanism favoring
radially-aligned gratings. The goal of this study was to investigate
the impact of refractive error and anisotropic peripheral blur on
the meridional effect for neural contrast sensitivity (CS) using an
adaptive optics (AO) vision simulator.
Methods: An AO vision simulator was used to correct subjects’
wavefront aberrations at 0, 10 and 20 degree temporal retinal
eccentricities. CS at 2 cpd was measured with horizontal and vertical
grating orientations at each eccentricity in monochromatic light
(630 nm). All vision testing was performed with a 5.8 mm artificial
pupil using the right eye of 10 cyclopleged subjects (refractive error:
-5.5 to +2.0 D). Subjects’ native aberrations were recorded at each
eccentricity with a Shack-Hartmann wavefront sensor to quantify the
modulation transfer function (MTF). Neural CS was defined as the
ratio of the CS divided by the diffraction-limited MTF.
Results: With increasing eccentricity, subjects’ native wavefront
aberrations led to significantly higher contrast of horizontal gratings
as compared to vertical gratings. The average ratio of horizontal to
vertical MTF values at 2 cpd at 0, 10 and 20 degrees for emmetropes
was 0.99+0.01, 1.22+0.19 and 1.50+0.32 and for myopes was
0.98+0.07, 1.20+0.29 and 1.55+0.39, respectively. The average
ratio of horizontal to vertical area under the MTF up to 10 cpd at 0,
10 and 20 degrees for emmetropes was 0.95+0.05, 1.15+0.13 and
1.34+0.27 and for myopes was 0.94+0.18, 1.20+0.36 and 1.64+0.57,
respectively. The meridional effect was observed for all subjects, with
a greater magnitude at 20 degree eccentricity in the myopic group.
The average ratio of horizontal to vertical neural CS at 0, 10 and 20
degrees for emmetropes was 1.04+0.09, 1.39+0.27 and 1.40+0.19 and
for myopes was 1.00+0.25, 1.31+0.29 and 1.89+0.89, respectively.
Conclusions: The meridional effect was observed in all subjects
in the absence of anisotropic blur, however, this effect was greater
in myopic subjects. In addition, the change in meridional effect
across the retina with respect to native aberrations was significantly
correlated with refractive error.
Commercial Relationships: Len Zheleznyak, None; Atanu Ghosh,
None; Antoine Barbot, None; Geunyoung Yoon, None
Support: NIH EY014999, NIH T32 EY007125, Research to Prevent
Blindness
Extended depth-of-focus contact lenses can slow the rate of
progression of myopia
Ravi C. Bakaraju1, Pauline Xu1, 2, Xiang Chen2, Martin Ma2,
Stephanie Song2, Monica Jong1, 2, Wayne Li2, Serge Resnikoff1, 3,
Brien A. Holden1, 3. 1Brien Holden Vision Institute, Sydney, NSW,
Australia; 2Brien Holden Vision Institute, Guangzhou, China; 3School
of Optometry and Vision Science, UNSW, Sydney, NSW, Australia.
Purpose: We investigated the effects of two different, novel
design, extended depth-of-focus (EDOF) contact lenses (CL) and
a commercially-available single vision control CL on the rate of
myopia progression in Chinese children.
Methods: A prospective, double-masked, randomized clinical trial
was initiated at the BHVI China research clinic in January 2014
to enrol 270 Chinese children, aged 8 to 13 years, with spherical
equivalent refractive error between -0.75D and -3.50D. Enrolled
patients were randomized into one of the following: a single vision
control CL, EDOF1 or EDOF2 prototype CL. The primary outcome
measures, cycloplegic autorefraction (AR, Shin-Nippon, Japan) and
axial length (AL, Lenstar, Switzerland), were measured at baseline,
and were scheduled to be measured every 6 months for at least 3
years. Each group was matched for age, gender, parental myopia, AL
and refractive error. Exclusion criteria included previous treatment
for myopia and systemic or ocular disease.
Results: To date, approximately twenty children in each group have
completed the 6 months visit. The mean rate of myopia progression
for the control group was AR: -0.49D ± 0.29 and AL: 0.17mm ± 0.09.
Statistically significant reduction in the rate of myopia progression
(p<0.001) was achieved in children wearing both types of EDOF
lenses; EDOF1: AR -0.24D ± 0.28 (51% reduction) and AL 0.07 mm
± 0.08 (58% reduction); EDOF2: AR -0.23D ± 0.28 (53% reduction)
and AL 0.08 mm ± 0.09 (53% reduction). The outcome measures
obtained with two EDOF lenses were not significantly different
between eachother (p>0.05).
Conclusions: The EDOF lenses significantly slowed the rate of
progression of myopia in children. Longer term results with greater
number of participants will be needed to substantiate the results
obtained at the 6-month visit.
Commercial Relationships: Ravi C. Bakaraju, WO2013/149303
A1, US 2013/0278888 A1 (P); Pauline Xu, Brien Holden Vision
Institute (E); Xiang Chen, Brien Holden Vision Institute (E); Martin
Ma, Brien Holden Vision Institute (E); Stephanie Song, Brien
Holden Vision Institute (E); Monica Jong, Brien Holden Vision
Institute (E); Wayne Li, Brien Holden Vision Institute (E); Serge
Resnikoff, Brien Holden Vision Institute (C); Brien A. Holden,
Brien Holden Vision Institute (E), WO2013/149303 A1 (P)
Support: Brien Holden Vision Institute, Australian Government
Cooperative Research Centres Grant Scheme and Vision CRC.
Clinical Trial: ChiCTR-TRC-14004227
Spherical aberration is a key determinant of refraction at night
Norberto Lopez-Gil1, Renfeng Xu2, Arthur Bradley2, Larry N.
Thibos2. 1Universidad de Murcia, Murcia, Spain; 2Indiana University,
Bloomington, IN.
Purpose: For more than 230 years we have known that eyes appear
to be more myopic at nighttime. Although spherical aberration has
been implicated in this refraction change, its exact role is still unclear.
We study if the correction of this refractive change is more closely
related to the improvement of the stimulus contrast or its resolution.
Methods: Refractive error was determined for a 7mm pupil,
objectively by using techniques based on wavefront refraction
and subjectively using small bright point stimuli (<1 arc minute,
1000 cd/m2) of an OLED microdisplay. Experimentally, the
amount and sign of ocular spherical aberration were controlled.
The objective refraction was computed after a through-focus
computational paradigm, which determine the correcting lens that
would be expected to optimize retinal image quality according
to a visual contrast metric (VSOTF) known to be an unbiased
predictor of refractive error for conventional letter charts viewed
under daylight conditions. Subjective refractions were determined
with a through-focus paradigm on paralyzed or presbyopic eyes,
for a contrast detection task (increment detection of a point source
on a uniform background) and again for a spatial resolution task
(minimum separation of two point sources on a black background).
Detection refraction was defined as the power of a correcting lens
that maximized contrast sensitivity and resolution refraction was
defined as the power of a correcting lens that maximized two-point
resolution.
Results: As the amount of the spherical aberration increases,
detection refraction becomes myopic relative to the daylight standard
refraction or two-point resolution refraction. Positive spherical
aberration usually reproduces the classic astronomer’s observation
of night myopia while negative spherical aberration reverses this
result (i.e. night hyperopia). Nullifying spherical aberration causes
detection, resolution and daylight standard refraction to be nearly
the same. The refractive change between resolution and detection
refraction ranged from 0.25 to 0.5 D for spherical aberration
coefficient C40 = ±0.5 microns (7mm pupil).
Conclusions: Night myopia is a phenomenon more closely related to
contrast detection than for spatial resolution. The sign and magnitude
of night myopia is determined primarily by the sign and magnitude of
ocular spherical aberration. These results have clinical implications
for optimum correction of the eye for nighttime vision.
Commercial Relationships: Norberto Lopez-Gil, Indiana
University (P); Renfeng Xu, None; Arthur Bradley, None; Larry
N. Thibos, Indiana University (P)
Support: Fundación Séneca Grant 15312/PI/10 and Grant ERC2012-StG 309416-SACCO
Objective measurements of transverse chromatic aberration
across the visual field of the human eye
Simon Winter1, Ramkumar Sabesan2, Pavan N. Tiruveedhula2,
Claudio Privitera2, Linda Lundstrom1, Austin Roorda2. 1Biomedical
& X-Ray Physics, KTH, Royal Institute of Technology, Stockholm,
Sweden; 2School of Optometry and Vision Science Graduate Group,
University of California, Berkeley, Berkeley, CA.
Purpose: The purpose of this study was to use a new image-based
technique to make the first-ever objective measures of TCA at
different eccentricities within the human visual field.
Methods: TCA was measured at visual field angles of 0.5, 2.5, 5,
7.5, 10, 12.5, and 15 degrees from foveal fixation in the right eye of
4 subjects. Interleaved retinal images were taken at wavelengths 543
nm and 842 nm in an adaptive optics scanning laser ophthalmoscope
(AOSLO) and were cross-correlated according to methods described
in Harmening et al., Biomed Opt Express, 2012. Pupil alignment
was controlled with a pupil-camera. To obtain true measures of
human eye TCA, the contributions of the AOSLO system TCA were
measured using an on-axis aligned model eye and subtracted from the
human eye data.
Results: The system TCA was stable at around 3 arcmin. On all
subjects, it was possible to measure TCA out to 12.5 degrees in the
nasal, 10 degrees in the temporal, 12.5 degrees in the inferior, and
15 degrees in the superior visual field. The absolute amount of TCA
between green and IR varied somewhat between subjects, but was
approximately 4 arcmin at 10 degrees out in the nasal visual field.
However, the increase in TCA was found to be linear with a slope
close to 0.2 arcmin / degree of visual field angle for all subjects.
Translating these results to the visual spectrum would yield a slightly
higher slope and larger image shifts, which agree with the theoretical
calculations by Thibos, J. Opt. Soc. Am. A, 1987.
Conclusions: We have performed the first objective measurement
of the TCA of the human eye across the central 30 degrees visual
field. The 4 arcmin of TCA at 10 degrees off-axis is very similar to
the resolution acuity of 0.5 to 0.7 logMAR at 10 degrees out in the
nasal visual field (about 3 to 5 arcmin). Additionally, the measured
cone-size at 10 degrees in the subjects of this study was about 1.4 –
1.7 arcmin, which means that the TCA blur covers around 2-3 cones.
Therefore, the peripheral TCA can be visually significant.
Commercial Relationships: Simon Winter, None; Ramkumar
Sabesan, None; Pavan N. Tiruveedhula, None; Claudio Privitera,
None; Linda Lundstrom, None; Austin Roorda, University of
Rochester, University of Houston (P)
Support: EU ITN OpAL - PITN-GA-2010-264605 (SW, LL), The
Swedish Research Council - 621-2011-4094 (SW, LL), Burroughs
Wellcome Fund Career Award at the Scientific Interfaces (RS), NIH R01EY023591 (PT, CP, AR)
272 Mechanisms of vision loss in early diabetes: Connecting
new findings from retinal imaging and functional techniques in
patients to basic models - Minisymposium
Monday, May 04, 2015 3:45 PM–5:30 PM
702/704/706 Minisymposium
Contributing Section(s): Multidisciplinary Ophthalmic Imaging,
Retina
Imaging damage to retinal vessels in diabetic patients
Stephen A. Burns. Indiana University, Bloomington, IN.
Presentation Description: Diabetic retinopathy has traditionally
been staged according to features visible from retinal examination
and retinal photography. Adaptive Optics retinal imaging is now
allowing us to visualize and charachterize changes that are not readily
detected with conventional imaging. This presentation will present
change to capillary structure and capillary density, as well as changes
to the vascular walls.
Commercial Relationships: Stephen A. Burns, AEON Imaging (I),
Nidek (C)
Support: NEI EY04395; Fight for Sight
Retinal pathology in diabetes and systemic comorbidities
Jennifer K. Sun. Joslin Diabetes Center, Harvard Medical School,
Boston, MA.
Presentation Description: High resolution imaging techniques
such as adaptive optics scanning laser ophthalmoscopy (AOSLO)
and spectral domain optical coherence tomography (SDOCT) allow
the assessment and quantification of cellular level changes in the
diabetic retina in vivo in the human eye. Thinning and disorganization
of the inner neural retinal layers as evaluated by SDOCT may have
functional implications for patients both prior to the development of
clinically visible vascular lesions and once these lesions have become
manifest. AOSLO imaging allows identification of subclinical
vascular lesions such as microaneurysms that are too small to be
visualized on standard fundus photographs or clinical examination.
The combination of these techniques potentially provides the ability
to better understand interactions within the neurovascular unit in
diabetes. The contribution of other systemic diabetic comorbidities
to retinal pathology is also being explored and will be discussed,
including available evidence for retinal vascular changes with
cardiovascular disease and diabetic nephropathy.
Commercial Relationships: Jennifer K. Sun, Boston
Micromachines (F), Optovue (F)
Support: NIH/NEI R01 EY024702-01; JDRF 3-SRA-2014-264M-R, 17-2011-359; NIDDK 5 P30 DK036836-24 P&F Grant;
Eleanor Chesterman Beatson Childcare Ambassador Program
Foundation Grant; Massachusetts Lion Eye Research Fund; Boston
Micromachines
Changes over time in retinal vessels in patients with early
diabetes
Richard B. Rosen. 1New York Eye and Ear Infirmary, New York, NY;
2
Ophthalmology, Ican School of Medicine at Mount Sinai, New York,
NY.
Presentation Description: Adaptive optics scanning light
ophthalmoscopy using an offset pinhole (OP AOSLO) configuration
enables non-invasive imaging of the dynamics of retinal
microvascular walls, lumen, and blood flow, without the need for
any exogenous contrast agent. We used OP AOSLO to survey and
monitor subclinical microvascular changes over time in patients with
diabetic retinopathy, including capillary perfusion remodeling, loop
formation and resolution, microaneurysm expansion and regression.
This technique provides a dynamic longitudinal view of the
histopathology of aberrant diabetic microvascular development.
Commercial Relationships: Richard B. Rosen, None
Support: Marrus Family Foundation, Bendheim-Lowenstein
Foundation, Wise Foundation, Edith C Blum Foundation, GRF, RPB,
Burroughs Wellcome Fund, and NIH grant P30EY001931
Dysregulation of blood flow in the diabetic retina
Eric A. Newman. University of Minnesota, Minneapolis, MN.
Presentation Description: Activation of the retina by flicker
stimulation evokes vasodilation and increased blood flow in the
retinal vasculature. This hemodynamic response, termed functional
hyperemia, brings added oxygen and glucose to active neurons.
Flicker-evoked vasodilation is mediated by neuronal stimulation of
retinal glial cells and the release of vasodilating agents, including
PGE2 and epoxyeicosatrienoic acids, from the glial cells. Signaling
from glial cells to retinal vessels is suppressed by nitric oxide (NO).
In patients with diabetic retinopathy flicker-evoked vasodilation
and functional hyperemia are substantially reduced, possibly
rendering the retina hypoxic. Inducible nitric oxide synthase (iNOS)
is upregulated and NO levels are increased in the diabetic retina.
Inhibition of iNOS by aminoguanidine reverses the loss of flickerevoked vasodilation in an animal model of diabetic retinopathy,
restoring functional hyperemia to normal. Previous work has
demonstrated the efficacy of inhibiting iNOS in slowing the
progression of diabetic retinopathy. This effect could be due, in part,
to the restoration of functional hyperemia.
Commercial Relationships: Eric A. Newman, None
Support: Fondation Leducq and NIH grant EY004077
Early functional changes in diabetic patients measured with
mfERG, contrast sensitivity, and SKILL Card
Marcus A. Bearse. UC Berkeley, Berkeley, CA.
Presentation Description: Vision and retinal function changes occur
early in diabetes, even in the absence of clinical signs and history of
diabetic retinopathy. This presentation will discuss our observations
of these changes, focusing primarily on local retinal function
measured with the multifocal electroretinogram (mfERG), and on
vision changes measured by contrast sensitivity and the SmithKettlewell Institute Low Luminance (SKILL) Card. These measures
indicate that significant changes are produced by diabetes, and tend to
worsen with the onset of clinical diabetic retinopathy. Models based
on the mfERG are highly predictive of the appearance of retinopathic
lesions.
Commercial Relationships: Marcus A. Bearse, None
Support: NIH Grant EY021811
277 Psychophysics, visual performance and low vision
Monday, May 04, 2015 3:45 PM–5:30 PM
Program #/Board # Range: 2216–2227/B0069–B0080
Contributing Section(s): Low Vision, Retina
Program Number: 2216 Poster Board Number: B0069
Independent effects of angular and relative distance
magnification on reading speed in normal and low vision subjects
Danielle Natale1, Nicole Ross2, 1, Chris Bradley1, Boger Yuval4, David
Teitelbaum4, Frank S. Werblin3, Robert W. Massof1. 1Johns Hopkins
University, Baltimore, MD; 2Low Vision, New England College
of Optometry, Boston, MA; 3University of California, Berkeley,
Berkeley, CA; 4Sensics, Inc, Columbia, MD.
Purpose: To describe the effects of angular and relative distance
magnification on reading speed in normal and low vision subjects.
Methods: A head mounted display (HMD) was used to present
images in virtual reality of 25 different paragraphs of texts. Each
subject then read each of the 25 paragraphs with total magnification
ranging from 1x to 25x. Magnification of the text was achieved with
all combinations of angular magnification (ranging from 1X to 5X)
and relative distance magnification (also ranging from 1X to 5X).
The time to read each paragraph was recorded and words per minute
reading speeds were calculated for each combination of angular and
distance magnification.
Results: Angular and relative distance magnifications have
independent effects on reading speed. In each normal subject, above
the critical print size reading speed declined linearly with the sum
of relative distance and angular magnification – not the product.
Reading speed declined at a faster rate with increases in angular
magnification than with increases in relative distance magnification.
In low vision subjects, reading speed increased from threshold with
increased angular or relative distance magnification until reading
speed reached the ceiling defined by normally sighted subjects and
then with further magnification reading speed declined following the
normal function.
Conclusions: The decline in reading speed as magnification increases
cannot be explained by decreased preview area alone because the
effects of angular and relative distance magnification on reading
speed are additive, not multiplicative. This phenomenon is present
in both normal and low vision subjects. One potential explanation
for the independent effects on reading rates for the two types of
magnification could be that relative distance magnification requires
larger head movements with increasing magnification, whereas
angular magnification does not, and angular magnification increases
the magnification of image motion velocity with head movements,
whereas relative distance magnification does not. The results we
observed with a HMD, which required head movements to navigate
text that extended beyond the field of view, might generalize to
other types of movements required to translate text when using
conventional low vision devices (e.g., moving the print to read with a
microscope or a CCTV or moving the magnifier across the print).
Commercial Relationships: Danielle Natale, None; Nicole Ross,
None; Chris Bradley, None; Boger Yuval, Sensics Inc (I); David
Teitelbaum, Sensics Inc (I); Frank S. Werblin, Visionize (I);
Robert W. Massof, Sensics Inc (I)
Support: Name: “Next Generation of Low Vision Enhancement”
Funding Source: Reader’s Digest Partners for Sight Foundation
Functional impact of task lighting on reading with low vision
Tony A. Succar1, 2, Laura Walker2, 1, karen kendrick1, Andra Mies1,
Donald C. Fletcher1, 2. 1Envision Research Institiute, Envison,
Inc, Wichita, KS; 2Smith-Kettlewell Eye Research Institute, San
Fransisco, CA.
Purpose: Individuals with low vision often complain of reading
difficulties and increased lighting has been shown to enhance visual
acuity (Fletcher et al. ARVO 2014 and ARVO 2015). The purpose of
this study was to investigate whether: (1) lighting impacts reading
function objectively; and (2) the LuxIQ is a useful or necessary tool
for prescribing specific lighting needs.
Methods: Reading function of low vision and control subjects was
assessed using MNRead Acuity Charts at 40cm under four light
settings: ambient room illumination (280 lux), preferred setting and
set points at 500 lux below and above the subjects’ preferred setting.
Preferred setting was measured as the participants’ subjective light
preference when reading their preferred size print on the MNRead
chart. Temperature was kept constant at 4500 oK, 575nm. Testing
began under ambient illumination and the testing order of the three
remaining light settings were randomized for each subject. The
LuxIQTM (Jasper Ridge, Inc) was positioned above the MNRead
chart and different charts were randomly selected and alternated for
each lighting condition. Charts were placed under an opaque cover
revealing only the sentence which subjects were required to read.
Reading rate was plotted as a function of print size to estimate critical
print size and maximum reading rates.
Results: In control subjects, the different light settings had little
effect on maximum reading rates, and variable effects on critical
print sizes. Initial patient data suggests a more consistent impact of
lighting on critical print size. Lighting preference may depend on the
type of ocular pathology (e.g. Fletcher et. al, ARVO 2015), however
this preference does not always confer a functional benefit to reading.
The outcome measures presented here will delineate which patients
are most likely to benefit from a specific lighting prescription versus
simply increasing task lighting to a subjectively comfortable level.
Conclusions: Low vision practitioners commonly recommend
the use of supplementary localized lighting to enhance near vision
tasks. The findings from this study provide guidance as to whether
practitioners can benefit low vision patients by providing an objective
lighting prescription.
Commercial Relationships: Tony A. Succar, None; Laura Walker,
None; karen kendrick, None; Andra Mies, None; Donald C.
Fletcher, None
Support: Envision Pilot Project Award
Optimizing the viewing position of words increases reading speed
in patients with central vision loss
Andrew T. Astle1, Ben S. Webb1, Paul V. McGraw1, Susana T. Chung2.
1
Visual Neuroscience Group, School of Psychology, The University
of Nottingham, Nottingham, United Kingdom; 2School of Optometry,
University of California, Berkeley, Berkeley, CA.
Purpose: Rapid serial visual presentation (RSVP) of words one at
a time at the same spatial location increases reading speed in people
with normal vision and those with central vision loss by minimizing
the need to make inter-word eye movements. Additionally, displaying
words such that the optimal viewing-position (OVP), a location
between the beginning and middle of a word, lies at fixation increases
reading speed in individuals with normal vision. It has recently been
suggested that a combination of OVP alignment and highlighting the
OVP using a different colored letter leads to improved reading speed
in normals (Spritz software). Here we examine whether aligning
the OVP of words with fixation, and/or highlighting it, can increase
RSVP reading speed in patients with central vision loss.
Methods: We measured reading speed for sentences in six patients
with central vision loss due to macular disease (age: 50–85, logMAR
acuity: 0.22–1.20). Participants fixated a gap between two vertical
bars while words were presented at seven different exposure
durations using the method of constant stimuli. Thresholds were
determined as the duration that corresponded to 80% of correctly
identified words. The effect of different combinations of horizontal
spatial position and the highlighting of individual letters (using letter
color or contrast polarity) on reading speed for sentences and word
identification speed for 7 and 9 letter words were investigated for
each patient.
Results: Word identification speed was not significantly affected by
changes in the horizontal spatial position of words or the highlighting
of letters. For sentence reading, the mean reading speed when the
central letter of words was aligned with fixation (standard RSVP) was
142 words per minute (wpm). When the OVP of words was aligned
with fixation, and all letters were the same color, mean reading speed
increased to 165 wpm, significantly higher (p = 0.02, Friedman test)
than the standard RSVP paradigm. Aligning the OVP at fixation and
highlighting the letter at fixation led to a mean reading speed of 124
wpm, which was not statistically different from the reading speed
obtained for the standard RSVP condition.
Conclusions: Aligning the OVP of words with fixation leads
to improved reading ability in patients with central vision loss.
Highlighting letters at the OVP location provides no benefit to
reading speed.
Commercial Relationships: Andrew T. Astle, None; Ben S. Webb,
None; Paul V. McGraw, None; Susana T. Chung, None
Support: This study was supported by a National Institute for Health
Research Post-Doctoral Fellowship (ATA) and a National Institutes
of Health research grant R01-EY012810 (STLC). This work presents
independent research funded by the NIHR. The views expressed are
those of the authors and not necessarily those of the NHS, the NIHR,
or the Department of Health.
Assessing Non-standard Vision Function in Early to Intermediate
AMD
Lori A. Lott1, Marilyn E. Schneck1, 2, Gunilla Haegerstrom-Portnoy1,
2
, Susan Hewlett1, John A. Brabyn1. 1Smith-Kettlewell Eye Research
Institute, San Francisco, CA; 2School of Optometry, UC Berkeley,
Berkeley, CA.
Purpose: It is difficult to predict which patients with early (E) to
intermediate (I) age-related macular degeneration (AMD) are at the
greatest risk of developing advanced AMD within a reasonable period
of time. The goal of this study is to determine whether performance
on simple, non-standard vision tests can improve the prediction of
AMD progression. This presentation will describe and present data
from the baseline session of a longitudinal assessment of vision
function in people with E/I AMD.
Methods: Participants tested to date (N=48, mean age =72.7 [SD
=12.1], range: 56-91 years, 64% female) are patients with E/I AMD,
and age-matched controls (C) with no AMD. All eyes have best
corrected high contrast acuity ≤0.30 logMAR (20/40 or better).
A dilated eye exam and fundus photos are used to confirm AMD
status. Each eye is categorized using the clinical classification scale
of Ferris et al. (Ophthalmology, 2013): E (medium drusen only), I
(large drusen and/or AMD pigmentary abnormalities), and C (no
drusen, or small drusen only).
In the vision test session, participants are refracted and then tested
monocularly on a battery of vision tests with appropriate correction
for the 40 cm test distance. The test battery includes: high contrast
acuity under conditions of high and low luminance, low contrast
acuity at low luminance, contrast sensitivity under conditions of
high and low luminance, shape discrimination hyperacuity, reading
performance, color vision, flicker modulation sensitivity at a
frequency of 14 Hz, and glare recovery.
Results: Preliminary results on the sample to date reveal statistically
significant differences between early to intermediate AMD
participants and controls on all measures, except high contrast acuity
measured at high luminance and glare recovery. The E/I group shows
greater variability than C, with some AMD patients showing results
similar to the C group, and others showing considerably reduced
function. The latter are the patients we hypothesize will progress to
advanced AMD in a shorter period of time.
Conclusions: This ongoing longitudinal study will test the hypothesis
that non-standard vision function measures can predict AMD
progression. The preliminary data from this baseline sample are
promising. Most of the measures tested show sensitivity to E/I AMD,
but with sufficient variation within each of the measures to be good
candidates for predicting who will develop advanced AMD.
Commercial Relationships: Lori A. Lott, None; Marilyn E.
Schneck, None; Gunilla Haegerstrom-Portnoy, None; Susan
Hewlett, None; John A. Brabyn, None
Support: NIH Grant EY023320A
Stability of performance of a handheld radial shape
discrimination test in patients at risk of developing neovascular
AMD
Noelia Pitrelli Vazquez1, Simon P. Harding1, 2, Heinrich Heimann2,
Paul C. Knox1. 1Eye and Vision Science, University of Liverpool,
Liverpool, United Kingdom; 2St Pauls Eye Unit, Royal Liverpool
University Hospital, Liverpool, United Kingdom.
Purpose: We are currently investigating a handheld Radial Shape
Discrimination (hRSD) test (Wang et al, 2013, IOVS 54:5497) as a
potential screening test for detecting new neovascular age-related
macular degeneration (nvAMD). The stability of performance of the
hRSD test over time was assessed in patients at risk of developing
nvAMD prior to disease development.
Methods: Thirty-three non-diabetic participants (mean±SD age:
77±7 years; range: 60-91 years, 19 female) were recruited from a
UK AMD clinic. Participants had nvAMD in one eye (for which
they were receiving treatment) and no evidence of nvAMD in their
fellow eye (study eye, SE) with a visual acuity of 0.4 logMAR
or better in that eye. They performed the hRSD test with the SE,
under supervision, on 5 occasions over a period of 5.5±0.8 months.
Presence or absence of large drusen (maximum vertical diameter
>70mm) and disruption of the ellipsoid zone (EZ) within 1500mm
of the foveal centre were assessed on Heidelberg Spectralis OCT at
baseline.
Results: Group mean (±SD) hRSD thresholds at each time
point were -0.54±0.18, -0.57±0.17, -0.56±0.17, -0.56±0.18 and
-0.59±0.22 logMAR. A repeated measures ANOVA demonstrated
that these thresholds were not statistically significantly different
[F(4, 116)=0.56, p=0.694]. Regression analysis of threshold over
time showed that the mean slope of individual regression lines
was -0.000252±0.001206. The mean (95%CI) difference in hRSD
threshold between the first and the last time points was -0.05 (-0.13 to
0.03) logMAR. Presence/absence of large drusen, or disruption to the
EZ had no statistically significant effect on hRSD test performance
(p=0.10 and p=0.23 respectively).
Conclusions: Stability over time prior to the development of the
target pathology is an important aspect of a diagnostic test. We have
confirmed that hRSD test performance was stable over a period of
approximately six months in the fellow (non-nvAMD) eyes of AMD
patients and that it remained consistently below the cut-off value for
the hRSD test previously suggested to be indicative of disease (-0.37
logMAR).
Commercial Relationships: Noelia Pitrelli Vazquez, None; Simon
P. Harding, None; Heinrich Heimann, None; Paul C. Knox, None
Support: Dunhill Medical Trust Grant R283/0213. Equipment and
software supplied by Vital Art & Science Inc.
Structural and functional correlation of serial follow-up of
patients with scarred choroidal neovascular membrane on
Microperimeter
.. Aishwarya1, Mathew Kurian Kummelil1, Robert Rosen2, Henk A.
Weeber2, Marrie Van der Mooren2, Subhash Chandra3, K Bhujang
Shetty1, Rohit Shetty4. 1Cataract and Refractive, Narayana Nethralaya,
Bangalore, India; 2Abbott Medical Optics, Groningen, Netherlands;
3
Retina, Narayana Nethralaya, Bangalore, India; 4Refractive
Department, Narayana Nethralaya, Bangalore, India.
Purpose: To evaluate the long term serial follow up of patients
with scarred choroidal neovascular membrane by imaging, using
microperimeter (MAIATM), in order to quantify the area covered
by the scarred choroidal neovascular membrane and to determine
changes in the area of the scar and bivariate contour ellipse area over
a period of time.
Methods: 8 eyes of 7 patients meeting the inclusion and exclusion
criteria were enrolled for the study and followed up for 6 visits at
6 weekly intervals. All patients underwent vision assessment and
microperimetry (MAIATM ) at each visit. Serial images were analyzed
using custom software for calculating the area of the scar and the
changes over the period of time.
Results: The analysis revealed average initial scarred choroidal
neovascular membrane area to be 92 degrees2 and showed statistically
no change over the course of follow up. Similarly, the initial bivariate
contour ellipse area (BCEA) was found to be 61degrees2 with no
change over time. The structural functional correlation between
the scar and the BCEA was studied, and there was no significant
correlation between the two.
Conclusions: Microperimeter can be used as an assessment tool
for serial changes over time in patients with scarred choroidal
neovascular membrane.
Commercial Relationships: .. Aishwarya, None; Mathew Kurian
Kummelil, None; Robert Rosen, Abbott Medical Optics (E); Henk
A. Weeber, Abbott Medical Optics (E); Marrie Van der Mooren,
Abbott Medical Optics (E); Subhash Chandra, None; K Bhujang
Shetty, None; Rohit Shetty, None
Support: Funding: Supported by the Ministry of Economic Affairs,
Netherlands, Grant OM111018, and by AMO
Scotopic and Photopic Microperimetry in Patients with Reticular
Drusen and Age-related Macular Degeneration
Julia S. Steinberg1, Frederick W. Fitzke3, Rolf Fimmers2, Monika
Fleckenstein1, Frank G. Holz1, Steffen Schmitz-Valckenberg1.
1
Department of Ophthalmology, University of Bonn, Bonn, Germany;
2
Institute of Biostatistics, University of Bonn, Bonn, Germany;
3
United Kingdom.
Purpose: To evaluate retinal function by scotopic and photopic
microperimetry patients with age-related macular degeneration
(AMD) and a well-demarcated area of RDR (reticular drusen).
Methods: A prospective case series of 22 eyes from 18 patients
(mean age 74.7 years, range 62-87) was performed. Using combined
confocal scanning laser ophthalmoscopy and spectral-domain optical
coherence tomography imaging, retinal areas with RDR (category
1), other AMD-related pathologies (category 2) and no visible
pathological alterations (category 3) were identified in each eye.
Scotopic and photopic microperimetry (MP1S, Nidek Technologies,
Padova, Italy) was performed using a grid with 56 stimulus points. A
comparison of the mean threshold sensitivities for each category for
scotopic and photopic microperimetry was performed.
Results: In all eyes, areas of categories 1 and 2 showed a relative and
sharply demarcated reduction of scotopic threshold values compared
to areas of category 3, while only less pronounced differences
were seen for photopic testing. Statistical analysis in the 18 eyes in
which the 1.0 log unit neutral density filter was applied revealed a
significant difference of scotopic threshold values in areas of category
1 (mean 13.5 ± 3.2 dB), category 2 (mean 7.8 ± 4.4 dB) and category
3 (mean 18.3 ± 2.0 dB) (p = 0.002). For photopic testing, the mean
threshold values were 16.8 ± 2.9 dB in category 1, 15.9 ± 5.4 dB in
category 2 and 18.4 ± 2.7 in category 3 (p = 0.03). Subtracting the
scotopic from the corresponding photopic threshold value for each
test point, the mean difference was 3.6 ± 3.0 dB for category 1, 8.1 ±
4.0 dB for category 2 and 0.1 ± 2.3 dB for category 3 (p = 0.002).
Conclusions: The results indicate that rod function is more severely
affected than cone function in areas with RDR and other AMDrelated pathological alterations. This differential structure-function
correlation underscores the functional relevance of RDR in AMD
subjects.
Commercial Relationships: Julia S. Steinberg, Heidelberg
Engineering (F), Optos (F); Frederick W. Fitzke, None; Rolf
Fimmers, None; Monika Fleckenstein, Heidelberg Engineering (C),
Heidelberg Engineering (F), Heidelberg Engineering (R), Optos (F),
US20140303013 A1 (P), Zeiss Meditec (F); Frank G. Holz, Acucela
(C), Acucela (F), Alcon (C), Alcon (F), Allergan (C), Allergan (F),
Bayer Healthcare (C), Bayer Healthcare (F), Boehringer Ingelheim
(C), Genentech (C), Genentech (F), Heidelberg Engineering
(C), Heidelberg Engineering (F), Heidelberg Engineering (R),
Novartis (C), Novartis (F), Optos (C), Optos (F); Steffen SchmitzValckenberg, Allergan (F), Bayer (F), Bayer (R), Heidelberg
Engineering (F), Heidelberg Engineering (R), Novartis (C), Novartis
(F), Novatis (R), Optos (F), Optos (R), Roche (C), Roche (F), Zeiss
MediTec (F)
Support: Gertrud Kusen foundation
Mesopic and Scotopic Threshold Sensitivity in Patients
with Choroideremia: Relationship with Residual Fundus
Autofluorescence Area
Ioannis Dimopoulos, Ian M. MacDonald. Ophthalmology and Visual
Sciences, University of Alberta, Edmonton, AB, Canada.
Purpose: To evaluate retinal sensitivity threshold under mesopic and
scotopic conditions in patients with choroideremia and correlate the
results with residual fundus autofluorescence area.
Methods: 22 eyes of 11 choroideremia subjects with no detectable
rod (DA 0.01) or cone (LA 3.0/30Hz) ERG responses were included.
Subjects underwent mesopic testing using MAIA custom-grid (121
stimuli) microperimetry (Centervue; Padova, Italy) and scotopic
testing using chromatic (white, blue, red) full-field stimulus threshold
(FST; Diagnosys LLC). Fundus autofluorescence images (Sonomed
Escalon, Inc.) were acquired with a modified fundus camera
system (Sonomed Escalon, Inc.) and the area of residual fundus
autofluorescence (FAF) in the posterior pole calculated using in-built
software (OphthaVisionTM). Mean and maximum microperimetry
sensitivity (dB) were correlated with FST (dB) and FAF area (mm2).
Rod- and cone-mediation of visual perception was determined based
on the difference between blue and red stimulus thresholds (Roman
et al. 2005).
Results: Residual remaining FAF areas ranged from 1.34 to 13.19
mm2 (mean±SD: 5.9±4.1 mm2). There was a strong correlation of
FAF area with white FST threshold (r=-0.82; p<0.001), while no
association was observed with maximum or average microperimetry
sensitivity (r=0.25 and 0.19, respectively; p>0.1). Microperimetry
maximum sensitivity showed a strong ceiling effect (skewness: 0.426;
range: 24-28 dB) compared to FST (skewness: 0.005; range: 20.4,
52.5 dB). The majority of eyes (7/8) with residual FAF areas>5mm2
demonstrated rod-mediated perception (blue-red difference>19.3dB).
A FAF area<4mm2 was associated with either cone (6/10) or rodmediation (4/10). Mean and maximum microperimetry sensitivity
values could not diffentiate between eyes with rod or cone-mediated
perception.
Conclusions: For the range of FAF area tested, microperimetry
mesopic testing showed a strong ceiling effect in terms of average
and maximum sensitivity. Progression of RPE degeneration in this
choroideremia cohort could be accurately followed by change in
scotopic FST threshold. FST allowed quantification of residual
rod function in subjects with severe RPE loss. Determining rod or
cone mediation of perception in these patients may allow better
classification and patient selection for future gene therapy clinical
trials.
Commercial Relationships: Ioannis Dimopoulos, None; Ian M.
MacDonald, None
Contrast sensitivity in patients with macular degeneration
Robert Rosen1, Jennifer Jayaraj2, Shrikant R. Bharadwaj2, Henk
A. Weeber1, Marrie Van der Mooren1, Patricia A. Piers1. 1Abbott
Medical Optics, Groningen, Netherlands; 2LV Prasad, Hyderabad,
India.
Purpose: Age-related macular degeneration (AMD) is a common
cause of visual impairment and blindness. It is of great interest to
measure contrast sensitivity in patients with AMD, as it has been
shown to correlate with e.g. risk of falling independently of acuity.
We investigated the use of a quick method to measure the contrast
sensitivity function (CSF) in both a group of patients with AMD
as well as a control group. In the group with AMD, other clinical
measurements were also taken
Methods: The study included 12 patients with AMD (acuity 0.5±0.4
logMAR) and 11 healthy volunteers of similar age (0±0.05 logMAR)
from Hyderabad, India. The CSF was measured for both groups. The
patients with AMD used their preferred retinal locus in the periphery.
We used a quick Bayesian method that gave the full CSF curve in less
than five minutes, which has earlier been tested for peripheral vision
on healthy experienced volunteers. None of the subjects in this study
had previous experience with psychophysical tests. Besides the CSF,
we also measured visual acuity, visual field, fixation stability, and
acquired autoflorescence images of the AMD lesion
Results: The CSF could be measured on at least one eye of 10 of
the subjects with AMD and all of the healthy volunteers. Two of
the subjects with AMD could not see enough of the screen to get
meaningful results. The average ± standard deviation of the CSF
can be seen in Fig 1. The area under the logarithm of the CSF
was significantly smaller for the patients with AMD than for the
healthy volunteers (p<0.05, 1.05±0.72 vs 2.1±0.51), with an average
individual standard deviation of 0.08 and 0.13 area units respectively.
The CSF of the healthy volunteers was similar to that of other healthy
subjects. For the patients with AMD, the loss of contrast sensitivity
was most pronounced in the lower spatial frequency range. The mean
peak of the curve was only 21, whereas it was 89 for the healthy
volunteers. Looking at individual spatial frequencies, the difference
was significant (p<0.05) at 15 cycles/deg and lower.
Conclusions: It is possible to quickly measure the CSF of
inexperienced elderly patients with AMD. Their total area under
the CSF and peak contrast sensitivity at lower spatial frequencies is
significantly lower than that of healthy volunteers.
Figure 1. Average and standard deviation of CSF for the patients with
AMD and the healthy volunteers
Commercial Relationships: Robert Rosen, Abbott Medical Optics
(E); Jennifer Jayaraj, None; Shrikant R. Bharadwaj, None; Henk
A. Weeber, Abbott Medical Optics (E); Marrie Van der Mooren,
Abbott Medical Optics (E); Patricia A. Piers, Abbott Medical Optics
(E)
Support: Supported by the Ministry of Economic Affairs,
Netherlands, Grant OM111018, and by AMO.
Precision of contrast sensitivity testing in glaucoma
Pradeep Y. Ramulu, Pujan Dave, David S. Friedman. Ophthalmology,
Wilmer Eye Inst/Johns Hopkins, Baltimore, MD.
Purpose: Contrast sensitivity (CS) is frequently affected in
glaucoma, but is not frequently used as part of clinical care. One
impediment to the use of contrast sensitivity to monitor disease
severity is the high variability of contrast values on repeat testing.
Here, we examine test-retest parameters of two contrast sensitivity
tests (the MARS contrast sensitivity chart and the Adaptive Sensory
Technology quick CSF test) in a group of glaucoma patients with a
range of disease severity.
Methods: Both CS tests were evaluated in 30 glaucoma patients
under the following 4 conditions: right eye, left eye, both eyes, and
worse-seeing eye (retested). The MARS test measured CS at a single
letter size, with letters read were converted into logCS. The quick
CSF test tested contrast sensitivity at varying letter size using a
thresholding algorithm. Results were summarized as the area under
the contrast/letter size curve (AULCSF), as well as logCS at 3 cycles/
degree (a text size roughly equivalent to the MARS print size).
Results: Thirty glaucoma patients completed the testing procedures.
Subjects had a mean visual field mean deviation of -12.3 dB in the
eyes where CS testing was repeated (SD=8.2 dB, range=-0.1 to -30.9
dB). Mean AULCSF values in retested eyes was 0.77 (0.48), and
the mean (SD) test-retest difference in AULCSF was 0.02 (0.09).
Bland-Altman plot showed no relationship between the difference
in AULCSF and the average AULCSF across the 2 trials (p=0.995),
and the coefficient of repeatability for AULCSF was 0.24. Mean
test-retest differences in MARS logCS and quick CSF logCS at
3 cpd were 0.12 (.10) and 0.03 (0.15), respectively, with neither
value showing a relationship between the difference in logCS and
average logCS across the 2 trials (P>0.9 for both). The coefficients of
repeatability for MARS log CS and quick CSF logCS at 3 cpd were
0.28 and 0.40, respectively.
Conclusions: Precision of contrast sensitivity testing is constant over
a wide range of glaucoma damage, suggesting that it may be useful
to gauge disease severity, particularly in patients with very advanced
disease. AULCSF may be more precise than logCS values calculated
from a single letter size, though longitudinal testing will be necessary
to determine which contrast sensitivity metrics, if any, are useful in
judging progression in eyes with advanced glaucoma.
Commercial Relationships: Pradeep Y. Ramulu, None; Pujan
Dave, None; David S. Friedman, None
Support: Research to prevent blindness; NIH Grant EY022976
Gaze-Directed Magnification: Developing a Head-Mounted, Wide
Field, Immersive Electronic Low Vision Aid
Frank S. Werblin1, Robert W. Massof2, Nicole C. Ross2, Danielle
Natale2, Chris Bradley2, Boger Yuval3, David Teitelbaum3. 1Molecular
and Cell Biology, UC Berkeley, Berkeley, CA; 2Low Vision Clinic,
Johns Hopkins, Baltimore, MD; 3Sensics, Columbia, MD.
Purpose: Design, develop and test a mobile head-mounted electronic
low vision enhancement device with immersive wide field of view
integrated with a region-of-interest gaze-directed magnification
“bubble” locked to the patient’s preferred retinal locus (PRL).
Methods: System has 120 degree binocular field of view in HMD
with 70 deg binocular overlap. We use two 5 inch 1080p smartphone
displays, one for each eye with resolution of 3 arcmin/pixel. The
images from a HMD-mounted central field camera resolution of 2
arcmin/pixel and a peripheral field camera resolution of 5 arcmin/
pixel, are “stitched” together to create a panoramic montage. The
magnification bubble is positioned and maintained at the patient’s
PRL by tracking pupil position. Eye tracker is NTSC miniature IRsensitive video camera placed below each eye illuminated with IR.
The display is enriched with edge and contrast enhancement, ambient
illumination level control, and additional image remapping.
Results: The sensor and processing systems minimize processing
delays so that eye tracking and natural image motion with head
movements run essentially in real-time. Pupils are tracked at 30
fps (with an angular resolution of 7 arcmin) providing bubble
position coordinates within 33 msec (one frame).The magnification
bubble is processed within ~10 msec, then rendered into the scene
and displayed in the HMD within 16 msec. Therefore, the overall
processing for repositioning the bubble in the scene, locked on the
PRL, is less than 60 msec, a delay short enough that subjects do not
experience motion of the bubble when making saccades.
Conclusions: Our proof-of-principle prototype demonstrates that
it is feasible to build a wide field of view head-worn low vision
enhancement device that can perform gaze-directed image remapping
and other forms of real time image processing. Currently, this
apparatus is being used to test the visual performance of low vision
patients while navigating and viewing with gaze-directed bubble
magnification
Commercial Relationships: Frank S. Werblin, Visionize LLC (C);
Robert W. Massof, None; Nicole C. Ross, None; Danielle Natale,
None; Chris Bradley, None; Boger Yuval, Sensics (E); David
Teitelbaum, Sensics (E)
Layer-specific fMRI subcortical damage in glaucoma and
amblyopia patients
Wen Wen1, Peng Zhang2, Sheng He3, Xing-Huai Sun1. 1Department of
Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai,
Shanghai, China; 2State Key Laboratory of Brain and Cognitive
Science, Institute of Biophysics, Beijing, China; 3Department of
Psychology, University of Minnesota, Minneapolis, MN.
Purpose: To segment the layers of subcortical nuclei (LGN, SC) with
fMRI, and to investigate selective pathway damage in glaucoma and
amblyopia patients.
Methods: Eighteen early-stage open-angle glaucoma patients,
eighteen adult unilateral amblyopia patients and eighteen controls
were enrolled in the study. The M and P stimuli were used to segment
the M and P functional layers of LGN. The M stimulus was low
spatial frequency sine wave patterns at low luminance contrast, and
counter-phase flickering at high temporal frequency. The P stimulus
was high spatial frequency, isoluminant red/green square wave
patterns, reversing contrast at low temporal frequency. MRI data were
collected with 3T scanner (Siemens Verio) and were analyzed using
Brainvoyger QX.The M layers of the LGN was identified as voxels
showing stronger response to the M stimulus than to the P stimulus,
and vice versa for the identification of the P layers.
Results: In normal group, the M layers were located more medially,
interiorly and anteriorly compare to the location of the P layers,
which is consistent with the human LGN anatomy. In glaucoma
group, nearly all LGN voxels showed stronger responses to the P
stimulus. In the M layers of LGN, a significant interaction was found
between the factors of stimuli and groups but there was no interaction
between stimuli and groups in the P layers. In amblyopia group,
fewer LGN voxels showed strong responses to the P stimulus in the
LGNs. In the P layers of LGN, a significant interaction was found
between the factors of stimuli and groups but no such interaction in
M layers. These results indicate that neuronal responses to the M and
P stimuli were selectively reduced in the LGNs of glaucoma patients
and amblyopia subjects, that is a greater loss of signals to the M
stimulus in the M layers in glaucoma and a greater loss of signals to
the P stimulus in the P layers in amblyopia. FMRI signals measured
at superior depth showed the same significant interaction as in LGNs
of patients. In glaucoma patients, the selective subcortical damage
were well correlated with OCT parameters and visual field loss
(p<0.05).
Conclusions: Using fMRI, we demonstrated clear segregation of
M and P divisions in human LGN noninvasively.This fMRI data
provide in-vivo and direct evidence to support selective function loss
in the two eye diseases and provide a promising paradigm to measure
functional defects related to the two parallel pathways.
Commercial Relationships: Wen Wen, None; Peng Zhang, None;
Sheng He, None; Xing-Huai Sun, None
310 Visual functions in the presence of eye diseases
Tuesday, May 05, 2015 8:30 AM–10:15 AM
Contributing Section(s): Low Vision
Novel dual arc stimulus aids sensitive detection of early AMD
Humza J. Tahir, Elena Cerio, Neil R. Parry, Jeremiah M. Kelly, David
Carden, Tariq M. Aslam, Ian J. Murray. University of Manchester,
Manchester, United Kingdom.
Purpose: The rate of recovery of rod vision following a bleach is
emerging as highly clinically significant. It is systematically slowed
in the older eye and in many clinical conditions, notably Age-Related
Macular Degeneration (AMD). It is not known for certain whether
this is a pan-retinal effect or if there are localised regions of impaired
rod function. To address this issue a dual arc stimulus was developed
that simultaneously samples sensitivity recovery in two retinal
locations and we present data for three groups of observers, younger
normals (n=13), older normals (n=13) and early AMD patients
(AREDS grade 2 or 3, n=47).
Methods: Arc-shaped white stimuli were presented on an otherwise
black CRT screen at two locations in the inferior visual field.
Recovery of sensitivity to the two stimuli was measured concurrently
using method of adjustment by alternately presenting them following
a localised bleach of at least 80%. Neutral density filters were used
to extend the luminance range of the CRT. Data were fitted by
non-linear regression to either a seven- or five- parameter model to
characterise the dark adaptation curves.
Results: The two stimuli produced similar cone recovery curves
within each normal age group. Rod recovery slope, S2, was
significantly different between the tested locations for the normal age
groups (young 6°=-0.21±0.03, 11°=-0.24±0.03, p=0.02; old, 6°=0.18±0.05, 11°=-0.20±0.04, p=0.01) but not for the AMD group (6°=0.10±0.06, 11°=-0.11±0.05, p=0.11). S2 slopes were significantly
shallower at both testing locations in the AMD group compared to
the age-matched normals (6° p <0.001 and 11° p<0.001). Alpha and
beta points were significantly delayed in the AMD group compared
to the age-matched normals at both testing locations (α, 6° p=0.035,
11°=0.038 and β, 6° p<0.001, 11° p<0.001). ROC analysis showed
testing the extra location enhanced the diagnostic capability of the
test in detecting early AMD.
Conclusions: The new technique increases the information yield
without placing any additional demands on subjects. Previous
findings regarding normal dark adaptation across the life span are
confirmed. Additional novel data are revealed by the technique
showing that the method has the potential to be of clinical benefit in
detecting and monitoring early signs of disease of the outer retina,
particularly AMD.
Commercial Relationships: Humza J. Tahir, None; Elena Cerio,
None; Neil R. Parry, None; Jeremiah M. Kelly, None; David
Carden, None; Tariq M. Aslam, None; Ian J. Murray, None
Support: NRAP and TA’s participation was facilitated by the
Manchester Biomedical Research Centre and the Greater Manchester
Comprehensive Local Research Network. HJT, ERCD, TA and
NRAP were supported by Newtricious R&D B.V. ERCD was also
supported by the National Eye Research Centre (NERC).
and AOSLO. Cone- and rod-mediated sensitivity was tested using
a microperimeter (MP1-S, Nidek) under mesopic and scotopic
conditions. Subjects were tested 3 times on different days to assess
the repeatability of rod-mediated testing since repeatability of MP1-S
scotopic sensitivity has not been reported. MP1-S targets were
overlaid on the AOSLO image in which the photoreceptor structure at
the MP1-S test locations were examined (Fig.1).
Results: Compared to controls, subjects with drusen only showed
similar cone- and rod-mediated light sensitivity, whereas those
with SDD only showed reduced sensitivity for both cone- and rodmediated vision (Table 1). MP1-S test targets with lower sensitivity
corresponded to retinal areas more affected by SDD, as revealed by
AOSLO. Mean rod-mediated sensitivity for the entire test region
was similar on repeat testing (7.95 dB, 8.83 dB, and 9.39 dB), with
correlations ranging from 0.64 to 0.74 (Pearson’s r). The MP1-S’s
20 dB dynamic range of sensitivity creates a ceiling effect for conemediated testing in normal and AMD eyes with drusen only and a
floor effect for rod-mediated testing in AMD patients with SDD only.
Conclusions: Microperimeters may be useful in assessing SDD’s
impact on cone- and rod-mediated vision in patients with AMD.
However, further visual function testing in additional patients using
instruments with a larger dynamic range is warranted.
Mesopic and Scotopic Microperimetry and Multi-Modal Imaging
in Eyes with Sub-retinal Drusenoid Deposits (SDD)
Yuhua Zhang, Xiaolin Wang, Mark E. Clark, Christine A. Curcio,
Cynthia Owsley. Ophthalmology, Univ of Alabama at Birmingham,
Birmingham, AL.
Purpose: To evaluate the impact of SDD on cone- and rod-mediated
vision in patients with age-related macular degeneration (AMD)
using mesopic and scotopic microperimetry, and correlate the
findings with retinal structures revealed by multimodal imaging
including a new generation research adaptive optics scanning laser
ophthalmoscope (UAB AOSLO).
Methods: Of 8 subjects enrolled, 3 patients had conventional
drusen only, 2 patients had SDD only, and all had intermediate
AMD (grade 6-7 on the AREDS 9-step severity scale). Three agesimilar adults in good macular health served as controls. SDD and
drusen were ascertained by presence in color fundus photographs,
infrared, autofluorescence images, optical coherence tomography,
Table 1, Mean (standard deviation) cone- and rod-mediated
sensitivity (dB) tested at 68 points in the central 10° radius of macula
with a Goldman size III target presented for 200 msec using a 4-2
threshold strategy.
Commercial Relationships: Yuhua Zhang, None; Xiaolin Wang,
None; Mark E. Clark, None; Christine A. Curcio, None; Cynthia
Owsley, None
Support: This project is funded by EyeSight Foundation of
Alabama (YZ), International Retina Research Foundation (YZ),
5R21EY021903 (YZ), R01AG04212 (CO), and R01EY06109
(CC) and institutional support from Research to Prevent Blindness,
EyeSight Foundation of Alabama, Buck Trust of Alabama, and NIH
P30 EY003039.
Fig. 1 A, B, Cone- and rod-mediated light sensitivity.
Impact of Simulated Micro-Scotomas on Foveal and Non-Foveal
RSVP Reading Speed
Arunkumar Krishnan, Hope M. Queener, Harold E. Bedell.
Optometry, University of Houston - College of Optometry, Houston,
TX.
Purpose: Reading is impacted negatively in most subjects with
central field loss. These subjects typically fixate with a non-foveal
preferred retinal locus, which can include areas of localized
sensitivity loss, or micro-scotomas. In this study, we simulated microscotomas at the fovea and in the peripheral retina of normal subjects
to assess their impact on rapid-serial-visual-presentation (RSVP)
reading speed.
Methods: A custom MATLAB program using Psychtoolbox-3
simulated 13 x 13 min micro-scotomas that were superimposed
on text presented in RSVP format. Reading material included
60-character MNread sentences and 53 ± 8 character sentences, taken
from novels. Five naïve subjects with normal vision (ages: 23-31
years) read words presented at or above the critical print size (CPS)
at the fovea and at 5 and 10 deg in the inferior visual field. At each
eccentricity, critical print size (CPS) was estimated as 0.4 + mean
logMAR reading acuity, determined in a preliminary experiment. Text
was presented monocularly to the preferred eye on an 85-Hz CRT
display as black ‘Courier’ letters on a uniform white background.
In different conditions, randomly distributed 13 x 13 min blocks
corresponding to 0, 13, 26 and 39% of the text area were set to the
background luminance to simulate micro-scotomas. The location
of the micro-scotomas was jittered (SDx, SDy = 0.3 deg) across
successive words to simulate fixational eye movements. A staircase
algorithm was used to estimate the threshold exposure duration for
each combination of retinal eccentricity and micro-scotoma density.
Reading speed in words per minute (WPM) was determined for each
subject from the average of two staircase estimates.
Results: Average foveal reading speed with no micro-scotomas was
688 ± 269 WPM. Reading speeds at 5 and 10 deg eccentricity were
similar and approximately half of the foveal value. With 39% microscotomas, average RSVP reading speeds decreased at the fovea, 5
and 10 deg locations by approximately 80, 65 and 25%, respectively,
from the no-scotoma condition.
Conclusions: The impact of simulated micro-scotomas on reading
speed for words that scale in size with eccentricity is greater in the
central compared to peripheral retina. This outcome can be accounted
for by the probability that randomly positioned micro-scotomas
“cluster” into groups that approximate individual letter features in
size.
Commercial Relationships: Arunkumar Krishnan, None; Hope
M. Queener, None; Harold E. Bedell, None
Support: Student Vision science Grant to advance Research (SVGR
- UHCO). We thank Drs. Gordon Legge, Steve Mansfield and Susana
Chung for providing the sentences used in this study.
Methods: We first estimated the extent of monocular scotoma and
the loci of fixation using a scanning laser ophthalmoscope. We also
estimated the location of the binocular scotoma using a custom
program that projected stimuli on a large screen. Our goal was to
train individuals to direct their PRL toward the scotoma, to uncover
missing information. The training paradigm involved comparing
two stimuli located on opposite sides of the PRL to determine if
they were the same or different. One stimulus was hidden behind the
individual’s binocular scotoma and the other was clearly visible in
the location opposite the scotoma. As the task required knowing the
identity of both stimuli, moving the PRL towards the scotoma was
the best way to reveal the obscured stimulus. Observers were trained
in multiple blocks over two practice sessions.
Results: At the start of training, patients initially looked at the visible
stimulus (away from the scotoma), but with practice they began
to direct their PRL toward the scotoma. The attached figure shows
how well participants were able to direct their saccades towards the
target, after training and at a 2-month follow-up viist. At the end of
training, 4 out of 7 individuals made saccades more than half way
toward the hidden target. At the 2-month retention assessment, all
observers consistently made saccades toward the the target hidden in
the scotoma. Self-reports suggest increased subjective awareness of
scotoma location for some, which could explain the high proportion
of saccades towards the scotoma.
Conclusions: A visual search task designed to direct eye movements
toward the scotoma improves both scotoma awareness and eye
movement efficiency.
Scotoma Awareness and Eye Movement Training in Age-Related
Macular Degeneration
Preeti Verghese1, Christian P. Janssen1, 2. 1Smith-Kettlewell Eye Res
Inst, San Francisco, CA; 2Utrecht University, Utrecht, Netherlands.
Purpose: As most individuals with age related macular degeneration
are unaware of their scotoma, we seek to: 1. Develop a paradigm to
increase scotoma awareness and 2. Train the preferred retinal locus
(PRL) to move towards the scotoma to reveal information obscured
by the scotoma.
capability. Because most low vision patients suffer from impaired
acuity and contrast sensitivity, their CSFs will differ from those of
people with normal vision. The goal of this study was to test the
hypothesis that the CSFs of people with low vision differ from a
“normal” CSF only in their horizontal and vertical positions along the
spatial frequency (SF) and the contrast sensitivity (CS) axes.
Methods: Contrast sensitivity for detecting the presence of a
horizontal sinewave grating was measured with a two temporalinterval forced-choice staircase procedure, for a range of SFs
spanning 5–6 octaves. CSFs were measured for 23 low-vision
eyes (11 with AMD, 5 with Stargardt’s disease and 7 with other
pathologies). CSFs were also measured for five adults with normal
vision, and the aggregate data were fit with an asymmetric parabolic
function. This “normal template”, with the width parameters (shape)
of the function constrained, was shifted horizontally and vertically
along the SF and CS axes (both in log coordinates) to find the best fit
for each of the 23 low-vision CSFs. The low-vision CSFs were also
directly fit with best-fitting asymmetric parabolic functions (“freefit”).
Results: A comparison of the peak CS, the SF at which peak CS
occurs (SFpeak) and the high-frequency cut-off derived from the two
fitting methods (template vs. free-fit) reveals that the values are
highly correlated (r=0.77 to 0.98) and in good agreement (BlandAltman analysis) with one another, suggesting that the template fit is
comparable with the free-fit method in estimating these parameters.
The width of the left-half of the low-vision CSFs was 1.72±0.64×
[mean±SD] that of the normal’s (p<0.0001) while the width of the
right-half of the low-vision CSFs was 0.90±0.15× that of the normal’s
(p=0.005), implying that the low-vision CSFs are wider on the left
and slightly narrower on the right than a normal CSF.
Conclusions: Although the low-vision CSFs are wider than that of
a normal CSF, a normal CSF template predicts the peak CS, SFpeak
and the high-frequency cut-off of low-vision CSFs reasonably well.
Our results suggest that a normal template provides an approximate
description of the spatial-pattern detection capability of low vision
patients, especially if the emphasis is on the high-SF half of the
function.
Commercial Relationships: Susana T. Chung, None; Gordon E.
Legge, None
Support: NIH Research Grants R01-EY012810 and R01-EY017835
The box plots show the distribution of saccade length relative to the
target distance from fixation, for each of 7 participants. (Saccades that
reach the center of target are denoted by 1, saccades that do not move
toward the target by 0.) The upper and lower panels show data at the
end of training and at a 2-month retention assessment, respectively.
Commercial Relationships: Preeti Verghese, None; Christian P.
Janssen, None
Support: NIH R01 EY022394; Pacific Vision Foundation
Comparing the Shape of the Contrast Sensitivity Functions of
Normal and Low Vision
Susana T. Chung1, Gordon E. Legge2. 1School of Optometry,
University of California, Berkeley, CA; 2Department of Psychology,
University of Minnesota, Minneapolis, MN.
Purpose: The contrast sensitivity function (CSF) provides a
comprehensive description of an individual’s spatial-pattern detection
Low Vision Patients Can Transfer Skills They Learned From
Virtual Reality to Real Streets
Ellen Bowman1, Lei Liu2. 1Vision Science, University of Alabama at
Birmingham, Birmingham, AL; 2Optometry, Univeristy of Alabama
at Birmingham, Birmingham, AL.
Purpose: Virtual reality holds great potential to improve efficiency,
affordability and accessibility of low vision rehabilitation. However,
whether patients with impaired vision can learn useful skills in a
virtual environment and then apply them to solve real world problems
has not been tested.
Methods: Twelve subjects with vision too poor to use pedestrian
signals to make a safe street crossing were trained to use the start
(surge) of the traffic in the lanes next to her (near lane) going in the
same direct (parallel) to determine the safest time to cross a street
within a WALK cycle. A safe surge came a few seconds after the
onset of the pedestrian signal, when cars entered the intersection. The
subject was asked to say “GO” on the curb when she felt the safest
to initiate crossing. The time of the onset of the pedestrian signal,
the surge time (first straight-going car passing through the outer
boundary of the crosswalk) and the GO time were recorded using
stopwatches by two testers. The GO time was converted to a safety
score (SS) which was the proportion of remaining “WALK” cycle
after GO. SS=0 if GO was in the red cycle. The SS for all subjects
was evaluated at 4 real street corners before and after training, at least
3 attempts per corner. A certified orientation & mobility specialist
taught the subjects how to use near lane parallel traffic surge. Eight
subjects were trained in virtual streets generated by a semi-cave
simulator (VS group) and 4 were trained in real streets (RS group).
Results: Both groups showed a significant increase in SS after
training (0.25 vs. 0.81, t=15.11; p<.0001 for VS; 0.29 vs. 0.76,
t=8.48, p<.0001 for RS). Repeated measure ANOVA showed no
significant interaction between training effect and group. Before
training, VS group said GO 65% of the time in the red cycle (InRed),
17% in the WALK cycle but before surge (BeforeSurge), 1% in the
WALK cycle but with less than half the cycle left (SafeLow) and
only 17% in the WALK cycle with more than half the cycle left
(SafeHigh). After training in virtual streets, the numbers became 3%,
4%, 2% and 91% (Fig. 1). The RS group showed a similar pattern
after real street training (Fig. 2).
Conclusions: Patients with severely impaired vision can learn
important visual skills in a virtual environment and can apply the
skills to solve real world problems. The effectiveness of virtual street
training can be as good as real street training.
Auditory spatial representations of distance are compressed in
blind individuals
Andrew J. Kolarik1, 2, Brian Moore2, 1, Silvia Cirstea1, Shahina
Pardhan1. 1Vision and Eye Research Unit, Anglia Ruskin University,
Cambridge, United Kingdom; 2Psychology, Cambridge University,
Cambridge, United Kingdom.
Purpose: Blind individuals primarily rely on sound for spatial
information about their environment in far space. However, it is
currently unknown how well they are able to judge the distance of
sound sources. We investigated whether lack of visual information,
which aids in calibrating audition in far space, leads to poorer
estimation of the apparent distance of sounds by blind participants.
Methods: Virtualization techniques were used to simulate virtual
anechoic and reverberant rooms. Single, unmoving sounds were
presented at virtual distances between 1.2 and 13.8 m to 10 blind and
12 normally sighted participants. All had normal hearing. Stimuli
were speech, music or noise. Participants were instructed to report the
apparent distance of each sound source. Within a series of trials the
stimulus type was held constant.
Results: For normally sighted participants, perceived distance
to farther sounds was underestimated. For blind participants, the
distances for closer sounds were overestimated, and those for farther
sounds were underestimated. Accuracy of distance judgements
was quantified as the mean unsigned error. For both groups, errors
increased with increasing virtual distance, and errors were higher
for the blind than the sighted group. A mixed-model ANOVA with
distance, room reverberation, stimulus and blindness as factors
showed main effects of distance and blindness (p<0.05). No other
main effects or interactions were significant.
Conclusions: Absolute auditory distance judgements are less
accurate for blind participants than for normally sighted controls.
The internal representation of auditory distance for blind participants
is compressed. These findings suggest that accurate calibration
and fidelity for sound cues used to perceive auditory distance is
compromised as a result of blindness.
Commercial Relationships: Andrew J. Kolarik, None; Brian
Moore, None; Silvia Cirstea, None; Shahina Pardhan, None
Support: MRC grant G0701870 and the Vision and Eye Research
Unit (VERU), Postgraduate Medical Institute at Anglia Ruskin
University.
320 IOL and Presbyopia Correction
Tuesday, May 05, 2015 8:30 AM–10:15 AM
Program #/Board # Range: 2966–2992/D0088–D0114
Contributing Section(s): Cornea, Lens
Commercial Relationships: Ellen Bowman, None; Lei Liu, None
Program Number: 2966 Poster Board Number: D0088
Alteration in mechanical properties of the lens capsule after
cataract surgery
Hiroyuki Matsushima, Yoko Katsuki, Koichiro Mukai, Wataru
Terauchi, Tadashi Senoo. Ophthalmology, Dokkyo Medical
University, Shimotsuga-Gun, Japan.
Purpose: To evaluate mechanical properties changes in the rabbit
posterior lens capsule over the postoperative course of cataract
surgery.
Methods: Phacoemulsification was performed for 9-week-old
Japanese white rabbits. A capsule tension ring (CTR) and an
intraocular lens (IOL: YA-60BB, HOYA) were implanted in the eye
(n=3). The lens capsule was extracted in the 4-week postoperative
and was fixed by fixture that was placed in normal saline at room
temperature. The tensile tester (MINI44, INSTRON) with a rod
was used to pierce for measuring the posterior capsule load and
displacement to breaking point under the following condition;
Gauge Length (1.5 mm), Speed (10 mm/min). The integral load
from 1.5 mm to the breaking point in displacement was defined as
total deformation energy. For comparison, five capsules, which were
extracted immediately after CTR-insertion surgery, were used.
Results: The results of the piercing-load measurement are shown
for the control group (Fig. 1) and the 4-week postoperative group
(Fig.2). For total deformation energy, the control group scored 0.038
Nmm, whereas the 4-week postoperative group scored 0.066 Nmm,
significantly higher than the control group (P=0.025).
Conclusions: The lens capsule needs more energy for deformation
over the postoperative course of cataract surgery.
Commercial Relationships: Hiroyuki Matsushima, None; Yoko
Katsuki, None; Koichiro Mukai, None; Wataru Terauchi, None;
Tadashi Senoo, None
Refractive and Corneal Astigmatism in Patients with Monofocal
Intraocular Lens
Sanjeev Kasthurirangan, Stan Bentow. CLINICAL R&D, Abbott
Medical Optics, Milpitas, CA.
Purpose: Toric intraocular lenses (IOLs) have led to a renewed
interest in understanding posterior corneal astigmatism and its
inclusion in the calculation of toric IOL power for implantation. In
this study, refractive astigmatism and anterior corneal astigmatism
were compared in patients with a monofocal IOL to calculate the
magnitude of posterior corneal astigmatism and surgically induced
corneal astigmatism.
Methods: Corneal astigmatism (CA) and refractive astigmatism (RA)
data from a previous multi-center clinical study in which subjects
were implanted with a non-toric monofocal IOL or a toric IOL were
analyzed. All corneal incisions were restricted to temporal 180 ± 15°
in the study. Notably, in the non-toric IOL group, subjects had
preoperative anterior CA of 0.75D to 1.50D. In the non-toric
IOL group, the difference between postoperative anterior CA and
postoperative RA can be attributed to the posterior CA, as the IOL
does not have any cylindrical power. Main outcome measures
were i) magnitude of posterior corneal astigmatism calculated as
postoperative RA minus postoperative CA in the non-toric group (n =
208 eyes) and ii) surgically induced astigmatism (SIA), calculated as
postoperative minus preoperative CA of all eyes (n = 535 eyes).
Results: The non-toric group had mean ± SD preoperative CA of
0.98 ± 0.32 D, postoperative CA of 0.95 ± 0.45D and postoperative
RA of 0.76 ± 0.53 D. Postoperative RA magnitude was statistically
significantly different (One-way ANOVA, p < 0.05) for postoperative
CA, grouped into “with-the-rule” (vertical steep meridians >60°120°, RA: 0.41 ± 0.33 D), “against-the-rule” (horizontal steep
meridians 0°-30° and >150°-180°; RA: 0.98 ± 0.53 D) and “oblique”
(steep meridians >30°-60° and >120°-150°; RA: 0.68 ± 0.36 D).
The mean posterior CA vector was 0.28D at 179.09°. The J0 vector
component of SIA was statistically significantly different (One way
ANOVA, p < 0.05) for preoperative CA into “with-the-rule” (SIA
J0: 0.00 ± 0.57 D), “against-the-rule” (SIA J0: -0.33 ± 0.60 D) and
“oblique” (SIA J0: -0.17 ± 0.55 D). The mean SIA vector was 0.19 D
at 90.35°.
Conclusions: Generally, “against-the-rule” posterior corneal
astigmatism resulted in reduced total refractive astigmatism when
anterior corneal astigmatism was “with–the-rule.” Induced SIA
was greater when the cataract incision was located along the steep
meridian of corneal astigmatism.
Commercial Relationships: Sanjeev Kasthurirangan, Abbott
Medical Optics (E); Stan Bentow, Abbott Medical Optics (E)
Accuracy of Intraoperative Wavefront Aberrometer for Toric
IOL in Post Refractive Eyes Undergoing Cataract Surgery
Nilufer Yesilirmak, Sotiria Palioura, Vasilios Diakonis, Daniel
Waren, Sonia H. Yoo, Kendall Donaldson. Cornea, Bascom Palmer
Eye Institute, Miami, FL.
Purpose: To compare preoperative toric intraocular lens (IOL)
calculater with intraoperative wavefront aberrometry and evaluate the
accuracy of intraoperative wavefront aberrometry in post-refractive
eyes that underwent cataract surgery with toric IOL.
Methods: Ten post-refractive eyes were implanted with toric IOLs by
using intraoperative wavefront aberrometry (ORA System, WaveTec
Vision) to select the lens power and to guide the final lens orientation.
Preoperative IOL power was calculated by IOL Master and toric
planner and its prediction error compared with ORA prediction
error. Predicted and measured residual refractive error was used to
determine the accuracy of ORA System.
Results: Mean preoperative keratometric astigmatism was 2.05 ±
0.63 D (range 1.15 to 3.33 D). Mean postop manifest astigmatism
was 0.91 ± 0.62 D (range 0.00 to 1.75 D). The mean ORA prediction
error (MAVPE) was 0.35 ± 0.24 D, compared to a mean prediction
error of 0.97 ± 0.72 for the calculated preoperative lens choice (p <
0.01). The prediction error was ≤ 0.25 D in 50% of eyes with ORA,
compared to 20% of eyes with the preoperative lens choice. The
prediction error was ≤ 0.75 D in 100% of eyes with ORA, compared
to 40% of eyes with the preoperative lens choice.
Conclusions: The ORA System is a useful device for selecting of
accurate toric IOL power and guiding final lens orientation in postrefractive eyes.
Commercial Relationships: Nilufer Yesilirmak, None; Sotiria
Palioura, None; Vasilios Diakonis, None; Daniel Waren, None;
Sonia H. Yoo, Alcon (C), Allergan (R), AMO (R), Bausch&Lomb
(C), Optimedica (C), SLACK (C), Transcend (C), Zeiss (R); Kendall
Donaldson, Alcon (C), AMO (C)
A novel liquid lens optical component capable of focus and
astigmatism correction: application to an innovative phoropter
Florent THIEBLEMONT, Hilario GATON, Bruno BERGE, Fannie
Castignoles, cécile barnoud, Anaïs curpanen, Nelly GARCIAJALDON, Régis DIMITRIOU, Eric SIMON. Product development,
Varioptic, Lyon, France.
Purpose: Today the most reliable measurements for eyeglasses
prescription rely on the use of a phoropter with an iterative
positioning of a set of spherical and cylindrical lenses in front of
the eyes. We present the design and the experimental evaluation
of a novel compact, portable and low cost system for visual acuity
measurement based on a single adaptive-optics component with
continuously variable optical power, cylinder power and cylinder
axis.
Methods: The adaptive-optics component, an 8mm optical aperture
diameter liquid lens based on electrowetting, was designed using two
encapsulated liquids with different refractive indexes, the interface
of which is centered within a conical part. The shape of the liquid
interface can be continuously controlled by bias voltages thanks to
a multi-electrode design on the conical part, leading to a variable
spherical and cylindrical diopter. The novel system for visual acuity
measurement consists of two liquid lenses installed on a trial frame,
with a driving electronics and a user command interface. The key
performances of the system for visual acuity measurement were
analyzed using a Shack-Hartmann optical wave-front analyzer. The
system was also tested on a few patients to check its operational
convenience.
Results: The lens with its driver provides a pure spherical power
correction from -13D (Diopter) to +15D and a cylinder correction up
to -6D with a spherical power included between -6D and +15D. Over
this range, an optical power accuracy lower than 0.25D has been
demonstrated. The cylinder axis can be controlled with an accuracy
better than 3°. The maximal optical wave-front error is below 120nmrms over a 4mm diameter pupil. And the focus control response time
is lower than 300ms.
Conclusions: The optical performances evaluation has demonstrated
the relevance of our system for visual acuity tests. The range of
correction should be large enough to examine ametropia on 98% of
the worldwide population and an additional fixed lens could be used
to measure extreme optical corrections. Moreover the first tests on
patients highlight the convenience of the system due to the absence
of disruption in the test chart visualization when the optical settings
are changed and to the possibility for the patient to tune the settings
by himself.
Commercial Relationships: Florent THIEBLEMONT, Varioptic
(E); Hilario GATON, Varioptic (E); Bruno BERGE, Varioptic
(E); Fannie Castignoles, Varioptic (E); cécile barnoud, Varioptic
(E); Anaïs curpanen, Varioptic (E); Nelly GARCIA-JALDON,
Varioptic (E); Régis DIMITRIOU, Varioptic (E); Eric SIMON,
Varioptic (E)
Parameters affecting vignetting and negative dysphotopsia in the
far peripheral visual field of the pseuodophakic eye
Michael Simpson. Optics R&D, Simpson Optics LLC, Arlington, TX.
Purpose: As visual angle increases, light becomes increasingly
vignetted (blocked) at the edge of an intraocular lens (IOL) for large
visual angles, and light that bypasses the IOL completely may also
create a second displaced image. These imaging characteristics are
likely to be the source of occasional reports of dark shadows in the
temporal visual field (negative dysphotopsia), and calculations have
been made to estimate the visual angles at which this occurs.
Methods: The Zemax raytrace software was used to extend the work
reported in J. Opt. Soc. Am. A v31, pp. 2642-2649 (2014), to evaluate
visual angles for a range of eye characteristics. The same basic eye
was used (Figure 1), but the pupil diameter and ocular distances were
varied. The main parameter of interest is simply the percentage of
light rays passing through the iris that also pass through the posterior
surface of the IOL. A routine was written in Zemax to determine this
for collimated light with different input visual angles.
Results: Representative plots are given in Fig. 2 for the eye described
in Fig. 1. The onset of vignetting varies with various parameters,
but the visual angle at which focused light is truncated by the IOL
can be as low as 50 degrees. By 75-80 degrees of input visual angle,
about half the light is no longer focused by the IOL for any pupil
diameter for this example. Vignetting is lower for smaller iris-toIOL separations, calculated separately, but even when this is 0.5 mm
about half the energy is obstructed for a visual angle of 85 degrees for
larger pupils.
Conclusions: The IOL is very much smaller than the natural
crystalline lens, and the visual angle at which about 50% of the light
is no longer focused by the IOL in a model eye may be a useful
parameter for evaluating “dark shadows”. Clinical data for the
relevant parameters are rarely reported and difficult to measure, but
the visual angle for the strongest shadow, along with the physical
characteristics of the eye, could be used to create individual eye
models for comparison to clinical date. Any decentrations and tilts
of the IOL and the iris should also be included, since these would
increase the effect for smaller pupils.
Figure 2. Percentage of light transmitted by the IOL for the eye in
Figure 1.
Commercial Relationships: Michael Simpson, None
Figure 1. Schematic eye with 4mm pupil at 4.1 mm from corneal
apex, IOL at 5.1 mm, and rays at 80 degrees of visual angle.
Higher-order Aberrations after Posterior Chamber Phakic
Intraocular lens Implantation
Hongting Liu2, 4, Jing Li3, Owhofasa Agbedia4, Jiangxia Wang1,
Xinyu Li3, Hujie Wang3, Lei Liu3. 1Biostatistics Department, School
of Public Health, Johns Hopkins, Baltimore, MD; 2Visual science
and Optometry Center, The People’s Hospital of Guangxi Zhuang
Autonomous Region, Nanning City, China; 3Refractive Surgery
Center, Tongji Hospital of Huangzhong Science and Technology
University, Wuhan, China; 4Wilmer Eye Institute, Johns Hopkins
University, Baltimore, MD.
Purpose: To evaluate the changes of higher-order aberrations
(HOAs) after implantable collamer lenses implantations (Visian ICL;
STAAR Surgical Co, Monrovia, California, USA).
Methods: In this prospective study, thirty-three eyes of 20 patients
with myopia who had ICL implantation were enrolled. Before
surgery and one month after surgery, the wavefront aberration data
were obtained with the Hartmann-Shack wavefront sensor (KR-1W
aberrometer, Topcon Corp, Tokyo, Japan). For patients with pupil size
< 6 mm, the root mean square (RMS) of total ocular HOAs, RMS
of third-order aberrations, RMS of fourth-order aberrations were
measured and analyzed for 4 mm-pupil diameter. For patients with
pupil size ≥ 6 mm, HOAs were calculated for 6 mm-pupil diameter.
Visual acuity, refraction, pupil size and intra ocular pressures were
also recorded.
Results: Significant improvements in visual acuities were found
postoperatively, with significant reduction in spherical equivalent
(P < 0.001). All HOAs in the 6 mm-pupil group were significantly
higher than that of the 4 mm-pupil group, this was observed prior to
and after the procedure.
After one month of the implantation of ICL, the induction of total
ocular HOAs, third-order aberrations, and fourth-order aberrations
in 4mm-pupil group were were 0.002 ± 0.061 μm, - 0.004 ± 0.045
μm, and 0.001 ± 0.039 μm, respectively. In the 6-mm pupil group,
the induction of total HOAs, third-order aberrations, and fourth-order
aberrations were 0.089 ± 0.144 μm, 0.042 ± 0.117 μm, and 0.034 ±
0.060 μm, respectively. The increase in total HOAs and third-order
aberrations were not statistically significant after the procedure in
both groups (all P > 0.05), however, the increase in fourth-order
aberrations was statistically significant in the 6mm-pupil group.
Conclusions: ICL implantation results in an improvement in visual
acuity with minor increase in HOAs among eyes with 4 mm and 6
mm-pupils. Larger longitudinal studies, with a greater number of
subjects are indicated to confirm these findings.
Table 1 and Table 2
Figure 1
Commercial Relationships: Hongting Liu, None; Jing Li, None;
Owhofasa Agbedia, None; Jiangxia Wang, None; Xinyu Li, None;
Hujie Wang, None; Lei Liu, None
OCT-based ray tracing on pseudophakic eyes to identify optimal
IOL centration
Mengchan Sun1, Pablo Pérez-Merino1, Sonia Durán2, Ignacio
Jiménez-Alfaro2, Susana Marcos1, 2. 1Consejo Superior de Invest Cient
CSIC, Madrid, Spain; 2Fundación Jiménez Díaz, Madrid, Spain.
Purpose: Quantitative 3D anterior segment Optical Coherence
Tomography (OCT) provides full anatomical information to build
customized eye models to identify the IOL centration that would
produce best optical quality.
Methods: 4 subjects implanted with monofocal aspheric IOLs
(Bausch and Lomb, US; Alcon, US) were measured 90 days after
cataract surgery. 3-D quantitative anterior segment geometry (corneal
topography; anterior chamber depth; IOL tilt & decentration; foveal
position) was measured using a custom-developed spectral OCT
840nm; acquisition rate=25,000 A-Scanss; acquisition time =0.72
s; 7(vertical)x15(horizontal)x7mm(axial). Total wave aberrations
were measured using custom-developed Laser Ray Tracing at
785nm laser beam sampled 35 positions of a 4-mm pupil. The IOL
geometry was characterized ex vivo using profilometry. OCT images
were processed and data were exported to ZEMAX to build full
OCT-based customized computer eye models. Optical quality was
calculated from measured/simulated wave aberrations in terms of
Visual Strehl Ratio (VSR), for 4-mm pupils, and estimated for the
native tilt & decentration, and simulated decentrations ranging from
-2 to +2 mm in 0.1 mm steps in horizontal and vertical meridians,
referred to the pupil center.
Results: There was a good correspondence between measured
and estimated wave aberrations using measured IOL tilt (VSR of
0.3 and 0.2, respectively). VSR varied across IOL decentrations,
with a highest mean value of 0.4±0.2. The IOL vertical centrations
producing optimal quality were decentered nasally in all cases,
ranging from 0.1–1mm. Optimal vertical centration ranged from
0.4-1 mm inferiorly. These positions differed by -0.3 mm horizontally
and 0.1 mm vertically on average from native IOL decentration
values. Centering the IOL in the estimated optimal location produced
an average improvement of 0.08 in VSR with respect to native
decentration values and an average improvement of 0.13 in VSR with
respect to zero decentration.
Conclusions: OCT-based customized eye models predict well
optical quality in pseudophakic eyes implanted with state-of-the-art
monofocal IOLs. Zero IOL decentration does not produce optical
quality. The best IOL decentration can be obtained for each patient
based on personalized models, and the achieved improvement may be
of clinical relevance.
Commercial Relationships: Mengchan Sun, None; Pablo PérezMerino, None; Sonia Durán, None; Ignacio Jiménez-Alfaro, None;
Susana Marcos, Patent PCT/ES2012/070185 (P)
Support: Support Detail: FIS2011-25637; ERC-2011-AdG-294099;
EU Marie Curie FP7-PEOPLE-2010-ITN #26405
Refractive Differences Among Intraocular Lens Formulas and
Correlation With Outcomes in the Fellow Eye
Steven M. Naids, Sarah E. Brown, Bradford L. Tannen.
Ophthalmology, Icahn School of Medicine at Mount Sinai, New
York, NY.
Purpose: Partial coherence interferometry (Zeiss IOL Master) selects
lens power based on targeted postoperative spherical equivalents.
Actual manifest refractive outcomes may differ from the targeted
refractive error. Also, error may occur if the same biometry
measurements are used in surgical planning of the second eye.
This study investigates the accuracy of targeted versus refractive
outcomes using SRK/T, SRKII and Holladay formulas, and whether
a correlation exists between the first and second eye post-operative
spherical equivalent prediction errors.
Methods: Retrospective review from January 2013 to September
2014 of 36 eyes of 18 patients that underwent bilateral subsequent
phacoemulsification. Biometry from the first surgery was also
used for the second eye. All surgeries were performed by the same
surgeon, and all patients received an Alcon SN60WF PCIOL. The
“refractive difference” was determined by the difference between the
predicted and manifest spherical equivalent at one month. Refractive
difference was determined for the SRK/T, SRKII, and Holladay
formulas using the same IOL power that was implanted. Linear
regression was used to investigate the relationship between the error
in the first and second eye for each formula.
Results: The mean refractive differences at one month for the first
and second eye, respectively, for each formula were as follows:
SRK/T (0.18+/-0.42, 0.04+/-0.431), SRKII (0.14+/-0.57, -0.001+/-
0.56), Holladay (0.23+/-0.41, -0.02+/-0.46) . While refractive
difference in the first eye was not related to the second eye using
the SRKT and Holladay formulas (p= 0.280, p=0.140, respectively),
refractive difference in the first eye was statistically correlated with
that of the second eye using SRKII (p=0.004).
Conclusions: The results of this study suggest that the amount of
refractive difference at one month after phacoemulsification in the
first operative eye has a significant correlation with the second eye
when using SRKII. This relationship was not found to exist for
SRK/T and Holladay. The mean SRKII refractive differences at one
month for both eyes were closer to the targeted spherical equivalent
than the other two formulas in this cohort, although results were
similar among the formulas. Confirmation of this statistical corelation
in a larger study is warranted, and may be a consideration for
adjusting the power of the lens used in the second eye using SRKII.
Commercial Relationships: Steven M. Naids, None; Sarah E.
Brown, None; Bradford L. Tannen, None
Correlation between factors related with previous myopic laser
in situ keratomileusis and refractive error after intraocular lens
implantation
Keiichiro Minami1, Yosai Mori1, Shiro Amano1, 2, Kazunori
Miyata1, Kazutaka Kamiya3, Kimiya Shimizu3. 1Miyata Eye
Hospital, Miyakonojo, Japan; 2Inoue Eye Hospital, Tokyo, Japan;
3
Ophthalmology, Kitasato University, Sagamihara, Japan.
Purpose: In eyes after myopic laser in situ keratomileusis (LASIK),
power of intraocular lens (IOL) is underestimated by using
conventional methods of IOL power calculation. Although plenty of
calculation methods have been proposed, regression analysis of IOL
power underestimation with respect to LASIK correction was rarely
performed. This retrospective study was to evaluate factors related
with refractive error after IOL implantation in post- myopic LASIK
eyes.
Methods: Clinical records of eyes that had previously undergone
myopic LASIK and received IOL in cataract surgery were observed.
The study comprised of 30 eyes of 20 patients whose mean age was
58.8 years at cataract surgery. Period between LASIK and cataract
surgeries was 2 to 13 years (mean: 9.6 years). All target refractions in
LASIK were intended to emmetropia. Manifest refractions spherical
equivalent (MRSEs) and keratometric refractions (Ks) were recorded
before LASIK, and before and 1 month after cataract surgery. Ocular
axial length (AXL) was also measured before cataract surgery.
Predicted postoperative refraction was obtained by SRK/T and
double-K formulas, and the difference from MRSE at 1 month was
calculated as refractive error. Correlations between refractive error
and, MRSE before LASIK, change in K between before LASIK and
cataract surgeries, and AXL were analyzed with linear and multiple
regression analyses.
Results: MRSE before LASIK was -2 to -13 D (mean: -7.5 D),
and change in K was -1.06 to -8.00 D (mean: -4.37 D). Refractive
error was 0.03 to 4.99 D (mean: 1.98 D) in the SRK/T, that was
significantly correlated with MRSE before LASIK, change in K,
and AXL (P < 0.0001, R2 = 0.51, 0.56, 0.52, respectively). Multiple
regression analysis showed that refractive error had significant
associations with change in K and AXL (P = 0.004 and 0.005, slope
= -0.54 and 0.46 D/mm, respectively). In the double-K, significant
correlation was found between refractive error and AXL (P = 0.001,
slope = 0.38 D/mm).
Conclusions: In post-myopic LASIK eyes, refractive error was
highly correlated with the amount of myopic correction in SRK/T
formula. Significant correlation with AXL were found in both SRK/T
and double-K formulas. This result demonstrated that compensation
of K values only is not sufficient for IOL power calculation of postLASIK eyes.
Commercial Relationships: Keiichiro Minami, None; Yosai Mori,
None; Shiro Amano, None; Kazunori Miyata, None; Kazutaka
Kamiya, None; Kimiya Shimizu, None
Validation of axial length optimization as a way to improve
refractive prediction error after cataract surgery
Jason R. Mayer, Zachary Landis, Ravi Patel, Christopher Weller,
Ingrid U. Scott, Seth Pantanelli. Ophthalmology, Penn State Hershey
Eye Center, Hummelstown, PA.
Purpose: Wang et al proposed a method of optimizing axial length
(AL) in eyes longer than 25.0 mm to reduce the proportion of eyes
with hyperopic outcomes. The objective of this study is to compare
the accuracy of predicting postoperative refractive error in eyes with
AL >25.0 mm undergoing cataract surgery at a large academic center
using the IOLMaster AL, 1-center and 2-center optimized ALs.
Methods: Retrospective consecutive case series including 50 eyes
with an AL >25.0 mm that underwent cataract extraction with
intraocular lens (IOL) implantation at Penn State Hershey Eye Center
between 12/2013 and 10/2014. Inclusion criteria were (1) biometric
measurements by partial coherence interferometry (IOLMaster, Carl
Zeiss Meditec, Inc.), (2) no previous ocular surgery or intraoperative
or postoperative complications, and (3) postoperative corrected
distance visual acuity of 20/30 of better. For each case, an optimized
AL was calculated using equations published previously by Wang
et al. These optimized ALs were then used to predict the residual
refractive error using the Holliday1, SRK/T, Haigis and HofferQ
formulas. The refractive prediction error was calculated as the
difference between the actual postoperative spherical equivalent
and the predicted postoperative spherical equivalent. Mean
numerical error (MNE) was calculated for the four formulas using
the IOLMaster AL, the 1-center optimized AL, and the 2-center
optimized ALs.
Results: Table 1 shows the mean numerical errors (MNE), ranges,
and proportions of eyes with a hyperopic outcome using the
IOLMaster AL, 1-center optimized AL, and 2-center optimized
AL. The MNEs using optimized ALs were significantly reduced
when compared to MNEs using IOLMaster ALs (all p <0.05).
The proportion of eyes with hyperopic outcomes was reduced for
all formulas using both the 1-center and 2-center optimized ALs
compared to the IOLMaster ALs (all p values <0.05).
Conclusions: The accuracy of predicting postoperative spherical
equivalent refractive error in axial myopes was significantly
improved using optimized AL equations recently proposed by Wang
et al. Based on our results, the Holladay1 2-center optimized AL
should be used for eyes with an AL >25.0 mm undergoing cataract
extraction with IOL implantation since its use was associated with the
highest accuracy of postoperative refraction and lower proportion of
eyes with hyperopic outcomes.
like the MTFa for multiple spatial frequencies and CCC were
shown to correlate well with the VA measured clinically. The area
under the clinical defocus curve estimates the mean intermediate
visual performance well and is well correlated with the AU MTFa.
Therefore, these pre-clinical metrics can be used to rank the
intermediate visual performance of different IOL models.
Commercial Relationships: Aixa Alarcon, AMO (E); Carmen
Canovas, AMO (E); Robert Rosen, AMO (E); Henk A. Weeber,
AMO (E); Linda Tsai, AMO (E); Kendra Hileman, AMO (E);
Patricia A. Piers, AMO (E)
Table 1
Commercial Relationships: Jason R. Mayer, None; Zachary
Landis, None; Ravi Patel, None; Christopher Weller, None; Ingrid
U. Scott, None; Seth Pantanelli, None
Pre-clinical metrics to predict visual outcomes in the intermediate
range for pseudophakic patients
Aixa Alarcon1, Carmen Canovas1, Robert Rosen1, Henk A. Weeber1,
Linda Tsai2, Kendra Hileman2, Patricia A. Piers1. 1Abbott Medical
Optics, Groningen, Netherlands; 2Abbott Medical Optics, Santa Ana,
CA.
Purpose: To compare the clinical visual performance in the
intermediate range measured in patients implanted with different IOL
models to optical bench testing on the same IOLs to determine an
optical metric capable of predicting intermediate vision.
Methods: Through focus modulation transfer function (MTF) for
different spatial frequencies and US Air Force (USAF) pictures for a
3mm pupil in white light were measured using an optical bench for
an aspheric monofocal IOL, three multifocal IOLs (MFIOLs) with
different add powers (2.75, 3.25 and 4D) and an extended range of
vision IOL. Pre-clinical metrics, such as the area under the MTF
(MTFa) for multiple spatial frequencies and the cross correlation
coefficient (CCC) based on USAF pictures were calculated for each
defocus position from -0.5D to -2D in 0.5D steps. Additionally, the
area under the MTFa (AU MTFa) over the intermediate defocus
range was computed for each IOL. Each pre-clinical metric was
compared to the defocus curves measured in patients bilaterally
implanted with the same IOL. In all cases, high contrast defocus VA
was measured binocularly using the ETDRS chart with best distance
correction.
Results: MTFa from 0 to 50cpmm and CCC showed very good
correlation with the decimal VA measured at each defocus position
in the intermediate range (r = 0.89 for both metrics). The average
intermediate visual performance, calculated as the area under defocus
curves was highly correlated (r= 0.81) with the AU MTFa from 0 to
50cpmm. Both clinical and pre-clinical data show that the monofocal
and the MFIOL with the highest add power had lower intermediate
performance. MFIOLs with lower add powers showed better
intermediate vision, while the extended range of vision IOL had the
best visual performance in the intermediate range.
Conclusions: Intermediate visual performance in pseudophakic
eyes can be predicted by optical bench testing. Pre-clinical metrics
A novel method of intraocular lens power selection in cataract
surgery using a Markov Chain Monte Carlo Simulator
Philip Kurochkin1, Rebecca Weiss1, Roy S. Chuck3, Jonathan Fay3,
choul yong2, Jimmy K. Lee3. 1Albert Einstein College of Medicine,
Bronx, NY; 2Department of Ophthalmology, Dongguk University,
Goyang, Korea (the Republic of); 3Department of Ophthalmology,
Montefiore Medical Center, Bronx, NY.
Purpose: To evaluate the validity of the FullMonte (FM) intraocular
lens (IOL) power computational process and compare its accuracy to
four popular formulas.
Methods: A retrospective analysis of the first operated eye from
160 patients who underwent cataract surgery with an Acrysof
SN60WF IOL (Alcon, Inc) implantation by a single surgeon (JL) was
conducted. Biometric data and keratometry obtained by IOLMaster
(Carl Zeiss Meditec) as well as pre- and postoperative visual acuities
and refractive errors were recorded. Data from the first 80 patients
were used to optimize the FM calculator, which was used to get the
predicted refraction for the next 80 patients. The absolute difference
between predicted refraction and postoperative refraction (spherical
equivalent (SE)) was calculated as the prediction error (PE). The PE
for Full Monte (FM) was compared to the PE for the Haigis, HofferQ,
Holliday1, and SKR/T in the same set of 80 patients. Subset analysis
was conducted for long (<26 mm, n=5) and short (<22 mm, n=6)
eyes. Repeatability of the FM computing process was also assessed
using the intraclass correlation coefficient (ICC).
Results: The average preoperative visual acuity and absolute SE
was 20/62 and 2.27 diopters. Postoperatively, the average visual
acuity was 20/33 and the SE was 0.49 diopters. The average PE for
the optimized FM was 0.48 +/- 0.43, for Haigis 0.60 +/- 0.45, for
HofferQ 0.52 +/- 0.42, for Holladay 0.50 +/- 0.43, and for SRK/T
0.48 +/- 0.43. For short eyes, the average PE for FM was 0.31
+/- 0.21, for HofferQ 0.44 +/- 0.32, for Holladay 0.52 +/- 0.45, for
SRK/T 0.40 +/- 0.42. For long eyes, the average PE for FM was 0.91
+/- 0.53, for HofferQ 0.92 +/- 0.44, for Holladay 0.78 +/- 0.42, for
SRK/T 0.46 +/- 0.18. The ICC for Full Monte was 0.69.
Conclusions: Markov Chain Monte Carlo estimations are based
on raw data simulations of results, and not on formulaic IOL
calculations. They are optimized to a particular surgeon’s outcomes
and predict future results directly from the data. This study shows that
the PE calculated from the Full Monte calculator was not statistically
different from current formulas, suggesting that it is at least as
accurate as existing popular formulas used in IOL power selection.
Subgroup analysis shows a trend toward better predictions by the Full
Monte in short eyes and therefore analysis of a larger sample size
may prove to be even more useful.
Commercial Relationships: Philip Kurochkin, None; Rebecca
Weiss, None; Roy S. Chuck, None; Jonathan Fay, None; choul
yong, None; Jimmy K. Lee, None
Correlation between clinical visual acuity and optical/visual
metrics at varied defocuses in pseudophakic patients implanted
with monofocal and multifocal IOLs
Lin He1, Myoung Choi2, Xin Hong2, Ramesh Sarangapani1. 1Global
Clinical & Regulatory Affairs, Alcon Laboratories, Novartis, Ft
Worth, TX; 2Optics Center of Excellence, Alcon Laboratories,
Novartis, Ft Worth, TX.
Purpose: Visual acuity and defocus curve are now commonly used
as primary clinical endpoints to evaluate the efficacy of newlydeveloped intraocular lenses (IOLs). Simulation of visual acuity and
defocus curve can potentially help to screen new IOL designs and
estimate their clinical outcomes.
Methods: A two-surface reduced model eye was constructed with
a corneal surface and an IOL surface. The corneal surface was
reconstructed using averaged or individual high-order corneal
aberration measured from the clinical studies. The IOL surface
was extracted from theoretical design or bench measurement as a
grid-sag profile with base curvature subtracted. Both surfaces were
scaled and combined at the corneal plane where defocus was defined.
One-hundred pupil sizes were randomly sampled from a normal
distribution of 3.50±0.80 mm and were used for each iteration of
simulation. Point spread function was derived by Fourier transform
of the pupil functions. Three metrics, light-in-the-bucket (LIB),
Strehl ratio (SRX) and visual Strehl ratio (VSOTF) were calculated at
varied defocuses. The LIB metric was further explored using a range
of multiples of bucket size (1 multiple of bucket size = 1 Airy disk).
Simulation were performed in two Alcon monofocal IOLs and two
Alcon multifocal IOLs under monochromatic conditions (λ=550nm)
and were linearly correlated with binocular visual acuity from four
clinical studies (n=104, 138, 116 and 130).
Results: Standard LIB (with 1 multiple of Airy disk size) and SRX
have shown good correlation with clinical visual acuity (R2=0.83
and 0.81). Increasing bucket size of LIB to 6 multiples of Airy disk
size helped to achieve the best correlation (VA = -0.57 * logLIB –
0.08, R2=0.88, Figure 1). This improvement is more obvious for two
diffractive multifocal IOLs with R2 increasing from 0.59 and 0.93
to 0.72 and 0.96. VSOTF has shown slightly worse and less linear
correlation (R2=0.70) than LIB and SRX.
Conclusions: Two-surface model eye can serve as a useful tool to
predict clinical visual acuity. Refining optical/visual metrics (e.g.,
increase bucket size for LIB metric) can better reflect the optical
efficiency of complicated IOL designs and therefore achieve better
clinical correlation. Polychromatic and binocular summation will
be further implemented to also potentially improve the clinical
correlation.
Commercial Relationships: Lin He, Alcon Laboratories Inc.
(Novartis) (E); Myoung Choi, Alcon Laboratories Inc. (Novartis)
(E); Xin Hong, Alcon Laboratories Inc. (Novartis) (E); Ramesh
Sarangapani, Alcon Laboratories Inc. (Novartis) (E)
Can Aberrometry Provide Rapid and Reliable Measures of
Subjective Depth of Focus following Multifocal Intraocular Lens
Implantation?
Raymond A. Applegate1, Sandeep K. Dhallu2, Amy L. Sheppard2,
Toshifumi Mihashi3, Tom Drew2, Sunil Shah4, James S. Wolffsohn2.
1
Visual Optics Inst/Coll of Optometry, University of Houston,
Houston, TX; 2Aston University, Birmingham, United Kingdom;
3
Tokyo Institute of Technology, Tokyo, Japan; 4Opthalmology,
Birmingham Midland Eye Centre, Birmingham, United Kingdom.
Purpose: To determine whether the ‘through-focus’ aberrations of
a multifocal and accommodative intraocular lens (IOL) implanted
patient can be used to provide rapid and reliable measures of their
subjective range of clear vision.
Methods: Eyes that had been implanted with a concentric (n = 8),
segmented (n = 10) or accommodating (n = 6) intraocular lenses
(mean age 62.9 ± 8.9 years; range 46-79 years) for over a year
underwent simultaneous monocular subjective (electronic logMAR
test chart at 4m with letters randomised between presentations) and
objective (Aston open-field aberrometer) defocus curve testing for
levels of defocus between +1.50 to -5.00DS in -0.50DS steps, in a
randomised order. Pupil size and ocular aberration (a combination of
the patient’s and the defocus inducing lens aberrations) at each level
of blur was measured by the aberrometer. Visual acuity was measured
subjectively at each level of defocus to determine the traditional
defocus curve. Objective acuity was predicted using image quality
metrics.
Results: The range of clear focus differed between the three
IOL types (F=15.506, P=0.001) as well as between subjective
and objective defocus curves (F=6.685, p=0.049). There was no
statistically significant difference between subjective and objective
defocus curves in the segmented or concentric ring MIOL group
(P>0.05). However a difference was found between the two measures
and the accommodating IOL group (P<0.001). Mean Delta logMAR
(predicted minus measured logMAR) across all target vergences was
-0.06 ± 0.19 logMAR. Predicted logMAR defocus curves for the
multifocal IOLs did not show a near vision addition peak, unlike the
subjective measurement of visual acuity. However, there was a strong
positive correlation between measured and predicted logMAR for all
three IOLs (Pearson’s correlation: P<0.001).
Conclusions: Current subjective procedures are lengthy and do
not enable important additional measures such as defocus curves
under differently luminance or contrast levels to be assessed, which
may limit our understanding of MIOL performance in real-world
conditions. In general objective aberrometry measures correlated well
with the subjective assessment indicating the relative robustness of
this technique in evaluating post-operative success with segmented
and concentric ring MIOL.
Commercial Relationships: Raymond A. Applegate, University of
Houston (P); Sandeep K. Dhallu, None; Amy L. Sheppard, None;
Toshifumi Mihashi, Topcon (F); Tom Drew, None; Sunil Shah,
LensAR (F), Lenstec (F), Refocus (F); James S. Wolffsohn, Johnson
and Johnson (F)
Support: NEI - NIH R01 EY 019105 (PI: RAA), NEI - NIH R01
EY 008520 (PI: RAA), NEI - NIH P30 EY0007551 - Core Grant (PI:
LJF), Inovative UK Funding (PI: JW)
Correlation between subjective visual performance and throughfocus retinal image quality metrics on presbyopic eyes
Eon Kim1, Ravi C. Bakaraju1, Klaus Ehrmann1, 2. 1Brien Holden
Vision Institute, Sydney, NSW, Australia; 2School of Optometry
and Vision Science, University of New South Wales, Sydney, NSW,
Australia.
Purpose: To correlate subjective visual performance responses
with through-focus retinal image quality (RIQ) metrics obtained on
presbyopic participants fitted with single vision (SV) and multifocal
(MF) contact lenses.
Methods: Thirteen presbyopic participants (50.2 ± 3.5 years, SE:
+1.38 to -5.50D) who needed adds of +1.00 or +1.25D were fitted
bilaterally with AirOptix Aqua™ SV and AirOptix Aqua™ MF lenses
[Alcon, USA]. Using the EyeMapper, a global aberrometer, on-axis
ocular wavefront aberration profiles with lenses were captured.
Five independent repeats were performed under natural pupils.
Additionally, participants pupil sizes were measured at different
illumination conditions (scotopic (0 Lux), mesopic (80 Lux) and
photopic (300 Lux)) using a custom-built instrument. Post-processing
routines in Matlab using the 6th order Zernike polynomial (z1 to z28)
obtained from the EyeMapper yielded through-focus retinal image
quality metrics (visual Strehl Ratio in the Fourier domain) over
natural and mesopic pupil sizes. The participants’ subjective visual
performance responses were obtained at far, intermediate and near
reading visual distances, separately for each eye when fitted with
both SV and MF lenses.
Results: Out of twenty-six eyes, approximately 70% of the RIQ
plots calculated each over natural and mesopic pupil size correlated
with the subjective visual performance response at far, intermediate
and near visual distances, for both SV and MF lenses. The shape
of the RIQ for most of the SV lenses produced a high peak at far
visual distance while MF lens produced gradual increase at far visual
distance and plateaued through intermediate and near reading visual
distances.
Conclusions: Through-focus retinal image quality metrics can
be used as a robust indicator to assess the visual performance for
presbyopic participants. The interpretation should however be
carefully aligned with the objective performance measures like visual
acuity and contrast sensitivity.
Commercial Relationships: Eon Kim, None; Ravi C. Bakaraju,
None; Klaus Ehrmann, None
Support: Brien Holden Vision Institute
Clinical Trial: ACTRN12613001380785
Psychophysical evaluation of the light sword optical element
(LSOE) without axial symmetry for presbyopia compensation
Walter Torres1, Alejandro Mira1, John F. Barrera1, Rodrigo Henao1,
Andrzej Kolodziejczyk2. 1Physics Institute, Universidad de Antioquia,
Medellin, Colombia; 2Faculty of Physics, Warsaw University of
Technology, Warsaw, Poland.
Purpose: Traditional methods for presbyopia compensation have
some limitations for a good correction. For this reason, in last years
new optical elements with extended-depth-focus has been proposed
for presbyopia correction. In this work it is evaluated the potential
application of the LSOE for that purpose, performing subjective test
with young people having artificially evoke presbyopia.
Methods: A monocular visual simulator has been implemented.
The refractive LSOE, with a range of depth-focus [0.00,3.00] D
simulating a contact lens was located at a pupil conjugated plane in
the optical setup. Visual simulator is composed of three sections: one
section for ocular aberrations measurements; other section is a Badal
system (BS) to present different defocus conditions to subjects; and
the last section contains the device for projecting dynamic stimuli.
Visual Acuity (VA) of 10 subjects was measured for different
defocus. The subjects had Presbyopia induced using Tropicamide.
The psychophysical evaluation was performed by a VA tumbling E
test in photopic conditions. For the evaluation, the refraction of the
subjects was first corrected using the BS. Later, the VA test was made
to defocus from -4D till +1D with step of 1D. At each defocus, two
forced choice VA tests were performed, with 48 repetitions each one.
Subjects had ages in a range [22, 35] years, with an average of
27.0±4.7 years. They presented a refraction from -1.56 D to +0.66 D
(-0.22±0.80 D in average). Further they demonstrated an astigmatism
-1.05±0.49 D in average, with a minimum and maximum value -1.79
D and -0.40 D respectively
Results: For the naked presbyopic eye, the expected decreasing
behavior of VA with the defocus grade was found. The decimal
VA goes from a maximum value of 1.16 for far vision condition,
until 0.49 for near vision at -2.00 D. When the LSOE was used for
correction, a relatively constant VA in the range of [-3.00,0.00] D was
obtained, with a mean decimal VA of 0.85±0.08.
Conclusions: Due to a relatively constant behavior of VA in the
range of the designed optical power of the LSOE, it is possible to
remark that it presents adequate features for presbyopia correction.
Experiments studying the decentering tolerance of the LSOE and
subjective contrast sensitivity measurements can complement the
LSOE characterization as a presbyopia corrector element.
Commercial Relationships: Walter Torres, None; Alejandro Mira,
None; John F. Barrera, None; Rodrigo Henao, None; Andrzej
Kolodziejczyk, None
Comparison of presbyopia correcting IOL’s profiles with a
clinical adaptive optics instrument
Bart Jaeken1, Lucia Hervella1, Jose María Marín2, Guillermo M.
Perez1, Pablo Artal3. 1R&D, Voptica, Murcia, Spain; 2Arrixaca
Hospital, Murcia, Spain; 3Laboratorio de optica, Universidad de
Murcia, Murcia, Spain.
Purpose: Although there are many types of IOLs to correct
presbyopia currently available, their final performance may be
strongly patient dependent. Adaptive optics (AO) based visual testing
has been proposed to optimize the optical correction before clinical
intervention. The validity of this approach is based on laboratory
studies (Schwarz et al., ARVO 2014). The aim of this work was to
extend this method to the standard clinical practice.
Methods: A commercially available clinical AO visual simulator
(AOnEye, Voptica SL, Spain) was used. This instrument combines
objective wavefront sensing with subjective visual testing for
different induced optical phase profiles. Those are generated with
a liquid crystal spatial light modulator which is conjugated with
the patient’s pupil plane. Visual stimuli are projected by an micro
OLED. Through focus visual acuity (VA) was measured (0, 1, 1.5,
2.0 and 3.0 D of object’s vergence). Four different lens profiles were
evaluated. Two diffractive multifocal IOLs (bifocal and trifocal) and
two IOLs with extended depth of focus (DOF) (mild/strong: sphere
+0,75/+1,30; spherical aberration -0,1/-0,4 μm for 4,5 mm pupil).
Unpaired t-statistics was used to analyze the difference between
the fixation distances. P-values smaller than 0.05 were considered
significant. The results were compared with theoretical predictions.
Results: The bifocal design showed significant better VA for the two
focus distances (0 and 3D). The mean (M) and standard deviation
(SD) of VA in decimal at the peaks was 0.81 ± 0.16 and 0.57 ± 0.13
at the other distances. The trifocal design showed no significant
difference between the distances (M ± SD: 0.74 ± 0.15). The mild
DOF lens showed a plateau at the intermediate values (1, 1.5 and
2D) and a decrease for far and near vision (worst for near). With
VA of 0.71 ± 0.11, 0.93 ± 0.23 and 0.46 ± 0.14 for respectively far,
intermediate and near. The strong DOF gave an improvement in VA
with decreasing distance, with a minimum of 0.46 ± 0.13 at far and a
maximum of 0.86 ± 0.15 at near. Both diffractive profiles performed
as theoretically predicted. The degradation of far vision for the DOF
profiles deviates from the expectations.
Conclusions: A clinical AO visual simulator proved to be functional
to test presbyopic correcting profiles in prospective cataract patients.
This instrument would permit customization/selection of the optimal
IOL for each patient.
Commercial Relationships: Bart Jaeken, VOPTICA (E),
VOPTICA (E); Lucia Hervella, VOPTICA (E), VOPTICA (E);
Jose María Marín, None; Guillermo M. Perez, VOPTICA (E),
VOPTICA (I); Pablo Artal, VOPTICA (I), VOPTICA (P)
Support: SEIDI, Spain (grant FIS2013-41237-R)
Analysis of the visual quality with multifocal intraocular lenses
before surgery
Anna Giner1, Mikel Aldaba1, Sergio O. Luque2, Maria Borrat3,
Montserrat Arjona1, Antoni Salvador4, Jaume Pujol1. 1Centre for
Sensors, Instruments and Systems Development (CD6), Terrassa,
Spain; 210Lens S.L.U., Terrassa, Spain; 3Centre ocular i quirurgic
de Terrrassa (COQT), Terrassa, Spain; 4Hospital Universitari Mutua
Terrassa, Terrassa, Spain.
Purpose: To evaluate the efficacy of a new instrument to predict the
visual quality obtained with a multifocal intraocular lens prior to
surgery
Methods: Non-cyclopegic distance and near visual acuity (VA) and
contrast sensitivity (CS) were obtained from 10 different subjects by
means of the new instrument VirtIOL. This device projects any IOL
behind the pupil plane which is equivalent to perform a virtual IOL
implant, while the patient sees any object at a determined distance.
There is no magnification effect and the refraction of the IOL is
compensated for far vision. The mean ± the standard deviation (SD)
in age of the subjects was 67±10years and the mean ± SD decimal
best distance corrected visual acuity (BDCVA) was 0.92±0.11 and
best distance corrected near visual acuity (BDCNVA) was 0.20±0.10.
Before patients were implanted with a bifocal refractive lens (MPlus
bifocal: Lentis® MPlus Oculentis®) VA and CS were evaluated
through VirtIOL by means of a virtual implant of the same IOL
model. Three weeks after surgery, same test were performed. All the
patients were corrected for distance vision. A subjective comparison
of the vision of a letter and a point light source were done between
virtual multifocal implant and post-op vision. The range of the
comparison was from 0 to 5, being 0 different and 5 completely the
same.
Results: The mean absolute difference in BDCVA and BDCNVA
between virtual multifocal implant and 3 weeks post-op were
0.10±0.13 and 0.16±0.12 respectively. In terms of CS the mean
absolute differences between virtual multifocal implant and real
post-op implant were 18.78±12.58 for 3 cycles/0 frequency,
22.22±14.81 for 8 cycles/0 frequency, 7.22±8.69 for 12 cycles/0
frequency and 3.28±3.94 for 18 cycles/0 frequency. Furthermore, the
results (mean±SD) of the subjective comparison were 3.20±0.79 and
2.50±0.71 for the letter and the point light source respectively.
Conclusions: The new instrument VirtIOL is a useful tool to predict
the visual performance of a patient before surgery. Differences
found between virtual and real implant are associated with little
opacification of the crystalline lens. It is required that the patient has
a clear eye at the simulation time as it happens in Refractive Clear
Lens Exchange. This was confirmed with one patient, who showed
very similar results between virtual multifocal implant and post-op
due to the normal transparency of his eye.
Commercial Relationships: Anna Giner, None; Mikel Aldaba,
None; Sergio O. Luque, 10Lens S.L.U. (I); Maria Borrat, None;
Montserrat Arjona, None; Antoni Salvador, None; Jaume Pujol,
None
Support: PhD Grant DPI2011-30090-C02-01
Binocular vision with rotationally asymmetric multifocal IOLs at
different orientations
Tjundewo Lawu1, 2, Kazuhiko Ohnuma1, Toru Noda3, Pablo Artal4.
1
Center for Frontier Medical Engineering, Chiba University, Chiba,
Japan; 2Research and Development, HOYA Corporation Medical
Division, Tokyo, Japan; 3Department of Ophthalmology & NISO,
National Hospital Organization Tokyo Medical Center, Tokyo, Japan;
4
Laboratorio de Optica, Universidad de Murcia, Murcia, Spain.
Purpose: Rotationally asymmetric multifocal IOL designs induced
asymmetric aberrations. This study will investigate the possibility
to improve visual outcomes with the binocular combinations of this
rotationally asymmetric multifocal IOL with optimal orientation for
each eye.
Methods: An artificial eye model with the rotationally asymmetric
multifocal IOL was used to produce retinal images. We used a 3D
display binocular visual simulator to produce a fixed orientation
in one eye of the subject, while different orientations were used
to simulate for the fellow eye. Calculations were made for object
distances at 0.0 D to -3.0 D in 0.25 D steps using the Landolt C
optotypes for a 3 mm pupil with induced spherical aberrations.
The monocular and binocular logMAR visual acuities (VA) were
examined as a function of object distances in nine subjects. Average
binocular VA for all object distances were compared to the monocular
VA.
Results: On average, binocular logMar VA improved by 0.048. The
maximum improvement was 0.053 in the orthogonal orientation
of the monocular orientation eye. Figure 1 shows the binocular VA
differences compared to monocular VA for all measured orientations.
Conclusions: Binocular VA with the rotationally asymmetric
multifocal IOL design improved about half line. Interestingly, it
was found that the VA of orthogonal orientation binocularly was
better compared to the other orientations. These findings suggest
that the use of orthogonal orientation of the rotationally asymmetric
multifocal IOL design can be another binocular approach to optimize
visual outcomes.
Fig. 1. Average binocular VA improvements compared to monocular
VA at different orientations. The monocular for reference is illustrated
in black, whereas the binocular is shown in red.
Commercial Relationships: Tjundewo Lawu, None; Kazuhiko
Ohnuma, None; Toru Noda, None; Pablo Artal, None
Defocus curve testing of pseudophakic patients: simulations and
clinical outcomes.
Henk A. Weeber3, Carmen Canovas3, Stan Bentow1, Sanjeev
Kasthurirangan1, Eugenia Thomas1, Silvestre Manzanera2, Pablo
Artal2, Patricia A. Piers3. 1Abbott Medical Optics, Santa Ana, CA;
2
Laboratorio de Optica, Universidad de Murcia, Murcia, Spain;
3
Abbott Medical Optics, Groningen, Netherlands.
Purpose: To compare different methodologies to predict defocus
curves of pseudophakic patients, and to compare these predictions
with clinically-obtained defocus curves.
Methods: The through-focus performance of the pseudophakic eye
was evaluated in laboratory and clinical settings. Measurements
included computer-simulated defocus curves, through-focus image
quality testing on an optical bench, and defocus curves obtained
for subjects using an adaptive optics vision simulator (AOVS). The
results were compared to available clinically obtained defocus curves
of two intraocular lens designs.
Results: Predicted visual acuity at distance was better than 0.0
logMAR for the two methods that determined visual acuity
(simulations, AOVS). This corresponded with the clinical results. For
eyes implanted with an extended range of vision IOL, the simulations
and AOVS predicted the clinicallyobtained defocus curve within
0.1 logMAR up to and including 2.0 diopters of defocus. For higher
values of defocus, the simulations overestimated the clinically
obtained visual acuity, and the AOVS slightly underestimated the
clinically obtained visual acuity. Correlation of the image quality on
the optical bench and the clinicallyobtained defocus curves varied,
depending on the spatial frequency evaluated.
Conclusions: Simulation of defocus curves and measurements using
an AOVS correspond well with clinicallyobtained defocus curves.
Prediction of defocus curves using through-focus image quality
measured on an optical bench depends on the spatial frequency
content evaluated.
Commercial Relationships: Henk A. Weeber, Abbott Medical
Opticss (E); Carmen Canovas, Abbott Medical Optics (E); Stan
Bentow, Abbott Medical Optics (E); Sanjeev Kasthurirangan,
Abbott Medical Optics (E); Eugenia Thomas, Abbott Medical Optics
(E); Silvestre Manzanera, Abbott Medical Optics (F); Pablo Artal,
Abbott Medical Optics (C), Abbott Medical Optics (F); Patricia A.
Piers, Abbott Medical Optics (E)
Support: Ministerio de Ciencia e Innovación, Spain (grants FIS201014926 and CSD2007-00013) and Fundación Séneca (Region de
Murcia, Spain), grant 4524/GERM/06, and AMO.
Early clinical result for restoring accommodation in Asian eyes
with LaserACE procedure using the VisioLite Er:YAG laser
David H. Ma1, AnnMarie Hipsley2, Chi-Chin Sun4, Mitchell A.
Jackson2, 3. 1Department of Ophthalmology, Chang Gung Memorial
Hospital, Taipei, Taiwan; 2Ace Vision Group, Inc, Silver Lake, OH;
3
Jacksoneye, Lake Villa, IL; 4Department of Ophthalmology, Chang
Gung Memorial Hospital, Kee-Lung, Taiwan.
Purpose: To evaluate accommodative benefits for near and
intermediate visual performance after bilateral LaserACE procedure
in Asian eyes.
Methods: This prospective single arm design clinical study evaluated
the LaserACE procedure results over 12 months. 20 Subjects ^40
years of age with a demonstrated loss of accommodative function
that had good uncorrected distance vision with less than 1.0 D of
refractive astigmatism or hyperopia were enrolled.
LaserACE surgery was performed using the VisioLite Er:YAG
ophthalmic laser system in 4 oblique quandrants on the sclera over
the ciliary muscle. The 9-spot matrix microexcisions were made with
a hand held probe at 600 um spot size.
Primary study targets were binocular defocus curve and unaided near
and intermediate visual acuity, with a secondary target of stereoacuity
and Patient Reported Outcome Questionnaire.
Results: All patients achieved some improvement of near &
intermediate vision. An average of 2-4 lines of improvement of
reading vision was demonstrated. At Post-operative 1 year, UCIVA
was 93% 20/30 or better; 86% 20/25 or better; 80% 20/20 or better;
UCNVA was 85% 20/30 or better; 80% 20/25 or better; 46% 20/20 or
better. The patients gained an averaged 1.5 D added accommodative
reading power after the procedure. No statistically significant
change was noted in UCDVA post-operatively, and stereoacuity
was unaffected. All patients improved from “very great difficultysome difficulty” pre-operatively to “some difficulty-no difficulty”
at post-OP 6 months in the CatQuest 9SF Activities of Daily Living
Questionairre.
Conclusions: Preliminary results of the Taiwan IRB-monitored
clinical trial of the LaserACE procedure appears to show promising
results for restoring range of visual performance for near and
intermediate visual tasks without compromising distance vision
or offending the visual axis. Patient satisfaction was high postoperatively and sustained beyond 1 year in this group of Asian eyes.
Commercial Relationships: David H. Ma, None; AnnMarie
Hipsley, None; Chi-Chin Sun, None; Mitchell A. Jackson, None
Support: CGMH XMRPG1A0124
Optical effects of an intracorneal annulus as a treatment for
presbyopia
Thomas W. Raasch. College of Optometry, Ohio State University,
Columbus, OH.
Purpose: A potential treatment for presbyopia is the use of an
intracorneal annulus, exploiting the pinhole effect to expand the
depth of field. The purpose of this study is to examine the effects of
an intracorneal annulus on the retinal image and retinal illumination
over a range of pupil sizes and visual field angles.
Methods: Analytical and numerical methods are used to determine
the effects on foveal image quality and on retinal illumination across
the visual field. Retinal image characteristics are calculated using
analytical formulae. Retinal illumination is calculated using ray
tracing techniques.
Results: An intracorneal annulus will expand the depth of field by
reducing the entrance pupil diameter, thereby improving the clarity
of the foveal image for near vision in a presbyopic eye. The opaque
band of the annulus occludes at least of portion of the entrance pupil
of the eye over a wide range of visual field locations, reducing retinal
illumination in an annular ring. Effects depend upon the dimensions
and centration of the annulus, anterior chamber depth, and pupil
size. In an eye with an extremely small pupil, the reduction in retinal
illumination has the potential to produce a relative scotoma. In an eye
with a very large pupil and/or a decentered annulus, the retinal image
will be formed by ray bundles traversing two paths, i.e. through the
center of the annulus and around the outside of the annulus, which
may degrade the quality of the retinal image.
Conclusions: Used as a treatment for presbyopia, a well-centered
intracorneal annulus produces a pinhole effect, expanding the
depth of field. When implanted unilaterally, this can be expected to
provide a near-emmetropic presbyope a greater degree of spectacle
independence by improving the quality of focus at near. This desired
effect may be accompanied by undesired consequences if the annulus
is decentered, if the entrance pupil of the eye is unusually small, or if
it is larger than the outside diameter of the annulus.
Commercial Relationships: Thomas W. Raasch, None
An Evaluation Of Vitreoretinal Surgery Through A Hydrophobic
Small Aperture Intraocular Lens In New Zealand Black Rabbit
Eyes
Gregory Empey1, Baruch Kuppermann2, Simon R. Bababeygy2,
Arlene Gwon2. 1AcuFocus, Irvine, CA; 2UCI, Irvine, CA.
Purpose: To evaluate the ease of performing vitreoretinal surgery in
eyes implanted with a hydrophobic small aperture intraocular lens
(IC-8 IOL, AcuFocus, Irvine).
Methods: Single-center, prospective, animal study. Six female New
Zealand black rabbits underwent crystalline lens extraction and IC-8
IOL implantation in one eye. In the opposite eye of three rabbits,
a control monofocal IOL (BioTech Vision Care) was implanted.
In the opposite eye of the remaining 3 rabbits, a Tecnis Multifocal
IOL (ZMB00, Abbott, Santa Ana, CA) was implanted. Two weeks
post-op, the following vitreoretinal procedures were performed:
anterior and posterior vitrectomy, air-fluid exchange, diathermy,
simulated epi-retinal membrane peel, simulated endo-retinal
laser photocoagulation, and binocular indirect ophthalmoscopic
visualization and indirect laser photocoagulation of the retrina.
Dilated pupil size varied between 5.0 to 9.5 mm. Procedural ease was
rated based on four primary measures of visualization: optical quality,
stereopsis, depth perception, and contrast sensitivity. Each measure
was rated on a scale of 0 to 4 (4=excellent). Slit-lamp examination
was performed to assess ocular status.
Results: All procedures and analysis were possible to perform with
minor adjustments to technique for the IC-8 IOL eyes. The overall
score for ease of performing vitreoretinal procedures in the IC-8 IOL
eyes was 3.4 (range 3.0-4.0). Mean scores for ease of performing
a vitrectomy procedure was 3.67 (range 3.5-4.0). Mean scores for
ease of performing diathermy and simulated epi-membrane peel
procedures were both 3.33 (range 3.0-3.5). The ease of performing
air-fluid exchange and indirect ophthalmoscopy were rated 3.2 and
3.0 (range 3.0-3.5) respectively. . For the monofocal and multifocal
IOL eyes, all scores were 4.0 for all measures. Slit-lamp examination
revealed no abnormal findings for any eye involved in this study.
Conclusions: Vitreoretinal surgery in eyes implanted with a small
aperture IOL can be performed with relative (?)ease and good
visibility of all retinal structures. Some minor modifications to
technique may be required.
Commercial Relationships: Gregory Empey, AcuFocus (E);
Baruch Kuppermann, None; Simon R. Bababeygy, None; Arlene
Gwon, None
Refractive outcomes following pars plana vitrectomy/pars
plana lensectomy (PPV/PPL) for retained lens fragments due to
complicated cataract surgery
Rachel Song, Steven Ness. Boston Medical Center, Boston, MA.
Purpose: To study differences in refractive outcomes following PPV/
PPL for retained lens fragments due to complicated cataract surgery
based on timing as well as type of intraocular lens (IOL) placed.
Methods: A retrospective chart review of 16 eyes was performed. All
subjects had at least 6 months of post-surgical follow-up. Predicted
refractive outcome (based on preoperative ophthalmic biometry)
was compared to the spherical equivalent (SE) of actual postoperative refractive outcome. Actual refractive outcome was based
on manifest refraction in subjects with vision better than 20/200 and
on autorefraction in subjects with vision 20/200 or worse. Variables
studied included the type of IOL placed as well as the timing of lens
placement (either at the time of initial cataract surgery or at the time
of PPV.)
Results: Sixteen eyes were included. 7 of 16 eyes (44%) had an IOL
placed during cataract extraction (CE), of which 4 of 7 (57%) had a
sulcus intraocular lens (SIOL). Thirty three percent (3 of 9) eyes with
IOL placement during PPV/PPL received SIOL.
In eyes implanted with an IOL at the time of CE, average actual
refractive error was 0.21D more myopic than predicted, as compared
to 0.74D more myopic in those eyes implanted with an IOL at the
time of PPV/PPL. Among eyes with lens placement at the time of
PE, SIOL placement resulted in an average SE difference of -0.64D,
while ACIOL placement had an average SE difference of +0.36D.
Among eyes with IOL placement at the time of PPV/PPL, SIOL
placement resulted in average SE difference of -0.72D, as compared
to -0.74D for ACIOL placement.
Conclusions: While this study is limited by a small sample size,
initial data indicates that IOL placement at the time of PPV/
PPL in cases of retained lens fragment may result in a more
myopic postoperative refractive error than expected, and that
ACIOL placement at the time of CE may result in an undesirable
postoperative hyperopic refraction. Surgeons should consider this
data when considering strength of lens to implant.
Commercial Relationships: Rachel Song, None; Steven Ness,
None
Passive Adaptive Contact Lens for Correction of Presbyopia
Guoqiang Li1, Thomas F. Mauger2. 1Depts of Ophthal and Vis Sci and
ECE, Ohio State University, Columbus, OH; 2Ophthalmology and
Visual Science, The Ohio State University, Columbus, OH.
Purpose: With aging, the crystalline lens of the human eye loses its
ability in accommodation, a natural phenomenon called presbyopia.
About 42% of American adults are presbyopic, and the number of
cases will keep increasing. To care for the vision of such a large
population is of great value. Various nonsurgical (spectacles and
contact lenses) and surgical techniques have been used. For spectacle
and contact lens correction, it is either based on area division which
limits field of view or monovision which loses stereopsis. The best
solution should allow natural binocular vision. It would be attractive
to develop passive adaptive lenses which generate invariant point
spread function across an extended depth of field for correction of
presbyopia. Here we show that, by engineering the phase profile
of the contact lens using special functions, we are able to correct
presbyopia with 20/20 to 20/25 visual acuity for near (40 cm),
intermediate (70 cm), and distance (4m) vision while maintain natural
binocular vision.
Methods: We started the design of the phase function with the
Gullstrand model eye in which the object is clearly imaged on the
retina without accommodation. We then simulate the effect of passive
adaptive wavefront-coding on extension of depth of field for nearand intermediate-vision. In contrast to the binary phase function, for
the first time to our knowledge, we are investigating other symmetric
and nonsymmetric phase functions for contact lens design. The
wavefront coding is optimized by considering the consistency of the
modulation transfer function for different object distances, different
fields at each object distance, and at different wavelengths.
Results: As an example, we have demonstrated the efficacy of
the passive adaptive contact lens for correction of presbyopia by
optimizing the lens profile using the cubic phase function. For the
emmetropic eye with presbyopia (3 mm pupil), the image for near
vision is greatly blurred. In contrast, using the passive adaptive
wavefront coding technique, all the images through the large depth of
field are almost the same, verifying the capability of offering 20/20
vision for all the vision tasks.
Conclusions: The passive adaptive contact lens can provide 20/20
to 20/25 visual acuity for all the vision tasks to the prebyopic eyes.
This new technique may have the potential to revolutionize the field
of vision care.
Commercial Relationships: Guoqiang Li, The Ohio State
University (P); Thomas F. Mauger, The Ohio State University (P)
Support: NIH NEI R01 EY020641
Comparative Assessment of Visual Performance of Multifocal
Soft Contact Lenses vs. Monovision
Cecile A. Maissa1, Robert Montés-Micó2, Cari Pérez-Vives2, Teresa
Ferrer-Blasco2, David Kramer1. 1Alcon Laboratories, Fort Worth,
TX; 2Dept. Óptica. Facultad de Física, Universidad de Valencia,
Valencia, Spain.
Purpose: The purpose of this study was to evaluate the visual
performance of DAILIES® Aqua Comfort Plus® (DACP) Multifocal
contact lenses compared with monovision correction in a population
of established presbyopes.
Methods: Soft contact lens wearers presenting with normal
corrected vision and established presbyopia (near add ≥+1.50)
were randomized into a five (±1) days cross over investigation
comparing DACP Multifocal (MF) contact lenses with DACP fitted
as monovision (MV). Binocular visual performance was measured in
terms of areas of focus for the distance, intermediate and near regions
calculated from the defocus curves, stereopsis and contrast sensitivity.
To generate defocus curves, binocular visual acuity was measured
with the Early Treatment Diabetic Retinopathy Study (ETDRS)
high-contrast logMAR chart under photopic conditions (85 cd/m2).
Binocular distance contrast sensitivity (CS) was measured using the
VCTS test (Vistech Consultants Inc) at five spatial frequencies (1.5,
3, 6, 12 and 18cpd). Stereoacuity was determined with the Howard–
Dolman system at a distance of 40 cm. Subjective ratings were
recorded on a 10 point scale with extreme anchors (1= poor to 10 =
excellent) for the subjects’ vision quality at distance, intermediate,
near as well as during computer use or while driving, at night.
Results: In this population of established presbyopes, using defocus
curves, the area of focus in the intermediate and near vision range
with DACP Multifocal was shown to be significantly larger than
with monovision (p=0.007 & p<0.0001). This was associated with
a wider range of vision with the multifocal correction. Furthermore,
DACP Multifocal was also shown to provide a significantly better
stereoacuity than monovision (MV: 84.25(12.96) v DACP MF:
27.17(5.75) sec arc p<0.0001). Subjective evaluations were in favor
of the DACP MF correction for all items by at least 1 point on
average.
Conclusions: The area-of-focus metrics used in this study were
able to differentiate between multifocal and monovision corrections.
DACP Multifocal contact lenses provided better stereoacuity
and greater area-of-focus in the intermediate and near zones than
monovision. The higher subjective perception associated with the
multifocal correction is likely to be due to the lower binocular
disruption observed, providing a better real-world visual function.
Commercial Relationships: Cecile A. Maissa, Alcon Research Ltd
(E); Robert Montés-Micó, Alcon (C), Alcon Research Ltd (F); Cari
Pérez-Vives, Alcon (F); Teresa Ferrer-Blasco, Alcon (F); David
Kramer, Alcon (E)
Support: The study was funded by Alcon Research Ltd
Application of Clinically Developed Eye and Vision Models to
Presbyopic Contact Lens Design Optimization
C. Benjamin Wooley, Tom Karkkainen. Johnson & Johnson Vision
Care, Inc, Jacksonville, FL.
Purpose: Vision for a contact lens patient is impacted by the
geometric and material properties of the contact lens, the physical
properties of the eye and the neural/brain system that interprets the
images on the retina. Improved vision requires a contact lens design
that is optimized by taking advantage of the properties of the eye and
brain components of the visual system. The purpose was to create,
from clinically measured data, eye and vision models that capture the
natural properties of the visual system suitable for optimization of a
presbyopic contact lens system.
Methods: A system of lenses for presbyopia generally consists of
a family of lenses designated for progressively higher add needs
(i.e. LOW, MID, and HIGH add lenses) along with a fit guide that
recommends how to select lenses. The lenses are often fit as disparate
pairs to provide the best binocular vision over the range of visual
conditions encountered. Therefore, design optimization requires a
Binocular Vision Model (BV) that can predict the quality of vision
for patients over a wide range of viewing distances and luminance
levels. Vision is optimized by minimizing the equation shown nearby
by changing the geometry of the contact lenses and the fit guide to
best match the target binocular vision (TargetBV) over a wide range
of luminance levels, viewing distance, patient ages, and patient
sphere prescriptions.
The Binocular Vision Model allows prediction of the quality of
vision by correlating properties of a Retinal Image Model with
clinical visual response. The Retinal Image Model depends upon
the properties of the eye (Eye Model), properties of the contact lens
(Contact Lens Model), and the properties of the tear film (Tear Film
Model). Each of these models is developed from a combination
of J&J Vision Care data, literature data, design data, and in-vitro
measurements.
Results: A contact lens design optimization method was developed
which incorporates a Binocular Vision Model developed from a
meta-analysis of data from multiple sources. This model-based design
optimization approach was used for vision optimization of a new
contact lens product.
Conclusions: Optical designs for presbyopic contact lenses
developed using the latest physiological and perceptual models
provide for potentially improved vision across the full range of
viewing conditions and patients.
Function to be Minimized
Commercial Relationships: C. Benjamin Wooley, Johnson &
Johnson Vision Care, Inc (E), Johnson & Johnson Vision Care, Inc
(P), Johnson & Johnson, Inc (I); Tom Karkkainen, Johnson and
Johnson Vision Care, Inc. (E), Johnson and Johnson Vision Care, Inc.
(P), Johnson and Johnson, Inc (I)
338 Exploring the distribution and expression of L-, M- and
S-cone photoreceptors - Minisymposium
Tuesday, May 05, 2015 11:00 AM–12:45 PM
702/704/706 Minisymposium
Contributing Section(s): Biochemistry/Molecular Biology
S- and M-cone opsin expression and distribution in the mouse
retina
Edward Pugh. Physiology & Membrane Biology, School of
Medicine, UC Davis, Davis, CA.
Presentation Description: Mice, like most mammals, express two
cone opsins, S-opsin (λmax = 360 nm) and M-opsin (510 nm), which
are members of opsin subfamilies (SW1, MW) that diverged by
the late Cambrian (500 Mya) and which are homologous to human
S-opsin (425 nm) and M/W-opsins (~530 nm, ~555 nm). Mouse cone
opsins, like those of many mammals, are expressed in dorso-ventral
gradients, with M-opsin much more prevalent in the dorsal retina,
and S-opsin in the ventral retina. M-opsin expression is controlled
by thryroid hormone (T3), its Trβ2 nuclear receptors and type 3
diodinase. Electroretinography (ERG) and single-cone recordings
reveal that most mouse cones co-express S- and M-opsin in a
dorso-ventral gradient, though a few cones in the extreme dorsal and
ventral retina may express null or functionally negligible amounts
of the non-dominant opsin. Mice with S- or M-opsin knocked out
express higher levels of the remaining opsin, revealing a normal
competition between the mRNAs of S- and M-opsin for access to
polyribosomes during translation. Work by Crouch, Rohrer, Baehr
and others on mouse models of Leber disease has shown that in the
absence of the RPE supply of 11-cis retinal, cone opsins mistraffic,
so that normal outer segments are not formed and opsin accumulates
in non-outer segment compartments. Recent work by Fu and
colleagues has revealed that in the absence of the RPE supply of
11-cis retinal S-opsin is especially susceptible to aggregation and is
poorly degraded, and that knocking out S-opsin serves to increase
the viability of cones in mouse models of Leber disease, revealing a
downside to co-expression. The work on Leber disease models and
other recent evidence suggests that during normal biosynthesis in the
ER correct folding of cone opsins is abetted by 11-cis retinal, while
in the absence of 11-cis retinal misfolded opsins tend to aggregate
(S-opsin), and/or overwhelm ER-associated degradation leading to
failure to traffick correctly through the Golgi and on to the outer
segment.
Commercial Relationships: Edward Pugh, None
Support: NIH Grant EY02660
Two-photon functional imaging of the photoreceptor mosaic
David R. Williams. University of Rochester, Rochester, NY.
Presentation Description: This talk will review the topography
of the primate photoreceptor mosaic followed by a description of
how two-photon imaging can be used to characterize the structure
and function of the photoreceptor mosaic in novel ways. Retinal
densitometry of single photoreceptors in the living primate eye has
provided valuable information about the topography of the cone
mosaic based on the selective bleaching of different cone classes with
different wavelengths of illumination. In this talk, I will show how
high-resolution two-photon fluorescence applied to the living monkey
eye provides a new way to reveal cone topography. It allows the in
vivo monitoring of a stage or stages in the retinoid cycle following
the bleaching of photopigment. Exposure of the retina to femtosecond
infrared illumination produces fluorescence, the intensity of which
depends on the production of a molecule, possibly retinol, that
increases with the fraction of photopigment bleached. Selective
bleaching of L and M cones causes their fluorescence to increase,
revealing the S cones as a mosaic of relatively dark cones in twophoton images.
Commercial Relationships: David R. Williams, Canon, Inc. (F),
Canon, Inc. (R), Polgenix, Inc. (F), University of Rochester (P), US
patent #6,199,986 (P), US patent #8,226,236 (P)
Support: Polgenix, Inc., NIH Grants P30-EY001319, R01EY004367, BRP-EY014375, T32-EY007125, R01-EY009339, R24EY021126, R43-EY020715
Explanatory power and predictions of a labeled line theory of
color perception
Jay Neitz. University of Washington, Seattle, WA.
Presentation Description: Helmholtz was instrumental in
developing and promoting trichromatic theory. He was also a
proponent of the idea of labeled-lines in which stimulation of each
type of color sensor was associated with a specific hue sensation.
Currently, Helmholtz’s idea has been replaced with the notion that
color vison is based on small-bistratified and midget ganglion cells
which perform second-stage processing of outputs from the three
cone types. Nonetheless, many vision scientists have assumed a
fundamentally labeled-line model with sensations of blue mediated
by S-ON small bistratified ganglion cells and sensations of red and
green mediated by red-ON and green-ON midget ganglion cells
respectively. There were indications at the time of discovery of coloropponent neurons in the early visual pathway—and it has become
increasingly clear—that predictions from the physiological properties
of the small bistratified and midget ganglion cells do not match
human hue perception and our color vision cannot be explained
by the activity of these cells. Attempts to reconcile the notion that
S-(L+M) and L vs. M ganglion cells serve color perception with
the fact that they do not have the required physiological properties
have led to suggestions that outputs of these cells are somehow
recombined in cortex to produce the appropriate color responses.
However, these proposals are vague, producing more questions than
answers and the physiological basis of color perception remains
a major unsolved problem in vision science. New experimental
evidence from the disciplines of genetics, anatomy, physiology and
psychophysics indicates that the solution to the problem is twofold.
1) Neither of the ganglion cell types of the standard model are the
basis for hue perception—they have other functions in vision. 2)
A small subset of midget ganglion cells that have been previously
unappreciated form the basis for labeled lines serving sensations or
red, green, blue and yellow. The activity of these cells explains many
aspects of our vision that were previously mysterious and accurately
predicts how genes and environment influence hue perception.
Commercial Relationships: Jay Neitz, None
Support: NIH Grants EY09303, EY016861
Learning the mosaic: Unsupervised typing of L and M cones
from natural image input
David H. Brainard. University of Pennsylvania, Philadelphia, PA.
Presentation Description: The trichromatic color vision of primates
differs from that of its dichromatic ancestors because the cones in the
primate retina can express an additional longer-wavelength-sensitive
cone photopigment. Thus in primates there are both L- and M-cones,
as well as an S cone. Interestingly, the only known difference
between primate L- and M-cones is the photopigment they contain;
there is no known biochemical marker that allows the post-receptoral
visual system to tell whether any particular cone is an L-cone or an
M-cone. For color vision to be possible, however, the post-receptoral
visual system must process the signals from these two types of
cones so as to preserve the separate spectral information carried by
each, and it must do so in a manner that preserves this information
in a fashion that is consistent in ‘sign’ across the retina and across
the two eyes. In the absence of a biochemical marker, how can
the post-receptoral visual system learn to do so? In addition, these
observations raise the question of how a post-receptoral visual system
that evolved in the context of inputs from a dichromatic retina detects
the presence of a newly expressed third cone type in the first place. In
this talk I will present recent work (Benson, Manning, and Brainard,
2014, PLoS Computational Biology) that approaches these questions
from a computational viewpoint. We asked whether there is sufficient
information in the initial encoding provided by the trichromatic retina
in response to natural image input to accomplish two goals: a) to
identify the number of spectral cone types present in the retina and
b) to allow identification of the spectral type of each cone. We show
that the answer is yes by demonstrating an unsupervised learning
algorithm that successfully accomplishes both goals. We used
simulations to explore the range of mosaic parameters (L:M cone
ratio, separation in lambda-max between L- and M-cones) over which
learning is possible and show these to be generally consistent with
observed variation in these parameters across trichromatic primates.
We also show that it is possible to detect the presence of a fourth
retinal cone type and obtain above-chance typing of the cones in a
simulated primate tetrachromatic cone mosaic, if mosaic parameters
are chosen to optimize the conditions for such learning.
Commercial Relationships: David H. Brainard, None
Support: Commonwealth Universal Research Enhancement (CURE)
program from the Pennsylvania Department of Health and NIH R01
EY10016.
371 Anterior segment optics and visual performance
Tuesday, May 05, 2015 3:45 PM–5:30 PM
OCT-based crystalline lens topography in accommodating eyes
Pablo Perez-Merino, Miriam Velasco-Ocana, Eduardo MartinezEnriquez, Susana Marcos. Instituto de Óptica (CSIC), Madrid, Spain.
Purpose: To measure anterior and posterior crystalline lens
topography in accommodating eyes. To evaluate the relationship
between anterior and posterior lens surface shape, cornea and lens
shape, and their changes with accommodation.
Methods: Custom spectral-domain optical coherence tomography
(SD-OCT) provided with automatic quantification and distortion
correction algorithms was used to characterize three-dimensionally
and in vivo the human crystalline lens in 4 subjects (7 eyes; 31±3
y.o), for accommodative demands between 0 to 6 D, in 1.5 D steps.
Anterior segment (cornea and lens) surfaces were fitted to 6th order
Zernike polynomials to quantify geometry and biometry (anterior
chamber depth (ACD), lens thickness, and corneal and lens radii).
Corneal and lens surface elevations were analyzed by means of
RMS (high order aberrations (HOAs), astigmatism, coma, trefoil and
spherical).
Results: Anterior and posterior radii of curvature decreased at rates
of 0.61±0.15 and 0.15±0.06 mm/D, ACD decreased 0.04±0.01 mm/D
and lens thickness increased 0.05±0.01 mm/D with accommodation
demand. Astigmatism was the predominant lens surface aberration
(69%-anterior; 56%-posterior). The RMS of HOAs of the posterior
lens surface was statistically significant higher than the anterior
surface (x2.92; p<0.05). The dominant HOAs of the posterior
lens surface were Z33, Z40 and Z42 (accounting for 12%, 14% and
16% of the variance). Astigmatism, coma and trefoil changed with
accommodation by a factor of x1.1, x1.3 and x1.4 respectively in
both lens surfaces. Spherical aberration showed higher changes with
accommodation in the anterior lens surface (x2.5 vs x1.15). The
astigmatic angle showed high degree of alignment among corneal and
anterior lens surfaces (<13 deg). However, the angle between anterior
and posterior lens astigmatism differed by 26 deg. In general, there
was slight correlation but not significant between HOAs terms of
the anterior and posterior lens surfaces (r=0.38, un-accommodated;
r=0.52, 6D accommodation).
Fig. 1. 3D full anterior segment image and lens surface elevation
maps for S#1(OS).
Conclusions: OCT provided with distortion correction is an excellent
instrument for evaluating the crystalline lens changes in shape and
surface produced by accommodation and for exploring the role of
the crystalline lens in the eye’s optics. The increased high order
aberrations of the posterior lens surface might be associated to the
zonular tension.
Commercial Relationships: Pablo Perez-Merino, None; Miriam
Velasco-Ocana, None; Eduardo Martinez-Enriquez, None; Susana
Marcos, PCT/ES2012/070185 (P)
Astigmatism of the isolated human crystalline lens: Surface shape
and gradient refractive index contributions
Judith Birkenfeld, Alberto De Castro, Susana Marcos. CSIC-Instituto
de Optica, Madrid, Spain.
Purpose: To estimate the contribution of lens surface shape and lens
gradient refractive index (GRIN) to the lens astigmatism in human
donor lenses as a function of age.
Methods: Thirty-five human donor lenses (age 19-71) were imaged
with quantitative custom-developed 3D-spectral optical coherence
tomography (840 nm SLD illumination; 12 mm x 12 mm lateral
scan, 1668 A-scans x 60 B scans, 6.9 um axial resolution). Laser Ray
Tracing was used to measure the lenses’ back focal length (BFL,
paraxial and non-paraxial). 3-D lens GRIN (described by a 4-variable
model) was reconstructed with an optimization genetic algorithm
using OCT optical path differences in 2 lens orientations, using 3-D
lens shape, and BFL as input data. Lens surface astigmatism was
obtained from ellipsoid fitting to the lens surfaces. Lens astigmatism
was estimated by computational ray tracing on the lens, assuming
either the reconstructed GRIN lens or an equivalent homogenous
Refractive index (EHRIN) lens. Astigmatism magnitude and
relative astigmatic angle between lens surfaces, GRIN lens and
lens astigmatism were evaluated using power vector notation, and
analyzed as a function of age.
Results: The astigmatism magnitude in the anterior lens surface
decreased with age (slope= -0.005 D/year; r= 0.397, p=0.018),
although the posterior surface astigmatism and the (total) lens
astigmatism were not age-dependent. Presence of GRIN altered
slightly the magnitude (average GRIN-EHRIN magnitude difference:
0.53 D) and the axis of the lens astigmatism (Average GRIN-EHRIN
axis difference: 22.17 deg). The total astigmatism of the GRIN
lens and the EHRIN lens correlated to the anterior lens surface
astigmatism (GRIN: p=3.9E-6 r=0.693; EHRIN: p=4.1E-4, r=0.565).
The average relative angle between anterior and posterior surface was
34.08 deg, and had no significant age dependency (r= 0.172, p= 0.32,
slope: -0.293).
Conclusions: The anterior lens surface astigmatism undergoes
changes with age, and has the largest impact on the total lens
astigmatism . The GRIN index plays only a minor role in lens
astigmatism magnitude and axis. Knowledge of the sources of
astigmatism in the lens gives insights in the understanding the
optical interactions between ocular components, with impact in the
understanding of presbyopia, myopia development and design of new
IOLs.
Commercial Relationships: Judith Birkenfeld, None; Alberto De
Castro, None; Susana Marcos, PCT/ES2012/070185 (P)
Support: I-LINK0609, JAE-Predoc 2010, FIS2011-25637, ERC2011-AdG-294099
Finite Element Analysis of Oxidative Stress-Induced Changes in
the Mechanical Properties of the Lens
Matthew A. Reilly. Biomedical Engineering, University of Texas at
San Antonio, San Antonio, TX.
Purpose: Age-related changes in lens mechanical properties have
been implicated in the pathogenesis of presbyopia. Damage due to
oxidative stress has been implicated in the pathogenesis of agerelated nuclear cataract. The present study simulates the accumulation
of oxidative damage to the lens with age and how this may result in
age-related stiffening of the lens.
Methods: A mechanochemical finite element model of the human
lens was constructed to simulate the effects of lens transport and
biochemical reactions within the lens. Transport and regeneration of
glutathione were simulated modeled. Denaturation and crosslinking
of crystallins were also modeled. A constitutive model was developed
relating crosslink density to elastic modulus. The model was used to
simulate the effects of 60 years of aging on the lens’ modulus.
Results: The modulus at the center of the lens increased slowly until
age 35 after which it increased rapidly (Fig. 1). The modulus near the
surface remained relatively constant throughout life.
Conclusions: The predictions of this model are in qualitative
agreement with the elastic modulus distribution data of Wilde et
al. (Exp. Eye Res. 97:36-48, 2012), suggesting that the change in
lens properties could be due to oxidative crosslinking. The slow
change in modulus with age in the young lens’ nucleus may be due
to the relative abundance of native crystallins which are protected
from crosslinking. The accumulation of denatured crystallins with
age gives rise to an age-related exponential increase in the elastic
modulus within the nucleus. Adding additional antioxidants (e.g.
ascorbate) and steps to the crystalline denaturation pathway to the
model further delays the onset of rapid lens stiffening in the model.
Each of these effectively buffer against oxidative stress, thereby
shifting the elbow in the curve further to the right on the aging axis.
Age-related changes in the elastic modulus at the center of the lens
due to oxidative stress-induced disulfide bridging.
Commercial Relationships: Matthew A. Reilly, None
MECHANISM OF ACCOMMODATION: NEW FINDINGS
AND THE IMPLICATIONS FOR PRESBYOPIA
Mary Ann Croft1, T Michael Nork1, Jared McDonald1, Gregg
A. Heatley1, Alexander Katz1, Paul L. Kaufman1, Elke LuetjenDrecoll2. 1Ophthalmology, Univ of Wisconsin-Madison, Madison,
WI; 2Anatomy, Institute of Anatomy II, University of Erlangen–
Nuremberg, Erlangen, Germany.
Purpose: To better understand the accommodative mechanism and
presbyopia.
Methods: In 10 rhesus monkeys (ages 8-22 yrs), maximum
accommodative responses were induced by electrical stimulation
of the E-W nucleus. Ultrasound biomicroscopy (UBM; 50 MHz, 35
MHz) images were collected in the region of lens, ciliary muscle
(CM), and zonular attachments during the accommodative response.
Images were collected before & after lens extraction. Various
contrast agents (i.e., triamcinolone, fluorescent microspheres) were
used to enhance visualization of the intraocular structures and fluid
movements during accommodation.
Results: PVZ INS-LE structure (which is attached directly to
the posterior lens equator and to the posterior insertion zone of
the vitreous zonule) remained straight during the accommodative
response (i.e., it did not relax). The anterior end of the PVZ INSLE moved forward during accommodation in the presence or
absence of the lens/capsule, pulled/pushed forward by the CM.
Intravitreal lacunae could be visualized and the mid-vitreous portion
of the lacunae moved posteriorly during accommodation while the
peripheral edge of the lacunae adjacent to and interconnected with
the vitreous zonule were pulled forward. During accommodation
there was fluid flow from the anterior chamber toward the cleft of
the anterior hyaloid membrane and then further posteriorly into the
cleft between the vitreous zonule and the pars plana. The reverse was
true during disaccommodation. These movements declined with age.
There was an age-related accumulation of vitreous membranes/fibers
in the region of the vitreous zonule, the PVZ INS-LE and the ora
serrata.
Conclusions: In the young eye, the PVZ INS-LE may act as a “strut”
to the posterior lens equator, facilitating accommodative forward
movement of the lens equator and thereby facilitating lens thickening.
The accommodative posterior/anterior segment fluid flow/exchange
represents fluid displacement in response to the lens thickening and
CM contraction, and the fluid exchange may allow for the elimination
of waste particles/material from the vitreous by transfer to the
anterior chamber and then out through the trabecular meshwork. With
age, the aggregation of vitreous fibers peripherally may contribute to
the posterior restriction of the CM, the vitreous zonule, and the PVZINS LE and thereby dampen the accommodative lens shape change
and fluid dynamics.
Commercial Relationships: Mary Ann Croft, Alcon (F), Bridge
Labs (R), Refocus Group (C), Z-lens LLC (F); T Michael Nork,
None; Jared McDonald, None; Gregg A. Heatley, None; Alexander
Katz, None; Paul L. Kaufman, Alcon (F), Lens AR (F), Refocus
Group (C), Refocus Group (R), Z-Lens LLC (F); Elke LuetjenDrecoll, None
Support: NIH Grant Support: NEI (RO1 EY10213 & R21
EY018370 to PLK, Core Grant for Vision Research Grant # P30
EY016665), RPB, NIH Grant # 5P51 RR 000167 to WNPRC,
OPREF.
Improved phase processing following long-term adaptation to
optical aberrations in keratoconus
Antoine Barbot1, 2, Ramkumar Sabesan3, Len Zheleznyak1, 2, Krystel
R. Huxlin1, 2, Duje Tadin2, 4, Geunyoung Yoon1, 2. 1Flaum Eye Institute,
University of Rochester, Rochester, NY; 2Center for Visual Science,
University of Rochester, Rochester, NY; 3School of Optometry,
University of California, Berkeley, Berkeley, CA; 4Brain and
Cognitive Sciences, University of Rochester, Rochester, NY.
Purpose: Optical aberrations detrimentally affect both the amplitude
and phase relationships between spatial frequencies (SFs) of visual
inputs. In addition, long–term presence of optical aberrations
progressively alters the way visual information is processed. Here,
we investigate the basic neural substrates of altered visual processing
resulting from prolonged, chronic exposure to optically degraded
retinal image quality by using keratoconus (KC) as a model of longterm adaptation to visual aberrations.
Methods: An adaptive optics (AO) vision simulator was first used to
measure KC patients’ habitual aberrations with their own corrective,
conventional lenses. We then used these measurements to simulate
KC optical quality in normal eyes using AO after correcting their
native aberrations. Under this identical optically-aberrated condition,
we measured tumbling E visual acuity (VA) and contrast sensitivity
function (CSF) for KC eyes (n=4) with their habitual aberrations and
normal eyes (n=3) with AO-induced KC aberrations, over a 6-mm
artificial pupil in white light. Each control subject was tested in both
experiments under each KC aberration profile.
Results: Under identical, optically-aberrated conditions (average
total and higher order RMS errors in KC eyes: 2.72±0.83μm and
1.36±0.29μm, respectively; residual RMS wavefront error of induced
KC aberrations in normal eyes: ~0.1μm), we found that the CSF
(single SF Gabor stimuli) did not differ between KC and normal eyes.
However, KC eyes showed better letter acuity (broadband SF stimuli)
than normal eyes under the same conditions. Specifically, neural
compensation in KC eyes accounted for ~1.2 line improvement in VA
relative to normal eyes and was stronger for advanced KC conditions
(~3 lines improvement for more severe cases). This difference in
visual performance with broadband SF stimuli indicates that phase
information plays an important role in long-term adaptation to visual
aberrations.
Conclusions: Our results suggest the existence of an adaptive neural
compensation mechanism in KC subjects that partially restores the
phase congruency across SFs, thus benefiting the processing of
optically degraded visual inputs. Altogether, our findings provide
fundamental insights into the mechanisms underlying long-term
neural adaptation to optical aberrations.
Commercial Relationships: Antoine Barbot, None; Ramkumar
Sabesan, None; Len Zheleznyak, None; Krystel R. Huxlin, None;
Duje Tadin, None; Geunyoung Yoon, None
Visual acuity evaluation with refractions prescribed by a novel
low-cost wavefront aberrometer
Eduardo Lage1, 2, Elena Garcia3, Shivang Dave2, 1, Maria C.
Ramirez3, Lara M Garcia3, Nicolás Alejandre Alba3, Daryl Lim2, 1,
Carlos Dorronsoro4, Susana Marcos4, Nicholas Durr2, 1. 1M+Vision
Consortium, MIT, Cambridge, MA; 2Plenoptika Inc., Allston, MA;
3
Department of Ophthalmology, Fundacion Jimenez Diaz, Madrid,
Spain; 4Instituto de Optica, CSIC, Madrid, Spain.
Purpose: To compare the visual acuity (VA) resulting from
eyeglasses prescribed by a novel autorefractor and by subjective
refraction.
Methods: A total of 81 eyes from 42 patients (mean age 38 ± 13yrs,
ametropia range -6.25 to +4.5D spherical equivalent power (SE))
were refracted and their VA tested in a clinical setting (Fundacion
Jimenez Diaz, Madrid). Refractions were obtained following a
standard non-cycloplegic subjective method and with a second
generation autorefractor prototype which is handheld, open-view
and binocular. This device is based on a simplified approach to
wavefront sensing that does not use a Badal relay lens system. The
autorefractor is composed of inexpensive off-the-shelf parts including
a 1.3-MP CMOS sensor, a 19-mm focal length lenslet array and an
850-nm laser diode. The subjects hold and look through the device
while a dynamic sequence of wavefront images is acquired. This
dataset is processed using a custom-developed algorithm that tracks
patient-device alignment and accommodation to generate a set of
measurements from which the prescription is calculated. Three 10-s
videos were recorded for each eye and the results of the two last
measurements were averaged to calculate the refraction. VA was
measured for prescriptions provided by each method and differences
between refraction measurements and VA achieved in each case were
evaluated.
Results: The average difference between SE measured subjectively
and with the prototype was 0.32 ± 0.35D. Refractions obtained from
either method were not statistically different (p= 0.96, paired t-test)
with a 95% confidence interval of ± 1.0D. The spherical power
measured subjectively and with the prototype agreed within 0.25D
and 0.5D in 60.5% and 79.0% of the eyes, respectively, while the
cylindrical power agreed in 84.0% and 96.4% of the cases for the
same thresholds. The average VA achieved with the device and by
subjective prescriptions was of 0.000 ± 0.067 and -0.012 ± 0.035
logMar, respectively. Using the prototype refraction, 81.5% of the
eyes achieved VA ≥ 20/20 and 98.7% ≥ 20/25.
Conclusions: The new prototype provided accurate measurements
of refractive errors in a community optometry clinic. Average
discrepancies between VA achieved with the device and subjective
refraction were smaller than 0.02 logMar (one letter). A low-cost
device, such as the one evaluated here, may be beneficial for
improving eye care in low-resource settings.
Commercial Relationships: Eduardo Lage, MIT (P), Plenoptika,
Inc. (S); Elena Garcia, None; Shivang Dave, MIT (P), Plenoptika,
Inc. (E); Maria C. Ramirez, None; Lara M Garcia, None; Nicolás
Alejandre Alba, None; Daryl Lim, MIT (P), Plenoptika, Inc. (S);
Carlos Dorronsoro, MIT (P); Susana Marcos, MIT (P); Nicholas
Durr, MIT (P), Plenoptika, Inc. (E)
Support: This work has been financially supported by the
Comunidad de Madrid through the Madrid-MIT M+Vision
Consortium.
CLINICAL VALIDATION OF CONTRAST SENSITIVITY
MEASURED BY VISUAL SIMULATION FOR
PSEUDOPHAKIC PATIENTS
Silvestre Manzanera1, Aixa Alarcon2, Carmen Canovas2, Pedro M.
Prieto1, Linda Tsai3, Kendra Hileman3, Patricia A. Piers2, Pablo
Artal1. 1Laboratorio de Optica, Universidad de Murcia, Murcia,
Spain; 2AMO, Groningen, Netherlands; 3AMO, Santa Ana, CA.
Purpose: Adaptive optics (AO) vision simulation predicts highcontrast binocular visual acuity following cataract surgery for
different IOL designs well (Schwarz, ARVO 2014). The purpose
of this study is to compare the clinical contrast sensitivity (CS)
measured in patients implanted with different IOL models to those
predicted by AO visual simulation for the phase profiles of the same
IOLs.
Methods: Phase profiles corresponding to five different IOLs (two
monofocal IOLs, one aspheric and one spherical, and three diffractive
multifocal IOLs) were generated bilaterally in a binocular AO visual
simulator. CS was measured in 5 subjects for a 4.5 mm pupil in white
light under mesopic conditions using the quick-CSF procedure. In all
cases, natural astigmatism and spherical aberration were corrected.
The measured CS was compared to the clinical outcomes measured
independently in two different clinical trials in pseudophakic
patients bilaterally implanted with the same IOL models. In these
clinical trials, mesopic CS was measured without glare at 1.5, 3, 6
and 12 c/deg with either a Vector Vision or an Optec 6500 chart.
Measurements were performed at 6 months postoperatively with best
distance correction in place, according to common clinical practice.
Results: CS measured in clinical studies was correlated with CS
measured in the AO instrument for the IOL models evaluated
(r^2=0.73). This correlation was higher for the lower and higher
spatial frequencies than for middle spatial frequencies. When
considering different IOL models independently, the correlation
between clinical and simulated CS decreased (r^2=0.49) for the
monofocal IOL design that corrects for spherical aberration, while the
remaining models provided correlated well (r^2>0.8 for all models).
Conclusions: AO visual simulation predicts clinical CS following
cataract surgery under binocular conditions for refractive and
diffractive IOL designs. The correlation was better for high and
low spatial frequencies and for multifocal and monofocal spherical
designs. These results validate the use of AO instruments as a tool for
developing new IOL optics and their impact on the quality of vision.
Commercial Relationships: Silvestre Manzanera, Abbott Medical
Optics (F); Aixa Alarcon, Abbott Medical Optics (E); Carmen
Canovas, Abbott Medical Optics (E); Pedro M. Prieto, Abbott
Medical Optics (F); Linda Tsai, Abbott Medical Optics (E); Kendra
Hileman, Abbott Medical Optics (E); Patricia A. Piers, Abbott
Medical Optics (E); Pablo Artal, Abbott Medical Optics (C), Abbott
Medical Optics (F)
Support: SEIDI, Spain (grant FIS2013-41237-R) & AMO
382 Psychophysics and vision testing: visual acuity, contrast
sensitivity, color vision and visual field
Tuesday, May 05, 2015 3:45 PM–5:30 PM
Contributing Section(s): Anatomy/Pathology, Clinical/
Epidemiologic Research
Slope of the psychometric function for low contrast logMAR
charts.
Andrew Carkeet1, 2, Ian L. Bailey3. 1Optometry and Vision Science,
QUT, Kelvin Grove, QLD, Australia; 2QUT, IHBI, Kelvin Grove,
QLD, Australia; 3School of Optometry, UC Berkeley, Berkeley, CA.
Purpose: Data from acuity charts can be analysed by fitting
psychometric functions. While psychometric functions are
traditionally used to yield acuity thresholds, the slopes of such
psychometric functions can be used to predict the variability of such
visual acuity thresholds. This repeated-measures research examined
whether high contrast and low contrast acuity charts yield different
slopes for their psychometric functions.
Methods: Ten participants, 6 female & 4 male, mean age 43 years
(SD 18 years), took part in this research. Participants were tested
with their preferred eye and wearing their best spectacle correction.
Stimuli were Sloan letters presented on an LCD computer monitor,
with 9 rows of letters arranged in randomized letter sequences with
a standard logMAR chart format. The background had a luminance
of 235 cd m-2 and the high and low contrasts were 99.2% and 18.7%
Weber contrast. Each participant read 32 charts, 16 at low contrast
and 16 at high contrast. For each chart, responses were analysed by
probit analysis to generate thresholds and slopes for the psychometric
functions.
Results: For our participants, the mean high and low contrast visual
acuity thresholds (logMAR) were -0.189 0.076 and -0.027 0.079
respectively. Probit sizes were used as a measure of the slopes of the
psychometric functions, with smaller probit sizes indicating steeper
slopes. Low contrast acuity charts yielded flatter psychometric
functions than high contrast acuity charts, indicating a more gradual
transition between seeing and non-seeing for the low contrast charts.
The difference was statistically significant (F1,9=12.8, p=0.006). The
estimates of slope differed slightly, according to whether a lower
asymptote of 0.1 (1 in 10 guess rate) or 0.0385 (1 in 26 guess rate)
was selected for probit fits. (F1,9=74.1, p<0.001). Probit sizes and
inter-subject standard deviations are shown in Table 1.
Conclusions: These results indicate that visual acuity measurements
are intrinsically more variable with low contrast charts. Previous
research has shown that low levels of optical blur also flatten the
psychometric function for visual acuity. Monte Carlo modelling
based on the probit values shows that stopping patients reading
down a low contrast acuity chart, after they’ve made three or more
mistakes on a 5-letter row, gives close to optimal precision of acuity
measurements.
Table 1. Mean probit sizes (logMAR) with inter subject standard
deviations.
Commercial Relationships: Andrew Carkeet, None; Ian L. Bailey,
None
Validation of the Dyop™ Visual Acuity Test
Paul A. Harris, Erin Keim. Southern College of Optometry,
Memphis, TN.
Purpose: Sloan and Snellen optotypes are the global eye chart
standard for visual acuity testing, but routinely patients struggle
with the required endpoint of response confusion. A new Dynamic
Optotype, or “Dyop”, using a dynamically sized, rotating, visual arcarea figure to measure acuity was prospectively, clinically compared
to Sloan measures of visual acuity under various test conditions.
The Dyop has a completely unique endpoint: the rotation animation
appears to suddenly stop when threshold is reached.
Methods: Acuity was assessed with 162 subjects each randomly
with the Dyop test (Konan Medical Chart2020) and Harris StairStep test (M&S Technologies) comparing each with the following
strategies: BCVA, UCVA, + Lens (+2, +3, +4) over spectacles. The
relationship between Sloan VA/20 and Dyop size in arc-minutes (both
log-transformed) was investigated using correlations and repeatedmeasures log-log regression models.
Results: There was a strong linear relationship between Sloan
and Dyop acuity measures (Pearson r=.94; p<001). In a single
predictor model, the Dyop measure explained 89% of the variance
in Sloan acuity. An interaction model relaxing the assumption of
common slopes by testing condition indicated a significant measure
X condition interaction (p=.004), and explained over 91% of the
variance in Sloan acuity. Optimal conversion algorithms between
Dyop and Sloan measures were developed via regression models.
Conclusions: The Dyop is a novel method of measuring visual acuity
that is strongly associated with, and may offer a viable alternative
to traditional visual acuity methods. Beyond high correlation with
standard methods, the Dyop was observed to be advantaged by
speed to threshold endpoint, finer acuity granularity compared to the
typically used acuity “line” steps, and ease of endpoint interpretation
by subjects.
Figure 1: Plot of the log of the Dyop size in arc minutes against the
log of the Sloan VA/20.
Rx Corrected = Dark Gray (x)
+2.00 blur = Orange (o)
+3.00 blur = Red (+)
+4.00 blur = Green (•)
to be presented avoiding the glare due to the glossy screen of the iPad
tablet.
Commercial Relationships: Jae-hyung Kim, None; Sang Yoon
Hyun, None; Ju Byung Chae, None; Soolienah Rhiu, None; Hye
Jin Lee, None
Figure 2: Scatter plots for each of the separate conditions.
Correlations were significant to the p <.001 level in all conditions.
Pearson correlations for each condition were: Rx Corrected r=.54, +2
blur r=.72, +3 blur r=.72, +4 blur r=.63, overall pooled r=.94.
Commercial Relationships: Paul A. Harris, None; Erin Keim,
None
A pilot trial for visual acuity testing using a random method
visual acuity application
Jae-hyung Kim1, Sang Yoon Hyun1, Ju Byung Chae1, Soolienah
Rhiu2, Hye Jin Lee3. 1Ophthalmology, Chungbuk National University
Hospital, Cheongju-si; 2Ophthalmology, Hallym University Dongtan
Sacred Heart Hospital, Hwaseong, Korea (the Republic of);
3
Ophthalmology, Jeju National University, Jeju, Korea (the Republic
of).
Purpose: A visual acuity (VA) testing app for the iPad tablet
computer using mirroring technique was developed which randomly
presented letters categorized by cognoscibility. The aim of this
study was to assess whether measurements of distance VA using this
application were in agreement with standard clinical tests of VA in
adults with normal vision.
Methods: Forty-three normally sighted subjects were tested using
Early Treatment of Diabetic Retinopathy Study (ETDRS) chart. The
logMAR VA results were compared with those from the iPad based
application which contains a Snellen chart, a Tumbling E chart, a
Landolt C chart and a VA chart consisted with Arabic figures. After
a 10-min break, subjects were retested with each test in the same
order. Repeatability was assessed by testing the subjects 1-day later
with each visual chart. Repeatability and agreement were assessed
by determining the 95% limits of agreement (LoA) ± 1.96 SD of the
differences between tests.
Results: The logMAR VA showed no significant difference between
the ETDRS chart and the iPad Snellen chart (P=0.66) and iPad
Arabic figure chart (P=0.29). The logMAR VA of the ETDRS chart
was significantly better than iPad Tumbling E chart (P<0.01) and
iPad Landolt C chart (P<0.01). The subjects showed no chart letter
memory of the ETDRS chart (P=0.05), iPad Snellen chart (P=0.62),
and iPad Arabic figure chart (P=0.12). The logMAR VA of Tumbling
E chart (P=0.03) and Landolt C chart (P=0.001) was significantly
better at 10 min.
Conclusions: The iPad-based application of VA charts showed
similar repeatability and may be a rapid and convenient alternative to
some existing measures. Mirroring technique allows the visual chart
A Comparative Clinical Evaluation of Two Visual Acuity Testing
Systems: ETDRS vs. FrACT
Linda Tsai, Eugenia Thomas, Janice Tarrant, Stan Bentow, Sanjeev
Kasthurirangan. Clinical R&D, Abbott Medical Optics, Santa Ana,
CA.
Purpose: Visual acuity (VA) results with physical Early Treatment
of Diabetic Retinopathy Study (ETDRS) letter charts are heavily
dependent upon the test administrator ability (i.e., better threshold VA
with persistent encouragement, accurate recording of correctly read
letters). In addition, the risk of subject memorization with physical
charts requires the administrator to change charts frequently. The
impact of such factors may be reduced with the use of a VA software
program that automates testing by allowing the test subject to view
randomized optotypes in a staircase size presentation and respond
with direct input to the software program, which then determines
threshold acuity. This clinical study evaluated results with both test
systems.
Methods: A total of 25 subjects were evaluated for distance-corrected
visual acuity at far, intermediate and near and distance defocus testing
from +2.00 diopters (D) to -4.00 D, in 0.5 D increments. Each subject
was tested monocularly with a retroilluminated ETDRS chart and a
computer-based vision testing software, the Freiburg Visual Acuity
and Contrast Test (FrACT). All results were obtained in logMAR
format, and analyses were conducted in paired comparisons between
the two testing systems.
Results: Across all test distances, visual acuity results with FrACT
were found to be within 0.05 logMAR of ETDRS chart results.
Generally, a difference less than 0.1 logMAR (1 line of Snellen
acuity) was found in 80% (20/25) of subjects. ETDRS visual acuities
were frequently better than that with FrACT; there was a 0.1 logMAR
difference at far and 0.06 logMAR differences at both intermediate
and near. With defocus testing, there was a mean difference of 0.05
logMAR across the defocus range, with the greatest differences
between -2.00 and -4.00 D (mean of 0.08 logMAR). The mean bestcorrected distance VA (BCDVA) was slightly better than the mean VA
with the manifest refraction (0.00 D defocus) in the defocus sequence
with both ETDRS (0.02 logMAR) and FrACT (0.03 logMAR).
Conclusions: VA test results with the FrACT system were found to
be slightly worse than that with the ETDRS letter charts. However,
the benefits of automated administration of VA testing with the
FrACT system merit further evaluation of test factors that may affect
results.
Commercial Relationships: Linda Tsai, Abbott Medical Optics
(E); Eugenia Thomas, Abbott Medical Optics (E); Janice Tarrant,
Abbott Medical Optics (E); Stan Bentow, Abbott Medical Optics
(E); Sanjeev Kasthurirangan, Abbott Medical Optics (E)
Evaluation of defocus curve performance with two visual acuity
testing systems: ETDRS and FrACT
Janice Tarrant, Eugenia Thomas, Linda Tsai, Sanjeev
Kasthurirangan. Abbott Medical Optics, Milpitas, CA.
Purpose: An important clinical method to evaluate multifocal and
accommodating intraocular lens performance is the defocus curve
test. To have a clear interpretation of the defocus curve data, the
test methods used and the metrics obtained from this test should
be evaluated relative to other clinical measures. The aim of this
study was to compare near visual acuity (VA) and defocus curve
measurements with two different methods, standard letter charts
(ETDRS) and a computer based technique (FrACT), in nonpresbyopic and presbyopic subjects.
Methods: A total of 25 subjects were recruited (22 to 80 years; mean:
46 ± 15 years). Outcome measures included monocular manifest
refraction of the right eye, distance corrected intermediate VA
(DCIVA) at 66 cm and distance corrected near VA (DCNVA) at 40
cm with both the ETDRS and FrACT systems. Defocus curves (far
visual acuity measured through trial lenses from +2.0 D to -4.0 D in
0.5 D steps) were measured with both systems. Near add power at 40
cm and push-down accommodative amplitude (AA) were obtained.
Two depth of focus (DOF) metrics from defocus curves were
evaluated: a 20/32 VA threshold (DOF-M1) and a 0.2 logMAR loss
in VA from the 0.0 D defocus VA (DOF-M2). Age related trends for
DCIVA, DCNVA and depth of focus measurements were evaluated
through regression analyses and slopes compared.
Results: Intermediate VA (DCIVA) declined at about 0.1 logMAR
per decade with both ETDRS (-0.367 + 0.009 * age; R2 = 0.51)
and FrACT (-0.430 + 0.011 * age; R2 = 0.61). Near VA (DCNVA)
declined at 0.14 logMAR per decade with both ETDRS (-0.455 +
0.014 * age; R2 = 0.58) and FrACT (-0.408 + 0.014 * age; R2 = 0.58).
Depth of focus metrics (DOF-M1) and (DOF-M2), measured with
ETDRS and FrACT, showed a significant relationship with age (p
< 0.05 for all regression slopes) and had slopes between -0.6 D and
-0.7 D per decade. Similarly, minimum near add declined at 0.6 D
per decade (R2 = 0.83). All non-presbyopes accommodated well to
the ETDRS chart, but some showed reduced accommodation with the
FrACT system, especially through -3.5 D and -4.0 D defocus levels.
Conclusions: The ETDRS charts and FrACT computer system
measured comparable reductions in intermediate visual acuity and
near visual acuity and depth of focus with increasing age. Generally,
with each decade increase in age, near vision declined at 0.1 logMAR
and depth of focus declined at about 0.6 D.
Commercial Relationships: Janice Tarrant, None; Eugenia
Thomas, None; Linda Tsai, None; Sanjeev Kasthurirangan, None
and an iPad, respectively. The tests were controlled by a 2-down,
1-up staircase procedure with 4 reversals. SDH was estimated using
a maximum likelihood fitting procedure. Results obtained from
162 eyes of these 86 subjects with BCVA 20/100 or better were
included for linear regression and Bland-Altman analysis to assess
the agreement of the self-testing results obtained with these two
paradigms.
Results: The linear regression of the SDH obtained with the 4AFC
mVTTM versus those obtained with 3AFC mVTTM showed that
the results of these two paradigms are highly correlated (r = 0.87,
p<0.0001). The slope of linear regression is 0.94 (95% confidence
interval, 0.85 – 1.02), including slope one, suggesting no significant
difference in SDH measurements by these two testing paradigms.
The Bland-Altman plot of the difference of 4AFC and 3AFC
measurements versus their means showed the mean difference is
0.057 logMAR, indicating that SDH measured by 4AFC paradigm is
slightly worse than that by 3AFC paradigm. This bias is significantly
different from zero because the 95% confidence interval (0.033 to
0.081 logMAR) of the mean difference doesn’t include zero.
Conclusions: The performance of mVTTM employing a 4AFC testing
paradigm is comparable to that of mVTTM using a 3AFC testing
paradigm. The slight bias of the 4AFC measurements compared
to 3AFC supports the hypothesis that the 4AFC paradigm reduces
chance level (lucky guesses), so that it reduces the likelihood
of overestimating patients’ ability to detect distortion in a shape
discrimination task.
Comparison of myVisionTrack® Vision Monitor Performance
with 3-Alternative Forced-Choice (3AFC) and 4AFC Testing
Paradigms for Assessing Shape Discrimination Hyperacuity
Michael B. Bartlett1, Gina Mitzel2, Song Zhang3, Yi-Zhong Wang2,
4 1
. Vital Art and Science, LLC, Richardson, TX; 2Retina Foundation
of the Southwest, Dallas, TX; 3Clinical Sciences, UT Southwestern
Medical Center, Dallas, TX; 4Ophthalmology, UT Southwestern
Medical Center, Dallas, TX.
Purpose: The myVisionTrack® (mVTTM), a mobile shape
discrimination hyperacuity (SDH) test, was originally developed as
a spatial 3-alternative forced-choice (3AFC) test (Wang, et al. IOVS
54:5501, 2013). Newer phones and tablets have bigger screens which
allow for additional stimulus patterns to be displayed simultaneously.
Increasing the number of choices will reduce the chance level and
so decrease the likelihood of overestimating the performance in a
psychophysical test. To test this hypothesis we compared the 4AFC
and 3AFC test paradigms among normal subjects and patients with
maculopathy in this study.
Methods: A cross-sectional study was conducted with 86 subjects
(40 with normal vision and 46 with various types of maculopathy).
The 3AFC and 4AFC SDH tests were implemented on an iPod touch
Commercial Relationships: Michael B. Bartlett, Vital Art and
Science, LLC (E), Vital Art and Science, LLC (I), Vital Art and
Science, LLC (P), Vital Art and Science, LLC (S); Gina Mitzel,
None; Song Zhang, None; Yi-Zhong Wang, Vital Art and Science,
LLC (C), Vital Art and Science, LLC (F), Vital Art and Science, LLC
(I), Vital Art and Science, LLC (P), Vital Art and Science, LLC (S)
Support: NIH Grant 5R44EY020016-03
Objective Alternanting Cover Test technique implemented in a
new vision analyzer.
Juan Carlos Ondategui Parra, Irene Claramunt, Rosa Borras,
Selena Gomez, Jaume Pujol. DAVALOR Research Center (DRC) Universistat Politècnica de Catalunya, Terrassa, Spain.
Purpose: To compare the values of near phoria measured with the
clinical Alternating Cover Test (CACT) commonly used in clinics,
objective method for the patient and subjective method for the
examiner, with the objective method using the Alternating Cover
Test Technique (OACT) implemented in a prototype of a new
fully autonomous and automated vision analyzer (Eye and Vision
Analyzer, EVA, DAVALOR, Spain). In this latter one eye movements
are recorded while the patient watches a true-3D short video game,
with a precise stimulation of accommodation and vergence.
Methods: 55 healthy subjects with no previous history of strabismus
or amblyopia, no ocular pathology, and no history of eye surgery
were enrolled in the study. All eyes achieved a visual acuity equal
o higher to 0.00 logMAR. The CACT method was the commonly
used in clinics consisting of alternating occlusion of each eye every
2 seconds and measuring the deviation angle with a prism bar in
prismatic diopters (PD). The phoria value was defined as the mean
value obtained with the maximum and minimal limit technique
of the compensation ocular movement. The OACT method was
implemented in the prototype of EVA device showing the video
game only in one eye during 2 seconds in an alternant manner. The
procedure was repeated 5 times. Phoria values were obtained as
the deviation angle before the occlusion of the other eye recorded
by the eye tracker. All measures were done at near vision (40 cm)
and the visual acuity for the test stimuli was 0.2 logMAR. Three
measurements were performed for each method.
Results: The mean age (mean ± standard deviation) of the sample
was 21.5±1.5 years (range: 19 to 24). The mean phoria values
obtained were -1.0±3.8 PD for CACT and -2.3±3.4 PD for OACT.
The mean value of difference between methods was 1.3±2.2 PD and
was statistically significant (p<0.01). The Bland and Altman plot
shows a confidence interval at 95% between -5.57 and 3.03 PD. The
Pearson Correlation Coefficient between both methods was 0.82 and
the Intraclass Correlation Coefficient (ICC) was 0.90, therefore, the
strength of agreement is very good.
Conclusions: The EVA prototype is a useful device to use the
Alternating Cover Test procedure to measure phoria. The results
obtained with EVA were similar to the results with the method used
commonly in clinics. Despite it is statistically significant; it is not
clinically significant, because the difference is lower than 2PD.
Commercial Relationships: Juan Carlos Ondategui Parra,
DAVALOR (F); Irene Claramunt, DAVALOR (F); Rosa Borras,
DAVALOR (F); Selena Gomez, DAVALOR (F); Jaume Pujol,
DAVALOR (F)
Support: DAVALOR, DPI 2011-30090-C02-01
Objective horizontal heterophoria measurements using a new
vision analyzer
Jaume Pujol, Rosa Borras, Irene Claramunt, Mireia Sanchez, Alfonso
Sanchez-Magan, Juan Carlos Ondategui Parra. Davalor Research
Center (DRC) - Universitat Politècnica de Catalunya, Terrassa, Spain.
Purpose: To compare the results of two subjective methods
commonly used in clinics to measure horizontal heterophoria
with an objective method implemented in a prototype of a new
fully autonomous and automated vision analyzer (Eye and Vision
Analyzer, EVA, DAVALOR, Spain), that records eye movements
while the patient watches a true-3D short video game
Methods: Measurements were performed in a group of 54 young
healthy subjects. Monocular visual acuity at far and near distances
equal or better than 0.0 logMAR was required. Subjective methods
consisted of Von Graefe with a line of letters (VGL) and the
Modified Thorington (MT) test. VGL was performed at 40 cm
with an increment speed of prismatic diopters (PD) of 2PD/sec and
under controlled conditions of ilumination (L≈450 lux). MT was
performed at 40 cm with a RAF ruler and spotlight under controlled
conditions of ilumination (L≈50 lux). Moreover, accurate instructions
about stimulus alignment were given to the patients. Three
measurements were performed for each method with an interval
of 5 seconds between them. Objective measurements were made
using an Alternant Cover Test procedure (OACT) showing the video
game only in one eye during 2 seconds and recording the ocular
movements. This procedure was also repeated three times. Runtime,
including time for instructions, was also measured
Results: The mean age of the sample was 21.5±1.5 years (range:19
to 24). The mean horizontal heterophoria values were -6.7±6.0
PD for VGL, -1.0±3.8 PD for MT and -2.0±3.0 PD for OACT.
The mean value of differences was -5,6±5,3 PD for VGL vs MT,
-4,6±4,6 PD for VGL vs OACT and 0,9±2,8 PD for MT vs OACT.
The 95% confidence interval (Bland & Altman plot) was 10,48 for
VGL vs MT; 9.83 for VGL vs OACT and 2.52 for TM vs OACT.
The Intraclass Coefficient Correlation (ICC) was 61,2% for MT vs
OACT; 61.9% for VGL vs OACT and 80.4% for TM vs OACT. The
runtime was 137±20 sec for VGL;, 83±13 sec. for MT and 26±5 sec.
for OACT
Conclusions: The EVA prototype is a useful device to objectively
measure horizontal heterophoria using an Alternating Cover Test
procedure. Results show a good ICC (>80%) when OACT is
compared with MT. Differences between both methods (1PD) are not
clinically significant and are within a good confidence interval. VGL
shows higher differences and lower ICC when it is compared with
OACT and MT. In addition, OACT is more than 3 times faster than
MT and more than 5 times faster than VGL
Commercial Relationships: Jaume Pujol, DAVALOR (F); Rosa
Borras, DAVALOR (F); Irene Claramunt, DAVALOR (F); Mireia
Sanchez, DAVALOR (F); Alfonso Sanchez-Magan, DAVALOR (F);
Juan Carlos Ondategui Parra, DAVALOR (F)
Support: DPI2011-30090-C02-01
A pilot trial for a self-testing application for reading speed
Ju Byung Chae1, Sang Yoon Hyun1, Soolienah Rhiu2, Hye Jin Lee3,
Jae-hyung Kim1. 1Ophthalmology-Coll of Med, Chungbuk National
University Hospital, Cheong-ju, Chung-buk, Korea (the Republic
of); 2Dongtan Sacred Heart Hospital, Hallym University College
of Medicine, Seoul, Korea (the Republic of); 3Department of
Ophthalmology, Jeju National University School of Medicine, Jeju,
Korea (the Republic of).
Purpose: To develop a reading chart app for the iPad tablet computer
in the Korean language and to investigate reading speed in a normalsighted population according to age groups.
Methods: Sixty-three Korean sentences were selected from textbooks
for second grade students in elementary school. Commonly used
typeface in everyday printed material, “Batangche” was used. Letter
size was presented logMAR 0.0 to 1.0 at 0.1 logMAR steps at a
reading distance 40 cm. A 3rd generation retina display iPad was
used to present the chart and the sentences were presented randomly
for each vision and reading speed was checked twice. Pilot testing
followed in 55 normal vision adults under 60 years old of age. The
subjects read aloud to prevent them from skipping reading words
Results: The average word count for the sentences was 6.5 0.7. The
mean reading speed for logMAR 0.5 optotype (point 10) was 133.9 ±
26.1 words per minute (wpm) in 20s (n = 19), 121.1 ± 31.6 in 30s (n
= 25), 96.8 ± 17.2 in 40s (n = 6), 67.7 ± 41.9 (n = 5) in 50s. The mean
reading speed for logMAR 0.0 optotype (point 3.5) was 121.2 ± 27.2
wpm in 20s, 106.6 ± 34.9 in 30s, 61.4 ± 20.1 in 40s, 43.6 ± 77.2 in
50s.
Conclusions: This Korean reading chart app can present a new
standard when checking reading speed according to age groups. The
app also provides portability and accessibility for this new reading
acuity chart.
Commercial Relationships: Ju Byung Chae, None; Sang Yoon
Hyun, None; Soolienah Rhiu, None; Hye Jin Lee, None; Jaehyung Kim, None
Average Precision as a test-retest reliability measure: a quick
CSF study on myopia
Michael Dorr1, 2, Luis A. Lesmes2, Tobias Elze3, Hui Wang4, 3, ZhongLin Lu5, Peter J. Bex6. 1Technische Universität München, Munich,
Germany; 2Adaptive Sensory Technology, Boston, MA; 3Mass Eye
and Ear, Boston, MA; 4Jilin University of Finance and Economics,
ChangChun City, China; 5Ohio State University, Columbus, OH;
6
Northeastern University, Boston, MA.
Purpose: The Contrast Sensitivity Function (CSF) provides a
comprehensive assessment of visual sensitivity, but its routine
evaluation in clinical care is hampered by practical challenges. We
evaluated test-retest reliability (TRR) of an iPad-based quick CSF
implementation (Dorr et al., IOVS 2013) in a cohort of myopes and
age-matched controls.
Methods: We collected repeated measurements of the full CSF on
a handheld device at a viewing distance of 60cm from 101 subjects
(63 myopes with 33 uncorrected/30 corrected eyes, 38 controls); in
each of 50 trials per measurement, a bandpass-filtered Sloan letter
was presented for 500ms. Spatial frequency (SF, 24 levels from .64 to
41cpd) and contrast (48 levels from .2 to 100%) were chosen by the
quick CSF algorithm to maximize information gain about the CSF.
Subjects then indicated their response (10-AFC) on the touch screen.
We computed cross-correlation coefficients (CC) and Bland-Altman
Coefficients of Repeatability (CoR) for contrast sensitivities at 6
individual SF, CSF Acuity (the SF where sensitivity=0), and the
Area under the Log CSF (AULCSF). However, both CC and CoR
are vulnerable to artefacts due to test score range and quantization.
Therefore, we also computed Average Precision, the area under the
Precision-Recall curve that more accurately describes test-retest
variance in terms of between-subject variability: how easily can a
repeat measurement be identified from the whole population-wide set
of measurements, given only the initial measurement?
Results: CC ranged from .873 for contrast sensitivity at 1.5cpd to .98
for the AULCSF. CoR were likewise small for AULCSF (.225) and
CSF Acuity (.193), and increased for individual contrast sensitivities
at higher SF (1.5cpd, CoR=.2; 18cpd, CoR=.308). Precision-Recall
scores were worst for low SF (1.5cpd, AveP=.79) and best for
AULCSF (AveP=.87). Notably, repeatability as assessed by AveP
was better for uncorrected eyes than for corrected eyes, despite much
higher Bland-Altman CoR (e.g. uncorrected AULCSF, AveP=.879,
CoR=.255; corrected AULCSF, AveP=.829, CoR=.168).
Conclusions: Despite very short testing times (2-3 minutes) and
without specialized laboratory equipment, the iPad-based quick CSF
test reliably assessed the full CSF in myopes and controls. While
Bland-Altman CoR is routinely used to quantify TRR, its absolute
scores cannot be compared across different test measures; Average
Precision should be used instead.
Commercial Relationships: Michael Dorr, Adaptive Sensory
Technology (I), US 14/399,136 (P); Luis A. Lesmes, Adaptive
Sensory Technology (E), Adaptive Sensory Technology (I), US
14/399,136 (P); Tobias Elze, None; Hui Wang, None; Zhong-Lin
Lu, Adaptive Sensory Technology (I), US 14/399,136 (P); Peter J.
Bex, Adaptive Sensory Technology (I), US 14/399,136 (P)
Hierarchical Bayesian adaptive estimation of the contrast
sensitivity function: Part I – effect of sample size
Hairong Gu, Woojae Kim, Fang Hou, Zhong-Lin Lu, Mark Pitt, Jay
Myung. Psychology, The Ohio State University, Columbus, OH.
Purpose: Lesmes et al (2010) developed a Bayesian adaptive method
for accurately and efficiently measuring the contrast sensitivity
function (CSF). Kim et al (2013) recently proposed a hierarchical
Bayesian extension, dubbed hierarchical adaptive design optimization
(HADO), that provides a judicious way to exploit prior information
gained from past experiments to achieve even greater efficiency. The
purpose of the present study is to evaluate the benefits and validity of
HADO in both human and simulated experiments.
Methods: We first conducted a 10AFC letter identification
experiment with 100 subjects using the quick CSF method of Lesmes
et al (2010) and used the data to construct informative priors. We
varied the amount of information in the priors by using four different
numbers of subjects (5, 12, 30,100) included in the prior construction.
We then repeated the experiment with 10 new subjects using the four
priors. Performance of the CSF estimation was compared between
these different prior conditions, and also against the quick CSF
method with a diffuse prior. The same HADO procedure was carried
out in Monte Carlo simulations as well to take the effect of sampling
error into account.
Results: Figure 1 shows root-mean-squared-error (RMSE) plots
of the area-under-the-log-CSF (AULCSF) averaged across all 10
subjects as a function of trial number. The results showed that the
informative priors increased the efficiency by lowering the RMSE
at a certain number of trials. From the diffuse prior, for comparison,
the reduction of RMSE for sample size 5 and 12 averaging over
the first 10 trials is about 6.47 dB and the reduction for sample size
30 and 100 is about 10.72 dB. The errors decreased for all priors
as the trials accumulated, with the differences among them being
indistinguishable at trial 50. Essentially the same (but less noisy)
pattern of results was obtained in simulated experiments.
Conclusions: Using well-informed priors in HADO shows higher
efficiency in estimating CSF than using the non-informative, diffuse
prior in the standard adaptive method. The advantage is considerable
even when a small number of subjects are available for constructing
the prior. Increasing the sample size brings further but small
advantage, which can still be beneficial in clinical settings.
Figure 1: Effect of sample sizes on the estimates of AULCSF.
Commercial Relationships: Hairong Gu, None; Woojae Kim,
None; Fang Hou, None; Zhong-Lin Lu, Adaptive Sensory
Technology, LLC. (I), Adaptive Sensory Technology, LLC. (P);
Mark Pitt, None; Jay Myung, None
Support: National Institute of Mental Health MH093838 ; National
Eye Institute EY021553
Hierarchical Bayesian adaptive estimation of the contrast
sensitivity function: Part II — effect of type of prior
Mark Pitt, Hairong Gu, Fang Hou, Woojae Kim, Zhong-Lin Lu, Jay
Myung. Psychology, Ohio State Univeristy, Columbus, OH.
Purpose: The contrast sensitivity function (CSF) characterizes
spatial vision in both normal and clinical populations. The quick
CSF method (Lesmes, et al, 2010) measures CSF precisely in only
a few trials. Kim et al. (2014) introduced a hierarchical Bayesian
framework in which adaptive estimation of the CSF can be
further accelerated and improved by using prior knowledge (e.g.,
parameter estimates) from previously tested participants. The current
experiment explored how the specification of priors influences
adaptive estimation by comparing conditions in which the priors
varied from correctly specified to incorrectly specified.
Methods: Priors were created from parameter estimates from a study
in which the CSF of 100 observers with normal vision were measured
using the quick CSF procedure in a 10AFC letter identification task
under three viewing conditions: no filter (Normal), weak neutral
density filter (ND1, 78.8% attenuation) and strong neutral density
filter (ND2, 97.2% attenuation). In the current study, 10 participants
were tested with quick CS in the Normal viewing condition three
times, each using a different prior: Normal (correctly specified), ND2
(misspecified) and a mixture prior consisting of equal parts Normal,
ND1, and ND2. Diffuse priors (no prior knowledge) were used in a
control condition.
Results: The root mean squared error (RMSE) of the Area Under the
log CSF (AULCSF) was calculated across trials for each participant
in all conditions using the estimated true AULCSF, obtained
after 100 trials in an additional diffuse condition. Aggregate data
over the first ten trials showed that, when compared to results in
the diffuse condition, estimation error in the ND2 (misspecified)
condition decreased by 0.41dB. The Normal (correctly specified)
prior condition yielded the greatest improvement (7.80 dB) over the
diffuse condition. Surprisingly, the mixture prior showed a significant
benefit (4.24 dB drop). Estimates improved for all conditions as
trials accumulated, with differences among them being almost
indistinguishable by trial 50.
Conclusions: Prior knowledge can influence the accuracy and
efficiency of adaptive CSF measurement. A correctly specified
prior can greatly improve estimation, but a misspecified prior is
comparable to a diffuse prior. When the prior is unknown, a mixture
prior is a smart choice, providing significant benefit without cost.
Commercial Relationships: Mark Pitt, None; Hairong Gu, None;
Fang Hou, None; Woojae Kim, None; Zhong-Lin Lu, Adaptive
Sensory Technology (S); Jay Myung, None
Support: National Institute of Mental Health (MH093838), National
Eye Institute (EY021553)
A large-sample study for evaluating the precision of the quick
CSF method
Zhong-Lin Lu1, Fang Hou1, Luis A. Lesmes2, Woojae Kim1, Hairong
Gu1, Mark Pitt1, Jay Myung1. 1Psychology, The Ohio State University,
Columbus, OH; 2Adaptive Sensory Technology, LLC., Boston, MA.
Purpose: The quick CSF method (Lesmes, et al, 2010) applies a
Bayesian adaptive algorithm to estimate the contrast sensitivity
function (CSF) with high precision and reduced testing time (~5
min). We collected a large dataset of CSF to 1) determine reliability
as a function of test duration, 2) evaluate the concordance between
estimates against intra- and inter-run variability (via Bayesian
confidence and repeated testing, respectively), and 3) conduct a
power analysis for detecting CSF change.
Methods: CSFs of 112 college students with normal vision were
repeatedly assessed using quick CSF with a 10-letter identification
task. For each observer, running CSF estimates were calculated for
each trial, via bootstrap statistics for the area under the log CSF
(AULCSF), computed by resampling from the Bayesian posterior
distribution of the CSF.
Results: 1) After 6 trials, the AULCSFs from the two repeated
measurements were significantly correlated. Pearson’s r increased
from 0.22 (p=0.02) to 0.84 (p<0.001) as trial number increased from
6 to 50. The 95% confidence interval of the ratio between the two
AULCSFs was [0.94, 1.02] at trial 6 and [0.99, 1] at trial 50.
2) The comparable metrics of intra- and inter-run variability provided
by standard deviations of AULCSF estimates were 0.20 and 0.25 log
units after 10 trials, 0.13 and 0.16 log units after 20 trials, and 0.07
and 0.09 log units after 50 trials, respectively.
3) From the posterior distributions of the CSFs, we computed the
minimum AULCSF difference (MAD) that can be detected by quick
CSF with 95% posterior probability as a function of both trial and
observer numbers (Figure 1). To detect MADs of 0.2, 0.1 and 0.05
l log units with 25 quick CSF trials, we needed to run 2, 6 and 27
observers, respectively. To detect the same MADs in 50 trials, only
1, 3 and 11 observers were needed. With 20 observers, we needed
5, 11, and 30 trials to detect MADs of 0.2, 0.1 and 0.05 log units,
respectively. With 112 observers, we needed only 3, 6 and 12 trials to
detect the same MADs, respectively.
Conclusions: The quick CSF method is very precise and highly
reliable. The high precision and reliability make it possible to use
the method to efficiently measure CSF and detect CSF changes with
greatly reduced sample size and costs in clinical trials.
Figure 1. The minimum AULCSF difference (MAD, in log units) that
can be detected by quick CSF as a function of both trial and observer
numbers.
Commercial Relationships: Zhong-Lin Lu, Adaptive Sensory
Fang Hou, None; Luis A. Lesmes, Adaptive Sensory Technology,
LLC. (E), Adaptive Sensory Technology, LLC. (I), Adaptive Sensory
Technology, LLC. (P); Woojae Kim, None; Hairong Gu, None;
Mark Pitt, None; Jay Myung, None
Support: Supported by the National Eye Institute (EY021553 to
ZLL) and by the National Institute of Mental Health (MH093838 to
JM and MP)
Evaluating the sensitivity for detecting contrast sensitivity
changes using the quick CSF method
Fang Hou1, Luis A. Lesmes2, Woojae Kim1, Hairong Gu1, Mark Pitt1,
Jay Myung1, Zhong-Lin Lu1. 1Department of Psychology, the Ohio
State University, Columbus, OH; 2Adaptive Sensory Technology,
LLC., Boston, MA.
Purpose: The contrast sensitivity function (CSF) has shown promise
for monitoring the progression of vision loss in eye disease or its
remediation with treatment (Barnes, et al., 2004). The quick CSF is a
novel Bayesian adaptive method developed to enable the wide, easy
application of precise CSF testing. Here, we 1) induced predictable
visual changes in a large sample of observers, 2) determined the
quick CSF’s sensitivity for detecting CSF changes, and 3) used the
large dataset to empirically determine the minimum sample sizes and
testing times needed to detect CSF changes.
Methods: CSFs of 112 college students with normal vision were
assessed by the quick CSF with a 10-letter identification task in low,
medium, and high mean luminance conditions: 2.65 (L), 20.2 (M) and
95.4 (H) cd/m2. Visual acuity (VA) was measured using the Snellen
eye chart. Data were analyzed using Bayesian and conventional
statistics. For each observer, CSF metrics across different luminance
conditions were calculated in each trial, via bootstrap statistics for the
area under the log CSF (AULCSF), computed by resampling from
the Bayesian posterior distribution of the CSF.
Results: 1) Average AULCSF values obtained in the L and M
conditions were only 38.7% and 72.1% of those obtained in the
H condition, while average relative VA values were 95% and
99%. Although both AULCSF (F(2,335)=293, p<0.001) and VA
(F(2,332)=5.89, p<0.001) reductions were significant, the magnitudes
of AULCSF changes were much greater than those of VA reduction
(F(1,443)=461, p<0.001).
2) After 10 trials, we needed only 1, 3, and 17 subjects to reliably
(with 95% posterior probability) detect AULCSF changes in
comparisons of L-H, L-M, and M-H conditions, respectively; after 25
trials, we needed only 1 subject to detect all the changes. In contrast,
we needed 16, 20, and 82 subjects to reliably detect VA changes in
those comparisons
3) With 10 subjects, we needed 3, 4, and 11 quick CSF trials to
reliably detect AULCSF changes between the L-H, L-M and M-H
luminance conditions, respectively. With 25 subjects, we needed only
2, 3, and 7 trials.
Conclusions: This assay calibration study demonstrates that the
quick CSF method is very sensitive in detecting CSF changes.
Whereas the current study uses the quick CSF to detect visual
changes modeled by different luminance conditions, future studies
will examine the performance of the method in clinical settings.
Commercial Relationships: Fang Hou, None; Luis A. Lesmes,
Adaptive Sensory Technology, LLC. (E), Adaptive Sensory
Woojae Kim, None; Hairong Gu, None; Mark Pitt, None; Jay
Myung, None; Zhong-Lin Lu, Adaptive Sensory Technology, LLC.
(I), Adaptive Sensory Technology, LLC. (P)
Support: Supported by the National Eye Institute (EY021553 to
ZLL) and by the National Institute of Mental Health (MH093838 to
JM and MP)
in first and second measurement and the limits of agreement as
assessed by the Altman and Bland plots. The AULCSF had upper
limit of agreement (ULA) -0.18 and lower limit of agreement (LLA)
+0.22. The CSF acuity had ULA -7.0 and LLA +10.9 cpd. The t-tests
revealed that all parameters, including AULCSF and CS at various
cpd, were not significantly different between the first and second sets
of measurement (paired t-test p>0.05). However, CSF acuity was
significantly higher in the second measurement compared to the first
measurement (mean difference 1.95 cpd; paired t-test t-statistic -2.09,
p= 0.04).
Conclusions:
The quick CSF provides contrast sensitivity parameters that are
repeatable in groups with normal and mild impaired vision.
Repeatability of measurements obtained using the quick CSF
method
Lilia Babakhan1, Anna Parfenova1, Katherine Ha1, Raymond Maeda1,
Steven Thurman2, Aaron Seitz2, Pinakin G. Davey1. 1College of
Optometry, Western University of Health Sciences, Burbank, CA;
2
UC Riverside, Riverside, CA.
Purpose:
Contrast sensitivity is a fundamental measure of visual function, and
obtaining quick and reliable estimates of contrast sensitivity is vital
in clinical settings. The quick CSF is an adaptive method that uses
Bayesian inference and a trial-to-trial information gain strategy to
obtain rapid measurements of contrast sensitivity and to produce an
estimate of the entire contrast sensitivity function (CSF) (Lesmes
et al Journal of Vision 2010, ARVO 2012 and 2013).The purpose
of the present study was to evaluate short term repeatability of CSF
parameter estimates using the quick CSF method.
Methods:
Twenty four individuals with normal or mild impaired vision
(glaucoma, cataract or age related macular degeneration) participated
in the study. Measurements were performed twice with the quick CSF
technique in binocular viewing conditions. The CSF was measured
with 50 trials and estimates of area under the log CSF (AULCSF),
high spatial frequency cutoff (CSF acuity), and contrast sensitivity
at 1, 1.5, 3, 6, 12 and 18 cycles per degree (cpd) were obtained
(see figure 1). Altman and Bland plots were performed to evaluate
the limits of agreement and paired t-tests were performed to assess
difference between the first and second measurements.
Results:
The median age of the study participants was 32 years (range 22-76).
The figure 2 provides the contrast sensitivity measures obtained
Commercial Relationships: Lilia Babakhan, None; Anna
Parfenova, None; Katherine Ha, None; Raymond Maeda, None;
Steven Thurman, None; Aaron Seitz, None; Pinakin G. Davey,
None
Support: NIH 1 R01EY023582
Clinical assessment of the Landolt C-CSF test-M&S Smart
System Contrast Sensitivity Testing Device
Kaydee McCray1, Violeta Paronian1, Aaron Seitz2, Pinakin G. Davey3.
1
Gradutate College of Biomedical Sciences, Western University of
Health Sciences, Pomona, CA; 2Psychology, University of CaliforniaRiverside, Riverside, CA; 3College of Optometry, Western University
of Health Sciences, Pomona, CA.
Purpose: Contrast sensitivity function is decreased in many disease
entities notably: cataract, age related macular degeneration and
glaucoma. It is also lowered in individuals that undergo keratorefractive surgery procedures. Traditional contrast sensitivity tests
printed on charts are limited in the fact that a certain working distance
is needed and are prone to degradation due to use. The electronic
M&S Smart System contrast sensitivity testing unit provides the
flexibility to use at variable distance and provides better resolution
capabilities especially at lower contrast due to the visual display
system. The purpose of the study was to evaluate the short-term
repeatability and use of Landolt C contrast sensitivity function test in
ocular healthy and in individuals with decreased visual function.
Methods: Twenty six individuals were tested twice using the Landolt
C-CSF test of the M&S Smart System contrast sensitivity testing
system. The mean age of the study participants was 37.3 years (SD
15). The Landolt C-CSF was performed for 20/20, 20/40 and 20/80
and all measurements were obtained viewing the chart binocularly
at a distance of nine feet. Repeatability was assessed using Altman
and Bland plots and 95% limits of agreement were calculated. The
difference in measurements of first and repeat measurements was
assessed using paired samples t-test.
Results: Table 1 below provides the mean of first and second
measurements of obtained data using the Landolt C contrast
sensitivity function test and the limits of agreement at different
acuities. Overall the contrast sensitivity peak measured as percent
contrast was very repeatable at different visual acuity levels with
average difference in percent contrast being not significantly different
in all three acuity levels (paired samples t-test p value 0.8, 0.9 and 0.9
respectively).
Conclusions: The Landolt C-CSF test of the M&S Smart System
contrast sensitivity testing system is repeatable and provides data that
can be useful in measuring contrast levels. Further tweaks may be
done to provide area under log CSF from the various peak contrast
sensitivity tested.
Commercial Relationships: Kaydee McCray, None; Violeta
Paronian, None; Aaron Seitz, None; Pinakin G. Davey, None
Support: NIH Grant 1R01EY023582
Assessment of Evans low contrast sensitivity in measuring log
contrast sensitivity
Pinakin G. Davey1, Raymond Maeda1, Aaron Seitz2. 1College of
Optometry, Western University of Health Sciences, Pomona, CA;
2
Psychology, UC Riverside, Riverside, CA.
Purpose: Clinically a quick and reliable estimate of contrast
sensitivity levels is desirable to evaluate patients with decreased
vision or difficulty of vision in dim illumination. The Evans Low
Contrast Test (ELCT) chart presents Sloan Letters optotypes line
size of 20/630 (a testing distance of 1m) varying contrast in sets of
3 letters of equal contrast level. All triplets are balanced for letter
difficulty and differ in contrast by 0.15 log contrast step. The purpose
of this study was to evaluate the short term repeatability of the ELCT
in measuring lowest log contrast appreciated in healthy and eyes with
ocular pathology.
Methods: Study participants were tested at 13 feet in a dark
environment and the retro illuminated box provided the background
illumination for the ELCT chart. Twenty five study participants with
either normal visual function or decreased visual function performed
assessment with ELCT twice viewing the chart binocularly.
Repeatability was assessed using Altman and Bland plots and 95%
limits of agreement were calculated. Difference in measurements was
assessed using paired samples t-test.
Results: The mean log contrast of attempt 1 and attempt 2 was
2.198 and 2.208 (standard deviation 0.17 and 0.08 respectively). The
mean difference between the groups was not statistically significant
(paired samples t-test: t statistic =0.36; p value =0.72). The test was
easy to perform and the results were obtained in a couple of minutes
maximum.
Conclusions: The Evans Low Contrast Test provides a quick and
easy method of estimating lowest log contrast and may be useful test
in identifying decreased contrast sensitivity in individuals with ocular
pathology.
Commercial Relationships: Pinakin G. Davey, None; Raymond
Maeda, None; Aaron Seitz, None
Support: NIH1R01EY023582
Assessment of the Impact of congenital dichromacy on the lives of
color blind adults
Amanda Bastos, Lívia Rego, Daniela Bonci, Dora F. Ventura, Mirella
Gualtieri. Experimental Psychology, University of São Paulo, São
Paulo, Brazil.
Purpose: Congenital color blindness affects 6 to 8% of the male
caucasian population. Recent developments point to gene therapy
as a possible treatment for this type of impairment. However, little
is known regarding the impact of dyschromatopsia on people with
congenital color blindness. Questionnaires assessing quality of life
in vision research have been effective in revealing the impact of
the visual losses. However, issues related to color vision are still
largely absent from these instruments.The objective of this work is
to evaluate the impact of congenital dyschromatopsia on the life of
adults
Methods: We investigated different dimensions of the impact of
color blindness in everyday life, based on the analysis of the content
of interviews - using the Sphinx software (Le Sphinx, UK). Twelve
male participants were interviewed (age = 33.6 years old ± 9.9;
educational level between undergraduate and graduate school). All
participants underwent psychophysical color vision assessment –
using the Cambridge Colour Test (Cambridge Research Systems,
UK) - as well as genotyping of the opsin genes (Gentra Systems
- QUIAGEM, Dusseldorf, Germany). The results were compared
to those from a control group for psychophysical assessment and
genetics of color vision. (age = 27,1 years old ± 4,7)
Results: Dyschromatopsias had direct negative impact on
professional daily life activities in 27% of the individuals; 12% of
the participants found to be color blind during childhood as a result
of self-assessment; 22% considered that their vision was good; 60%
revealed that life would be no different if they had no visual defect;
29% depended on someone else in their daily life and 30% would like
to undergo treatment for color blindness cure. The psychophysical
colour vision results revealed: Protan: 320 ± 129,61; Deutan: 684,45
± 392,2 Tritan: 76,64 ± 24,3 and control group Protan: 50 ± 26,5
Deutan: 50,2 ± 16,9 e Tritan: 77,5 ± 26,9. Genetic analysis confirmed
the psychophysical results
Conclusions: Color blindness has an impact on individuals, as
revealed by semi-structured interviews. However, the extent of the
impact is not homogeneous among subjects most participants had
different difficulties in daily life, mostly related to professional
activity developed. A questionnaire being designed based on these
results might constitute a tool for identifying individuals who are
more strongly affected by congenital dyschromatopsia
Commercial Relationships: Amanda Bastos, None; Lívia Rego,
None; Daniela Bonci, None; Dora F. Ventura, None; Mirella
Gualtieri, None
Genetic analysis, the Color Assessment and Diagnosis (CAD) test,
and the Cambridge Color Test (CCT) yield the same color vision
classifications in humans
Victoria Honnell2, 1, Daniela Bonci2, Mirella T. Barboni2, Mirella
Gualtiere2, Amanda Bastos2, Lívia Rego2, Givago S. Souza2,
Malinda E. Fitzgerald3, Luiz Carlos L. Silveira2, Dora F. Ventura2.
1
Neuroscience, Rhodes College, Memphis, TN; 2University of Sao
Paulo, Sao Paulo, Brazil; 3Christian Brothers University, Memphis,
TN.
Purpose: To determine whether the three color vision classification
procedures produce identical results in trichromats and dichromats.
Methods: Blood samples were analyzed from trichromat (26.5±5.2
years old, 5 males and 14 females) and dichromat (31.1±8.1 years
old, 8 males) volunteers living in Sao Paulo, Brazil. The opsin
genes, specifically Exon 5, of all subjects were sequenced after DNA
extraction and PCR amplification procedures. The amino acids in
place 277 and 285 on Exon 5 were identified and the visual pigment
alleles were assessed. Each participant was also tested using the
Cambridge Colour Test (CCT) and the Colour Assessement Diagnosis
test (CAD) using the full assessment protocol (N=26).
Results: 26 subjects were evaluated using psychophysical tests and
genetic analysis. The subjects that self identified as daltonic (N=8)
showed only one M or L allele through the genetic analysis. Seven of
the eight dichromat patients were classified as deutan and only one
subject was classified as protan by the psychophysical tests, CCT and
CAD. Of the eight dichromats that had their genes sequenced, seven
were classified as deutan and one was protan. The psychophysical test
results match the genetic test results for each daltonic patient. The
subjects that self identified as trichromats (N=18) had normal results
for the genetic analysis, CCT, and CAD.
Conclusions: Equal classifications were obtained with the three
methods of color vision classification. This suggests that each testing
method in itself is a reliable measure.
Commercial Relationships: Victoria Honnell, None; Daniela
Bonci, None; Mirella T. Barboni, None; Mirella Gualtiere, None;
Amanda Bastos, None; Lívia Rego, None; Givago S. Souza, None;
Malinda E. Fitzgerald, None; Luiz Carlos L. Silveira, None; Dora
F. Ventura, None
Support: MHIRT Grant NIH 2T37 MD001378-13
Neural Compensation for Color Deficiency: Binocular
Enhancement of Cone-Specific Color VEPs
Jeff C. Rabin, Dan Lam, Andrew Kryder. Optometry, UIW Rosenberg
School of Optometry, San Antonio, TX.
Purpose: Central nervous system (CNS) degeneration often precedes
glaucomatous retinal changes suggesting that glaucoma is a CNS
disease. Moreover, preservation of the binocular field in glaucoma
as well as cognitive function in Alzheimer’s disease are mediated by
CNS control.1,2 Our purpose was to determine if comparable CNS
control mechanisms operate developmentally to optimize function in
hereditary color vision deficiency (CVD) by comparing binocular to
monocular cone specific color VEPs.
Methods: Red (L), green (M) and blue (S) cone specific VEPs were
recorded in pattern-onset mode with colored checkerboards on a grey
background (L&M cone: 1 deg. checks, S cone: 2 deg., 2 onsets/
sec., Diagnosys LLC). Display luminance and CIE chromaticity
were transformed to cone contrasts to selectively stimulate L, M and
S cones. Subjects included 17 color vision normal (CVN) and 11
hereditary red or green CVDs confirmed to be CVD on a battery of
tests. The ratio of binocular VEP amplitude (N1-P1) to mean (RE &
LE) monocular amplitude was used to quantify enhancement.
Results: CVDs showed binocular facilitation of VEP amplitude
(enhancement >2X; mean = 3.1X) for the color corresponding to
their CVD. Values exceeded enhancement for other cone types within
CVDs (3.1X vs. 1.2X, p<0.003) and compared to CVNs (3.1X vs.
1.2X, p<0.007). Binocular facilitation of CVD VEPs remained high
(2.4X) even when quantified as binocular amplitude/higher amplitude
from right or left eyes (2.4X vs. 1.1X, p <0.008). Dichromatic CVDs
did show an enhancement effect.
Conclusions: Hereditary CVDs with anomalous trichromacy
show binocular facilitation of VEPs for the color corresponding
to their CVD. This suggests neural compensation for CVD similar
to preservation of function in glaucoma and Alzheimer’s disease.
Other congenital anomalies and rod-cone, macular and/or corneal
dystrophies may be subject to neural compensation. Elucidation of
underlying mechanisms could lead to new treatments for visually
debilitating disease.
1
Crish et. al, PNAS 2010;107:5196–5201. 2Sponsel et. al TVST
2014;1-13.
Commercial Relationships: Jeff C. Rabin, None; Dan Lam, None;
Andrew Kryder, None
Comparison of interpolation algorithms for static visual field
data
Travis Smith1, Ning Smith2, Richard G. Weleber1. 1Ophthalmology,
Oregon Health & Science University, Portland, OR; 2Center for
Health Research, Kaiser Permanente, Portland, OR.
Purpose: Static perimetry generates 3-D data (x-y test location and
z sensitivity value) representing the visual field (VF), sometimes
called the hill of vision (HOV), which is often sparsely sampled.
Data interpolation produces a finer HOV representation to aid
interpretation, visual display, and quantitative analysis. The goal
of this study is to compare the accuracy of several scattered data
interpolation algorithms and identify the optimal one for VF data.
Methods: Full-field VF data was analyzed from 129 exams of 10
normal subjects and 10 retinitis pigmentosa (RP) patients that passed
quality assessment. Data was acquired with the Octopus 900 with 164
radially oriented, centrally condensed test points using GATEi, target
size V, and a 10 cd/m2 background. Repeated exams for each subject
were included if obtained within 90 days of the first. Interpolation
accuracy was assessed by the root mean square error (RMSE) and
mean absolute error (MAE) from leave-one-out cross-validation
(LOOCV) after blind spot removal. In LOOCV, each location’s
z-value is interpolated from the other 163 points and compared with
a target value to produce an error residual; this is repeated for all
locations in each exam. Two types of target values were considered:
the median z-value at each location across all exams for that eye
(Target 1), and the measured z-value itself (Target 2). LOOCV was
performed with the 8 nonparametric interpolation methods in the top
row of Table 1. Significance was assessed by one-sided paired t-tests
with Bonferroni correction.
Results: Table 1 summarizes the interpolator performances. Linear
radial basis function (RBF) interpolation had the smallest mean
RMSE and MAE compared to all other methods for both target
types, significant (p<0.006) in each case except those identified by
* in Table 1. Linear RBF performance was significantly better in RP
patients than in normals in all scenarios.
Conclusions: Interpolation of static VF data was most accurate with
a linear RBF kernel. Accuracy improved in subjects with visual
field loss, likely due to higher spatial correlation in the data. Future
work will assess parametric and regularized methods to mitigate
overfitting, incorporate a larger number of exams, and analyze
the influence of perimetric test grid density and target size on
interpolation accuracy.
Weleber, AGTC SAB (S), Foundation Fighting Blindness ESAB
(F), U.S. patent no. 8657446, Method and apparatus for visual field
monitoring, also known as Visual Field Modeling and Analysis (P)
Support: Supported by an Unrestricted Grant from Research to
Prevent Blindness, Foundation Fighting Blindness, and Hear See
Hope
Automated static threshold perimetry using a remote eye tracker
Pete R. Jones1, 2, Sarah Kalwarowsky1, Gary S. Rubin1, 2, Marko
Nardini3, 1. 1Institute of Ophthalmology, UCL, London, United
Kingdom; 2NIHR Moorfields Biomedical Research Centre, London,
United Kingdom; 3Department of Psychology, Durham University,
Durham University, United Kingdom.
Purpose: Current methods of Static Threshold Perimetry require
(i) an explicit, button-press response (precluding testing of infants)
and (ii) expensive, specialised equipment. Here we present a novel
measure that addresses these problems by combining a cheap,
commercially available, eye tracker (Tobii EyeX: $135), with an
ordinary desktop computer.
Methods: Luminance detection thresholds were measured
monocularly in 7 healthy adults (additional data collection ongoing),
using both a Humphrey Field Analyzer [HFA] and an automated
remote eyetracking [ARE] procedure (Fig 1A). The eye tracker was
used to present stimuli relative to the current point of fixation, and
to assess whether the participant made an eye-movement towards
the stimulus. In both tests, Goldman III stimuli were arranged on a
24-2 grid, and were presented individually against a 10 cd/m2 white
background. Participants completed each test twice (same eye) in
order to assess test-retest reliability.
Results: The pointwise Coefficient of Repeatability was similar
for the two tests (ARE: 8.1 dB. HFA: 6.3 dB). Differences in mean
sensitivity to stimuli in the central 10° and those located more
peripherally (10—24°) were observed in both the ARE (CI95% =
0.9—2.7 dB) and the HFA (CI95% = 2.3—4.6 dB). Furthermore, as
shown in Fig 1B, the ARE was able to differentiate between the blind
spot and surrounding retinal locations (t6 = -3.1, p = 0.021).
Conclusions: An eye tracker can be used to perform Static Threshold
Perimetry based on eye movement responses alone. The ARE was
sensitive to normal variations in sensitivity across the healthy eye,
and could isolate the blind spot. It may therefore be capable of
detecting visual field deficits, including acute scotomas. Its low price
and ease of use could make such a test particularly effective as a
means of screening infants.
Mean RMSE and mean MAE values (both in dB) across all exams for
each interpolator analyzed, as assessed by LOOCV.
Commercial Relationships: Travis Smith, Foundation Fighting
Blindness (F), Hear See Hope (F); Ning Smith, None; Richard G.
Fig 1. (A) Example trial for the ARE. Here a test point is presented
at [-3° -6°], relative to the current point of fixation. Fixation at trial
onset was unconstrained. The monitor was a Samsung 305T LCD,
gain-corrected in software for uniformity. (B) Mean threshold data
from the ARE, computed from 4 participants tested with their left
eye. Numbers show the final threshold estimate at each location, in
dB (higher = more sensitive). Note that the blind spot was measured
in an identical manner to all other points, with no prior assumptions
or constraints, in order to simulate an unknown scotoma.
Commercial Relationships: Pete R. Jones, None; Sarah
Kalwarowsky, None; Gary S. Rubin, None; Marko Nardini, None
Support: This work was supported by Fight for Sight, the NIHR
Biomedical Research Centre at Moorfields Eye Hospital NHS
Foundation Trust and UCL Institute of Ophthalmology, the Special
Trustees of Moorfields Eye Hospital, and the Leverhulme Trust.
Influence of visual field threshold fluctuation on high resolution
perimetry with 0.5-degree interval
Takuya Numata1, Chota Matsumoto1, Sachiko Okuyama1,
Fumi Tanabe1, Shigeki Hashimoto1, Mariko Eura1, Tomoyasu
Kayazawa2, Sayaka Yamao1, Yoshikazu Shimomura1, Ted Maddess3.
1
Ophthalmology, Kinki Univ Faculty of Medicine, Osaka-Sayama
City, Japan; 2Ophthalmology, Kinki University Faculty of Medicine,
Nara Hospital, Ikoma, Japan; 3Biology & Environment, Australian
National University College of Medicine, Canberra, ACT, Australia.
Purpose: It is well known that visual field threshold can fluctuate.
The fluctuation is small where the visual field threshold is small, and
the fluctuation is large where it is large. The visual field threshold
also fluctuates at localized areas such as scotoma. We performed an
observational clinical study using high resolution perimetry with
0.5-degree interval to investigate the factors for the visual field
threshold fluctuation.
Methods: Sixteen eyes of 16 patients with glaucoma (mean age: 63.1
± 5.9) were studied. Octopus 900 Custom test program was used with
target size III and background luminance of 31.4 asb to measure the
sensitivity on the upper temporal meridian of 45 degrees from the
fixation point to the eccentricity of 30 degrees with the interval of 0.5
degrees. The sensitivity was evaluated 3 times at each point. Visual
field threshold was determined by computing the mean sensitivity of
the 3 repeats at each test point. The standard deviation was defined
as test- retest SD. In order to evaluate local visual field threshold
fluctuation at scotoma or else, we also computed Spatial SD along
each sample line using a moving window of between 3 and 20 points
wide.
In addition, we computed the independent variable Spatial Interaction
(SI) multiplying visual field threshold by Spatial SD at each point.
Using univariate correlation analysis, associations were examined
between test- retest SD and visual field threshold, Spatial SD, SI, and
the eccentricity. We also did a multivariate regression analysis to look
for the independent factors that best determined test- retest SD.
Results: Univariate correlation analysis revealed test- retest SD
was significantly correlated (p < 0.002) with the eccentricity, visual
field threshold, Spatial SD, and SI. Test- retest SD showed strongest
correlation with visual field threshold (p < 0.002; r = -0.342) and
Spatial SD (p < 0.002; r = 0.452). Multivariate regression analysis
showed test- retest SD was affected by visual field threshold (p <
0.01; t-value 5.05) and Spatial SD (p < 0.01; t-value 12.5).
Conclusions: Visual field threshold fluctuation was mostly affected
by visual field threshold and Spatial SD.
Commercial Relationships: Takuya Numata, None; Chota
Matsumoto, None; Sachiko Okuyama, None; Fumi Tanabe,
None; Shigeki Hashimoto, None; Mariko Eura, None; Tomoyasu
Kayazawa, None; Sayaka Yamao, None; Yoshikazu Shimomura,
None; Ted Maddess, None
411 Color and neural circuitry
Wednesday, May 06, 2015 8:30 AM–10:15 AM
Retinal Mediator of Uniform Hue Perceptions
Nathaniel D. Douda, Jamie K. Opper, Andrew I. Wilson, Katie
T. Youngpeter, Vicki J. Volbrecht. Psychology, Colorado State
University, Fort Collins, CO.
Purpose: Stimuli presented either to the fovea or to the peripheral
retina differ in color, yet in everyday living we usually do not
view stimuli in isolation as we do in the laboratory. How is color
perception determined when a stimulus covers both the fovea and the
peripheral retina? Does the fovea determine the overall perception,
does the peripheral retina determine the overall perception, or does
the overall perception represent an average of the different retinal
areas? This study investigated how information from the fovea and
peripheral retina are combined to give one uniform perception.
Methods: Monochromatic (420-660 nm) circular (1°, 23°) or annular
(17° inner diameter, 23° outer diameter) stimuli were equated to 1.3
log td and presented for 500 ms. After 30 min dark adaptation the
four observers described their hue perceptions using the “4 + 1” huenaming procedure.
Results: Similar to previous findings from our laboratory, the hue
perceptions for the 1° foveal stimulus differed from that for the
annular stimulus. In particular, the annular stimulus appeared greener
across the visible spectrum and more yellow and saturated in the
midspectral region of the visible spectrum compared to the foveal
stimulus. The hue-naming data were strikingly similar between the
annular and 23° circular stimuli.
Conclusions: Initial findings indicate that when a stimulus covers
both the foveal and peripheral regions of the retina, the peripheral
retina determines the overall hue perception of the stimulus.
Commercial Relationships: Nathaniel D. Douda, None; Jamie
K. Opper, None; Andrew I. Wilson, None; Katie T. Youngpeter,
None; Vicki J. Volbrecht, None
Support: NSF112771
Functional organization of color in the trichromatic cone mosaic
Ramkumar Sabesan1, Brian Schmidt2, William S. Tuten1, Alexandra
Boehm1, Austin Roorda1. 1School of Optometry and Vision Science
Graduate Group, University of California, Berkeley, Berkeley, CA;
2
Graduate program in Neuroscience, University of Washington,
Seattle, WA.
Purpose: At the scale of single receptors, luminance and color are
indistinguishable in the retinal image, yet the visual system is capable
of reconstructing fine spatial detail and rich color experience from
the external world. The mechanisms by which percepts of color are
derived from individual cones and facilitated by the postreceptoral
circuitry remain unclear. Our goal was to investigate the contribution
of individual cones to color perception and how it depends on the
spectral topography of the cone mosaic.
Methods: The cone mosaic at 1.5 deg eccentricity was spectrally
classified with adaptive optics(AO) imaging and densitometry. Hue
percepts were recorded by individually stimulating cones in this
region with AO-corrected, cone-sized and retinally-stabilized stimuli
at 543nm. The stimuli appeared on a neutral white background. While
an entire gamut of hue choices was available, pilot experiments
revealed that responses were categorized under only red, green, white
and not-seen under these stimulus conditions. Color responses were
analyzed for purity, dependence on local cone-type environment and
spatial clustering.
Results: Purity, defined as the number of responses in the most
frequently named color category divided by the total number of
trials, was 0.73 on average across cones and departed consistently
from random behavior. White was reported 50% of the time across
L & M cones. In cases when a color other than white was reported,
L-cones signaled red while M-cones signaled green in 90% of trials.
Color responses depended significantly on the surrounding cone
environment. For L-cones, the proportion of ‘red’ decreased and
‘white’ increased with increasing M+S cones in the surround. For
M-cones, the proportion of ‘green’ decreased and ‘white’ increased
with increasing L+S cones in the surround. Overall, sub-mosaics of
same color responses, consisting of more than one cone, emerged.
Conclusions: Color sensations elicited from individual cones were
repeatable and showed a strong dependence on cone-type. White
reporting cones were situated in a mixed cone-type neighborhood,
while color (red/green) reporting cones were situated amidst their
same cone-types. Overall, these findings were inconsistent with
models of single cone-center opponent midget ganglion cells at
the fovea. It rather suggests spatial pooling via cone coupling,
correlations between neighboring ganglion cell outputs or
convergence elsewhere in the visual pathway.
Commercial Relationships: Ramkumar Sabesan, None; Brian
Schmidt, None; William S. Tuten, None; Alexandra Boehm, None;
Austin Roorda, University of Houston (P), University of Rochester
(P)
Support: NIH R01EY023591, Burroughs Wellcome Fund Career
Award at the Scientific Interface, Fight for Sight Postdoctoral
Award, NIH K23EY022412, American Optometric William C. Ezell
Fellowship,NIH T32EY07031, NIH T32EY007043
Studying the neural circuitry of blue with single cone stimulation
Brian Schmidt1, Ramkumar Sabesan2, William S. Tuten2, 3, Jay
Neitz4, Austin Roorda2, 3. 1Graduate Program in Neuroscience,
University of Washington, Seattle, WA; 2School of Optometry,
University of California, Berkeley, CA; 3Vision Science Graduate
Group, University of California, Berkeley, CA; 4Department of
Ophthalmology, University of Washington, Seattle, WA.
Purpose: More than a half-century of psychophysical experiments
have indicated blue-yellow and red-green neural channels are
responsible for color perception. Physiological recordings have
identified single neurons early in the visual pathway with red-green
and blue-yellow responses. However, the cone inputs necessary to
produce color sensations as measured psychophysically do not align
with the characteristics of opponent cells measured physiologically.
To reconcile biology with perception, we measured color percepts
elicited by stimulation of identified single cones in a human subject.
Methods: An adaptive optics scanning laser ophthalmoscope was
used with retinal densitometry to classify (as L, M or S) ~1000
cones in a subject. Using the same system, single cone stimulation
(543 nm) was achieved following published methods [Harmening
et al. 2014 J Neuroscience]. The subject was instructed to report the
sensation elicited by each stimulus using an electronic tablet. Pilot
work indicated that, under our experimental conditions, red, green,
blue, yellow and white were sufficient color categories to adequately
describe the percepts.
Results: On a dim white background these single cone conditions did
not elicit blue percepts. To encourage blue sensations, we adopted
a background dominated by short wavelengths to preferentially
hyperpolarize S-cones. Under these conditions, when the flash was
detected, the percentage of percepts named blue was 22%, white 60%
and red 18%. Stimulation of L-cones rarely resulted in blue percepts
(9% of trials). M-cones were significantly more likely to result in
blue responses (43% of trials). Finally, when M-cones were targeted,
the probability of seeing blue decreased as distance to the nearest
S-cone increased.
Conclusions: These results provide direct evidence that blue
percepts can be driven by stimulation of individual M-cones. The
increased likelihood of blue responses with M-cone proximity to
S-cones suggests this sensation arises when M-cones sum with
S-cones in post-receptoral pathways. Small bistratified ganglion
cells, assumed to be the retinal pathway responsible for blue color
perception, however, difference S- and M-cone signals, exactly the
opposite of the trend found here. Our results are consistent with the
existence of alternative neural circuitry in the retina responsible for
mediating blue sensations in which outputs of S + M cone signals are
differenced from L-cones.
Commercial Relationships: Brian Schmidt, None; Ramkumar
Sabesan, None; William S. Tuten, None; Jay Neitz, None; Austin
Roorda, University of Rochester, University of Houston (P)
Support: NIH R01EY023591 to AR, American Optometric William
C. Ezell Fellowship and NIH K23EY022412 to WT, Burroughs
Wellcome Fund Career Award at the Scientific Interface & Fight for
Sight Postdoctoral Award to RS, and Vision Research Training Grant
T32EY07031 to BPS
Six-year follow-up of individuals heterozygous for the T190I
mutation in the S-cone-opsin gene (OPN1SW)
Lene A. Hagen, Stuart J. Gilson, Rigmor C. Baraas. Department of
Optometry and Visual Science, Faculty of Health Sciences, Buskerud
and Vestfold University College, Kongsberg, Norway.
Purpose: Heterozygotes for the T190I OPN1SW mutation have been
reported to have a mild tritan deficiency associated with abnormal
S-cone function (Baraas, Hagen et al. 2012). We carried out a followup study to investigate whether there was any deterioration of S-cone
function six years after the initial examination.
Methods: Females (aged 30–42 yrs) heterozygous for the T190I
mutation in the S-cone-opsin gene (OPN1SW) with an associated
tritan color-vision-deficiency and healthy color normal controls
(aged 30–44 yrs) were included in this study. All participated in the
initial study (Baraas, Hagen et al. 2012), and all had normal logMAR
letter acuity and no observed ocular abnormalities. Color vision
was examined with a battery of standard tests, including Moreland
anomaloscopy and Cambridge Colour Test.
Achromatic and isolated S-cone spatial acuity were measured in the
dominant eye with a Sloan E letter at 90% achromatic contrast and
at 23, 46, 69 and 90% S-cone contrast. The Sloan E was presented
at 5 deg eccentricity, and fixation was verified by an eye-tracker.
Observers were corrected to best logMAR letter acuity and viewed
the stimuli monocularly from a distance of 2.3 m. Average luminance
of the stimuli was 10 cd m-2.
Results: Observers with the T190I mutation showed poorer
performance along the tritan axis on standard color tests, whereas
normal controls showed no change six years after the initial test.
Achromatic acuity ranged from logMAR 0.26–0.44. S-cone spatial
acuity increased with increasing cone contrast for all observers, but
those with the T190I mutation could not perceive the S-cone stimuli
at the lowest cone contrast. Their performance was more than 2 SD
poorer than the controls at 46 and 69% and 1–2 SD poorer at 90%
cone contrast.
Conclusions: Tritan color vision deficiency caused by T190I
OPN1SW mutation appears not to be stationary. The results from
measurements of S-cone acuity at different levels of cone contrast
confirm that the T190I mutation is consistent with a loss of function
in a single dose.
Commercial Relationships: Lene A. Hagen, None; Stuart J.
Gilson, None; Rigmor C. Baraas, None
Melanopsin-mediated light adaptation measured from human
pupil flicker responses
Dingcai Cao, Pablo A. Barrionuevo. Ophthalmology and Visual
Sciences, University of Illinois at Chicago, Chicago, IL.
Purpose: Intrinsically photosensitive retinal ganglion cells (ipRGCs)
can be activated by intrinsic melanopsin phototransduction as well as
by extrinsic inputs from rods and cones. Studying melanopsin-based
functions is challenging in humans, due to the difficulty in isolating
melanopsin activation from rod and cone inputs. Here we introduced
a five-primary photostimulator that can control the excitations of
rods, S-, M-, L-cones and melanopsin at a constant light level to
allow for assessment of melanopsin-, rod- or cone-mediated light
adaptation.
Methods: The photostimulator included a bundle of five optic
fibers to transmit the lights from the five bright LEDs through a
homogenizer and diffuser to achieve a homogeneous field. The lights
from 5 LEDs (dominant wavelengths of 456 nm, 488 nm, 540 nm,
592 nm, and 632 nm) were controlled by a laboratory-created board
using Pulse Width Modulation dimming. Using a silent substitution
method, the photostimulator could generate photoreceptorisolating stimuli that modulated the rod excitations alone (R), cone
excitations alone (S-, M- or L), melanopsin excitation alone (I),
or any combinations of the photoreceptor signals. We measured
human pupil responses with the L, M, S, R, I, L+M, L+M+S,
L+M+S+R, L+M+S+R+I modulations (16% contrast, 1 Hz, mean
retinal illuminance of 2 Td-20000 Td in a one log unit step), using an
EyeLink II Eyetracker (SR Research). For each condition, pupillary
response amplitude and phase were derived from Fourier analysis.
Results: For all modulation types, the pupil response amplitudes
increased with increasing light levels, although the pupil responses
were not measurable for the melanopsin modulation at 2 Td due to
below melanopsin activation threshold, for the rod modulation at
2000 and 20000 Td due to saturation, and for the S- modulation at 2
and 20 Td due to low contrast sensitivity. The melanopsin-mediated
pupil responses had similar phases to rods, L, M, L+M stimuli but
was out of phase with the S-cone-mediated response. While the
phases with the rod or cone-mediated responses were relatively stable
over 2 Td -20000 Td, the phase of melanopsin-mediated responses
increases with increasing light levels, suggesting speeding up of the
melanopsin phototransduction.
Conclusions: Melanopsin displays a unique light adaptation
characteristic compared with rod- and cone-mediated light adaptation
in pupil flicker responses.
Commercial Relationships: Dingcai Cao, None; Pablo A.
Barrionuevo, None
Support: P30-EY01792 (UIC core grant for vision research) and
Unrestricted Departmental Grant from the Research to Prevent
Blindness
Longitudinal Imaging of Foveal Cone Structure in Congenital
Achromatopsia
Christopher S. Langlo1, Frederick T. Collison2, Phyllis Summerfelt3,
Carol White2, Alfredo Dubra3, 4, William W. Hauswirth5, Gerald
A. Fishman2, 6, Joseph Carroll1, 3. 1Cell Biol, Neurobiol, Anatomy,
Medical College of Wisconsin, Milwaukee, WI; 2The Pangere Center
for Hereditary Retinal Diseases, The Chicago Lighthouse for People
Who Are Blind or Visually Impaired, Chicago, IL; 3Ophthalmology,
Medical College of Wisconsin, Milwaukee, WI; 4Biophysics, Medical
College of Wisconsin, Milwaukee, WI; 5Ophthalmology, University
of Florida, Gainesville, FL; 6Ophthalmology and Visual Sciences,
The University of Illinois at Chicago, Chicago, IL.
Purpose: Achromatopsia (ACHM) is a disorder associated with
absent or severely limited function and variably-disrupted structure
in cone photoreceptors. In order to monitor the efficacy of gene
therapy efforts in this condition, it will be necessary to quantitatively
monitor cone structure over time in individual retinas. Here we
demonstrate the use of split-detection adaptive optics scanning light
ophthalmoscopy (AOSLO) to longitudinally evaluate foveal cone
structure in patients with ACHM.
Methods: Seven subjects with genetically confirmed ACHM were
recruited. Confocal and split-detector AOSLO and SD-OCT imaging
were performed at baseline and 9-10 months later. Peak foveal cone
density was determined by manually outlining the rod-free zone as
seen on confocal imaging – a variably sized area between image sets
– and marking cells in that region, then measuring 27x27μm areas
centered on each pixel.
Results: One subject had outer retinal atrophy in the fovea
preventing foveal analysis. Another had a corneal abrasion at the
first examination that prevented imaging, though this resolved
by the second visit, and in a third subject the foveal center was
not captured with the split-detector method at the first visit. The
remaining 4 subjects showed little variability of residual foveal
cone structure between the baseline and follow up visit. The peak
densities at baseline for these subjects were 19,204, 16,460, 8,230,
and 21,948 cones/mm2 and 15,089, 19,204, 5,487, and 26,063 cones/
mm2 on follow-up respectively. The change in density between visits
corresponded to an average difference of 2.5 cones in the search
window. The OCT images showed no change in phenotype between
visits based on previously published grading criteria (Sundaram V, et
al. Ophthalmology 2014;121:234-245).
Conclusions: Due to nystagmus this is a particularly challenging
patient population in which to obtain reliable longitudinal measures
of cone structure. Despite this, we have demonstrated that we can
re-image the exact same photoreceptors over a 9-month follow-up
period and that there does not appear to be substantial change in
foveal cone structure. The ability to obtain repeated measurements of
structure will allow sensitive monitoring of the biological response to
treatment in these patients.
Commercial Relationships: Christopher S. Langlo, AGTC (F);
Frederick T. Collison, AGTC (F), AGTC (R); Phyllis Summerfelt,
AGTC (F); Carol White, AGTC (F); Alfredo Dubra, AGTC (F), US
Patent 8,226,236 (P); William W. Hauswirth, AGTC (C), AGTC (F),
AGTC (P); Gerald A. Fishman, AGTC (F); Joseph Carroll, AGTC
(F)
Support: NIH Grants R24-EY022023, R01-EY017607, P30EY001931, T32-GM080202; Glaucoma Research Foundation
Catalyst for a Cure, Research to Prevent Blindness Career
Development Award, Pangere Family Foundation
disparity between test and basic objects – stereo-acuity are recorded
and presented in tables and diagrams.
Given the lack of stereovision it is induced and trained with special
exercises. The movements “forward – backward” are trained and
the references where a test object must be located may be provided.
Significant role is played by two factors: sight shifting from the
closer object to the more distant one and its coordination with hand
movements.
In trainings with the disparity of 6-15 arcminutes (6’-15’) the
stereoscopic view corresponding the movement of hand and eyes is
gradually accumulated and formed. Trainings increase the stereoacuity. By seeing his/her results and receiving references a trainee
corrects the movements of his hand and eyes gradually increasing his/
her stereo-acuity.
Results: More than 50 individuals passed the tests, 15 of those were
instructed and received the stereovision training.
Static stereo-acuity of 35 individuals was up to 2’ and dynamic
stereo-acuity was about 4’-6’. They had no complaint of stereoacuity and those values may be considered as sufficient. Out of 15
individuals who had no stereovision only one of them failed to induce
it by training in a few months.
Tests may be used for the evaluation of acuity of stereovision and
stereo-activity of individuals of different occupations, drivers and
surgeons inclusive.
Conclusions: Evaluation and training of characteristics of
stereovision by using an integral model with feedback confirm its
high integrity, precision and effectiveness.
423 Visual performance: Normal vision
Wednesday, May 06, 2015 8:30 AM–10:15 AM
Contributing Section(s): Eye Movements/Strabismus/Amblyopia/
Neuro-Ophthalmology, Low Vision
Research and Training of Stereovision with Integral Feedback
Mecislovas Vrubliauskas4, 1, Igor Rabichev3, 2. 1Aesthetic Dentistry
Center Vivadens, Vilnius, Lithuania; 2Center of Investigation and
Vision Correction ‘Perception’, Moscow, Russian Federation; 3The
department of anatomy and physiology of humans and animals,
Moscow State Pedagogical University, Moscow, Russian Federation;
4
VISUS-4D Center, Vilnius, Lithuania.
Purpose: Sensorimotor models of visual perception are distinguished
for their effectiveness in evaluation and training of stereovision, but
they lack integrity, feedback and accuracy.
This study researches an integral model and method of stereovision
with a feedback which increase the accuracy and effectiveness of
measurement, inducing and training of stereovision.
Methods: Method and software may test, induce and train the
stereovision for people with healthy and disordered binocular
vision. It consists of a personal computer, optic system and VISUS4D software. Basic and test - static or dynamic stereo objects are
projected on a monitor screen. A basic stereo object is operated by
the software and a test object - manually by a tested individual.
The scheme of the model is presented in the image. The results of
Commercial Relationships: Mecislovas Vrubliauskas, None; Igor
Rabichev, None
Learning to read using peripheral vision through non-task-based
training: prerequisites for learning and its transfer
Deyue Yu. College of Optometry, Ohio State University, Columbus,
OH.
Purpose: Reading speed in peripheral vision can be improved
through perceptual learning. Perceptual learning paradigms typically
require practicing a demanding task hundreds of trials per day,
which can be an impediment to compliance from patients. To
minimize training effort, Yu (ARVO 2013) developed a non-taskbased training procedure utilizing stimulus exposure and identity
priming. The goal of this study is to identify the factor(s) that
determine the effectiveness of non-task-based learning in improving
peripheral reading speed. The findings will be of great importance for
developing a useful form of low-vision reading rehabilitation.
Methods: Twenty-eight normally-sighted young adults were
randomly assigned to a no-training control group or one of four
training groups that differed with respect to the inclusion of different
design components. Pre- and post-tests consisted of measurements of
visual-span sizes (number of letters recognized without moving the
eyes) and reading speeds using the rapid serial visual presentation
method at 10° above and below fixation. Training occurred at 10°
below fixation. Three design components were visual exposure to
crowded letter (target letter flanked by two other letters on the left
and right), visual exposure to uncrowded letter (target letter alone),
and identity priming (pre-knowing target letter identity). In five
training sessions (1430 trials/session), group A viewed crowded
letters, group B viewed crowded letters with identity priming,
group C viewed uncrowded letters with identity priming, and group
D viewed letters with identity priming under both crowded and
uncrowded conditions.
Results: Comparisons between different groups revealed an essential
role of crowding in ensuring reading-related learning. Groups
A, B and D showed significant improvement in visual-span size
(gaining 1.2 to 1.4 letters; all p<0.0005). Only stimulus exposures
that occurred simultaneously with identity priming enabled learning
transfer to the untrained reading task (62% increase for group B and
78% for group D; all p<0.0005). Learning also transferred from the
trained (lower) to the untrained (upper) visual field (all p<0.03).
Conclusions: Non-task-based training can greatly reduce learning
effort. Furthermore, including crowding and identity priming in
the training paradigm is the prerequisite for effective learning in
improving peripheral reading speed.
Commercial Relationships: Deyue Yu, None
New postural behaviors related to the use of digital devices
involve new characteristics for occupational lenses
Damien Paille, Jean-Luc Perrin, Amandine Debieuvre. Vision
Science, ESSILOR, Paris, France.
Purpose: Since the last decade, we see an explosion in the use of
smartphones, tablets, e-book readers and hybrid devices which
combine laptop and mobile functions. Those tools, also called
“handheld or mobile devices”, can be use everywhere: standing up
whilst commuting, sat in a couch, lying in bed... This study aims
to investigate the impact of the use of new technology devices on
postural behavior in everyday life.
Methods: 22 subjects wearing their usual correction were recruited
in the experiment. They wore a helmet with 4 reflective markers and
were equipped with 4 additional markers (Left and right shoulder,
torso and clavicle). Once fitted, they performed a scenario mixing
7 different tasks (weather forecast, writing an email, reading an
email, video game, video, searching information, reading a text) on
three digital devices (smartphone, tablet and ebook reader) in three
different conditions (standing, sitting and lying). Postural data were
recorded thanks to a VICON motion tracking system. Subjects were
asked to act as they would do in real life during the experiment. For
each task, several parameters such as distance between the eyes and
the middle of the device, head declination, eye declination, head roll,
head in trunk rotation and shift were then computed.
Results: During all the tasks, the head stays perpendicular to the
trunk (Mean Head in trunk rotation: 0.13±1.4°) with no roll (Mean
Head roll: 2.87±1.23°). The middle of the device remains centered
on the sagittal plane of the user (Mean head shift: 2.3±2.5°). Contrast
analysis showed that eye declination was higher when standing
compared to sitting and lying tasks (difference 6.68°, CI(95%) [4.87;
8.50], p<0.01). The distance of use was smaller with smartphones
compared to tablets or ebook readers (difference 5.35cm, CI(95%)
[3.92; 6.78], p<0.01). Results showed small reading distances with
digital devices (smartphones: 33.79cm, tablets: 39.70cm, ebook
readers: 38.05cm).
Conclusions: The experiment showed that digital device users
are adopting rigid postures in front of their devices. Moreover, the
distance of use is smaller and eye declination higher with electronic
devices compared with traditional paper media. Occupational lenses
must thus take into account these new postural behaviors in order to
answer all the wearer needs.
Commercial Relationships: Damien Paille, ESSILOR (E); JeanLuc Perrin, ESSILOR (E); Amandine Debieuvre, ESSILOR (E)
Exploring the role of biological motion in enhancing night-time
pedestrian recognition: assessment of eye movements
Joanne M. Wood1, Richard Tyrrell2, Alex A. Black1, Philippe F.
Lacherez1. 1Queensland University of Technology, Brisbane, QLD,
Australia; 2Clemson University, Clemson, SC.
Purpose: To examine drivers’ eye movements as they approach
pedestrians wearing retroreflective markers in a configuration that
conveys biological motion (known as “biomotion”).
Methods: Twenty visually normal participants (M=24.35 ± 6.42
years) drove an instrumented vehicle (incorporating a custom-built
distance measurement system) around a 1.8 km closed-road circuit
at night. Pedestrians wore black clothing and walked in place at
two different locations along the course, and faced either towards
or away from the roadway. Pedestrians wore two conspicuity
treatments – either a standard retroreflective vest or a retroreflective
vest with additional retroreflective tape positioned on the extremities
in a configuration that conveyed biological motion (biomotion).
Participants pressed a response pad when they first recognized
that a pedestrian was present and again when they first detected
the direction that the pedestrian was walking. Eye movements
were recorded (ASL Mobile Eye) to characterize drivers’ fixation
behaviours when viewing the pedestrians; the time to first gaze at the
pedestrian and response time to first recognize the pedestrian were
expressed as time relative to the moment when the pedestrian was
first in the drivers’ field of view.
Results: Eye movement patterns revealed that the biomotion
configuration attracted drivers’ attention significantly sooner
compared to the vest (time to first gaze: 1.1 vs 3.5 s). Drivers spent
significantly less time fixating on the pedestrian wearing biomotion
prior to recognition compared to the vest (3.4 s vs. 6.1 s). As a
result the drivers’ response time to first recognize the pedestrian was
approximately half that for biomotion compared to the vest (6.4 vs
13.9 s). Consistent with these findings, drivers recognized pedestrians
at significantly longer distances when wearing biomotion compared
to the vest (331.6 m vs. 185.2 m) and identified the direction of
walking at longer distances (220.2 m vs. 87.7 m).
Conclusions: At night the biomotion configuration facilitated
earlier recognition of pedestrians and identification of their walking
direction, thus enhancing drivers’ capacity to avoid pedestrians.
Patterns of eye movements reveal the impact of pedestrian
conspicuity on drivers’ attention and gaze behaviors at night-time.
Commercial Relationships: Joanne M. Wood, None; Richard
Tyrrell, None; Alex A. Black, None; Philippe F. Lacherez, None
Support: ARC Linkage LP0990292
Visual performance and perception with bifocal and trifocal
presbyopia corrections simulated using a hand-held simultaneous
vision device
Carlos Dorronsoro, Jose Ramon Alonso-Sanz, Daniel Pascual,
Aiswaryah Radhakrishnan, Miriam Velasco-OCana, Pablo PerezMerino, Susana Marcos. Instituto de Optica, CSIC, Madrid, Spain.
Purpose: To evaluate visual performance/perception in patients
with simulated multifocal corrections, using a novel hand-held
simultaneous vision simulator and clinically-suited visual tests. To
identify the optimal multifocal correction in individual patients.
Methods: 5 cyclopeged subjects were evaluated with a miniaturized
see-thru simultaneous vision simulator. Multifocal corrections are
simulated by a tunable lens (Optotune, AG) operating in temporal
multiplexing, able to scan through a 3-diopters (D) addition focus
range at 50 Hz, giving a static appearance of multifocal retinal
images. Evaluation of the lens by HS-aberrometry and laser ray
tracing focimetry reveal high linear response of optical power vs
voltage (r=0.997), high optical quality (RMS<0.05 μm), and high
reproducibility of thru-focus energy distribution. Seven lenses were
simulated, with different energy distributions at far (F) intermediate
(I; 1.5D add) and near (N; 3D add): 3 monofocal (100F, 100I &
100N), 2 bifocal (50F50N & 70F30N) and 2 trifocal (33F33I33N &
50F20I30N) patterns. With each lens, high contrast visual acuity (VA)
was measured at F, I and N distances using randomized optotypes on
a high definition display. Also, subjects scored the perceived quality
of a real visual scene containing F, I and N targets, and compared
visual quality (2AFC) through 60 random pairs of multifocal
corrections.
Results: Average logMAR VA at F ranged between -0.05 (100F) and
0.52 (100N) for monofocal, and between 0.17 (50F20I30N) and 0.43
(33F33I33N) for multifocal corrections (mean 0.25). VA ranges at N
were 0.12 (100N) to 0.61 (100F) with monofocal, and 0.26 (50F50N)
to 0.42 (70F30N) with multifocal corrections (mean 0.31). Highest
multifocal VA at I (0.25) was found for 33F33I33N. On average
across distances the highest VA and perceptual scores were found for
100I. Direct comparisons revealed a systematic preference of 50F50N
over 70F30N and 50F20I30N over 33F33I33N. However, consistent
intersubject differences occurred in VA and perception with the
different multifocal corrections.
Conclusions: Temporal multiplexing of a tunable lens provides
new ways to simulate multifocal corrections, mimicking existing
IOLs/CLs. All multifocal designs outperform monofocal corrections
focused at far and near, but not at intermediate distance. Visual
quality differed across multifocal designs and patients.
Commercial Relationships: Carlos Dorronsoro,
PCT/2014ES/070725 (P), PCT/ES2010/070218 (P); Jose Ramon
Alonso-Sanz, PCT/2014ES/070725 (P), PCT/ES2010/070218
(P); Daniel Pascual, PCT/2014ES/070725 (P); Aiswaryah
Radhakrishnan, None; Miriam Velasco-OCana, None; Pablo
Perez-Merino, None; Susana Marcos, PCT/2014ES/070725 (P)
Support: FIS2011-25637; ERC-2011-AdG-294099; EU Marie Curie
FP7-PEOPLE-2010-ITN #26405
Exposure to green laser decreases driving performance
Per G. Soderberg1, Stig Sandberg2, Ulf Hörberg2, Rolf Persson2,
Folke Berglund2, Kjell Karlsson2, Johan Öhgren2, Zhaohua Yu1, Ove
Steinwall Ove Steinwall2. 1Gullstrand lab, Ophthalmology, Dept. of
Neuroscience, Uppsala university, Uppsala, Sweden; 2Laser Systems
group, Swedish Defense Research Agency, Linköing, Sweden.
Purpose: To determine the impact of 532 nm laser exposure on
vision and thereby driving performance.
Methods: Ten non-professional drivers aged [24;50] yrs drove a test
track through gates of 4 plastic cones with randomly placed openings,
allowing free passage. A 532 nm laser beam, 45 mrad divergence,
was directed against the advancing test driver every second test drive.
Irradiance increased from 2 Wm-2 at the entrance of the test track
to 5 Wm-2 at the last gate (MPE = 10 Wm2). The spatial distribution
and the irradiance of the beam was verified before and after each
test drive. Driving speed was 25 kmhr-1 at the entrance gate and then
at the drivers choice. For each driver, the background illuminance
varied from daylight to darkness, [1000-0.01 lux]. Altogether, 32 test
drives per driver were analyzed. The significance level was set to
0.05.
Results: None of the subjects recruited had any ophthalmological
disorder before or after test driving.
A driver perceives less driving certainty with laser exposure than
without as indicated by Wilcoxon’s paired sample test.
An analyses of variance supported that laser exposure increases
driving time and indicated an interaction between laser exposure and
background illumination.
A chi2 analysis indicated that laser exposure is associated with more
wrong choices of gate and more hits of cones than driving without
laser exposure. A descriptive analysis indicated more wrong choice of
gate and more hit cones with less background luminance.
Sun visor folded down when exposed to laser was advantageous
on driving time, number of wrong gates chosen per driver, and
accumulated number of cones hit as indicated by paired t-test and chi2
analysis.
Conclusions: Exposure to 532 nm laser light while driving below
25 kmh-1 in dark conditions decreases perceived safe driving
speed, causes wrong decision of road geometry, increases risk of
mispositioning the vehicle, and decreases the subjective perception
of controlled driving. Sun visor folded down during green laser
exposure improves the driving performance and the perception of
driving certainty.
Commercial Relationships: Per G. Soderberg, None; Stig
Sandberg, None; Ulf Hörberg, None; Rolf Persson, None; Folke
Berglund, None; Kjell Karlsson, None; Johan Öhgren, None;
Zhaohua Yu, None; Ove Steinwall Ove Steinwall, None
Support: Swedish defense research agency (FOI), The Uppsala
university/Uppsala Läns Landsting’s ALF Research grants,
Synskadades vänner, Uppsala, Kronpricessan Margaretas
Arbetsnämnd för synskadade
The sensitivity of human infrared vision is age-dependent
Katarzyna Komar1, Patrycjusz Stremplewski1, Agnieszka Zielinska1,
Grazyna Palczewska2, Krzysztof Palczewski3, Maciej Wojtkowski1.
1
Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus
University, Torun, Poland; 2Department of Medical Devices, Polgenix
Inc, Cleveland, OH; 3Department of Pharmacology, Cleveland Center
for Membrane and Structural Biology, School of Medicine,, Case
Western Reserve University, Cleveland, OH.
Purpose: Pulsed IR laser light is detectable by humans and causes
sensation of color corresponding to roughly half of the stimulus
wavelength. Some authors recently explained this phenomenon
as resulting from two-photon isomerization of chromophore in
human photoreceptors. Here we describe the effect of age on this
phenomenon.
Methods: A beam from a laser source emitting a 1040 nm train of
200-fs pulses was coupled into an optical fiber of 2 m or 1 km length
to obtain the different pulse lengths, 1 ps or 300 ps, respectively.
After the fiber, the test set-up was arranged to create a linear scan on
the fundus, perceived by the volunteer as a horizontal line (Fig. 1). To
measure minimal power of the laser beam causing a visual sensation
(sensitivity threshold), a neutral density filter (NDF) filter was
adjusted by the subject during the test. Values measured by the power
meter were saved in PC memory after the subject pressed a mouse
button and measurements were repeated 10 times.
The setup was isolated from residual ambient light by its dedicated
housing, a subject’s head was covered by a black curtain attached to
the housing. All individuals were dark adapted.
The study was performed in 16 healthy volunteers of ages ranging
from 24-84 years. All tests were conducted in compliance with ANSI
Z136.1 and EN 60825−1. The study was approved by the Ethics
Committee of the Collegium Medicum NCU. Examinations were
carried out after written informed consent was obtained.
Results: The results are presented in Fig. 2. Volunteers were divided
into two groups differing in age. Mean threshold power values for
short pulses of the two groups were: 52±8 uW for subjects of age
<50 and 169±33 uW for the more elderly. For long pulses, means for
both groups were: 184±44 uW and 300±280 uW, respectively. The
one-way ANOVA test performed in the two groups with significance
level ≤0.05 showed that the mean values were significantly different
for short pulses but not for long ones.
Conclusions: This study indicated that the sensitivity threshold for
human IR vision is age-dependent for short pulses. The two-photon
absorption process is stronger for short pulses causing a statistically
significant correlation with age.
1. Optical set-up for sensitivity measurements.
2. Sensitivity thresholds for a 1040 nm beam with different pulse
lengths. Grey bars show mean values calculated for two subgroups
of volunteers: <50 years old (black symbols) and >50 years old (red
symbols).
Commercial Relationships: Katarzyna Komar, None; Patrycjusz
Stremplewski, None; Agnieszka Zielinska, None; Grazyna
Palczewska, Polgenix Inc (E); Krzysztof Palczewski, Polgenix
Inc (E), US patent 7,706,863 (P), US patent 8,346,345 (P); Maciej
Wojtkowski, None
Support: This work was supported by TEAM project of Foundation
of Polish Science and by NIH R44 AG043645.
Evaluation of three distinct parameters for visual fatigue
assessment
Nisha Singh. R&D, Essilor, Singapore, Singapore.
Purpose: Various studies have measured accommodative
microfluctuations (AM) and Critical Flicker Fusion Frequency
(CFFF) for visual fatigue assessment. Also, several products are
available these days claiming relief from eyestrain mostly either by
relaxing accommodation or enhancing contrast. Apart from AM,
either CFFF or contrast measurements are not well established for
visual fatigue assessment. Therefore, this study aims to measure three
distinct parameters: AM, Contrast Sensitivity (CS) and CFFF in one
study; to compare their efficacy for the assessment of visual fatigue.
Methods: 30 non-symptomatic & non-presbyopic emmetropes (age
19-42 years) performed 30 min of visual search task displayed on
a LCD monitor placed 40 cm away from the eye. During the task,
fixation target was displayed for 1 min at the beginning and end of
the task. AM were analyzed from refraction recorded using PowerRef
II during fixations that is, before and after task. CS using Functional
Acuity Contrast Test (FACT) and CFFF with a Visual fatigue detector
(developed by a local company in China) was also measured before
and after the task. To obtain AM, Low frequency component (LFC)
<1Hz and High frequency component (HFC) 1.0Hz–2.5Hz were
acquired using FFT. In addition, subjective measurement of visual
fatigue was done using a questionnaire before and after the task.
Results: Subjective measurement of visual fatigue showed significant
increase after task (Wilcoxon signed rank test; p<0.05). Before and
after measurements were compared using paired t-test. Only LFC
of AM increased significantly (p<0.05) while CS (p >0.05 for all
measured spatial frequencies), CFFF (p =0.53) did not change after
the task.
Conclusions: Out of 3 parameters measured, only AM changed
significantly after performing 30 minutes of visually taxing task
which is in coherence with subjective measurement. Thus, reinforces
that AM is an effective indicator for visual fatigue assessment. As
induced visual fatigue could cause changes in the microfluctuations
of accommodation of non-symptomatic people implies that
symptomatic visual fatigue people would probably have exhausted
& fragile accommodative system and needs to be taken care of in the
management of visual fatigue.
Commercial Relationships: Nisha Singh, ESSILOR (E), ESSILOR
(F), ESSILOR (P)
Comparison of Psychophysical and Electrophysiological Acuity
Measurements in Non-Human Primates (NHPs).
William H. Ridder1, Kai-Ming Zhang2, James A. Burke2. 1Marshall B.
Ketchum University, Fullerton, CA; 2Allergan, Inc, Irvine, CA.
Purpose: Non-human primates are frequently investigated to
understand human diseases of the visual system. A common clinical
measurement for many visual diseases is visual acuity. Visual acuity
can be measured by employing psychophysical (e.g., the contrast
sensitivity function) or electrophysiological (e.g. the sweep visual
evoked potential (sVEP)) techniques in NHPs. The purpose of this
investigation was to determine the relationship between acuities
determined with psychophysical and electrophysiological techniques
in the same NHPs.
Methods: Four normal, adult NHPs took part in this project.
The PowerDiva was used to measure the sVEP on three separate
occasions. The NHPs were anesthetized and paralyzed for the
measurements (10 mg/kg ketamine and 0.45 mg/kg zemuron). The
active electrode (i.e., a stainless steel needle) was placed over the
lunate sulcus of each hemisphere. Ten spatial frequencies from 3 to
30 cpd were presented at 80% contrast. The stimulus was focused
on the retina with a fundus camera stimulator. A minimum of 10
sweeps (minimum S/N 3.0) were averaged for an acuity estimate.
The psychophysical estimate of acuity was determined from the
contrast sensitivity function (measured three times on different days).
The monkeys were trained to release a lever when they detected a
sine wave grating on a monitor. Threshold was determined with a
descending method of limits. The contrast sensitivity functions were
fit with a double exponential function and the acuity was taken at the
80% contrast level.
Results: The average sVEP acuity was 18.6 ± 0.045 cpd and the
average acuity estimated from the contrast sensitivity function was
27.5 ± 7.86 cpd for the four NHPs. A paired t-test indicated that the
two test results were not significantly different (p = 0.109).
Conclusions: Even though the visual acuity is higher with the
psychophysical technique, there is no statistically significant
difference between the two measurements. Both results produced
repeatable data for a given NHP. Similar results are seen in human
subjects.
Commercial Relationships: William H. Ridder, None; Kai-Ming
Zhang, None; James A. Burke, None
Spatial vision in the mesopic range: the effect of illumination
spectra
Hanna Gillespie-Gallery, Gary Bargary, Wei Bi, John L. Barbur. City
University London, London, United Kingdom.
Purpose: The variation in the spatial resolving power of the cone and
rod systems with the level of illumination is well established. In the
mesopic range, when both cones and rods are active and operating at
the limit of their range, the situation is more complex. Recently, the
ability to fine-tune the spectral power distribution of LED lighting
installations has led to the potential for optimisations of illumination
spectra. These optimisations are limited by our current understanding
of how cones and rods contribute to functional vision in the mesopic
range. This study assessed visual acuity (VA) over some 4.7 log units
change in illumination with emphasis on the mesopic range. A fourprimary LED system was used to provide controlled rod and cone
stimulation.
Methods: VA thresholds were estimated on an eink reflective display
by a staircase procedure. The participants’ task was to indicate the
orientation of a Landolt C by button press. The illumination was
set to five different photopic luminances (0.001, 0.01, 0.1, 1 & 50
cd/m2). At each light level six different scotopic luminances were
investigated; scotopic/photopic (S/P) luminance ratios varied from
0.5-5.5. Measurements were carried out at the fovea and 12 degrees
in the periphery. Pupil diameter was recorded throughout and used to
calculate retinal illuminance. To ensure adequate fixation eye position
was measured and trials were repeated if fixation deviated more than
±1.5 degrees.
Results: The fovea was only affected significantly by variation in
S/P luminance ratios at the lowest light level when VA thresholds
were high and led to part of the stimuli lying outside the rod free
zone of the retina. In the periphery S/P ratios significantly improved
vision at light levels below 1 cd/m2. In the mid-mesopic range (0.1
and 0.01 cd/m2) VA was improved with increasing S/P ratio, whereas
at the lowest light level VA thresholds only improved only up to
an S/P ratio of 2.5. The change in pupil diameter with variations
in illuminants S/P ratio was small. Based on these findings we
explore the possibility that rod-cone interactions play a role in the
improvement of VA in the mid- to high-mesopic range.
Conclusions: In the mesopic range, VA in the periphery can be
improved by increasing the S/P ratio of the illuminant. When vision is
dominated by rod signals, VA improves significantly with increasing
S/P ratio.
Commercial Relationships: Hanna Gillespie-Gallery, None; Gary
Bargary, None; Wei Bi, None; John L. Barbur, None
Support: Engineering and Physical Sciences Research Council
The benefits of a Red Background when measuring Dark
Adaptation
Elena Rodrigo Diaz de Cerio, Jeremiah M. Kelly, David Carden,
Ian J. Murray. Faculty of Life Sciences, University of Manchester,
Manchester, United Kingdom.
Purpose: Dark Adaptation (DA) is now accepted as important for
the study of retinal health. The slope of the rod-mediated sensitivity
recovery function, called S2, is particularly affected in aging and
several diseases such as early age-related macular degeneration
(AMD). DA has not been extensively studied in clinics because of
the prolonged testing time and patient discomfort. Introducing a red
background, which is blind to the rods, should theoretically reduce
testing time and also be more acceptable compared with a black
background. Here we test this idea in a novel digital set up, designed
for application in a clinical setting.
Methods: A custom setup was used to measure DA curves in 11
subjects (mean age 32.5, sd 10.13 years). The test was performed
four times under four experimental conditions using zero and three
different red backgrounds (0.05, 0.10 and 0.20 cd.m-2 photopic) (λ
max=655 nm). Following a localized bleach, (min 30%), a method of
adjustment technique was used to respond to a flickering (4Hz) green
stimulus (λ max= 530 nm) at 80 on the temporal retina.
Results: Results: The time to rod cone break, sometimes called the
alpha point, was significantly shortened when the red background
was used. The mean alpha time decreased from 4.9 min, for the black
background to 4.0 min for the highest intensity red background (p
<0.001). Crucially the mean slope of the rod recovery, S2, (-0.29
(0.08) log10 (cd.m-2). min-1) was independent of background intensity
(p= 0.39) and matched values in the literature. Cone threshold rose
systematically as the red background increased (p<0.0001).
Conclusions: Conclusions: The addition of a cone-suppressing
background allows significantly quicker measurement of S2
compared with no background and is also more acceptable to
patients. Our technique has the potential to be useful for clinical
measurements of rod function in older and diseased eyes, particularly
in AMD where early diagnosis is important.
Commercial Relationships: Elena Rodrigo Diaz de Cerio, None;
Jeremiah M. Kelly, None; David Carden, None; Ian J. Murray,
None
Support: NERC Charity / scholarship Ref: 13194
Automated Photosensitivity Assessment in Achromatopsic and
Healthy Subjects
Mariela C. Aguilar1, Alex Gonzalez1, Cornelis J. Rowaan1, Potyra
R. Rosa2, Karam Alawa1, Byron L. Lam2, Jean-Marie A. Parel1,
3 1
. Ophthalmic Biophysics Center, Bascom Palmer Eye Institute,
University of Miami Miller School of Medicine, Miami, FL;
2
Ophthalmology, Bascom Palmer Eye Institute, University of Miami
Miller School of Medicine, Miami, FL; 3Brien Holden Vision
Institute, UNSW, Sydney, NSW, Australia.
Purpose: To assess and compare the photosensitivity discomfort
threshold in Achromatopsic and healthy subjects using the 2nd
Generation BPEI Photosensitivity Tester.
Methods: The 1st Generation instrument (Aguilar MC et al, IOVS.
2014; 55: E-Abstract 4108 and Alawa K, IOVS. 2014; 55: E-Abstract
4109) was modified to comprise a bi-cupola concave light array panel
with 210 white LED’s that are either manually controlled with a knob
or computer controlled. The light intensity ranges from 1-32,000 lux
at 50 cm. The instrument has two testing modes; one for subjects with
normal light tolerance, the other has an enhanced mode for subjects
having low light tolerance. The audio prerecorded testing instructions
can be provided in four languages (English, Spanish, French, and
Portuguese). The automated instrument varies the intensity of the
light stimuli and the subject is instructed in their preferred language
to indicate if it is uncomfortable by pressing a hand-held button.
The testing is complete after 10 response reversals, from which a
predicted photosensitivity threshold is calculated.
Thus far, seven Achromatopsic subjects (5 females and 2 males, age
= 14.3±6.0) and eleven healthy subjects (5 females and 6 males, age
= 31.9±8.5) were tested under an IRB approved protocol. Prior to
testing, the subjects rested during a 5 min. adaptation period in the
examination room illuminated with 4 lux. Ambient conditions are
monitored utilizing: humidity, temperature, and lux meters.
Results: Seven Achromatopsic subjects were found to have a
mean predicted photosensitivity threshold of 0.75±0.66 log(lux).
Eleven healthy subjects were found to have a mean predicted
photosensitivity threshold of 3.32±0.66 log(lux). A one-way analysis
of variance was performed and there is a statistically significant
difference (p<0.0001) in the threshold of photosensitivity experienced
between the Achromatopsic and healthy subject groups.
Conclusions: The autonomous 2nd Generation BPEI Photosensitivity
Tester can assess a wide range of photosensitivity thresholds by
detecting, quantifying, and recording the individual differences in
sensory capabilities. Ongoing studies are being conducted in order to
better understand the wide range of photosensitivity thresholds.
None; Karam Alawa, None; Byron L. Lam, None; Jean-Marie A.
Parel, None
Support: NEI Grant R24 EY022023, DOD Grant DAMDW81XWH-09-1-0675, Florida Lions Eye Bank, Drs. KR Olsen
and ME Hildebrandt, NIH Center Grant P30EY14801, Research to
Prevent Blindness, Henri and Flore Lesieur Foundation (JMP).
Halo size and subjective complaints of dysphotopsia in a normal
population
Maana Aujla, James S. Wolffsohn, Amy L. Sheppard. School of
Life and Health Sciences, Aston University, Birmingham, United
Kingdom.
Purpose: Dysphotopsia is common with multifocal intraocular lenses
(MIOLs), with complaints from as many as 45% of those implanted.
Some find it severely problematic in day-to-day tasks, such as night
driving. Several objective and subjective techniques are available
to investigate dysphotopsia, but the relationship between objective
and subjective measures is unclear and it is difficult to predict preoperatively those who might be worst affected subjectively. The aim
of this prospective study was to investigate the relationship between
objective measures and subjective complaints of dysphotopsia. The
normal range of subjective/objective grade (the glare effect ratio) will
be determined.
Methods: Measurements were taken both binocularly and
monocularly from 100 healthy participants (mean age: 22 ± 3.21
years; range 18 to 33 years). A bespoke halometer device with
glare source was used to quantify the extent of the glare area in 8
meridians. The commercially available C-Quant objectively assessed
the amount of straylight falling on the retina using the compensation
comparison method. Subjective grading of glare was performed
using simulated images from the Photographic Images of Photic
Phenomena plates.
Results: Monocular glare areas (median: 4.25 cm2; range 1.97 to
19.61 cm2) were significantly larger than the binocular glare areas
(median: 3.24 cm2; range 1.64 to 8.26 cm2) with the halometer (P <
0.001). There was no relationship between halometer glare area and
subjective complaints (rs = -0.048, rs2 = 0.002, P = 0.635); C-Quant
and subjective complaints (rs = 0.109, rs2 = 0.012, P = 0.279);
halometer and C-Quant (rs = 0.121, rs2 = 0.015, P = 0.231). The
normal ranges for the glare effect ratio were 0 - 2.47 (median: 0.87)
for halometry, and 0 - 9.41 (median: 3.23) for C-Quant.
Conclusions: Binocular summation was evident with binocular halos
being smaller than monocular halos, suggesting halometry should be
performed binocularly. The lack of relationship between subjective
and objective measures highlights the difficulty of predicting the
potential subjective complaints a patient may experience from an
objective measure alone. The normal range of the glare effect ratio
could be used for comparison purposes pre- and post- refractive
surgery; individuals with the highest ratios may be less suitable for
refractive surgery procedures that may induce glare.
Commercial Relationships: Maana Aujla, None; James S.
Wolffsohn, None; Amy L. Sheppard, None
Figure. 2nd Generation BPEI Photosensitivity Tester
Commercial Relationships: Mariela C. Aguilar, None; Alex
Gonzalez, None; Cornelis J. Rowaan, None; Potyra R. Rosa,
Development of Mapping Methods with Simulated Phosphenes
for Implementation in Intracortical Visual Prosthesis Recipients
Gayatri P. Kaskhedikar1, Lindsey Yang2, Thomas Boucher3, Philip
Troyk1, Gislin Dagnelie2. 1Biomedical Engineering, Illinois Institute
of Technology, Chicago, IL; 2Ophthalmology, Johns Hopkins
University, Baltimore, MD; 3Johns Hopkins University, Baltimore,
MD.
Purpose: Cortical visual prostheses evoke phosphenes spatially
scattered throughout the visual field in a complex pattern unlike the
geometric distribution of the implanted electrode array. Determining
consistent and reliable phosphene maps in the prosthesis recipients
to effectively convey visual information is crucial. We have devised
phosphene mapping methods with simulated phosphenes in sighted
individuals based on both absolute estimation of single phosphene
locations and relative positions of phosphene pairs.
Methods: Three mapping methods were tested in 3 normally sighted
individuals. Thirty-two simulated phosphenes or dots were presented
in the right hemifield one by one on a display screen while central
fixation was monitored by an infrared pupil tracker. The subject’s
perceived location was recorded on a touchscreen. The subjects’
head position was stabilized and calibration of the pupil tracking and
touchscreen systems was conducted. In the first absolute mapping
method, dots were sequentially presented and the subject indicated
the perceived position on the touchscreen while maintaining central
fixation. In the second absolute method, an eye movement made to
the remembered eccentric dot location was recorded. Maps from
these two tests were super-positioned by two-dimensional translation
and scaling. As a relative method to locate and reduce angular
distortions, 20 pairs of dots were selected. Each pair was sequentially
presented, and the subject traced the relative direction of the two dots
on the touchscreen. Three trials were conducted for each test.
Results: The radial distortion from the touchscreen tests in S1
(1.37±0.54) and S2 (1.74±1.12) was higher than those from the eye
movement tests (1.17±0.45 and 1.62±0. 70, resp.). In both tests,
distortions were lower with higher eccentricity. Angular distortions
were substantial, with SD up to 25°. Combining the results from
the dot-pair test reduced both radial (1.15±0.27) and angular
(0.016°±7.0°) distortions in S1. In S2 and S3 only the angular
distortion was relatively reduced while reduction of radial distortions
was inconsistent.
Conclusions: The results from these preliminary tests indicate that
the combination of the mapping methods can provide phosphene
maps with greater accuracy. The optimal integration of information
from all 3 tests to obtain reliable phosphene maps is being examined.
Enhancing the efficiency of non-image-forming visual stimulation
in humans
Garen Vartanian1, Kwoon Y. Wong2. 1Macromolecular Science
& Engineering, University of Michigan, Ann Arbor, MI;
2
Ophthalmology & Visual Sciences, University of MIchigan, Ann
Arbor, MI.
Purpose: Melanopsin-expressing retinal ganglion cells mediate
various non-image-forming (NIF) visual functions such as the
pupillary light reflex (PLR), circadian entrainment, and suppression
of pineal melatonin release. Inadequate daytime NIF photostimulation
can cause depression, sleep disorders and cognitive impairment,
which can be treated with phototherapy. In an attempt to increase the
efficacy of phototherapy, significant work has been done to identify
wavelengths optimal for NIF vision. Here, we seek to enhance NIF
visual stimulation using flickering light instead of steady light.
Methods: Five subjects were studied. An infrared pupillometer
was used to present 463 nm light to the right eye and image the
consensual PLR from the left eye. Each subject was tested with a
three-dimensional matrix of 63 flickering stimuli: 3 total photon
counts (13.8, 14.8 and 15.8 log photons cm-2), 3 duty cycles (12%,
47% and 93%) and 7 flicker frequencies (0.1, 0.25, 0.5, 1, 2, 4 and
7 Hz). Each stimulus was presented for 4 min and steady-state pupil
constriction measured during the final min. For comparison, steady
lights with equivalent intensities or total photons were also tested.
Results: Among stimuli delivering a total of 13.8 log photons cm-2,
the one flickering at 2 Hz with a 12% duty cycle evoked the greatest
PLR, constricting the pupil by 48%. This constriction was ~70%
greater than that evoked by an equal-intensity (12.4 log photons cm-2
s-1) light presented continuously for 4 min. For stimuli containing
14.8 log photons cm-2, the most potent was again the 2 Hz light with
a 12% duty cycle, inducing a 58% constriction. This was ~40% more
than that caused by a 4-min continuous light of an equal intensity
(13.4 log photons cm-2 s-1). For 15.8 log photons cm-2 stimuli, the 1Hz
light with a 47% duty cycle was the best although the constriction
was the same as that evoked by the best 14.8 log photons cm-2 light.
While this constriction was ~20% greater than that caused by a 4-min
continuous light totaling 15.8 log photons cm-2, it was statistically
indistinguishable from that evoked by a continuous light of an equal
intensity (13.8 log photons cm-2 s-1).
Conclusions: This is the first demonstration that the magnitude of the
PLR is affected by the duty cycle of the light. Under our recording
conditions, a 13.4 log photons cm-2 s-1 stimulus flickering at 2 Hz with
a 12% duty cycle stimulates the NIF visual system most efficiently.
Commercial Relationships: Garen Vartanian, None; Kwoon Y.
Wong, None
Support: NIH Grants EY013934 and EY007003
Phosphene Map of S1
Commercial Relationships: Gayatri P. Kaskhedikar, I (); Lindsey
Yang, None; Thomas Boucher, None; Philip Troyk, None; Gislin
Dagnelie, None
Support: TATRC W81XWH-12-1-0394, R01 EY021220
436 Vision during childhood development
Wednesday, May 06, 2015 11:00 AM–12:45 PM
Contrast threshold of the preterm infant
Angela M. Brown1, Delwin T. Lindsey2, 1, Edward Kopidlansky3,
Michael R. Stenger4. 1College of Optometry, Ohio State University,
Columbus, OH; 2Department of Psychology, Ohio State University,
Mansfield, OH; 3Precision Vision, Inc., La Salle, IL; 4Department of
Pediatrics, Ohio State University College of Medicine, Columbus,
OH.
Purpose: Preterm infants are at risk for many blinding disorders,
but there is no body of normative data available to support the
development of methods of testing their visual function. Particularly,
it is not known whether the contrast sensitivity of preterm infants
is good enough to allow visual acuity to be measured using
printed gratings of ~0.9 contrast. For example, if median preterm
infant contrast sensitivity were 0.9, acuity measurement would be
impossible for half the infants, and it would probably be difficult for
the remainder. Here, we measured the contrast sensitivity of preterm
infants in the Neonatal Intensive Care Unit (NICU) to determine
whether their contrast sensitivity is high enough in the neonatal
period to support visual acuity measurement.
Methods: Healthy, awake, preterm infants (born 33.5 SD=1.4 wks
gestational age, tested at 34–38 wks corrected gestational age,
avg=36 wks SD=1 wk; N=11) were tested in the NICU just before or
after feeding. Stimuli were 31x61 cm gray cards with 3-cycle, 0.05
cy/deg vertical square-wave gratings in the center. The tester placed
each card along the infant’s line of sight, then moved it laterally,
observing the presence or absence of fixation-and-following behavior.
The stimulus was “seen” if the infant attempted to refixate the
grating. After presentation of a 0.96-contrast “easy” stimulus, testing
at contrasts 0.50, 0.71, and 0.96 was under the method of constant
stimuli (MCS), with the tester unaware of the contrast values or their
order during presentation. The tester made a yes-no decision on each
card, and infant contrast threshold was the lowest contrast judged to
be “seen”.
Results: The main challenge in testing preterm infants is finding
them awake for long enough to test them, and all the infants in this
study were alert and awake. All of them saw at least the first “easy”
stimulus, and all but one saw at least the 0.96 contrast stimulus
during MCS testing. The average contrast threshold was 0.705 (SEM
= 0.055), and 8/11 (72%) of the infants had contrast thresholds at or
better than 0.71. When we combined the present results with previous
data on full-term infants, neonatal contrast threshold improved
with age (r=-0.414, p<0.005) at an overall rate of 0.042 contrast
improvement per week.
Conclusions: The contrast sensitivity of most preterm infants can be
measured starting by age 34 weeks. The contrast thresholds of many
infants were good enough to allow visual acuity measurement.
Commercial Relationships: Angela M. Brown, Precision Vision
(F); Delwin T. Lindsey, None; Edward Kopidlansky, Precision
Vision (E); Michael R. Stenger, None
Support: R41EY022545, UL1TR001070
Global Motion Perception is Independent of Contrast Sensitivity
and Visual Acuity in 4.5-year-old Children
Arijit Chakraborty1, Nicola Anstice1, Robert J. Jacobs1, Jane E.
Harding2, Trecia A. Wouldes3, Benjamin Thompson1, 4. 1Optometry
& Vision Science, University of Auckland, Auckland, New Zealand;
2
Liggins Institute, University of Auckland, Auckland, New Zealand;
3
Psychological Medicine, University of Auckland, Auckland, New
Zealand; 4Optometry & Vision Science, University of Waterloo,
Waterloo, ON, Canada.
Purpose: Global motion perception is a function of area V5 within
the dorsal visual stream and may be a biomarker for abnormal
visual cortex development. The use of global motion perception
to assess dorsal stream function assumes this ability is relatively
independent of functions related to V1 such as contrast sensitivity
and visual acuity. In this prospective, observational study we tested
this assumption by assessing the relationships among global motion
perception, contrast detection thresholds for the global motion
stimulus and visual acuity in a cohort of children with perinatal risk
factors.
Methods: One hundred and seventeen 4.5-year-old children who
were enrolled in the CHYLD (Children with Hypoglycemia and Later
Development) or IDEAL (Infant, Development, Environment and
Lifestyle) studies participated. All children were born with at least
one of the following risk factors: small for gestational age, large for
gestational age, babies of diabetic mothers, or prenatal drug exposure.
Motion coherence thresholds (MCT), a measure of global motion
perception, were measured using random-dot-kinematograms (100
dots, speed 6 deg/sec). The contrast of the stimuli was fixed at 100%
and coherence was varied using a 2-down-1-up staircase. Contrast
detection thresholds (CDT) were measured for the same stimuli,
whereby motion coherence was fixed at 100% and dot contrast was
varied. Visual acuity (crowded Lea symbols / Keeler LogMAR test)
and stereopsis (stereo fly test) were also measured.
Results: MCT and CDT were not significantly correlated (rho=0.04,
p=0.5). Children with both the best and poorest MCTs (threshold
values in the first and fourth quartiles, respectively) had similar CDTs
(p = 0.8). MCT was also not correlated with visual acuity (rho=0.005,
p=0.9). However, MCT was moderately but significantly correlated
with stereoacuity (rho=0.36, p<0.001). A weak but statistically
significant correlation between CDT and visual acuity (rho=0.26,
p=0.004) was observed, suggesting a partial relationship between
these two measures of spatial vision.
Conclusions: Global motion perception for high contrast stimuli
appears to be independent of contrast detection thresholds and visual
acuity in children born with developmental risk factors. This suggests
that global motion perception can be used to assess the function of
dorsal extra striate visual areas.
Commercial Relationships: Arijit Chakraborty, None; Nicola
Anstice, None; Robert J. Jacobs, None; Jane E. Harding, None;
Trecia A. Wouldes, None; Benjamin Thompson, None
Support: CHYLD - NIH Grant 1R01HD06922-01; IDEAL National Institute on Drug Abuse Grant R01DA021757 and Auckland
Medical Research Foundation
Relationship between monocular grating acuity at 12-months and
recognition acuity at 4.5-years in the Infant Aphakia Treatment
Study
E Eugenie Hartmann1, Lindreth DuBois2, Michael Lynn2, Scott R.
Lambert2. 1Department of Vision Sciences, Univ of Alabama at
Birmingham, Birmingham, AL; 2Emory University, Atlanta, GA.
Purpose: To determine the relationship between grating acuity
measured at 12-months and recognition acuity at 4.5-years of age in
the treated eyes of infants enrolled in the Infant Aphakia Treatment
Study (IATS).
Methods: IATS is a multi-center, randomized clinical trial sponsored
by NEI to compare contact lenses (CL) and intraocular lenses (IOL)
for initial correction of unilateral aphakia in patients with an infantile
cataract whose surgery was performed from 1 to <7 months of age.
Patients were enrolled in IATS at 12 sites (2004-2009;n=57 per
treatment). Grating acuity was tested at 12 months of age (Teller
Acuity Cards) and recognition acuity at 4.5 years of age (ATS-HOTV
protocol) by a traveling tester masked to the treatment groups. Visual
acuity (VA) was obtained on all 114 patients at 12-months and 112
patients at 4.5-years. The relationship between VA at the two ages in
the treated eye was evaluated using the Spearman rank correlation
coefficient.
Results: There was no significant difference in logMAR VA at either
age between the two treatment groups. A comparison of logMAR VA
at the two ages for all patients is shown in the scatter plot. Correlation
was 0.47 (p<0.001). This plot shows that almost equal numbers of
patients demonstrated improved versus worsened VA. When the data
are categorized relative to norms for grating VA and specific ranges
of recognition VA, it is apparent that infants whose grating VA was
>20/150 (lower 95th% predictive limit of normal) were more likely to
have >20/200 recognition VA. More infants whose grating acuity was
<20/150 at age 12 months were able to maintain a reasonable level of
acuity, with only 32% of these patients having VA of >20/200 at age
4.5 years.
Conclusions: Our results suggest that grating VA at 12 months can
provide some indication of long-term recognition VA. While there
is not a strict predictive relationship between the two measures, as
expected, infants whose VA was within the 95% predictive limits for
normal at 12 months were more likely to demonstrate recognition VA
up to 20/80 in the treated eye compared with infants whose grating
acuity was below this level (48% vs 26%). Thus, a grating VA within
normal limits at 12 months is reason for cautious optimism. On the
contrary, a grating VA below normal limits cannot be conclusively
interpreted as an eye that will ultimately be considered legally blind.
Commercial Relationships: E Eugenie Hartmann, None; Lindreth
DuBois, None; Michael Lynn, None; Scott R. Lambert, None
Support: National Institutes of Health Grants U10 EY13272 and
U10 EY013287 and in part by NIH Departmental Core Grant
EY06360 and Research to Prevent Blindness, Inc New York, New
York
Developmental changes in chromatic discrimination at 5-14 years
Caterina Ripamonti2, 1, Sarah Kalwarowsky1, Marko Nardini3, 1.
1
United Kingdom; 2Cambridge Research Systems Ltd, Rochester,
United Kingdom; 3Department of Psychology, Durham University,
Durham, United Kingdom.
Purpose: Previous studies have shown that chromatic discrimination
thresholds across the life span are characterised by a dipper function
that has its minimum at 20-30 years; after this age thresholds tend to
rise due to age-related ocular and neuronal changes. However, it is
unclear why thresholds should be elevated in the paediatric age range.
In this study we tested psychophysically if the elevated
discrimination thresholds of a paediatric population reflect a real
anatomical and/or functional visual development; or if they are
biased by the difficulty in performing the discrimination task, and the
attentional resources required to execute the test.
Methods: We compared paediatric performance at two chromatic
discrimination tests: the Universal Colour Discrimination Test
(UCDT), and the Fansworth-Munsell 100 Hue Test (FM100HT). The
UCDT used a simple 2-alternative-forced-choice task to measure
the minimum saturation required to discriminate the chromatic
target from its achromatic background. Saturation thresholds were
measured along the protan, deutan, and tritan confusion lines. Each
threshold took about 2 minutes and was repeated twice for a measure
of reliability. The FM100HT required the observer to sort a large
number of caps according to their hue, and on average it took about
20 minutes to complete the test. The two tests were run on the same
day and in random order.
We tested a population of 56 paediatric observers: 18 aged 5-6 years,
20 aged 9-10 years and 18 aged 13-14 years; all had normal colour
vision, as assessed by either the Ishihara or the HRR plates. Our
control group consisted of 25 adult observers aged 20-40 years; all
had normal colour vision.
Results: Expectedly, we found that the mean total error scores
measured with the FM100HT dramatically varied with age (Figure
1). Surprisingly, chromatic discrimination thresholds measured with
the UCDT were approximately constant across age for all confusion
axes. In fact, apart from a few outliers, all paediatric observers
showed chromatic discrimination thresholds that fell within the
normal trichromatic range (see, for example, tritan thresholds in
Figure 2).
Conclusions: We found that chromatic discrimination in our
paediatric population can be as good as chromatic discrimination
in young adults, when assessed with a sensitive and fast colour
discrimination test based on a simple task, like the UCDT.
Total error scores from the FM100HT.
Tritan thresholds from the UCDT.
Commercial Relationships: Caterina Ripamonti, None; Sarah
Kalwarowsky, None; Marko Nardini, None
Support: Fight for Sight, NIHR Biomedical Research Centre
for Ophthalmology at Moorfields and the UCL Institute of
Ophthalmology.
Effect of blur adaptation on peripheral visual performance in
myopes and emmetropes
Atanu Ghosh, Len Zheleznyak, Antoine Barbot, Geunyoung Yoon.
Flaum Eye Institute, University Of Rochester, Rochester, NY.
Purpose: To investigate the effect of blur adaptation (2D myopic
defocus) at fovea (0°) and parafovea (10°) over time in emmetropes
and myopes with and without higher order aberrations (HOAs).
Methods: An adaptive optics (AO) vision simulator was used to
measure high contrast tumbling E visual acuity (HCVA) at fovea
and at 10° nasal visual field before, during and after a 60 min blur
adaptation. 6 young adults (3 emmetropes and 3 myopes) participated
in this study, and were dilated with phenylepherine eye drops. Visual
performance was measured over 6-mm pupil under two conditions:
(i) HCVA measured with corrected HOAs before and after a 60 min
adaptation in which aberrations were dynamically corrected with
closed-loop AO, and (ii) HCVA measured with subject’s native HOAs
every 10 min over a 60 min adaptation period; i.e., the time course
of blur adaptation observed. During blur adaptation subjects watched
video at 2m distance using their foveal (0°) and parafoveal (10°)
vision, while wearing a +2D trial lens and 6-mm artificial pupil, in
two separate, counter balanced sessions.
Results: Defocused HCVA with corrected HOAs improved
significantly after 60 min of blur adaptation for both foveal (group
mean logMAR: 0.65±0.06 and 0.58±0.07 before and after adaptation,
respectively, p=0.03) and parafoveal vision (group mean logMAR
0.85±0.03 and 0.78±0.06 before and after adaptation, respectively,
p=0.01). When the subjects’ native HOAs remained uncorrected we
also observed significant improvements in HCVA over time for both
foveal (R2= 0.859; mean HCVA improved by 36%) and parafoveal
(R2= 0.788; mean HCVA improved by 11%) vision (ANOVA, time,
p<0.01). Myopic subjects had significantly greater improvement in
parafoveal HCVA after 60 min of adaptation with the corrected HOAs
condition (mean HCVA improvement: logMAR 0.10±0.02), than
that of emmetropic subjects (mean HCVA improvement: logMAR
0.04±0.03). However there was no significant difference observed in
parafoveal HCVA after 60 min of adaptation between refractive error
groups (mean difference: logMAR 0.02±0.02), when subject’s HOAs
remained uncorrected.
Conclusions: Myopes exhibited a greater level of adaptation to
peripheral defocus than emmetropes, while optics of the eye in
both groups was fully corrected. This finding suggests that neural
compensatory response to myopic defocus might have different
impact on peripheral visual performance in myopes and emmetropes.
Commercial Relationships: Atanu Ghosh, None; Len Zheleznyak,
None; Antoine Barbot, None; Geunyoung Yoon, None
Long-term visual follow-up in children with malarial retinopathy
Paul C. Knox1, Ian J. MacCormack1, 2, Macpherson Mallewa2, Simon
P. Harding1. 1Eye and Vision Science, University of Liverpool,
Liverpool, United Kingdom; 2University of Malawi College of
Medicine, Malawi-Liverpool-Wellcome Trust Clinical Research
Programme, Blantyre, Malawi.
Purpose: Paediatric cerebral malaria (CM), which results in coma,
is associated with a distinct group of changes in the retina (eg retinal
whitening, retinal haemorrhages) which together are called malarial
retinopathy. These retinal changes have considerable diagnostic and
prognostic value (Beare et al, 2004, Arch Ophthalmol 122:1141).
What is less clear is whether CM has long term visual consequences
either due to retinal or central nervous system damage.
Methods: We recruited 54 participants who had retinopathyconfirmed paediatric cerebral malaria (CM group; mean age at time
of admission: 57 months; mean time since admission: 76 months;
mean age at time of testing: 124±26 months) and compared their
performance with 49 hospital admission controls (CON group;
mean age 116 ± 23 months; t-test for group ages: t=1.6, p>0.05).
Monocular visual acuity (VA), contrast sensitivity (both tested using
Lea symbols) and vernier offset hyperacuity were tested in both eyes
using Test Chart Pro 2000 software run on a laptop computer. In
order to examine higher order vision, and an aspect of visual function
which has a temporally extended developmental profile, we used a
handheld test of global radial shape discrimination (hRSD; Wang et
al, 2009, OVS 86:695). This measured the threshold for detecting
distortions in circular radial frequency patterns, recording them as a
LogMAR value.
.
Results: We found no statistically significant differences between
groups for any of the aspects of vision tested. For VA, values
were as expected for the ages tested (CM RE:-0.07±0.14; LE:
-0.08±0.15 LogMAR; CON RE:-012±0.14; LE:-0.09±0.12 LogMAR;
mean±SD). However, for the hRSD test, thresholds for detecting
distortion were higher than anticipated based on published reports.
For participants aged 9-11y average thresholds were CM: -0.41±0.17,
CON: -0.44±0.24 LogMAR. In both groups this was well above the
previously published value for this age range of approximately -0.80
LogMAR.
Conclusions: We have confirmed that the retinal damage observed
in CM does not appear to have long-term consequences for visual
function. However, higher level visual function may be generally
compromised in the population we have studied.
Commercial Relationships: Paul C. Knox, None; Ian J.
MacCormack, None; Macpherson Mallewa, None; Simon P.
Harding, None
Support: Wellcome Trust
471 High Resolution Photoreceptor Imaging
Wednesday, May 06, 2015 3:45 PM–5:30 PM
Contributing Section(s): Multidisciplinary Ophthalmic Imaging,
Physiology/Pharmacology, Retinal Cell Biology, Retina
The relationship between visual acuity, perifoveal achromatic-, Land M-cone acuity and retinal structure as imaged with OCT
Elisabeth Bratlie Finstad, Siri Bjørnetun Jacobsen, Jon B. Gjelle,
Stuart J. Gilson, Rigmor C. Baraas. Department of Optometry and
Visual Science, Faculty of Health Sciences, Buskerud and Vestfold
University College, Gjøvik, Norway.
Purpose: A negative correlation between best-corrected visual
acuity (BCVA) and photoreceptor and retinal pigment epithelium
aggregate (PR+RPE) thickness has been reported in high myopes. We
investigated BCVA, perifoveal achromatic-, L- and M-cone acuity
and retinal structure in healthy young male Norwegians.
Methods: Twenty-eight healthy males aged 20-38 yrs, with normal
logMAR letter acuity and no observed ocular abnormalities, were
included in the study. Color vision was examined with a battery of
standard tests. Perifoveal achromatic and isolated L- and M-cone
spatial acuity was measured in the dominant eye with a Sloan E letter
of 90% achromatic or 23% cone contrast, respectively. The Sloan E
was presented at 5 deg eccentricity and fixation was verified by an
eye-tracker. Observers were corrected to best logMAR letter acuity
and viewed the stimuli monocularly from a distance of 2.3 m. The
central 30 deg of the dominant eye was imaged with the Heidelberg
Spectralis OCT. Retinal layers were analyzed by calculating
longitudinal reflectivity profiles.
Results: Axial lengths ranged from 22.60–25.18 mm and spherical
equivalent refraction from -4.50–2.43D. Foveal thickness and
PR+RPE thickness ranged from 187–241 mm and 86–110 mm,
respectively. Perifoveal retinal thickness ranged from 287–335 mm
and perifoveal PR+RPE thickness from 63–80 mm. No correlation
was found between BCVA (logMAR -0.16–0.04) and PR+RPE (r=0.305, p=0,11) or foveal thickness (r=-0.237, p=0.226). Perifoveal
achromatic, L- and M-cone logMAR acuity ranged from 0.28–0.53,
0.46–0.80 and 0.54-1.25, respectively. Observers with red-green
color-vision deficiencies (n=4, 13.3 %) had achromatic acuity within
the normal range and performed as expected according to type
and degree of deficiency. No correlation was found between either
perifoveal achromatic, L- or M-cone acuity and retinal thickness (r=0.20, p=0.31; r=-0.141, p=0.48; r=-0.07, p=0.74) or thickness of the
PR+RPE (r=-0.28, p=0.15; r=-0.11, p=0.60; r=0.28, p=0.14) at 5 deg
temporal eccentricity.
Conclusions: The correlation between BCVA and foveal PR+RPE
thickness in high myopes could not be replicated in low hyperopes to
moderate myopes. The lack of correlation between different retinal
thicknesses and perifoveal measures of achromatic and isolated cone
acuity support this finding.
Commercial Relationships: Elisabeth Bratlie Finstad, None; Siri
Bjørnetun Jacobsen, None; Jon B. Gjelle, None; Stuart J. Gilson,
Repeatability and inter-observer variability of in vivo retinal
cone imaging using a modified Heidelberg Retinal Angiography
(HRA2) in normal subjects
Marketa Cilkova1, 2, Juliane Matlach2, Reena Chopra2, Andy
Rider1, Nilpa Shah1, 2, Padraig Mulholland2, Steven C. Dakin3,
Adnan Tufail2, 1, Roger S. Anderson1, 4. 1Institute of Ophthalmology,
University College London, London, United Kingdom; 2Moorfields
Eye Hospital, NIHR Biomedical Research Centre, London, United
Kingdom; 3Optometry and Vision Science, University of Auckland,
Auckland, New Zealand; 4Vision Science, University of Ulster,
Coleraine, United Kingdom.
Purpose: To determine whether the modified narrow-angle
Heidelberg Retina Angiograph (HRA2) is repeatable and reliable for
acquiring good quality in vivo cone images, and the future potential
to develop such an instrument for routine high resolution imaging in
primary and secondary care.
Methods: 3 x 3 degrees retinal images were acquired at an
eccentricity of six degrees from the fovea, in a group of thirty healthy
subjects (21 – 65 years of age), using the 680nm laser arm of the
modified Heidelberg Retinal Angiograph (HRA2). Two different
operators performed the cone imaging and one operator repeated the
measurements over two separate sessions. The images were analysed
and cone counts generated by using customized software.
Results: The mean cone count was 4797 cones per scan area (7054
cones/mm2) ranging from 4258 to 5125 cones per scanned area. The
cone counts acquired by the two operators were on average different
by 12 cones (<1%) within the scan window with a coefficient of
repeatability of 212 cones (1.96 x SD). Cone counts from images
acquired by the same observer on two different occasions ranged
from 4258 to 5120 with mean bias of 46 cones and coefficient of
repeatability of 284 cones per scan area.
Conclusions: The narrow-scan HRA2 showed very good inter- and
intra-examiner repeatability in comparison with alternative adaptive
optics cone imaging devices.1 However, our data were acquired in a
younger population (<66 years) and therefore more data are needed to
determine the level of repeatability in an older population.
The modified HRA2 could be used in patients with diseases affecting
retinal cone density to determine how density relates to visual
function at the early stages of the disease. The method has a potential
for diagnosis and monitoring of retinal disease in a clinical setting.
in cone density was found between healthy controls and moderate/
severe NPDR group (figure); however, no statistical significance was
found between controls and no retinopathy or mild NPDR groups.
An inverse relationship between cone density and Hb1Ac was
observed in all parafoveal regions; however, no relationship could be
correlated for the duration of diabetes.
Conclusions: Patients with diabetes may have loss of photoreceptors
with increasing severity of DR. AO provides assessment of
photoreceptors, which may allow better understanding of the disease
pathology.
Commercial Relationships: Marketa Cilkova, None; Juliane
Matlach, None; Reena Chopra, None; Andy Rider, None; Nilpa
Shah, None; Padraig Mulholland, None; Steven C. Dakin, None;
Adnan Tufail, None; Roger S. Anderson, None
Support: Fight For Sight Clinical Fellowship grant
High Resolution Imaging of Parafoveal Cones in Different Stages
of Diabetic Retinopathy using Adaptive Optics Fundus Camera
Mohamed K. Soliman1, 2, Mohammad A. Sadiq1, Aniruddha Agarwal1,
Salman Sarwar1, Mostafa S. Hanout1, Frank E. Graf1, Robin High3,
Diana V. Do1, Quan Dong Nguyen1, Yasir J. Sepah1. 1Ophthalmology
and Visual Sciences, University of Nebraska Medical Center, Omaha,
NE; 2Ophthalmology, Assiut University, Assiut, Egypt; 3College of
Public Health, University of Nebraska Medical Center, Omaha, NE.
Purpose: Neurodegeneration has been proposed as one of the
possible pathophysiological mechanisms underlying diabetic
retinopathy (DR). In this prospective cohort study, we investigated
parafoveal cone density in different stages of DR using adaptive
optics (AO) retinal imaging.
Methods: An AO retinal camera (rtx1; Imagine Eyes, Orsay, France)
was used to acquire images of parafoveal cones from patients with
diagnosis of diabetes mellitus with or without retinopathy and from
healthy controls with no known systemic or ocular disease. Eyes with
myopia (> 10 diopters), media opacity, current macular edema, or any
coexistent retinal diseases other than DR were excluded. The final
image produced by the AO camera is equivalent to ≈ 1.2 × 1.2 mm
(4° × 4°) based on axial length (AL) of the eye. The density of the
parafoveal cones was calculated in 100 × 100 mm square located at
300 and 500 mm from the foveal center (a minimum of 250 mm from
the foveal center is recommended for feasible cone assessment) along
nasal, temporal, superior and inferior quadrants. The measurements
(cones/mm2) were done using automated AOdetect Ver. 0.1. Software
provided by the manufacturer. AL were measured using non-contact
biometry (IOL Master®; Carl Zeiss Meditech, Germany). Correlation
between diabetes control (Hb1Ac) and severity of DR with cone
density was analyzed using Spearman correlation test.
Results: Ten subjects (10 eyes) with no known ocular or systemic
diseases and 14 (17 eyes) with diabetes were included (Table).
Among those with diabetes, 4 patients (5 eyes) did not have
retinopathy, 3 (4 eyes) had mild NPDR, 5 (6 eyes) had moderate
NPDR and 2 (2 eyes) had severe NPDR. The mean Hb1Ac among
patients with diabetes was 8.5 ±2. A significant difference (P< 0.001)
Figure - Cone density in different stages of diabetic retinopathy
Commercial Relationships: Mohamed K. Soliman, None;
Mohammad A. Sadiq, None; Aniruddha Agarwal, None; Salman
Sarwar, None; Mostafa S. Hanout, None; Frank E. Graf, None;
Robin High, None; Diana V. Do, None; Quan Dong Nguyen, None;
Yasir J. Sepah, None
Novel adaptive optics imaging biomarkers to investigate the early
pathologic changes of the cone mosaic in patients with type 1
diabetes mellitus
Marco Lombardo1, Maria Cristina Parravano1, Daniela Giannini1,
Sebastiano Serrao1, Lucia Ziccardi1, Giuseppe Lombardo2. 1IRCCS
Fondazione GB Bietti, Rome, Italy; 2IPCF, CNR, Messina, Italy.
Purpose: To evaluate the accuracy of adaptive optics (AO)-based
imaging biomarkers to assess the spatial arrangement of cones in
patients suffering from type 1 diabetes mellitus (DM1).
Methods: An AO flood-illumination retinal camera was used to
obtain images of the cone mosaic in 16 DM1 patients, aged 22-57
years old. Eight DM1 patients had mild non proliferative diabetic
retinopathy (NPDR) and eight patients had no sign of diabetic
retinopathy (noDR); 16 healthy volunteers were recruited as controls.
Cone density, spacing between cones, and the preferred packing
arrangements of cones were assessed in 160x160 mm sampling areas
at 1.5 degree eccentricity from the fovea along all retinal meridians.
The cone spacing and preferred arrangements of cones were
calculated using the Nearest Neighbours Distance (NND) and the
Voronoi diagrams respectively. The novel metrics included the linear
dispersion index (LDi) and the heterogeneity packing index (HPi).
The LDi is the ratio between the standard deviation and the mean of
the NND; the HPi represents the fraction of hexagonal Voronoi tiles
over the non-hexagonal tiles and is expressed in percentage. Logistic
regression analysis was performed to identify patients with DM1
using cone density, LDi and HPi parameters as descriptors.
Results: The cone density was lower in DM1 patients than controls,
though the differences reached statistically significance only
between NPDR cases and controls (P<0.001). The LDi was higher
in DM1 patients than controls, though the difference was statistically
significance only between NPDR cases and controls (P=0.01). The
HPi was statistically significantly lower in patients with DM1, both
NPDR and noDR cases, than controls (P≤0.01). Logistic regression
analysis achieved 94% classification accuracy for DM1 patients based
on the complementary use of the AO-based imaging biomarkers.
Conclusions: The complementary use of cone metrics shows great
potential to detect early pathologic changes of the cone mosaic in
patients affected by diabetes mellitus.
Commercial Relationships: Marco Lombardo, None; Maria
Cristina Parravano, None; Daniela Giannini, None; Sebastiano
Serrao, None; Lucia Ziccardi, None; Giuseppe Lombardo, None
Support: PON01_00110; Italian Ministry of Health 5x1000 funding
Multimodal investigation of the pathologic changes of the retinal
microstructure in patients with type 1 diabetes mellitus using
adaptive optics
Maria Cristina Parravano1, Lucia Ziccardi1, Giuseppe Lombardo2,
Daniela Giannini3, Monica Varano1, Paola Giorno1, Marco
Lombardo1. 1Ophthalmology, Fondazione GB Bietti-IRCCS, Rome,
Italy; 2IPCF - Unit Support of Cosenza, CNR, Cosenza, Italy;
3
Statistics, University of Rome La Sapienza, Rome, Italy.
Purpose: to explore the correlation between metrics of the cone
mosaic imaged by an adaptive optics (AO) flood illumination retinal
camera and retinal thickness in cross-section SD-OCT images in type
1 diabetes mellitus (DM1).
Methods: AO retinal images of the photoreceptor mosaic were
acquired in 16 DM1 patients; 16 healthy subjects were recruited as
controls. Cone density, spacing of cones and packing arrangements of
cones, estimated using Voronoi diagrams, were calculated within 1.5
degree eccentricity from the fovea along the vertical and horizontal
meridians. From spacing of cones and Voronoi diagrams, two novel
descriptors of the cone mosaic, the Linear Dispersion index (LDi) and
the Heterogeneity Packing index (Pi), were calculated respectively.
The subfoveal retinal thickness (SRT) was estimated in retinal
cross-sections in SD-OCT images. Linear correlation analysis was
performed to determine the relationships between cone metrics and
SRT.
Results: Patients had diagnosis of DM1 from 9 to 21 years earlier.
Eight patients were diagnosed with no signs of diabetic retinopathy
(noDR) and 8 with mild signs of DR (NPDR). The SRT was
statistically significant thicker in DM1 eyes than controls (194±18
mm in NPDR, 199±31 mm in noDR and 153±36 in controls, p<0.05).
Cone density showed no significant correlation with SRT (r=-0.30,
p=0.09); the LDi approached statistical significance (r=0.35; p=0.05)
and the HPi showed a high statistically significant correlation with
SRT (r=-0.45, p=0.009).
Conclusions: Cone density alone is not descriptive of the pathologic
changes of the cones. The novel metrics based on spacing and
packing arrangements of cones showed to correlate with the
pathologic changes of foveal retinal thickness in patients with type 1
diabetes mellitus.
Commercial Relationships: Maria Cristina Parravano, None;
Lucia Ziccardi, None; Giuseppe Lombardo, None; Daniela
Giannini, None; Monica Varano, None; Paola Giorno, None;
Marco Lombardo, None
Analysis of the Photoreceptor Mosaic Within, On and Outside the
Borders of Hyperautofluorescent Rings in Retinitis Pigmentosa
Using Adaptive Optics Scanning Light Ophthalmoscopy
Emily S. Smith1, Toco Y. Chui2, Ching-Lung Chen3, 4, Joseph Carroll5,
Alfredo Dubra5, Robert F. Cooper6, Richard B. Rosen2, Donald Hood1,
3
, Vivienne C. Greenstein3. 1Department of Psychology, Columbia
University, New York, NY; 2Ophthalmology, New York Eye and Ear
Infirmary of Mount Sinai, New York, NY; 3Ophthalmology, Columbia
University, New York, NY; 4Ophthalmology, Chang Gung Memorial
Hospital, Chiayi, Taiwan; 5Ophthalmology, Medical College of
Wisconsin, Milwaukee, WI; 6Biomedical Engineering, Marquette
University, Milwaukee, WI.
Purpose: To compare the appearance, density, and spatial
organization of photoreceptor cells (PRCs) in patients with retinitis
pigmentosa (RP) to measures of visual function and retinal structure
within, on and outside the borders of the hyperautofluorescent
(hyperAF) ring.
Methods: A custom research adaptive optics scanning light
ophthalmoscope (AO-SLO) [1] was used to image the PRC mosaic in
8 eyes of 8 RP patients with visual acuities 20/20-20/30, and hyperAF
rings and in 5 healthy eyes. Cone photoreceptor densities and mean
nearest neighbor distances were estimated along the horizontal
meridian (fovea ± 10°) using custom semi-automated cone counting
software.[2] In addition, 10-2 visual fields (Carl Zeiss Meditec Inc.)
and dark-adapted cone and rod mediated visual sensitivities were
measured (Haag-Streit AG). Fundus autofluorescence and spectral
domain-optical coherence tomography (OCT) line scans through
the fovea were also obtained (Spectralis HRA+OCT Heidelberg
Engineering GmbH). Total receptor layer thickness (R+: Bruch’s
membrane to the border between the inner nuclear layer and outer
plexiform layer) was measured and compared to values for 30 agesimilar normals.
Results: Within the hyperAF ring, the ellipsoid zone band was
preserved in all eyes. However, R+ thickness was significantly
decreased and cone mediated visual sensitivities ranged from 0 to
-8dB of normal. The AO-SLO images showed dark regions, and cone
densities were decreased for 3 eyes that had significantly decreased
cone sensitivities and R+ thickness values from the fovea to the
inner ring border. On the ring border, for all 8 eyes, the clarity of the
mosaic decreased, the number and extent of dark regions increased
and PRCs appeared misshapen/fragmented. Outside the border, where
sensitivities and R+ thickness values were markedly decreased, cones
could not be reliably identified, although the size and shape of the
cells were consistent with retinal pigment epithelium cells.
Conclusions: In patients with RP, both decreased cone density and
cone structure abnormalities were observed, even within the hyperAF
ring (i.e. in “relatively healthy” parafoveal regions). 1. Sulai, Dubra.
Biomed Opt Express. 2012, 3:1647-61. 2. Garrioch et al. Optom Vis
Sci. 2012, 89: 632-43.
Commercial Relationships: Emily S. Smith, None; Toco Y. Chui,
None; Ching-Lung Chen, None; Joseph Carroll, None; Alfredo
Dubra, US Patent No: 8,226,236 (P); Robert F. Cooper, None;
Richard B. Rosen, Advanced Cellular Technologies (C), Allergan
(C), Carl Zeiss Meditech (C), Clarity (C), OD-OS (C), Opticology (I),
Optovue (C); Donald Hood, TOPCON (F); Vivienne C. Greenstein,
None
Support: NIH Grant R01 EY09076, R01 EY017607, P30EY001931,
Research to Prevent Blindness, The Starr Foundation, Chairman’s
Research Fund of NYEEI, Marrus Family Foundation, BendheimLowenstein Family Foundation, Wise Family Foundation, RPB
Career Development Award, & Glaucoma Research Foundation
Catalyst for a Cure
Commercial Relationships: Angela N. Baldwin, NIH K-12
Career Development Grant (F); Shane Griffin, None; Nicolas
Sippl-Swezey, None; Panagiota Loumou, None; Jaskiran Mann,
None; Ravi Keshavamurthy, None; Travis Porco, None; Austin
Roorda, Foundation Fighting Blindness (F), NIH EY014375 (F),
US 6,890,076 (P), US 7,118,216 (P); Jacque L. Duncan, FDA
R01-41001 (F), Foundation Fighting Blindness (F), Hope for Vision
(F), NIH Grant EY002162 (F), Research to Prevent Blindness (F),
That Man May See Inc. (F), The Benard A. Newcomb Macular
Degeneration Fund (F)
Support: NIH Grant EY002162, NIH K-12 Career Development
Grant, NIH EY014375
Cone spacing measures over 12 months in eyes with retinitis
pigmentosa
Angela N. Baldwin1, Shane Griffin1, Nicolas Sippl-Swezey1,
Panagiota Loumou1, Jaskiran Mann1, Ravi Keshavamurthy1, Travis
Porco1, 2, Austin Roorda3, Jacque L. Duncan1. 1Ophthalmology,
University of California San Francisco, San Francisco, CA;
2
Ophthalmology, University of California San Francisco, Francis I.
Proctor Foundation, San Francisco, CA; 3School of Optometry and
Vision Science Graduate Group, University of California Berkeley,
Berkeley, CA.
Purpose: To determine the inter-visit, inter-grader and inter-ocular
variability of Adaptive Optics Scanning Laser Ophthalmoscopy
(AOSLO)-derived cone spacing measures in eyes with retinal
degenerations (RD) followed for 12 months.
Methods: Six patients with inherited RD including retinitis
pigmentosa and choroideremia underwent AOSLO imaging at 3
visits (2 baseline visits separated by no more than 1 month and one
visit 12 months after the first visit). Cone spacing was measured in
multiple regions in each image by 2 independent graders. Variability
of cone spacing measures between visits and between graders was
determined. Standard macular measures, including visual acuity,
foveal sensitivity, Goldmann perimetry, static perimetry in the central
20 degrees, and spectral-domain optical coherence tomography (SDOCT)-derived outer segment length and inner/outer segment junction
or Ellipsoid Zone (EZ) band width were obtained.
Results: Overall, cone spacing was measured in 309 regions.
Agreement between graders for cone spacing measures at each
location and each visit was acceptable (intraclass correlation
(ICC=0.75, 95% CI 0.61-0.87); mean difference between graders
was 0.08 arcminutes (95% CI 0.07-0.1). Cone spacing measures were
similar at the two baseline visits; median absolute difference was
0.044 arcmin (95% CI= 0.041-0.057). Cone spacing measures at 12
months compared to spacing measures at baseline increased by 0.027
arcminutes (95% CI 0.02-0.04). There were no significant changes
in standard clinical measures of disease progression including
visual acuity, foveal threshold, area of I4e and V4e kinetic isopters,
sensitivity in the central 20 degrees, EZ band width or outer segment
thickness in the central 3 degrees.
Conclusions: Cone spacing measures using AOSLO showed
substantial inter-grader agreement. Measures were similar between
baseline visits separated by less than 1 month. Cone spacing
increased over 12 months in eyes with inherited RD, although
standard clinical measures showed no significant change during this
period. This information establishes the repeatability for current and
future clinical trials involving AOSLO imaging of eyes with inherited
RD.
Adaptive optics and high-resolution imaging of structure and
function in retinitis pigmentosa patients with verses without a
hyper-autofluorescent ring
Grace K. Han, Tomas S. Aleman, Jessica I. Morgan. Scheie Eye
Institute, Ophthalmology, University of Pennsylvania, Philadelphia,
PA.
Purpose: Hyper-autofluorescent (AF) rings are prevalent in patients
with retinitis pigmentosa (RP). This study uses multimodal highresolution imaging, including confocal adaptive optics scanning light
ophthalmoscopy (AOSLO), to compare the structural and functional
phenotypes in RP patients with verses without hyper-AF rings.
Methods: 10 RP patients aged 11-63 years were imaged using
AOSLO (Canon, Inc. and/or a custom system), spectral domain
optical coherence tomography (SD-OCT) and AF (Heidelberg
Engineering, HRA), fundus photography (8 patients), and
microperimetry (Nidek MP1, 8 patients). One patient participated
in retinal densitometry (10 deg, temporal retina) using the Optos
P200C-AF SLO. Images from all modalities were registered in
Photoshop. Cell density was measured using a semi-automated
Matlab script.
Results: AF imaging revealed a hyper-AF ring in parafoveal retina
in 6 of 10 patients. 2/4 who did not show the hyper-AF ring were
diagnosed as X-linked RP. Foveal sensitivity was reduced 7.3 ±
5.5dB and was not significantly different in patients with vs. without
a hyper-AF ring. Outside of the hyper-AF ring, OCTs showed loss of
the IS/OS layer and thinning of the outer nuclear layer (ONL). The
retinal area corresponding to the ring appeared as a transition zone
to photoreceptor layer loss. OCTs of patients without the hyperAF ring showed severe ONL thinning with a smoother transition
in thickness. AOSLO revealed a regular cone mosaic central to the
parafoveal hyper-AF rings. Images of retinal areas corresponding to
the hyper-AF ring showed sparsely remaining cones. Outside of the
hyper-AF ring, the cone mosaic was not visible. In images showing
a contiguous cone mosaic, parafoveal cone density was normal
between 1 and 1.5 mm eccentricities. At 0.5mm eccentricity one
third of locations showed reduced cone density while two thirds were
normal. The increase in reflectance from retinal densitometry was
~1/6 of the normal response.
Conclusions: AOSLO imaging demonstrates a dramatic transition in
the organization of the cone photoreceptor mosaic co-localizing with
the hyper-AF rings commonly described in retinal degenerations. The
outer boundary of the hyper-AF ring demarcates the transition zone
to loss of the cone photoreceptor mosaic, a region that may be used to
monitor disease severity and progression.
Commercial Relationships: Grace K. Han, None; Tomas S.
Aleman, None; Jessica I. Morgan, 8226236 (P), Canon Incorporated
(C), Canon Incorporated (F), Optos PLC (F), Optos PLC (R)
Support: National Institutes of Health (Grants: EY019861,
R24EY019861, 8DP1EY02317), Foundation Fighting Blindness,
Choroideremia Research Foundation, Research to Prevent Blindness,
the F. M. Kirby Foundation, the Paul and Evanina Mackall
Foundation Trust, Lois Pope Life Foundation, Canon Inc, Optos PLC
Reliability of cone density measurements on adaptive optics
images in Stargardt disease
Melissa Kasilian1, Michael G. Ring1, Rupert W. Strauss2, Moataz
M. Razeen3, Alfredo Dubra3, 4, Tunde Peto1, Catey Bunce2,
Joseph Carroll3, 5, Adam M. Dubis2, 6, Michel Michaelides2,
6 1
. Reading Centre, Moorfields Eye Hospital, London, United
Kingdom; 2Moorfields Eye Hospital, London, United Kingdom;
3
Ophthalmology, Medical College of Wisconsin, Milwaukee, WI;
4
Biophysics, Medical College of Wisconsin, Milwaukee, WI; 5Cell
Biology, Neurobiology and Anatomy, Medical College of Wisconsin,
Milwaukee, WI; 6Genetics, University College London, London,
United Kingdom.
Purpose: Quantification of the photoreceptor mosaic in normal
subjects has been done using manual and automated methods,
however in patients with retinal degeneration, cone cell identification
becomes increasingly challenging. It is critically important to
determine how reliable cone counting measurements are and what
factors affect reliability. This knowledge can then be applied to
natural history studies and clinical trials that intend to use it to
monitor progression and efficacy respectively.
Methods: Twelve patients (8-37 years) with molecularly confirmed
Stargardt Disease (STGD) were imaged using a custom built
adaptive optics scanning light ophthalmoscope (AOSLO) designed
to simultaneously acquire images in confocal and split detection
imaging modes. Cone photoreceptors were identified by two graders
(G1 and G2) in the confocal and split detector images acquired at
100 parafoveal regions of interest (ROI). All 200 images were graded
twice by each observer. Reliability of cone cell identification was
compared between trials, between observers and between imaging
modes. Statistical significance for all tests was assessed at the 5%
level.
Results: The between trial average variance was 11% for G1 and
19% for G2 (p 0.04, paired t-test). The average variance in cones
identified between observers was 15%, which did not result in a
statistically significant difference in number of cones identified
(p=0.06, t-test). There was a significant difference in mean cones
identified (p <0.0001, paired t-test) between imaging modes. For both
graders, the between trial average variance was 18% for confocal
images compared to 3% for split detection images.
Conclusions: Split detection greatly facilitated more reliable cone
photoreceptor identification and will be the mode of choice for
natural history studies and clinical trials using AOSLO. There was
significant variance between the graders, which may in part relate to
the fact that this group is the first one to use non-medically trained
graders in a reading-center setting to analyse images. Understanding
the factors behind these differences, establishing detailed training and
standardised protocols, will lead to increased measurement reliability
in order to take the first step towards a reading center-based format of
AOSLO analysis for large multi-centre trials.
Commercial Relationships: Melissa Kasilian, None; Michael G.
Ring, None; Rupert W. Strauss, None; Moataz M. Razeen, None;
Alfredo Dubra, US Patent 8,226,236. (P); Tunde Peto, None; Catey
Bunce, None; Joseph Carroll, None; Adam M. Dubis, None;
Michel Michaelides, None
Support: National Institute for Health Research Biomedical
Research Centre at Moorfields Eye Hospital National Health Service
Foundation Trust and UCL Institute of Ophthalmology; National
Institutes of Health Grants R01EY017607, P30EY001931, and
C06RR016511; Fight For Sight; Moorfields Eye Hospital Special
Trustees; the Foundation Fighting Blindness; Retinitis Pigmentosa
Fighting Blindness; and an unrestricted departmental grant (Medical
College of Wisconsin) from Research to Prevent Blindness. Also
supported by a multiuser equipment grant from The Wellcome Trust
(099173/Z/12/Z); a Burroughs Wellcome Fund Career Award at the
Scientific Interface and a Career Development Award from Research
to Prevent Blindness (AD); and a Foundation Fighting Blindness
Career Development Award (MM). Supported in part by the National
Center for Advancing Translational Sciences, National Institutes of
Health (Grant UL1TR000055).
Longitudinal adaptive optics imaging reveals regional variation
in cone and rod loss in Stargardt disease
Maxwell A. Reback1, Hongxin Song2, Lisa R. Latchney3, Mina
M. Chung3, 2. 1School of Medicine and Dentistry, University of
Rochester, Rochester, NY; 2Center for Visual Science, University
of Rochester, Rochester, NY; 3Flaum Eye Institute, University of
Rochester, Rochester, NY.
Purpose: Stargardt disease (SD) is defined clinically by lipofuscin
deposition and atrophy of the retinal pigment epithelium (RPE), but
the causative ABCA4 gene encodes a protein uniquely expressed
in cone and rod outer segments. How mutations in ABCA4 lead to
clinically detectable RPE changes, or whether photoreceptors are
affected prior to the RPE remains unclear. Using adaptive optics
scanning laser ophthalmoscopy (AOSLO), we investigated the
sequence of changes in the photoreceptor mosaic in the macular
atrophy phenotype of SD.
Methods: Two brothers with genetically confirmed SD underwent
comprehensive eye exams and AOSLO imaging 3 times in
a 28-month period. Reflectance images of the cone and rod
photoreceptors were obtained from the central fovea to 10 degrees
inferior. Photoreceptors were counted in sampling windows at 100μm
intervals of 200x200mm for cones and 50x50mm for rods, using
custom semi-automated software. Photoreceptor density and spacing
were measured and compared across imaging sessions using one-way
ANOVA.
Results: Over 28 months, visual acuity declined from 20/30 to
20/150 with an expanding bull’s eye lesion in the younger, more
mildly affected brother; the older brother maintained 20/150 visual
acuity with a central scotoma and expanding macular RPE atrophy.
In the younger brother, AOSLO showed a 30% decline in peak foveal
cone density after 8 months, and complete loss of foveal cones at 28
months; the older brother had no detectable foveal cones at baseline.
In the peripheral macula, cone and rod spacing was greater than
normal in both patients. Rod spacing increased significantly in the
younger brother after 28 months (p<0.01) and remained unchanged
in the older brother. There was no change in peripheral cone spacing
in either patient over 28 months. The ratio of cone to rod spacing
was greater than normal over all eccentricities tested, with greater
divergence closer to the foveal center.
Conclusions: AOSLO demonstrates early foveal cone loss and
increasing rod spacing in the peripheral macula in SD. Cones and
rods are reduced in the peripheral macula in areas that appear normal
by conventional imaging methods. The ratio of cone to rod spacing
is increased, particularly near the foveal center. These findings
suggest that central cone loss may be an early pathogenetic step in
SD. AOSLO provides the capability to track individual cone and rod
changes in SD longitudinally.
Commercial Relationships: Maxwell A. Reback, None; Hongxin
Song, None; Lisa R. Latchney, None; Mina M. Chung, None
Support: NEI EY021786, EY014375, EY001319, Research to
Prevent Blindness Unrestricted Grant, Edward N. & Della L. Thome
Memorial Foundation to Mina Chung
Factors Affecting Cone Photoreceptor Identification in RPGRAssociated Retinopathy
Michael G. Ring1, 2, Melissa Kasilian1, 2, James Tee2, 1, Alfredo Dubra3,
4
, Tunde Peto1, Catey Bunce1, Ana Quartilho1, Joseph Carroll3, 5,
Michel Michaelides6, 7, Adam M. Dubis6, 7. 1Moorfields, London,
United Kingdom; 2Inst Opthalmology - Genetics, UCL, London,
United Kingdom; 3Ophthalmology, Medical College of Wisconsin,
Milwaukee, WI; 4Biophysics, Medical College of Wisconsin,
Milwaukee, WI; 5Cell Biology, Neurobiology and Anatomy, Medical
College of Wisconsin, Milwaukee, WI; 6Moorfields Eye Hospital,
London, United Kingdom; 7Institute of Ophthalmology, University
College London, London, United Kingdom.
Purpose: Cone photoreceptor quantification has been carried
out in normal subjects using either manual or semi automated
methods. Natural history studies and clinical trials of subjects with
degenerative retinal diseases need to have a reliable and objective
method of assessing the cone mosaic if this technique is to be
incorporated into trial protocols. We present data on cone counting
reliability in subjects with RPGR-associated retinopathy.
Methods: Fourteen subjects (8-51 years) with molecularly confirmed
RPGR-associated retinopathy were imaged using a custom built
adaptive optics scanning light ophthalmoscope (AOSLO) designed
to simultaneously acquire images in confocal and split detection
imaging modes. Cone photoreceptors were manually identified by
two graders (G1 and G2) in the confocal and split detection images
acquired at 42 parafoveal regions of interest. All 84 images were
graded twice by each observer. Reliability of cone cell identification
was compared between trials, between observers and between
imaging modes. Statistical significance for all tests was assessed at
the 5% level.
Results: Mean variance between trials was 9% for G1 and 16% for
G2 across all images, however the mean number of photoreceptors
identified was not statistically significantly different for either
grader (p=0.1 for G1, p = 0.06 for G2, paired t-test). There was
not a significant difference in mean variance between imaging
modes (p=0.28, paired t-test). There was no statistically significant
difference in mean variance between trials for confocal (5 ± 34%) or
split detection (2 ± 6%).
Conclusions: While there was no statistical difference in mean
variance between split detection and confocal images, the standard
deviation of the variance was significantly different. Therefore
split detection greatly facilitated the reliability of photoreceptor
identification. The significant difference between graders will require
further investigation to identify the underlying contributing factors,
with refinement of training and certification methods likely to also
help address this difference and thereby allow this image analysis
modality to enter the reading center-based format for future large
multi-center trials.
Commercial Relationships: Michael G. Ring, None; Melissa
Kasilian, None; James Tee, None; Alfredo Dubra, US 8,226,236
(P); Tunde Peto, None; Catey Bunce, None; Ana Quartilho, None;
Joseph Carroll, None; Michel Michaelides, None; Adam M.
Dubis, None
Support: National Institute for Health Research Biomedical
Research Centre at Moorfields Eye Hospital National Health Service
Foundation Trust and UCL Institute of Ophthalmology; National
Institutes of Health Grants R01EY017607, P30EY001931, and
C06RR016511; Fight For Sight; Moorfields Eye Hospital Special
Trustees; the Foundation Fighting Blindness; Retinitis Pigmentosa
Fighting Blindness; and an unrestricted departmental grant (Medical
College of Wisconsin) from Research to Prevent Blindness. Also
supported by a multiuser equipment grant from The Wellcome Trust
(099173/Z/12/Z); a Burroughs Wellcome Fund Career Award at the
Scientific Interface and a Career Development Award from Research
to Prevent Blindness (AD); and a Foundation Fighting Blindness
Career Development Award (MM). Supported in part by the National
Center for Advancing Translational Sciences, National Institutes of
Health (Grant UL1TR000055).
Adaptive optics imaging of putative cone inner segments within
geographic atrophy lesions
Ethan A. Rossi1, Kenichi Saito2, Charles E. Granger3, Koji Nozato2,
Qiang Yang1, Tomoaki Kawakami4, Jie Zhang1, William Fischer5,
David R. Williams1, 3, Mina M. Chung5. 1Center for Visual Science,
University of Rochester, Rochester, NY; 2Canon U.S.A., Inc.,
Melville, NY; 3The Institute of Optics, University of Rochester,
Rochester, NY; 4Canon, Inc., Tokyo, Japan; 5Flaum Eye Institute,
University of Rochester Medical Center, Rochester, NY.
Purpose: The time course of cone loss relative to the formation of
geographic atrophy (GA) lesions in age-related macular degeneration
is not well characterized. Confocal adaptive optics scanning light
ophthalmoscopy (AOSLO) images of GA lesions contain hyperreflective cone-like features, but such images are difficult to interpret
in advanced disease states such as GA. Non-confocal split-detector
imaging in AOSLO has been shown to reveal structures consistent
with cone inner segments (Scoles et al. 2014). Here we use two nonconfocal AOSLO methods to determine whether putative cone inner
segments exist within GA lesions and if they correlate with the conelike structures seen in confocal AOSLO images.
Methods: Six patients were imaged, five with near-infrared (NIR)
light in a compact commercial AOSLO prototype modified for
split-detector imaging. The central portion of the PSF was directed
to one detector for confocal imaging and a knife edge prism split
the remaining light into two additional detectors. Five patients were
imaged with visible light in a research AOSLO with a novel nonconfocal method based on offset aperture (Chui et al. 2012) and
split-detector methods. At each location, images were sequentially
obtained with a ~10 Airy disk aperture offset by ~6 Airy disks to
8 equally spaced radial positions. Images were co-registered with
simultaneously acquired NIR images. Registered images from each
position were averaged and combined to enhance contrast. Identical
locations were imaged in both instruments in some eyes permitting
method comparison.
Results: Structures consistent in appearance to putative cone inner
segments were observed within some small GA lesions. Cone-like
features in confocal AOSLO images did not always co-localize with
putative cone inner segments, suggesting that some hyper-reflective
features in confocal AOSLO arise from light scattered by other
structures. Conversely, some areas where cones were not visible in
confocal AOSLO contained putative cone inner segment structures in
non-confocal images.
Conclusions: Some cones survive in small GA lesions. Images
similar to those obtained with the split-detector method can be
obtained using a single detector. Cone survival in small GA lesions
offers hope that future treatments aimed at restoring RPE health may
rescue remaining cones. Further study is needed to understand the
rate of cone survival after RPE cell loss is initiated in AMD.
Commercial Relationships: Ethan A. Rossi, University of
Rochester (P); Kenichi Saito, Canon U.S.A., Inc. (E), Canon,
Inc. (F), Canon, Inc. (P), University of Rochester (P); Charles E.
Granger, Canon, Inc. (F); Koji Nozato, Canon U.S.A., Inc. (E),
Canon, Inc. (F), Canon, Inc. (P), University of Rochester (P); Qiang
Yang, Canon, Inc. (F), Canon, Inc. (P), Montana State University
(P), University of Rochester (P); Tomoaki Kawakami, Canon,
Inc. (E), Canon, Inc. (P); Jie Zhang, Canon, Inc. (F), Canon, Inc.
(P), University of Rochester (P); William Fischer, Canon, Inc. (F);
David R. Williams, Canon, Inc. (F), Canon, Inc. (R), University of
Rochester (P), University of Rochester (P); Mina M. Chung, Canon,
Inc. (F), GlaxoSmithKline (C)
Support: This research was supported by the National Eye Institute
of the National Institutes of Health under Awards R01 EY021786,
F32 EY021669, P30 EY001319, BRP EY014375, R01 EY004367,
and EY007125. The content is solely the responsibility of the authors
and does not necessarily represent the official views of the National
Inst. of Health. This work was also supported by a research grant
from Canon, Inc., a grant from the Edward N. & Della L. Thome
Memorial Foundation to Mina M. Chung, and an unrestricted grant
to the University of Rochester Department of Ophthalmology from
Research to Prevent Blindness, New York, New York.
Quantitative analysis of photoreceptor recovery in acute zonal
occult outer retinopathy (AZOOR) using adaptive optics
scanning laser ophthalmoscope
Hisashi Fukuyama1, Takashi Fujikado2, Suguru Miyagawa3, Kazuo
Kitamura3, Hiroyuki Kanda2, Takeshi Morimoto2, Kohji Nishida1.
1
Ophthalmology, Osaka University Graduate School of Medicine,
Osaka, Japan; 2Applied Visual Science, Osaka University Graduate
School of Medicine, Osaka, Japan; 3Optical Engineering Laboratory,
Topcon Corporation, Tokyo, Japan.
Purpose: To assess the photoreceptor abnormalities quantitatively
in eyes with acute zonal occult outer retinopathy (AZOOR) in the
recovery phase by adaptive optics scanning laser ophthalmoscope
(AO-SLO).
Methods: Four consecutive patients with unilateral AZOOR were
examined at the Osaka University Hospital (4 women; ages ranged
from 23 to 32 years). A custom built wide-field AO-SLO (Topcon)
was used to evaluate the cone density of the affected retinal area
before and after treatment by oral corticosteroids. Four hundred
retinal images were photographed sequentially at 30 frames/sec. The
wavefront aberrations were continuously corrected. The field of view
of the retinal images was 0.920 ×1.250 for counting the cone density
and 6.90 ×8.30 for evaluating the affected area. The cone density was
measured at 30 and 50 nasal and temporal to the fovea. The size of
lesion area was determined by a prototype software.
Results: The lesion was located on the nasal side in 3 patients and
on the temporal side in one patient. The visual fields improved in all
four patients after the treatment. The cone density in lesion area was
11069 ± 2287 cones/mm2 at 30 and 7286 ± 937 cones/mm2 at 50.
After the treatment, the cone density in lesion area increased to 15931
± 3611 cones/mm2 at 30 (P=0.097), and to 14021 ± 2055 cones/mm2
at 50 (P=0.010). The size of the lesion was reduced from 20069 ±
4871 to 7933 ± 3370 pixels (60%) after the treatment (P=0.013).
Conclusions: Our results demonstrated that AO-SLO can detect
the decrease in the lesion area and the increase in cone density
quantitatively after corticosteroid therapy in eyes with AZOOR. We
recommend the use of AO-SO to evaluate the retinal structure of eyes
with AZOOR during the recovery phase.
Commercial Relationships: Hisashi Fukuyama, None; Takashi
Fujikado, Topcon Corporation (F); Suguru Miyagawa, Topcon
Corporation (E); Kazuo Kitamura, Topcon Corporation (E);
Hiroyuki Kanda, None; Takeshi Morimoto, None; Kohji Nishida,
None
Extrafoveal Cone Packing Density and Geometry in Retinopathy
of Prematurity (ROP)
Ramkumar Ramamirtham1, Garima Soni1, 2, James D. Akula1, 3, Emily
A. Swanson1, Tara L. Favazza1, Mircea Mujat4, R D. Ferguson4, Toco
Y. Chui5, Anne Moskowitz1, 3, Anne B. Fulton1, 3. 1Ophthalmology,
Boston Children’s Hospital, Boston, MA; 2Psychology, Northeastern
University, Boston, MA; 3Ophthalmology, Harvard Medical School,
Boston, MA; 4PSI Corp, North Andover, MA; 5Department of
Ophthalmology, New York Eye & Ear Infirmary, New York, NY.
Purpose: To study cone packing density and geometry using an
adaptive optics scanning laser ophthalmoscope (AOSLO) in eyes
with history of ROP and age matched control subjects.
Methods: Subjects with a history of severe, treated ROP (n=3,
SROP), with a history of mild ROP that resolved without treatment
(n=3, MROP), and term born controls (n=6, CT) were studied.
The subjects were aged 15–23 (median: 19.8) years at test. Two
to four confocal and offset-pinhole AOSLO videos (64 frames)
subtending 1°×1° visual angle were obtained from each subject at
retinal eccentricities 4.5°, 9°, 13.5° and 18° (Chui et al, Biomed Opt
Exp, 2012) by directing the subjects’ gaze using a fixation target.
Offline, non-rigid registration was used to obtain a final image for
analysis. Cones were counted using a custom MATLAB program
and cone geometry was assessed by fit of Voronoi polynomials. Cone
density (cones/mm2) was estimated after correction of the image
magnification based on axial lengths (ROP = 22.5 ± 1.11 mm vs. CT
= 23.6 ± 1.10 mm). Effects of group and eccentricity were detected
by repeated-measures ANOVA.
Results: Cone density decreased with increasing retinal eccentricity
(4.5° to 13.5°) in all groups. Cone density was markedly lower in
SROP than in CT and MROP eyes (p<0.01); however, image quality
was also lower in SROP subjects. The Voronoi polygons were
significantly more irregular in SROP than in MROP and CT eyes (p<
0.05).
Conclusions: SROP (but not MROP) subjects displayed reduced
number and organization of cone photoreceptors. This may indicate
loss of cone photoreceptors, consistent with recognized visual deficits
in SROP subjects. Alternatively, low cone counts maybe due to the
relatively poor quality of images obtained from SROP eyes.
Commercial Relationships: Ramkumar Ramamirtham, None;
Garima Soni, None; James D. Akula, None; Emily A. Swanson,
None; Tara L. Favazza, None; Mircea Mujat, PSI Corp (E), PSI
Corp (E); R D. Ferguson, PSI Corp (E); Toco Y. Chui, None; Anne
Moskowitz, None; Anne B. Fulton, None
Support: EY10597
The optical Stiles-Crawford effect strongly affects photoreceptor
imaging in diseased retina
Michel Paques1, Chahira Miloudi1, Laurent Mugnier2, José Sahel1,
Isabelle Bloch3, Florence Rossant4, Sarah Mrejen1. 1Clinical
Investigation Center 1423, Quinze-Vingts Hospital, Paris, France;
2
DOTA, ONERA, Chatillon, France; 3Telecom ParisTech, Institut
Mines-Telecom, Paris, France; 4LISITE, ISEP, Issy-les-Moulineaux,
France.
Purpose: The optical Stiles-Crawford effect (oSCE) describes the
directional reflectance of cone photoreceptors. To which extent
does it affect cone photoreceptor imaging in diseased eyes is poorly
documented. Here we investigated by adaptive optics (AO) en face
imaging and optical coherence tomography (OCT) the directional
reflectance of photoreceptors in patients recovering from macular
edema.
Methods: AO fundus images were obtained through dilated pupils
with a commercially available flood imaging AO camera (rtx1™
camera; Imagine Eyes, Orsay, France) in normal eyes (n=6) and eyes
recovering from macular edema (n=6). Cone density counts were
compared in sets of three images with three different entrance pupils:
one through the central cornea (termed here coaxial image) and two
after laterally shifting the entry pupil by 2.3° in both directions.
Fusion maps were constructed after realignment of the three maps.
The optical characteristics of control and diseased retina were
analyzed in homologous areas. In parallel, OCT scans taken through
these different entry pupils were aligned and fused.
Results: In patients, coaxial AO images and OCT scans both showed
patchy defects of photoreceptor structures. Comparison of AO images
at different entrance pupils showed that, in diseased areas, 65%
(range, 47-79%) of cones were detected only through one of the 3
entry pupil versus 34% (range, 23-41%) in controls. Fusion maps
increased the amount of detected cones by a mean of 69% (range,
26-113%) versus 24% (range, 5-56%) in controls. Final cone counts
on fusion maps ranged from 31% to 56% of controls. On OCT scans
of the same areas, the interdigitation line showed the most important
directional reflectance; fusion of multiangle OCT scans markedly
reduced the extent of outer layer destructuration.
Conclusions: Following retinal edema, photoreceptors show striking
modifications of their optical properties which may lead to an
overestimate of destructuration of the outer retina. Integration of AO
images as well as OCT scans taken at different entry pupils improves
the characterization of photoreceptor density and structure. These
changes may participate to visual impairment. Further investigations
are needed to determine if this is due to increased oSCE and/or to
cone misalignment, the evolution of these changes over time and their
presence in other retinal diseases.
Commercial Relationships: Michel Paques, ImagineEye (C),
ImagineEye (C), UPMC (P), UPMC (P); Chahira Miloudi, None;
Laurent Mugnier, None; José Sahel, ImagineEye (S); Isabelle
Bloch, None; Florence Rossant, None; Sarah Mrejen, UPMC (P)
Support: ANR-09-TECS-009 and ANR-12-TECS-0015-03
Perifoveal correlations between cone mosaic, achromatic acuity
and L-cone acuity
Siri Bjørnetun Jacobsen, Jon B. Gjelle, Elisabeth Bratlie Finstad,
Stuart J. Gilson, Rigmor C. Baraas. Optometry and Visual Science,
Buskerud and Vestfold University College, Kongsberg, Norway.
Purpose: To investigate perifoveal measures of achromatic acuity
and L-cone acuity and its association with cone density in healthy
young men using experimental psychophysics and high-resolution
retinal imaging.
Methods: Twenty-one healthy males aged 21–31 years, with
normal logMAR letter acuity and no observed ocular abnormalities,
were included in the study. Color vision was examined with a
battery of standard tests. Achromatic and isolated L-cone spatial
acuity was measured in the dominant eye with a Sloan E letter
of 90% achromatic decrement contrast or 23% L-cone increment
contrast, respectively. The Sloan E was presented at 5 deg temporal
eccentricity and fixation was verified by an eye-tracker. Observers
were corrected to best logMAR letter acuity and viewed the stimuli
monocularly from a distance of 2.3 m. Average luminance of the
stimuli was 10 cd/m2. Para- and perifoveal areas within the central 12
deg of the dominant eye were imaged with the Kongsberg Adaptive
Optics Ophthalmoscope II. The subject’s eye was dilated and
accommodation suspended with Cyclopentolate 1% prior to imaging.
Cone density and nearest-neighbor distance (NND) analysis was
performed using custom software.
Results: LogMAR acuity for achromatic and L- cone experiments
ranged from 0.330.53 and 0.460.80, respectively. All observers had
cone densities within the normal range. There was no correlation
between achromatic logMAR and cone density or achromatic
logMAR and mean NND at 5 deg. There was, however, a significant
correlation between higher cone density and better L-cone logMAR
(r =0.58, p<0.01) and lower mean NND and better L-cone logMAR
(r=0.51, p<0.05).
Conclusions: The results indicate that L-cone acuity, but not
achromatic acuity, may be a useful clinical measure to determine
changes in the perifoveal cone mosaic.
Commercial Relationships: Siri Bjørnetun Jacobsen, None; Jon
B. Gjelle, None; Elisabeth Bratlie Finstad, None; Stuart J. Gilson,
Automatic cones counting in adaptive optics images in healthy
subjects
Konstantin E. Kotliar1, Peter Linder1, Lislotte A. Sigha Yongua1, Ines
Lanzl3, Jose A. Sahel2, Ieva Sliesoraityte2. 1Biomedical Engineering,
FH Aachen University of Applied Sciences, Juelich, Germany;
2
Institut de la Vision, INSERM, CIC 1243, Paris, France; 3Eye Clinic,
Munich University of Technology, Munich, Germany.
Purpose: Reliable automatic cone detection and cone mosaic
assessment using adaptive optics (AO) is of the key importance
in tracking of macular pathologies, especially ones related to the
inherited retinal degenerations (e.g. Usher syndrome). The automatic
cone detection (especially fovea centered) in AO is an unsolved issue
mainly due to the dense cones concentration both in healthy retina
and in retinal pathologies. An automatic cone quantification tool was
developed with the aim to provide quick and reliable cone counting
in fovea centered AO images. The tool was first tested in healthy
subjects. In addition cone mosaic profile was compared between
healthy subjects and patients with Usher syndrome.
Methods: A flood-illumination AO retinal camera (rtx1, Imagine
Eyes, France) was used to acquire fovea centered images of the
cone mosaic. The cone mosaic in 10 images of 8°x8° (1500x1500
pixel) corresponding to the macular area of 1181x1181 mm were
analyzed in healthy subjects. The automatic tool in LabVIEW visual
programming language (National Instruments, USA) with sequenced
image filtration was employed to obtain clearly discerned cell mosaic.
The reliability of the automatic tool was compared to an expert
based manual counting using a set of 30 images with 120x120 pixel
(95x95mm), which were randomly selected from the initial large
images. The repeatability of manual and automatic counting was
tested in 3 randomly selected images. In addition, healthy subjects’
cone mosaic profile was compared with ones having genetically
confirmed Usher syndrome.
Results: The mean amount of cones per 1 mm2 was 23120(21760 –
23530) [median(1st quartile – 3rd quartile)]. There was no significant
difference in cones count comparing automatic counting: 248(213
– 282) cells/picture, and manual counting: 248(214–273) cells/
picture (p = 0.8, Wilcoxon test). The repeatability amounted to 100%
(automatic counting) and to 98% (manual counting). Comparing
healthy subjects’ cone mosaic profile with ones having Usher
syndrome significant decrease of 30% in cones quantity per area was
shown.
Conclusions: Our developed automatic cone detection tool seems to
be reliable for automatic cone quantification and mosaic assessment
in the normal fovea using AO images. In addition, the automatic tool
could be potentially used for tracking macular pathologies, especially
ones related to inherited retinal degenerations.
Commercial Relationships: Konstantin E. Kotliar, None; Peter
Linder, None; Lislotte A. Sigha Yongua, None; Ines Lanzl, None;
Jose A. Sahel, None; Ieva Sliesoraityte, None
Support: ERAREl N°58: Eur-USH
Reliability and Repeatability of a Quality Grading System for
Para-foveal Cone Photoreceptor Adaptive Optics Images
Nick M. Muthiah1, Fred K. Chen4, Joe Zhong3, Zoe McClelland3,
Ferenc Sallo1, Tunde Peto1, Pete Coffey2, Lyndon da Cruz1.
1
NIHR Biomedical Rsrch Ctr for Ophthalmology, Moorfields Eye
Hospital & UCL IOO, London, United Kingdom; 2UCL Institute of
Ophthalmology, London, United Kingdom; 3Moorfields Eye Hospital,
London, United Kingdom; 4Centre for Ophthalmology and Visual
Science, University of Western Australia, Perth, WA, Australia.
Purpose: To investigate the reliability and repeatability of an image
quality – grading system for cone photoreceptors imaged on an
adaptive optics (AO) camera.
Methods: 50 healthy subjects, aged 20-35 years old, with no eye
diseases were recruited prospectively. The left eyes of the participants
were imaged using an AO camera (rtx1, Imagine Eyes, Orsay,
France) at 5 degrees of retinal eccentricity, twice. The 2 images
acquired on each subject were anonymized and randomized and the
resulting 100 independent unpaired images were graded. A set of
AO images validated by two independent experts in AO images and
confirmed by a master grader was used as the basis of the 3-level
grading system. Two masked independent observers (A and B) graded
all the 100 images twice. Grading concordance was assessed by
percentage of perfect agreement and kappa statistics.
Results: Exact intra-grader agreement on the quality of images for
A and B were 90% and 79% respectively, (unweighted k statistics
0.85 and 0.68 respectively, P’s<0.001). Exact inter-grader agreement
between A and B’s, 1st grade was 73% and 2nd grade in 76%
(unweighted κ statistics 0.59 and 0.63 respectively, P’s < 0.001).
Conclusions: The high intra and inter – grader agreement of observer
A and B’s 1st and 2nd grades from this study demonstrates a high
degree of reproducibility of the grading scores. This AO image
grading system can be used as a reliable indicator for assessing the
quality of images acquired on this AO camera prior to assessing
changes in cone counts.
Commercial Relationships: Nick M. Muthiah, None; Fred K.
Chen, None; Joe Zhong, None; Zoe McClelland, None; Ferenc
Sallo, None; Tunde Peto, None; Pete Coffey, None; Lyndon da
Cruz, None
Evaluating Descriptive Metrics of the Human Photoreceptor
Mosaic
Robert F. Cooper1, Melissa A. Wilk2, Alfredo Dubra4, 3, Joseph
Carroll2, 3. 1Biomedical Engineering, Marquette University,
Wauwatosa, WI; 2Cell Biology, Neurology and Anatomy, Medical
College of Wisconsin, Milwaukee, WI; 3Ophthalmology, Medical
College of Wisconsin, Milwaukee, WI; 4Biophysics, Medical College
of Wisconsin, Milwaukee, WI.
Purpose: Vital to expanding the clinical utility of adaptive optics
(AO) ophthalmic imaging is the development of robust geometrical
metrics for describing the photoreceptor mosaic. This requires a firm
theoretical understanding of the strengths and limitations of various
metrics as well as empirical data on the sensitivity of individual
metrics and the relationships between metrics. Here we explore
the relationship between individual metrics as a potential space to
identify abnormalities across subjects. In particular, we focus on the
effects of diffuse and focal photoreceptor loss.
Methods: Between 10 and 90 regions of interest were extracted
from 14 normal confocal and split-detector AO scanning light
ophthalmoscope photoreceptor montages, and cone locations were
identified using a previously described algorithm. Density, nearest
neighbor distance (NND), inter-cell distance (ICD), furthest distance
(FD), percent six-neighbor cells, nearest neighbor regularity (NNR),
number of neighbors regularity (NoNR), and Voronoi cell area
regularity (VCAR) were extracted from coordinates with bound
Voronoi regions. Confidence intervals (CIs) with 95% significance
were calculated for each of the metric relationships. Between 5-80%
of cones were removed to simulate diffuse and focal cell loss.
Results: NND, ICD, and FD fell outside their CIs at 50, 80 and
30% diffuse cell loss, respectively. Percent six-neighbor cells, NNR,
NoNR, and VCAR fell outside their CIs at 10, 30, 60 and 10% cone
loss, respectively. All regularity metrics were more sensitive to cell
loss at lower densities. VCAR was most sensitive to focal cell loss,
with its values falling outside the CI at 5% loss. ICD was sensitive to
focal changes in high-density mosaics above 15% focal loss, whereas
FD fell outside its CI at 31% focal loss in only low-density mosaics.
NND, NoNR, NNRI, and percent six-neighbor cells were insensitive
to any focal cell loss.
Conclusions: Spacing metrics are insensitive to cell undersampling,
which enables estimating mosaic spacing in cases where every cell
cannot be reliably identified. However, these same metrics are unable
to detect early pathology. Conversely, regularity metrics are highly
sensitive to both focal and diffuse cell loss, but require accurate
cell identification. Thus, both types of metrics may be needed in
combination to provide complete and accurate assessments of mosaic
integrity.
Commercial Relationships: Robert F. Cooper, None; Melissa
A. Wilk, None; Alfredo Dubra, US Patent 8,226,236 (P); Joseph
Carroll, None
Support: T32EY014537, R01EY017607, P30EY001931, Research
to Prevent Blindness, Departmental and Career Award (Dubra)
Cone density estimates derived from the reflectivity of the inner
segment ellipsoid band on en-face spectral domain OCT
Maher Saleh1, Alois Bully2, 1, Mathieu Flores1. 1Department of
Ophthalmology, University Hospital of Besançon, Besançon,
France; 2The Superior Institute for Biomedical Engineering (ISIFC),
Besancon, France.
Purpose: The objective of this project is to develop, test and validate
a software allowing to estimate photoreceptor density derived from
the inner segment ellipsoid (ISe) band reflectivity on en-face OCT.
Methods: Eight eyes displaying various degrees of outer retinal
impairment (five eyes with resolved central serous chorioretinopathy,
one with hydroxychloroquine toxicity, and two healthy eyes) were
imaged using a spectral-domain OCT (Spectralis, Heidelberg,
Heidelberg Engineering, Germany). En-face OCT was generated
from horizontal transverse scans, 11m apart, with a resolution of
384A scan/Bscan. Segmentation of the Ise band was automatically
performed with the Heidelberg Explorer plug-in provided by the
manufacturer. The relevance of the “PR1” segmentation line was
checked by two readers. At the same time, a software running on
Matlab, (Matlab, Mathworks Inc., Natick, USA) that transforms the
grey level into cone density was developed. Its algorithm is based
on a previous work comparing OCT reflectivity and adaptive optics.
The program determines the cone density in a ring ranging from 1.5
to 2 degrees of eccentricity from the fovea. In order to validate the
estimates, cone densities were measured in the same eyes, in a blind
manner, by an independent observer, using adaptive optics (AOdetect
v0.2, Imagine Eyes, Orsay, France).
Results: Thirty five points of comparison were obtained. The
program estimates were closely correlated with the results of the
reference counting method, i.e. adaptive optics (r2=0.81, p<0.05).
Bland-Altman plot displayed a moderate estimated bias of 204±2660
cellules/mm2(CI95%: 5008-5418). The estimatation was considered
relevant (defined as a difference of more and less 10%) in 80% of the
cases.
Conclusions: It has become possible to estimate cone density with
an OCT device currently used in routine practice, at least in a defined
retinal area. Improvement in the acquisition procedure (resolution,
artefact management...) will eventually improve the accuracy of the
results.
Commercial Relationships: Maher Saleh, None; Alois Bully,
None; Mathieu Flores, None
Support: This work was supported by AFCRO grant number
[130712].
Adaptive optics photoreceptor mapping : Compensation of
photoreceptor scintillation by image fusion
Chahira Miloudi1, Laurent Mugnier2, Jose A. Sahel1, Florence
Rossant3, Isabelle Bloch4, Michel Paques1. 1CIC 1423, Quinze-Vingts
Hospital, Paris, France; 2ONERA, Chatillon, France; 3ISEP, Issy les
Moulineaux, France; 4Telecom ParisTech, Paris, France.
Purpose: Adaptive optics (AO) images of photoreceptors are affected
by spatial and temporal variability. In particular, high frequency
(>10Hz) variation of reflectance of individual cones, termed here
scintillation, may be observed. We hypothesized that scintillation is
a major source of photoreceptor reflectance variability and hence of
cone counting. In order to improve the reliability of cone countings,
we developed a procedure for compensating scintillation based on
fusion of deconvolved AO images.
Methods: AO fundus images were obtained through dilated pupils
with a commercially available flood imaging AO camera (rtx1™
camera; Imagine Eyes, Orsay, France; illumination wavelength
840nm) within an IRB-approved clinical study in 5 normal eyes. The
routine acquisition procedure comprised a stack of 40 raw images
acquired over 4.2 seconds, 2° from the fovea. For each subject, raw
images were deconvolved with a myopic deconvolution method
[Blanco and Mugnier, 2011] and underwent automatic cone detection
[Loquin et al. 2011] over a 94x94mm area. Cone maps obtained from
raw images were fused; the increment in cone density at every step
was measured. The results were compared to cone maps obtained by
image averaging (AO image 2.0)
Results: In three subjects, the increment in cone density reached an
asymptotic plateau between the 10th and 20th map integration. In one
subject the plateau was not obtained (i.e. the addition of new raw
images increased the total amount of cone detected). The last subject
had limited scintillation, hence there was limited increment. The
relative improvement in total number of detected cone by fusing 20
raw deconvolved images compared to the number of cones detected
on averaged image ranged from 5% to 71%.
Conclusions: Fusion of deconvoluted raw images improves the
quality of cone detection from flood-illuminated AO images.
Commercial Relationships: Chahira Miloudi, None; Laurent
Mugnier, None; Jose A. Sahel, ImagineEye (S); Florence Rossant,
None; Isabelle Bloch, None; Michel Paques, ImagineEye (C)
Support: the Institut National de la Santé et de la Recherche
Médicale (Contrat d’Interface 2011), the Agence Nationale de la
Recherche (ANR-09-TECS-009 and ANR-12-TECS-0015-03), the
Foundation Fighting Blindness (C-GE-0912-0601-INSERM02) and
the French Ministry of Research (CIFRE131145A10).
Evaluate Reproducibility and Repeatability of Automatic Cone
Cell Count Comparing to Manual Count Using Adaptive Optics
Scanning Laser Ophthalmoscopes
Jackie Ching-Lung Chen1, 2, Huei-Chung Huang3, Alice Jih3, Won
Seok Choi1, Stanley Chang1. 1Ophthalmology, Columbia University
medical center, Newyork, NY; 2Ophthalmology department, Chang
Gang Memorial Hospital, Chiayi, Taiwan; 3Programs in Occupational
Therapy, Columbia University, New York, NY.
Purpose: To present the reproducibility and repeatability of cone
distribution and density measurement, comparing the automatic count
to the manual count. The imaging quality and individual differences
of operators are also considered using by adaptive optics scanning
laser ophthalmoscopes (AOSLO) images and preprocessing with
software of ARIA system, Canon Inc.
Methods: Total 22 eyes of 11 healthy subjects were included for
repeatability test of AOSLO imaging system, prototype II Canon.
The S1(340X340um) image was taken at each different meridian
of macula of the same 1.0mm distance from fovea by the same
operator in 3 different days. Another 18 eyes of 9 healthy volunteers
were recruited for reproducibility test and P0 (680X680um) images
were also obtained by the same method above, but performed
by 3 different skilled operators following totally randomized
order within 30 minutes. The 100X100um area was selected by
choosing the entirely same cone mosaic location of 3 different
images from different times (repeatability) and different operators
(reproducibility). All the selected 100X100um images were measured
automatically by ARIA and point-by-point by manual counting. Each
selected image was also evaluated using the subjective score grading
level from 0 to 10. Using blocking analysis of variance (ANOVA)
and regression methods, image quality, counting method, and
meridian of macula were evaluated on the measurements at statistical
significant level of 0.05.
Results: Results of repeatability analysis: within each meridian, there
is no significant difference between automatic and manual counting
(p = 0.294). We also observed no statistically significance for the
interaction effect between meridian and image quality (p = 0.408).
However, when the quality of image increased the average difference
in auto counting and manual counting measurements shrunk (p <
0.01). Results of reproducibility analysis: we found no significant
difference between two counting methods and each meridian of
macula (p = 0.27). There is also no statistical significance between
both methods and different operator (p = 0.94).
Conclusions: The repeatability and reproducibility analyses of
AOSLO showed that both automatic and manual counting methods
were reliable, but as image quality decreased manual counting
remained accountable. Bad image quality induced counting error.
Commercial Relationships: Jackie Ching-Lung Chen, None;
Huei-Chung Huang, None; Alice Jih, None; Won Seok Choi,
None; Stanley Chang, Alcon (C)
In situ Densitometry of Cone Photoreceptors in Human Eyes by
Adaptive Optics Scanning Laser Ophthalmoscopy
Masakazu Hirota1, Suguru Miyagawa1, 2, Hiroyuki Kanda1,
Takao Endo3, Tibor K. Lohmann1, 4, Takeshi Morimoto1, Takashi
Fujikado1. 1Applied Visual Science, Osaka University, Suita-shi,
Japan; 2Fundamental Technology Sec, R&D Department, Topcon,
Itabashi, Japan; 3Ophthalmology, Osaka University, Suita-shi, Japan;
4
Ophthalmology, RWTH Aachen University, Aachen, Germany.
Purpose: To measure the changes in the reflectance of human
cone photoreceptors in situ with an adaptive optics scanning laser
ophthalmoscope (AO-SLO) before and after bleaching.
Methods: Eight eyes of 8 healthy young adult subjects (age:
21-33 years) were studied. The changes in the cone reflectance
were measured with a custom-built AO-SLO (developed by Osaka
University and Topcon) with a sampling rate of 5-Hz. The AO-SLO
had a resolution of 512 × 512 pixels and had a 12-bit gray scale
resolution. The field of view was set at 7×7 degrees with the center at
1 or 3 degrees temporal to the fovea. We calculated the cone density
in this area. For bleaching, we used 630-nm red light emitting diodes
(LEDs, brightness of 3600 cd/m2). Twenty-one red LEDs were set in
a circular pattern and placed 7 cm in front of the cornea of the right
eye. After mydriasis and 10 min of dark-adaptation, images of the
cone mosaics were recorded continuously for 300 seconds without
light stimulation, then after bleaching by the LEDs for 300 seconds,
and then for 300 seconds after the cessation of light stimulation. The
measurements were made in a dark room of 0.01 lx. The average
cone reflectance was computed by the ImageJ software (Rasband W,
NIH, USA), and the average cone reflectance before light stimulation
was set as the baseline. The reflectance at the baseline was compared
to that during and after light stimulation at 1 and 3 degrees.
Results: The average cone density was significantly higher at
51283.87±2736.97 cells/mm2 at 1 degree than the 30388.38±2176.05
cells/mm2 at 3 degrees (P<0.001 Wilcoxon). After light-adaptation,
the reflectance increased relative to that at the baseline by
134.3±13.8% at 1 degree and by 126.0±10.2% at 3 degrees (P<0.001,
Wilcoxon). The increase in the cone reflectance after bleaching at
1 degree was significantly greater than that at 3 degrees (P<0.05,
Wilcoxon).
Conclusions: The significantly greater reflectance change where
the cone density was higher (1 degree) indicates that the amount of
reflectance change is related to the cone density.
Commercial Relationships: Masakazu Hirota, None; Suguru
Miyagawa, Topcon (E); Hiroyuki Kanda, None; Takao Endo,
None; Tibor K. Lohmann, None; Takeshi Morimoto, None;
Takashi Fujikado, None
Cone spacing measures in visually normal eyes imaged at
baseline and 12 months
Shane Griffin1, Angela N. Baldwin1, Nicolas Sippl-Swezey1, Jaskiran
Mann1, Panagiota Loumou1, Ravi Keshavamurthy1, Travis Porco1,
Austin Roorda2, Jacque L. Duncan1. 1Ophthalmology, University of
California San Francisco, San Francisco, CA; 2School of Optometry
and Vision Science Graduate Group, University of California
Berkeley, Berkeley, CA.
Purpose: To determine the inter-visit and inter-grader variability of
Adaptive Optics Scanning Laser Ophthalmoscopy (AOSLO) derived
cone spacing measures in normal eyes monitored longitudinally over
12 months. Analysis of cone spacing measures in normal eyes will
establish the variability of cone spacing as an outcome measure for
use in clinical studies of photoreceptor change utilizing AOSLO.
Methods: Eight visually normal patients underwent AOSLO imaging
at 3 visits; 2 baseline visits were separated by no more than 1 month,
and one visit occurred 12 months after the baseline visits. Cone
spacing was measured in each image by two independent graders.
Cone spacing measures were compared between visits and graders,
and then correlated with standard macular measures including visual
acuity, foveal sensitivity, Goldmann perimetry, and spectral-domain
optical coherence tomography (SD-OCT)-derived outer segment
layer thickness.
Results: Cone spacing was measured in 424 regions within 3.5
degrees of the fovea. Agreement between graders was strong (ICC
= 0.87, 95% confidence interval (CI) 0.81-0.90); mean difference
between graders was 0.07 arcminutes (95% CI 0.05-0.08). Median
absolute difference between cone spacing measures at each ROI
between the 2 baseline visits was 0.047 arcminutes (95% CI=0.040.059). Cone spacing at 12 months decreased by -0.0039 arcminutes
(95% CI: -0.01 to 0.0023), consistent with no change over time in
this normal population. Similarly, there were no significant changes
in any clinical measures of retinal degeneration.
Conclusions: A high degree of inter-visit and inter-grader agreement
of AOSLO-derived cone spacing measures was observed in visually
normal eyes examined twice at baseline and at 12 months. The
reproducibility of cone spacing measures in normal eyes lends
support to the future use of AOSLO in clinical trials studying
photoreceptor change over time.
Commercial Relationships: Shane Griffin, None; Angela N.
Baldwin, None; Nicolas Sippl-Swezey, None; Jaskiran Mann,
None; Panagiota Loumou, None; Ravi Keshavamurthy, None;
Travis Porco, None; Austin Roorda, University of Houston, US
7,118,216 (P), University of Rochester, US 6,890,076 (P) (P); Jacque
L. Duncan, None
Support: NIH Grant EY002162, FDA R01-41001, Research to
Prevent Blindness, The Bernard A. Newcomb Macular Degeneration
Fund, That Man May See, Inc., Hope for Vision, NIH EY014375,
Foundation Fighting Blindness
Stimulus-evoked optical response of individual cone
photoreceptors observed with adaptive optics scanning light
ophthalmoscopy
Kenneth M. McKay1, Zachary Harvey2, Grace K. Han3, Alfredo
Dubra2, 4, Jessica I. Morgan3. 1Perelman School of Medicine,
University of Pennsylvania, Philadelphia, PA; 2Ophthalmology,
Medical College of Wisconsin, Milwaukee, WI; 3Scheie Eye Institute,
Ophthalmology, University of Pennsylvania, Philadelphia, PA;
4
Biophysics, Medical College of Wisconsin, Milwaukee, WI.
Purpose: In vivo functional assessment of the retina at the cellular
level remains elusive and is increasingly important as therapies for
blinding conditions are developed. Though the physiology is largely
unknown, stimulus-evoked intrinsic signals have potential to assess
photoreceptor function. Here, we describe a stimulus-evoked optical
response, visible at the cellular level.
Methods: Neither dark adapted nor bleached parafoveal cones
in 3 normal controls (2 females, ages 34 and 24 and 1 male, age
27) were imaged using a custom adaptive optics scanning light
ophthalmoscope. A one-degree square field was illuminated with
8.3μW of 848nm for wavefront sensing, 75μW of 795nm Δ15nm for
reflectance imaging, and a background of 344.7nW at 675nm. Half of
the field was stimulated with 17.4μW of 675nm for 2s. Images were
acquired at 16Hz for 5s before, during, and 20s after stimulation.
Intensities of stimulated cones in the 795nm image were normalized
by the average intensity of non-stimulated cones in the same image.
The change in intensity ratio over time was calculated by subtracting
the average pre-stimulus intensity ratio from the intensity ratio
for each stimulated cone in each frame. Then, for each image, the
standard deviation of the change in intensity ratios over all stimulated
cones was calculated to describe the global reflectance variability
across the stimulated cones.
Results: We observed a stimulus-evoked response in approximately
just under half of cones in the stimulated field of all 3 subjects.
Following the stimulus onset, the cone intensity ratio either
oscillated between bright and dim, increased, decreased, or remained
unchanged. While an individual cone’s change in intensity ratio
pattern was not repeatable, each trial did produce a response. On
average, the reflectance variability metric reliably increased 229ms
(188, 250, 250ms) post-stimulus onset. Non-stimulated cones did not
show a response.
Conclusions: We describe a cellular-level near infrared optical
response to visible red light stimulation, possibly showing L cone
function. Future studies will correlate this optical response to
physiological function and examine the response in conditions where
photoreceptor function is compromised.
Commercial Relationships: Kenneth M. McKay, None; Zachary
Harvey, None; Grace K. Han, None; Alfredo Dubra, 8226236 (P),
Canon, Inc. (C); Jessica I. Morgan, 8226236 (P), Canon Inc. (C),
Canon Inc. (F), Optos, PLC (F), Optos, PLC (R)
Support: Foundation Fighting Blindness, Glaucoma Research
Foundation Catalyst for a Cure, Research to Prevent Blindness
Career Development Award, National Institutes of Health (Grant
EY019861), Research to Prevent Blindness, the F. M. Kirby
Foundation, the Paul and Evanina Mackall Foundation Trust, Lois
Pope Life Foundation, and the Jeffrey W. Berger Medical Student
Research in Ophthalmology Award.
504 High-resolution Blood Flow Imaging
Thursday, May 07, 2015 8:30 AM–10:15 AM
Contributing Section(s): Eye Movements/Strabismus/Amblyopia/
Neuro-Ophthalmology, Multidisciplinary Ophthalmic Imaging
High resolution imaging of retinal vascular network geometry
Jonathan Benesty1, 2, Edouard Koch2, David Rosenbaum3, Xavier
Girerd3, José Sahel1, 2, Florence Rossant4, Isabelle Bloch5, Michel
Paques1, 2. 1CHNO des Quinze Vingts, Paris, France; 2CIC 503
INSERM, Paris, France; 3Pitié-Sapetrière Hospital, Paris, France;
4
Institut Supérieur d’Electronique de Paris, Paris, France; 5Telecom
ParisTech, Paris, France.
Purpose: An energetically optimal vascular network should
theoretically respect some physical principles among which the cubic
mathematical relationship between parent and daughter vessels at
bifurcations (Murray’s law). Deviations from this optimal geometry
have been reported in several vascular diseases. The availability
of high resolution imaging of vessels offers the opportunity to
reevaluate these results. Here, following our initial evaluation of
adaptive optics (AO) retinal vascular imaging (Koch et coll. 2014),
we mathematically analyzed arterial and venous bifurcations to
calculate more precisely the junction exponent and to evaluate the
effect of cardiovascular risk factors.
Methods: Flood-illumination AO imaging was done in 93 arterial
and 25 venous bifurcations of 21 controls and 65 patients (mean age
45.7 years ±15.2; M/F 44/49) with various cardiovascular risk factors
(hypercholesterolemia, hypertension, diabetes, smoking). A semiautomated procedure was used to measure vascular diameters and
angles.
Results: In control arteries, the mean value of the arterial junction
exponent (theoretically equal to 3) was 2.80 (±0.44). The linear
regression for measured vs predicted parent arterial diameter was
0.993 with a coefficient of determination R2=0.942. Mean arterial
bifurcation angle measured was 85.05° (±11.7°), which was
significantly different from the mean optimal angle 71.7°(±13.9°)
(p<0.01). In the cardiovascular risk group, the arterial junction
exponent was significantly higher than controls (3.24±1.4 versus
2.8±0.44; p=0.02) but not the venous junction exponent (2.47 ±0.45
versus 2.42 ±0.46; p=0.8). The junction exponent in the diabetic
group (n=9) was 3.9 (±2.5), no difference was found with the control
group (p=0.25) but it might be a consequence of the small number of
diabetic patients.
Conclusions: In arterial bifurcations of normal eyes, the junction
exponent is not significantly different from 3, further confirming
Murray’s law as a general principle for small arteries but not veins.
Patients with cardiovascular risk factors have a higher arterial
junction exponent, suggesting an alteration of flow distribution.
AO imaging of arterial bifurcations may therefore provide a novel
biomarker of the general vascular state. Further studies are needed to
understand the anatomical, functional and clinical significance of this
finding.
Commercial Relationships: Jonathan Benesty, None; Edouard
Koch, None; David Rosenbaum, None; Xavier Girerd, None; José
Sahel, Imagine Eyes (S); Florence Rossant, None; Isabelle Bloch,
None; Michel Paques, C (C)
Follow-up of morphometric parameters of retinal arterioles in
hypertensive subjects: an adaptive optics imaging study
Edouard Koch4, 1, Florence Rossant2, Nicolas Lerme2, Marthe
Lagarrigue2, Isabelle Bloch3, José Sahel4, Xavier Girerd5, Jonathan
Benesty4, David Rosenbaum5, Michel Paques4. 1Ophthalmology,
Hospital, Versailles, France; 2ISEP, Paris, France; 3Telecom Paristech,
Paris, France; 4Clinical Investigation Center, Quinze-Vingts Hospital
- INSERM, Paris, France; 5Cardiology, Pitié Salpétrière Hospital,
Paris, France.
Purpose: Morphological changes affecting the wall of small retinal
arteries are observable using adaptive optics (AO) imaging (Koch
et al, J Hypertens. 2014). Here, we prospectively and quantitatively
investigated the changes of the inner diameter (ID) and wall-to-lumen
ratio (WLR) of retinal arterioles in hypertensive humans during
treatment.
Methods: In a group of hypertensive subjects (n = 21; mean age
50 years [32;71]) the ID and the WLR of the superotemporal artery
from AO images (rtx1; ImagineEyes, France) was measured using
a dedicated software. Two groups of hypertensive subjects were
followed and analysed : the first group of naïve patients (n=9) before
and after initiation of hypotensive treatment, the second group of
treated patients (n=12).
Results: The mean follow-up was 234 days [range, 42-552]. The ID
increased within three months of initiation of hypotensive treatment
(69μm [60-83] before versus 73μm [range, 57-87] after), and
remained stable thereafter. Accordingly, the WLR was smaller after
initiation of hypotensive treatment patients (0.35 [0.17-0.51] before
versus 0.32 [0.17-0.47] after initiation of hypotensive treatment).
In the group of treated patients the WLR and ID did not change
over time (0.35 [0.23-0.5] versus 0.34 [0.27-0.45], 69.5 [59-90]
versus 70.24 [61.4-83.8]. These modifications were not significantly
correlated to changes in arterial pressure.
Conclusions: Initiation of hypotensive treatment induces vasodilation
of arteries, independantly of the changes of arterial pressure.
This suggests that microvascular changes may provide additional
medical information, in particular regarding cerebral perfusion
given the functional similarities between the retina and the brain
microcirculations. For instance, arterial pressure drop without change
in microvascular resistances may decrease downstream perfusion.
Additional studies are needed to identify drug-specific effects.
Commercial Relationships: Edouard Koch, None; Florence
Rossant, None; Nicolas Lerme, None; Marthe Lagarrigue, None;
Isabelle Bloch, None; José Sahel, None; Xavier Girerd, None;
Jonathan Benesty, None; David Rosenbaum, None; Michel
Paques, None
Support: ANR_09_TECS_009_01_iPhot
Clinical Trial: C10-03
Imaging of Periarteriolar Capillary Free Zone using Offset
Pinhole Adaptive Optics Scanning Light Ophthalmoscopy
Toco Y. Chui1, 2, Nikhil Menon1, 2, Nadim Choudhury1, 2, Alexander
Pinhas1, 2, Michael Dubow1, 2, Nishit Shah1, Alfredo Dubra3, 4, Richard
B. Rosen1, 2. 1Ophthalmology, New York Eye & Ear Infirmary of
Mount Sinai, New York, NY; 2Ophthalmology, Icahn School of
Medicine at Mount Sinai, New York, NY; 3Ophthalmology, Medical
College of Wisconsin, Milwaukee, WI; 4Biophysics, Medical College
of Wisconsin, Milwaukee, WI.
Purpose: Previous studies have shown that the dimension of the
periarteriolar capillary free zone (CFZ) is associated with the retinal
oxygen level. In this study, we imaged and quantified the CFZ in
healthy controls using an offset pinhole adaptive optics scanning light
ophthalmoscope (AOSLO).
Methods: Periarteriolar CFZ imaging was performed on 7 healthy
controls (7 eyes, 6 males) using an offset pinhole AOSLO with an
imaging wavelength centered at 790nm. Images were obtained along
the retinal vascular arcades starting at the superior or inferior optic
disc margin. Image sequences were acquired using a 1.5-degree field
of view at a frame rate of 15Hz. After sinusoidal distortion and eye
motion artifacts were removed, averaged vascular structural images
and motion contrast vascular perfusion maps were obtained for
quantitative measurements of lumen diameter, vessel wall thickness,
and periarteriolar CFZ width using a semi-automatic MATLAB
software.
Results: Arteriolar lumen diameter, vessel wall thickness, and CFZ
width were visualized in all subjects. CFZ was found at the same
retinal depth as the arterioles. Vessels with a lumen diameters ranging
in size from 16 to 76 mm were imaged and measured. The mean±SD
mm of lumen diameter, vessel wall thickness, and CFZ was 42±15
mm, 10±2 mm, and 46±7 mm, respectively. The wall-to-lumen ratio
was 0.24±0.08 mm (range: 0.13-0.44). The CFZ width measurements
ranged from 36 to 71 mm. Although there was a weak positive
correlation, no statistical significance was found between the CFZ
width and lumen diameter (Linear Regression; p>0.05).
Conclusions: Offset pinhole AOSLO provides the ability to
noninvasively and quantitatively assess periarteriolar CFZ. This
has the potential for better understanding of the retinal vascular
development in the healthy retina and in disease states such as
diabetic retinopathy and retinopathy of prematurity.
Commercial Relationships: Toco Y. Chui, None; Nikhil Menon,
None; Nadim Choudhury, None; Alexander Pinhas, None;
Michael Dubow, None; Nishit Shah, None; Alfredo Dubra, Canon
USA Inc (C), US patent 8,226,236 (P); Richard B. Rosen, Advanced
Cellular Technologies (C), Advanced Cellulat Technologies (C),
Allergan (C), Clarity (C), OD-OS (C), Opticology (I), Optovue (C)
Support: Marrus Family Foundation, Wise Family Foundation,
Glaucoma Research Foundation Catalyst for a Cure and RPB Career
Development Award.
Comparison of retinal vascular caliber measured by adaptive
optics and from fundus photographs softwar.
granados loic1, Edouard Koch2, Jonathan Benesty2, Florence
Rossant3, Nicolas Lerme3, Max Villain1, Vincent Daien1, 4, Michel
Paques2. 11Department of Ophthalmology, Gui De Chauliac Hospital,
Montpellier, France; 2Clinical Investigation Center 503, Centre
Hospitalier National des Quinze-Vingts, INSERM and Université
Pierre et Marie Curie-Paris6, Paris, France; 33Institut Supérieur
d’Electronique de Paris, Paris, France; 4Inserm, U1061, Montpellier,
France.
Purpose: Retinal vascular caliber analysis has been linked with
increased cardiovascular risk and is predictive of cardiovascular
pathology. The main purpose of this study was to compare 2
methods to evaluate retinal vascular caliber: IVAN® software from
fundus photography and retinal vascular diameters from adaptive
optics optics (AO) imaging. Secondary objective was to assess the
relationships of each retinal vascular variables with systolic blood
pressure (BP).
Methods: 25 treatment-naive individuals underwent both AO
imaging and fundus photography. Central Retinal artery equivalent
(CRAE) was measured from fundus photographs using semiautomated standardized IVAN® software. Adaptive optics imaging of
the superotemporal retinal artery was performed and semi-automated
segmentation allowed extracting parietal thickness and lumen
diameter. Pearson’s correlation coefficient and Bland-Altman method
were used to assess relationship between both technics of retinal
vascular caliber assessment.
Results: Mean (+/- standard deviation [SD]) CRAE from IVAN®
software was 135.37 +/- 14.0 mm and mean arterial diameter from
adaptive optics was 76.41+/- 11.7 mm. Mean systolic BP was 130.2
+/- 20 mmHg. Correlation coefficient between arterial diameter using
AO and CRAE was 0.66 (p=0.0003). The biais between both technic
(95% confidence interval) according to the Bland–Altman definition
was 58.8 (54.7-63.2) mm. Inverse correlation was found between
CRAE and wall to lumen ratio (r=-0.52, p=0.008). Systolic BP was
significantly correlated with arterial parameters (r=-0.41, p=0.04; r=0.50, p=0.01 and r=0.71, p<0.001; for CRAE, arterial diameter from
AO and wall to lumen ratio from AO respectively).
Conclusions: Our study shows correlation between adaptive optics
measures (both diameters and wall to lumen ratio) and central retinal
artery equivalent from fundus photography. All parameters were
correlated with systolic BP. Larger studies are necessary to confirm
these results and to compare variables derived from retinal arterial
caliber with cardiovascular outcome.
Commercial Relationships: granados loic, None; Edouard Koch,
None; Jonathan Benesty, None; Florence Rossant, None; Nicolas
Lerme, None; Max Villain, None; Vincent Daien, None; Michel
Paques, None
In vivo retinal vascular wall imaging in patients with diabetic
retinopathy using non-confocal Split Detection Adaptive Optics
Scanning Light Ophthalmoscopy
Nikhil Menon1, 2, Nadim Choudhury1, 2, Toco Y. Chui1, 2, Alexander
Pinhas1, 2, Yusufu N. Sulai3, Alfredo Dubra3, 4, Richard B. Rosen1, 2.
1
Department of Ophthalmology, New York Eye and Ear Infirmary of
Mount Sinai, New York, NY; 2Icahn School of Medicine at Mount
Sinai, New York, NY; 3Department of Ophthalmology, Medical
College of Wisconsin, Milwaukee, WI; 4Department of Biophysics,
Medical College of Wisconsin, Milwaukee, WI.
Purpose: To measure lumen diameter and wall thickness of perfused
retinal vasculature, and to quantify changes in diabetic retinopathy
(DR) relative to healthy control eyes.
Methods: The retinal vasculature of 5 subjects with DR [2
background DR (BDR), 1 nonproliferative DR (NPDR), 2
proliferative DR (PDR)] secondary to type II diabetes mellitus
(mean age 54, range 41-62; mean HbA1c 8.2) and 5 healthy control
subjects (mean age 31, range 25-55, mean HbA1c 5.2) was imaged
with non-confocal split detection adaptive optics scanning light
ophthalmoscopy (SD AOSLO; Scoles et al., 2014) using 790 nm
light. Images of arterioles and venules along the retinal vascular
arcades starting at the optic disc margin, as well as of the capillaries
adjacent to the foveal avascular zone were acquired. After sinusoidal
distortion and eye motion were removed, lumen diameter, vessel
wall thickness, and wall to lumen ratio (WLR) were estimated in
averaged images semiautomatically using custom Matlab software
(MathWorks, Natick, MA) (Hillard et al, IOVS 2013. E-Abstract
6061).
Results: Lumen (diameter) of arterioles and venules ranged between
8 and 135 μm. Mean ±SD of arteriolar wall thickness in DR subjects
was 14±2 μm (range 5-27) as compared to 12±2μm (range 5-23) in
controls (p<0.07). Mean±SD venular wall thickness was 9±1 μm
(range 5-18) in DR as compared to 8±1 μm (range 4-17) in controls
(p=0.50). DR subject eyes had significantly higher arteriolar WLR
than control eyes (mean±SD: 0.35±0.06 vs. 0.26±0.03, unpaired t
test, p<0.03). The same was also true of venular WLR in DR subject
eyes as compared to controls (mean±SD: 0.19±0.03 vs. 0.15±0.02,
unpaired t test, p<0.02).
Conclusions: Microscopic non-invasive imaging of the fine retinal
vasculature using SD AOSLO allows quantification of lumen
and wall thickness. This technique has potential both for early
detection of DR, as well as accurate monitoring of progression and
personalizing treatment.
Commercial Relationships: Nikhil Menon, None; Nadim
Choudhury, None; Toco Y. Chui, None; Alexander Pinhas, None;
Yusufu N. Sulai, None; Alfredo Dubra, Canon USA Inc. (C),
RPB Career Development Award (F), US Patent No: 8,226,236 (P);
Richard B. Rosen, Advanced Cellular Technologies (C), Allergan
(C), Carl Zeiss Meditech (C), Clarity (C), OD-OS (C), Opticology
(I), Optovue (C)
Support: Marrus Family Foundation, Wise Family Foundation,
Glaucoma Research Foundation Catalyst for a Cure, RPB Career
Development Award
Murray’s law and vascular branching in normal and diabetic
subjects
Ting Luo, Thomas Gast, Tyler Vermeer, Stephen A. Burns. Indiana
University Bloomington, Bloomington, IN.
Purpose: To examine the branching pattern of the retinal vasculature
using high resolution imaging with regard to vessel diameters and
angle. The branching of the retinal vasculature is constrained by
physical principles, which are expressed in Murray’s law, which
states that the cube of a parent vessel’s diameter is equal to the sum
of the cubes of the branches. Studies have suggested that this is
followed relatively well in normal for the large vessels of the eye and
deviates for smaller vessels.
Methods: We used an adaptive optics scanning laser ophthalmoscope
to measure the outer diameters for retinal vessels. We tested 10
normal and 11 diabetic subjects. Following imaging the resulting
videos were averaged. Photoshop was used to measure the diameters
of both parent and daughter branches of the images. For each vessel
location, measurements were repeated five times and averaged.
Averaged data were fit to a Murray’s law type power law, but
determining the best fit exponent.
Results: Vessels could be reliably measured for sizes from 10 to over
100 microns. While Murray’s law predicts a cubic relation between
the parent vessel radius and the sum of the cubed daughter vessels we
found that the best fit exponent was not 3. For both the arterioles and
venules of normals, the best fit exponet for vessels greater than 10
microns was 2.4 (95% CI 2.3-2.5). For the diabetics we found a value
of 2.5 (95% CI 2.3-2.8), also a deviation from the expected value of
3 . Angles for capillaries could be measured in the normals, and they
had a high exponent of 3.4 (95% CI 3.0-3.8). In the diabetics, due to
the variability in caillary diameter observed, we were unable to make
a comparison to.
Conclusions: While diabetes changes capillary diameters, it does not
seem to be changing the bifurcation relations of vessels slightly larger
than capillaries. In our analysis we measured sizes very close to the
vessel bifurcation and it could be that the size relations vary more at
larger distances from the bifurcation.
Commercial Relationships: Ting Luo, None; Thomas Gast, None;
Tyler Vermeer, None; Stephen A. Burns, None
Support: EY04395
Retinal arterial and venous wall visualization using nonconfocal
split-detector adaptive optics laser scanning ophthalmoscopy
Shigeta Arichika, Akihito Uji, Nagahisa Yoshimura. Kyoto University
Graduate School of Medicine, Kyoto, Japan.
Purpose: As it is well known that Adaptive Optics Scanning Laser
Ophthalmoscopy (AOSLO) is a noninvasive technique enabling
direct visualization of photoreceptors and vasculature, we decided to
study the vascular wall structure of 3 normal subjects using our novel
prototype of nonconfocal split-detector AOSLO system developed by
Canon Inc.
Methods: In our split-detector nonconfocal AOSLO, confocal and
2 split nonconfocal signals were simultaneously recorded. The splitdetector signal results from the difference between the intensities of
the 2 nonconfocal signals divided by their sum at every pixel. The
imaging light wavelength of our AOSLO was 840 nm and its optical
resolution was 3 μm. The nonconfocal AOSLO images including
split-detector images were acquired for 3 normal subjects (5 eyes;
mean age, 35 years). The retinal area scanned was 1.4 × 1.4° and 2.8
× 2.8°, and AOSLO images of the upper largest temporal artery and
vein were obtained. The scans were recorded for 3 s per area (frame
rate, 32 Hz).
Results: For all 3 subjects, artery and vein were clearly described.
The average literal arterial and venous wall thickness was 10.8 mm
and 4.91 mm for subject A, 8.96 mm and 5.13 mm for subject B, and
11.0 mm and 5.99 mm for subject C, respectively.
Conclusions: Nonconfocal split-detector AOSLO is a noninvasive
technique which enables clear vascular visualization for both arteries
and veins. This technique has the potential to identify preclinical or
histological microvascular changes. However, further clinical studies
are needed to validate our results.
Commercial Relationships: Shigeta Arichika, None; Akihito Uji,
None; Nagahisa Yoshimura, Canon (C), Canon (F)
Adaptive Optics imaging patterns of retinal vasculitis.
Marie-Helene Errera1, 2, Jonathan Benesty1, 2, Edouard Koch1, 2,
Céline Chaumette1, 2, Jose A. Sahel1, 2, Bahram Bodaghi3, Michel
Paques1, 2. 1Hopital des Quinze-Vingts, Paris, France; 2DHU
ViewMaintain, INSERM-DHOS CIC 1423, Paris, F-75012, France,
INSERM & Université Pierre et Marie Curie-Paris 6, Paris, France;
3
Ophthalmologydepartment, DHU ViewMaintain, Pitié-Salpêtrière
Hospital, Université Pierre et Marie Curie-Paris 6,, Paris, France.
Purpose: To describe the morphologic features of eyes with retinal
vasculitis using adaptive optics (AO) imaging
Methods: We analyzed the AO images (rtx1 camera, ImagineEye,
Orsay, France) of a series of 12 eyes from 12 patients with various
etiologies of retinal vasculitis (toxoplasmosis (n=3), multiple
sclerosis (n=3), birdshot chorioretinopathy (n=2), and syphilis,
dengue, sarcoidosis, and tuberculosis (n=1 each). We paid particular
attention to perivascular opacification and changes in lumen diameter.
Results: Besides areas of paravascular opacification which was
observed in all eyes, we identified by AO several novel features:
glistening whitish dots similar to Gunn’s dots on the surface of retinal
vessels (3 eyes); focal irregularities in the lumen diameter of arteries
with (6 eyes) or without perivascular opacification (n=5); focal
reduction of vein lumen with perivenous opacification (3 eyes).
Conclusions: AO imaging reveals novel patterns of fundus changes
related to retinal vasculitis. An interesting finding was the frequent
presence of focal narrowing of arterioles. Additional studies are
needed to understand the significance of these features.
Commercial Relationships: Marie-Helene Errera, None;
Jonathan Benesty, None; Edouard Koch, None; Céline
Chaumette, None; Jose A. Sahel, None; Bahram Bodaghi, None;
Michel Paques, ImagineEye, Orsay, France (C)
Clinical Trial: ClinicalTrials.gov number, NCT0154618
Detecting Early AMD with Retinoscopy
Clinton N. Sims. C. Norton Sims, MD PA, Ft Myers, FL.
Purpose: To evaluate the detection of AMD by a retinoscopic
technique. Pupillary streaks produced using a calibrated streak
retinoscope (Fig. 1) and parallel light vary in reflectance with the
pigment and health of the retinal pigment epithelium (RPE). The
brightness of the reflected pupillary streak was evaluated using
a reflectance scale of #5 to #1, with #5 describing a bright streak
decreasing to #2, a faint streak, and #1, no visible streak reflex.
Methods: This was a retrospective study of patients seen in a
general ophthalmology practice. Patients with healthy streaks
and those with conditions which interfere with retinoscopic
streaks were excluded. Patients with depressed streaks, 1-3, and/
or abnormal fundus exams were referred to retinal specialists.
Patient’s ages ranged 27-93; 25% of the patients had previous
diagnoses of AMD, 83% had negative personal or family history
of AMD and 98% were Caucasian with 64% female.
The parallel retinoscopic technique (Fig. 2) was performed
after the preliminary ophthalmic examination and a subjective
refraction. Slide locks maintained the calibration alignment of
the thumb slide of the retinoscope. Pupils were dilated for fundus
exams.
Results: Of the 124 eyes with depressed 1-3 streaks, 96% were
subsequently diagnosed with AMD by a retinal specialist, i.e.
there was a high correlation between abnormal retinoscopic
streaks and AMD. Of the 44 eyes previously diagnosed with
AMD, 100% had depressed streaks. Of eyes not previously
diagnosed with AMD but with depressed streaks, 86% were
confirmed to have AMD by the retinal specialist.
Conclusions: This study demonstrates that retinoscopy can
detect early and late AMD. Macular pigment is the common
element in retinoscopy and AMD. Current evidence suggests
that a decrease in the RPE function may contribute to the onset
and progression of AMD. This retinoscopic technique may be a
useful tool for monitoring the progression and response of AMD
to various therapeutic interventions, evaluating patients with
AMD scheduled for cataract surgery and improving one’s skills
in recognizing early AMD pigment changes. Eye physicians are
trained in retinoscopy making inexpensive mass screenings for
AMD possible. Early detection could greatly benefit research,
patients and society.
Fig. 2 Fig. 2 Retinoscopic requirements to evaluate the melanin
pigment reflectance.
Commercial Relationships: Clinton N. Sims, C. Norton Sims, MD
(P), C. Norton Sims, MD (P)
Fig. 1 Retinoscope calibrated for parallel and +0.50D converging
retinoscopy.
Wavefront sensorless adaptive optics fluorescence imaging in
mouse retina
Daniel Wahl1, Yifan Jian1, Robert J. Zawadzki2, Marinko V.
Sarunic1. 1Engineering Science, Simon Fraser University, Burnaby,
BC, Canada; 2Department of Cell Biology and Human Anatomy,
University of California Davis, Davis, CA.
Purpose: Transgenic mice expressing Green Fluorescent Protein
(GFP) as a reporter molecular are particularly important for vision
research. The ability to image molecular markers has the potential to
accelerate vision research by allowing retina function to be observed
in vivo. To achieve cellular resolution imaging in the mouse eye, a
wavefront sensorless adaptive optics (WSAO) bio-microscope with
fluorescence detection was developed and evaluated by imaging
various types of transgenic mice expressing GFP.
Methods: We developed a lens-based WSAO mouse retinal imaging
system that allowed a more compact optical design. An objective
lens focused the light through a glass slide placed on the mouse eye
to cancel refraction at the cornea and retain the mouse eye moisture
to prevent corneal clouding. The numerical aperture of the imaging
system was 0.17, providing an estimated focal waist of 0.9 μm. We
utilized a segmented deformable mirror from IrisAO Inc. to perform
modal control wavefront sensorless correction, using the intensity
of the fluorescence signal as the merit function. Wildtype (c57BL/6)
mice, and GFP labeled microglia (Cx3cr1-GFP) and ganglion
cell (Thy1-GFP) mice were used in this research. The mice were
anesthetized and dilated prior to the imaging session. A generous
amount of artificial tear gel was applied in order to maintain corneal
hydration. The optical power at the mouse eye was ~100μw which is
below the ANSI standard.
Results: Representative WSAO bio-microscope images acquired
from a mouse with GFP labeled microglia before and after correction
are presented in Fig. 1. Optimization was performed on the small
field of view (Top), which was then expanded (Bottom). After WSAO
optimization the features in the focal plane were sharper and the
overall image brightness was increased.
Conclusions: We have demonstrated a lens based WSAO biomicroscope for high resolution fluorescence imaging in the mouse
eye. The WSAO technique is an accessible method of improving
image quality with increasing numerical aperture.
Fig.1 : Images acquired from a mouse retina with GFP labeled
microglia before and after WSAO correction. Scale bar: 10μm (Top),
20μm (Bottom)
Commercial Relationships: Daniel Wahl, None; Yifan Jian, None;
Robert J. Zawadzki, None; Marinko V. Sarunic, None
Support: CIHR, NSERC, Michael Smith Foundation for Health
Research, and Simon Fraser University Vice President of Research.
NEI (R01 EY024239), UC Davis RISE Grant, NSF I/UCRC CBSS
Grant.
can be detected robustly by measuring the amount of polarization
change that the surrounding birefringent nerve fibers cause during
double passage of a beam of polarized light through them upon
fundus reflection in double-pass systems. Polarized near-infrared
light is reflected from the foveal and optic disc areas in bow-tie or
propeller patterns of polarization states. These patterns are of constant
shape, size, and location, for a given type of polarized light entering
the eye, and are therefore detectable, offering the opportunity for
eye tracking. The major advantage of this eye-fixation detection
and tracking method is that it uses true information coming directly
from retinal landmarks, as opposed to existing eye-tracking systems
which use reflections from other structures, to identify the direction
of foveal gaze.
Methods: A coaxial emitter/detector sensor was developed,
consisting of a solid state laser diode, a polarizer, a filter and a
photodetector. Several such sensors could be used to interrogate
different spots on the retina, thus eliminating the need for scanning
systems with moving parts. To test the signal quality obtainable,
using just one sensor, the test subject was asked to fixate successively
on twelve “glow-in-the-dark” targets located on a circle around the
emitter/detector to simulate the retina’s being interrogated by twelve
sensors placed on a 3-deg diameter circle surrounding the projection
of the fovea (Fig 1).
Results: The resulting signals were plotted (Fig. 2). They are close
to the ideal sine wave that would have been recorded from an ideal
propeller-type birefringence pattern from a human fovea. We deem
these results satisfactory, considering factors such as imperfect bowtie, imperfect fixation by the test subject, and signal noise.
Conclusions: The method can be used in the detection of central
fixation for medical and other purposes. It does not require
calibration, strict restrictions on head position, or head-mounted
appliances.
Fig. 1
A no-moving-parts sensor for detection of eye fixation using
polarized light and retinal birefringence information
Boris I. Gramatikov, David L. Guyton. Ophthalmology, Johns
Hopkins Wilmer Eye Inst, Baltimore, MD.
Purpose: When an individual looks at a target, that target is imaged
on the fovea. It is thus foveal fixation that correlates precisely with
gaze direction. Recent research has shown that techniques which
effectively track the optical projection of fundus landmarks out from
the eye afford a more direct measurement of fixation direction. It has
also been shown that landmarks such as the fovea and the optic disc
Processing of 10° data for subject 2 is ongoing. NND measurements
are consistent with the 2D power spectra estimations of 11.9 μm and
12.9 μm of subject 1 (3° and 10°), and 12.7 μm of subject 2 (3°).
Conclusions: AO-OCT imaging permits visualization and
quantification of the RPE packing geometry in the living human
retina.
Commercial Relationships: Zhuolin Liu, None; Omer P.
Kocaoglu, None; Tim L. Turner, None; Donald T. Miller, U.S.
Patent 7,364,296 (P)
Support: NEI grants 1R01 EY018339 and P30 EY019008.
Fig. 2
Commercial Relationships: Boris I. Gramatikov, Johns Hopkins
University (P); David L. Guyton, Johns Hopkins University (P)
Support: Individual Research Award from The Hartwell Foundation
533 Adaptive optics and retinal imaging
Thursday, May 07, 2015 12:00 PM–1:45 PM
Imaging the retinal pigment epithelium mosaic with AO-OCT
Zhuolin Liu, Omer P. Kocaoglu, Tim L. Turner, Donald T. Miller.
School of Optometry, Indiana university, Bloomington, IN.
Purpose: The retinal pigment epithelium (RPE) is critical for support
and maintenance of photoreceptors. While dysfunction of the RPE
underlies numerous retinal pathologies, biomarkers sensitive to
early changes in RPE have been elusive. Because such changes
start at cellular level, there has been increased interest in targeting
the spatial arrangement and distribution of individual RPE cells. To
do so in the living human retina is extremely challenging, owing
to the lack of intrinsic contrast of RPE, optical waveguiding by the
overlying photoreceptors, and blurring by ocular aberrations. In this
study, we take advantage of the micron-level 3D resolution afforded
by adaptive optics and optical coherence tomography (AO-OCT)
to overcome these obstacles in order to visualize RPE cells and
investigate their packing geometry.
Methods: Using the Indiana AO-OCT imaging system (λc=790 nm,
Δλ=42 nm), volumes of 1°×1° field of view were acquired at 3° and
10° temporal retina in two normal subjects. Volumes were registered,
segmented, and RPE en face images extracted. Voronoi analysis was
applied to the en face images to determine number of neighbors (NN)
and center-to-center nearest neighbor distance (NND) of the RPE
cells. 2D power spectra were used to provide additional information
about cell spacing.
Results: RPE cell mosaics were resolved in both subjects and retinal
eccentricities. Voronoi analysis indicates hexagonal cells (with six
NN) are most frequent (>50%) at 3° retinal eccentricity and are
of lower frequency (<50%) at 10° retinal eccentricity. NND was
11.4±2.2 μm and 12.8±3.0 μm for subject 1 at 3° and 10° retinal
eccentricities respectively, and 12.0±2.0 μm for subject 2 at 3°.
Photoreceptor topography and marked discontinuity at the optic
nerve head in young healthy subjects
Ann E. Elsner, Joel A. Papay, Christopher A. Clark, Lucie Sawides,
Alberto De Castro, Stephen A. Burns. Optometry, Indiana University,
Bloomington, IN.
Purpose: Individual differences in photoreceptor topography include
a higher density of cones in the fovea and different rates of decrease
of cone density with increasing eccentricity. We investigated the lack
of a smooth change in cone density at the border of and extending
into the scleral crescent, where there are no apparent retinal pigment
epithelial (RPE) cells.
Methods: To measure cone density at the optic nerve head
without the presence of confounding factors such as high myopia
or glaucoma, we recruited two subjects < 35 yr with wide scleral
crescents despite healthy eyes and low refractive errors. The
topography of the scleral crescent was documented with SD-OCT
(Spectralis). The hyperreflectivity indicating the lack of melanincontaining RPE cells and the scleral pattern of birefringence were
localized with scanning laser polarimetry (GDx). For high resolution
imaging at the scleral crescent, a focus series with the Indiana
Adaptive Optics Scanning Laser Ophthalmoscope (AOSLO) was
used to document the thinned aspect of the scleral crescent and
topography change, along with depigmentation. We used the AOSLO
to image photoreceptors, the scleral crescent, and the overlying
retinal blood vessels. The AOSLO had two channels for imaging
photoreceptors via direct backscatter and multiple scattering, using
center wavelengths of 785 and 810 nm. We documented cones in the
scleral crescent with two operators. Two masked graders counted
cones in 6 sampled regions per image, computing cone density with
visual angle.
Results: Cones density changed markedly near the scleral crescent
over RPE cells and within the scleral crescent, where there was no
evidence of RPE cells. Patches of higher cone density were found
near the scleral crescent, but also regions of low density and even
cones that appeared sideways in or near the scleral crescent. The ratio
of cone density on and near the edge of scleral crescent to farther
away and having RPE cells varied from 0.50 to 1.4 within a single
image. In contrast, cones sampled within a single image but nearer to
the fovea had more uniform coverage, ranging in density by only .83
to .99.
Conclusions: Cone density, known to decrease systematically with
increasing distance from the fovea, increases in some patches near
the optic nerve head. Cones that are not over RPE cells have irregular
densities and sometimes orientations.
Commercial Relationships: Ann E. Elsner, None; Joel A. Papay,
None; Christopher A. Clark, None; Lucie Sawides, None; Alberto
De Castro, None; Stephen A. Burns, None
Support: NIH Grants EY007624, EY004395, and P30EY019008
Variability in human cone topography enabled by adaptive optics
scanning laser ophthalmoscopy (AOSLO) imaging of foveal
centers
Tianjiao Zhang2, 1, Christine A. Curcio1, Yuhua Zhang1, 2.
1
Ophthalmology, The University of Alabama at Birmingham,
Birmingham, AL; 2Biomedical Engineering, The University of
Alabama at Birmingham, Birmingham, AL.
Purpose: Accurate assessment of variability of the human cone
topography is important for interpreting the effects of aging and
disease on the photoreceptor mosaic. We measure foveal cone
densities to acquire a better estimation of variability between eyes of
single individuals and between individuals, using a new generation
research AOSLO.
Methods: Forty eyes of 20 subjects with normal retinal health aged
19-29 years were studied. The refractive errors of the participants
range from -3.0 D to 0.63 D and the fellow eye refractive error
difference of individual subject is less than 0.50 D. AOSLO was
performed to image the cone photoreceptors. Cone density was
assessed on a two-dimensional mesh grid over the central 2.4 mm x
2.4 mm macula at up to 139 points. Mean cone densities, standard
deviation, the coefficient of variation (CV), and cumulative cone
numbers as a function of eccentricity were calculated to estimate
the inter-subject variability. Cone density difference between fellow
eyes was statistically assessed with a mixed model approach and
quantified by the root-mean-square (RMS) and the maximum
difference.
Results: The peak densities of all eyes are 168,162 ± 23,529 cones/
mm2 (mean ± SD) (CV = 0.14). The mean cone density agrees well
with the histological data (p = 0.9983 for both eyes). The total
number of cones within the cone-dominated foveola is 38,311 ±
2,319 (mean ± SD) (CV = 0.06). The RMS cone density difference
between fellow eyes is 6.78%, and the maximum intra-subject
difference is 23.6%. There is no difference in the association between
eccentricity and cone density in fellow eyes for the superior/nasal
(p=0.8503), superior/temporal (p=0.1551), inferior/nasal (p=0.8609),
and inferior/temporal (p=0.6662) quadrants of the retina.
Conclusions: By measuring the foveal center cone density in a
large number of eyes, we were able to determine the center of many
retinae, thereby accurately assessing the cone density variability.
Our results agree well with data provided by classical histology. We
have confirmed that in living human eyes, though cone densities vary
significantly in the fovea, the total number of cones within the conedominated foveola is less variant both within and between subjects.
Thus, the total number of foveola cones may serve as an important
measure for assessing cone loss due to aging or disease.
Cone density and total cone counts.
Commercial Relationships: Tianjiao Zhang, None; Christine A.
Curcio, None; Yuhua Zhang, None
Support: This project is funded by EyeSight Foundation of
Alabama (YZ), International Retina Research Foundation (YZ),
5R21EY021903 (YZ), and R01EY06109 (CC) and institutional
support from Research to Prevent Blindness, EyeSight Foundation of
Alabama, Buck Trust of Alabama, and NIH P30 EY003039.
Structural properties of the cone photoreceptor packing: Cone
spacing and local anisotropy assessed with a cone-averaging
method
Lucie Sawides, Alberto De Castro, Stephen A. Burns. School of
Optometry, Indiana University, Bloomington, IN.
Purpose: To rapidly estimate cone spacing properties of the normal
cone photoreceptor mosaic and to measure local anisotropies in the
hexagonal pattern using a cone-averaging method.
Methods: The Indiana high-resolution Adaptive Optics Scanning
Laser Ophthalmoscope was used to image the cone photoreceptors of
5 normal healthy subjects (refractive error: -2.25±1.35 D, 28.8 ± 3.4
years old, 0.5% tropicamide dilated pupil).
Measurement of cones were recorded while the subjects looked
at each corner and the center of a 1 degree imaging field (0.5 Airy
disk confocal aperture). In addition four strips of 2x5 degrees of
cones corresponding to the four primary meridians (Temporal (T),
Nasal (N), Superior (S), Inferior (I)) were recorded using a 2degrees
imaging field (and 1.5 Airy disk confocal aperture).
Montages of average images were generated using an automated
algorithm (combining Matlab, i2k Retina and Adobe Photoshop).
Cone spacing properties were analyzed using a custom program that
automatically identified individual cones, within a window (50 or
100 microns) that varied with retinal location. Within each window,
interior subregions around each cone were extracted and averaged,
providing a “kernel” image of an average cone and its surrounding
retina. From each kernel image, we measured the averaged cone
spacing –computed as the first maximum of the radial profile, then
estimated the orientation and spacing anisotropy of the hexagonal
patterns based in determining the principle axes of the packing
(fig.1).
Results: There was a lower averaged cone spacing (higher cone
density) along the horizontal (T, N) meridians than along the vertical
(S, I) meridians. Locally the cone spacing was lower in vertical
than in horizontal axes for all meridians near the fovea (<1°) with
horizontal/vertical ratio of: 1.08±0.04 (T), 1.04±0.05 (N), 1.03±0.03
(S) and 1.05±0.01 (I). This tendency was maintained for Temporal
and Nasal meridians in the parafovea (up to 5°) while it reversed
for Superior meridian (1.11±0.07 (T), 1.10±0.06 (N), 0.97±0.05 (S),
1.00±0.03 (I)).
Conclusions: The method allows rapid automated estimates of cone
packing properties and provides an analysis of individual difference
in cone spacing and local anisotropies of the hexagonal cone array.
fig1: Kernel images with axes of the hexagonal packing (one subject,
Temporal and Superior meridians from 0.1° to 4° eccentricity)
Commercial Relationships: Lucie Sawides, None; Alberto De
Castro, None; Stephen A. Burns, None
Support: NIH EY04395; P30EY019008
Magnification Characteristics on Optical Coherence Tomography
Systems
Dirk-Uwe G. Bartsch. Ophthalmology-Shiley Eye Ctr, Univ of
California-San Diego, La Jolla, CA.
Purpose: Recent advances in optical coherence tomography (OCT)
technology have led to the expansion of this technology into all areas
of medicine. A large number of clinical studies have been conducted
in areas such as glaucoma, macular degeneration, Alzheimer’s
disease, and others. In these studies patients with different refractive
errors are studied with different OCT devices using a variety of
imaging protocols that measure retinal thickness. Our purpose was
to study the lateral and axial magnification characteristics in six
different optical coherence tomography devices in a model eye and
draw conclusions for clinical studies.
Methods: We build an eye model with a simulated retina and
an achromatic doublet lens. The axial length of the eye model
was adjustable to yield a corresponding defocus of +4D to -10D
from emmetropia. We imaged the model eye with six different
optical coherence tomographs (CirrusOCT, Optos OCT, Optovue,
SpectralisOCT, StratusOCT, and Topcon DRI). We measured the
lateral dimension of features on the simulated retina with each
instrument. Additionally, we measured the axial dimension of a
microscope cover glass.
Results: In the first study we analyzed lateral magnification. The
SpectralisOCT was the only telecentric imaging system and showed
no magnification error with axial length. The Topcon DRI and
Optovue showed 12% and 13% variability over the defocus range,
respectively. The CirrusOCT and StratusOCT showed 30% variability
and the Optos OCT showed 45% variability over the defocus range.
In the second study we analyzed axial magnification error. None of
the instruments showed any axial magnification error.
Conclusions: Optical coherence tomography has dramatically
altered retinal imaging and anatomical understanding. Recently,
the instruments have been used to collect cross-sectional normative
databases in large number of patients. These studies rely on the
accuracy of the instrument for different refractive powers and
different axial lengths. It appears that several instruments exhibit
lateral magnification errors that need to be considered in crosssectional studies. Our studies indicate that none of the instruments
exhibit axial magnification error.
Commercial Relationships: Dirk-Uwe G. Bartsch, Heidelberg
Engineering (R), Heidelberg Engineering (R)
Support: NIH grant R01EY016323, NIH grant R01EY016323, NIH
grant 1P30EY022589, Research to Prevent Blindness
Adaptive optics SLO/OCT for visualizing retinal vasculature
Michael Pircher, Franz Felberer, Matthias Rechenmacher, Richard
Haindl, Bernhard Baumann, Christoph K. Hitzenberger. Center for
Med Pyhs & Biomed Eng, Medical University of Vienna, Vienna,
Austria.
Purpose: To investigate the capability of our previously developed
adaptive optics scanning laser ophthalmoscope / optical coherence
tomography (AO-SLO/OCT) instrument for visualizing retinal
vasculature on a cellular level.
Methods: The SLO/OCT instrument records both imaging modalities
simultaneously and is operated at frame rates between 10 and 40 fps.
The field of view of the system can be varied between 1° x 1° and
4°x4°. The small field of view allows for an optimum adaptive optics
correction and high resolution imaging. The larger field of view is
used to generate overview images of the retina that enable an easy
determination of the imaged location. A typical measurement takes
several seconds. The en-face OCT technique provides two different
operating modes. In the first mode, a 3D volume scan of the retina is
recorded. Since the system is equipped with a dynamic focus scheme,
an entirely sharp 3D volume can be recorded. In the second mode,
the coherence plane and the focus plane can be set into a layer of
interest (such as a layer containing a vessel) and several en-face OCT
images of this layer are recorded with high speed. This enables the
visualization of dynamic processes such as blood flow and frame
averaging (similar to AO-SLO instruments) in order to increase
the signal to noise ratio. Axial eye motion is compensated using
active axial eye tracking and transverse motion is corrected in a post
processing step.
Results: Retinal blood flow on a cellular level was visualized
using this technology. For larger vessels the coherence gate was
set at different locations (anterior vessel wall, center part of vessel,
posterior vessel wall) within the tissue enabling the visualization of
different structures. The en-face OCT images show subtle details
such as individual erythrocytes or vessel walls. Frame averaging
enabled the visualization of different blood streams within a vessel.
In addition new structures within the surrounding tissue of the vessels
were found.
Conclusions: The AO-SLO/OCT instrument is well suited to study
dynamic processes such as blood flow on a cellular level. The high
depth resolution provided by OCT enables a clear separation between
different structures of the retina. The overview images and the 3D
information that can be recorded by the same instrument allow an
exact localization of the imaged region.
Commercial Relationships: Michael Pircher, None; Franz
Felberer, None; Matthias Rechenmacher, None; Richard Haindl,
None; Bernhard Baumann, None; Christoph K. Hitzenberger,
None
Support: Austrian Science Fund P22329-N02
Structural and Functional Correlation of Retinal Photoreceptors
Overlying Lesions in White Dot Syndrome
Aniruddha Agarwal1, Mohamed K. Soliman1, 2, Nithya Rajagopalan1,
Mostafa S. Hanout1, Mohammad A. Sadiq1, Loren S. Jack1,
Salman Sarwar1, Diana V. Do1, Quan Nguyen1, Yasir J. Sepah1.
1
Ophthalmology, University of Nebraska Medical Center, Omaha,
NE; 2Ophthalmology, Assiut University, Assiut, Egypt.
Purpose: Lesions in white dot syndromes (WDS) may be associated
with photoreceptor (PR) loss. A prospective cohort study was
performed to evaluate PR density and correlate it with retinal
sensitivity overlying lesions in WDS.
Methods: Lesions of WDS (≤ 3 chosen/eye), within 5° foveal
eccentricity, were imaged using adaptive optics (AO) (rxt1, Imagine
Eyes, France), spectral-domain optical coherence tomography (SDOCT) and fundus autofluorescence (FAF) (Heidelberg Spectralis®,
Germany). In this study, lesions were defined as active if there were
presence of hyper-autofluorescence within the lesions. Eyes with
choroidal neovascularization, high myopia (> 6 diopters), media
opacity and other concomitant diseases were excluded. PR density
was calculated using manufacturer-provided AO Detect 1.0 software
after adjustment for axial length using IOLMaster® (Zeiss Meditech,
CA). Retinal sensitivity was assessed using microperimetry (MP)
(Optos SLO, UK) and correlated with PR density using Spearman
Rank Correlation test.
Results: Twenty-six lesions (9 patients: 7 females, mean age of
54.9 ± 16.6 years; 16 eyes) were analyzed. Diagnoses included
serpiginous choroiditis (2 eyes), birdshot choroidopathy (3 eyes),
presumed ocular histoplasmosis syndrome (2 eyes), punctate inner
choroidopathy (6 eyes) and multifocal choroiditis (4 eyes). Mean
PR density overlying 8 active lesions was 3076 ± 4654.89 cones/
mm2 and 6943.5 ± 5739.51 cones/mm2 overlying 18 inactive lesions
(p = 0.117). Mean PR density over 20 lesions with disrupted inner
segment-outer segment (IS-OS) junction on SD-OCT was 5005.64 ±
5024.89 cones/mm2 and 6943.5 ± 5739.51 cones/mm2 over 6 lesions
with intact IS-OS junction (p = 0.28). Mean retinal sensitivity (7.42 ±
4.70 dB) showed fair correlation with PR density (ρ = 0.43, p = 0.04).
Mean retinal sensitivity over lesions with intact IS-OS junction was
13 ± 2.45 dB and 5.71 ± 4.16 dB over lesions with disrupted IS-OS
junction (p = 0.007). Appearance of lesions on AO imaging is shown
in figure.
Conclusions: AO imaging may allow high-resolution analysis of
PR loss among lesions in WDS. Such microstructural changes may
correlate with functional loss.
Image shows an active lesion on FAF (A) associated with focal
hypo-intensities on AO imaging (yellow asterisks) suggestive of PR
loss (B). Healed lesions (C) show circumferential hypo-intense halo
(white arrowheads) surrounding area of scarring (D).
Commercial Relationships: Aniruddha Agarwal, None; Mohamed
K. Soliman, None; Nithya Rajagopalan, None; Mostafa S. Hanout,
None; Mohammad A. Sadiq, None; Loren S. Jack, None; Salman
Sarwar, None; Diana V. Do, None; Quan Nguyen, None; Yasir J.
Sepah, None
538 Accommodation and optical quality
Thursday, May 07, 2015 12:00 PM–1:45 PM
Contributing Section(s): Lens, Multidisciplinary Ophthalmic
Imaging
Ciliary muscle morphology in emmetropia and ocular biometric
correlates
Richa Saigal, Leon N. Davies, Amy L. Sheppard. School of Life and
Health Sciences, Aston University, Birmingham, United Kingdom.
Purpose: Recent studies have documented a link between axial
myopia and ciliary muscle morphology; yet, the variation in
biometric characteristics of the emmetropic ciliary muscle are not
fully known. Ciliary muscle morphology, including symmetry, was
investigated between both eyes of emmetropic participants and
correlated to ocular biometric parameters.
Methods: Anterior segment optical coherence tomography
(Zeiss, Visante) was utilised to image both eyes of 49 emmetropic
participants (mean spherical equivalent refractive error (MSE) ≥
-0.55; < +0.75 D), aged 19 to 26 years. High resolution images
were obtained of nasal and temporal aspects of the ciliary muscle in
the relaxed state. MSE of both eyes was recorded using the Grand
Seiko WAM 5500; axial length (AXL), anterior chamber depth
(ACD) and lens thickness (LT) of the right eye were obtained using
the Haag-streit Lenstar LS 900 biometer. A bespoke semi-objective
analysis programme was used to measure a range of ciliary muscle
parameters.
Results: Temporal ciliary muscle overall length (CML) was greater
than nasal CML, in both eyes (right: 3.58 ± 0.40 mm and 3.85 ± 0.39
mm for nasal and temporal aspects, respectively, P < 0.001; left:
3.65 ± 0.35 mm and 3.88 ± 0.41 mm for nasal and temporal aspects,
respectively, P < 0.001). Temporal ciliary muscle thickness (CMT)
was greater than nasal CMT at 2 mm and 3 mm from the scleral spur
(CM2 and CM3, respectively) in each eye (right CM2: 0.29 ± 0.05
mm and 0.32 ± 0.05 mm for nasal and temporal aspects, respectively,
P < 0.001; left CM2: 0.30 ± 0.05 mm and 0.32 ± 0.05 mm for nasal
and temporal aspects, respectively, P < 0.001; right CM3: 0.13 ± 0.05
mm and 0.16 ± 0.04 mm for nasal and temporal aspects, respectively,
P < 0.001; left CM3: 0.14 ± 0.04 mm and 0.17 ± 0.05 mm for nasal
and temporal aspects, respectively, P < 0.001). AXL was positively
correlated with ciliary muscle anterior length (AL) (e.g. P < 0.001, r2
= 0.262 for left temporal aspect), CML (P = 0.003, r2 = 0.175 for right
nasal aspect) and ACD (P = 0.01, r2 = 0.181).
Conclusions: Morphological characteristics of the ciliary muscle in
emmetropic eyes display high levels of symmetry between the eyes.
Greater CML and AL are linked to greater AXL and ACD, indicating
ciliary muscle growth with normal ocular development.
Commercial Relationships: Richa Saigal, None; Leon N. Davies,
None; Amy L. Sheppard, None
Support: UK College of Optometrists Research Studentship (20132016)
Anatomically-accurate paraxial optical model of cynomolgus lens
accommodation with continuous gradient
Fabrice Manns1, 2, Bianca Maceo Heilman1, 2, Arthur Ho3, 1, JeanMarie A. Parel1, 4. 1Ophthalmic Biophysics Center, Bascom Palmer
Eye Institute, University of Miami, Miami, FL; 2Biomedical Optics
and Laser Laboratory, Department of Biomedical Engineering,
University of Miami, Coral Gables, FL; 3Brien Holden Vision
Institute, Sydney, NSW, Australia; 4Vision Cooperative Research
Center, Sydney, NSW, Australia.
Purpose: To develop an anatomically-accurate model of the primate
crystalline lens with continuous refractive index gradient that predicts
the accommodative response.
Methods: We used data acquired on 6-year old cynomolgus
monkey lenses (n=7, age=6.0 to 6.8 years) during simulation of
accommodation in a lens stretcher (Ehrmann et al, Clin Exp Opt,
2008). During stretching, lens power was measured with a system
based on the Scheiner principle. Anterior and posterior curvature
and thickness were obtained from cross-sectional optical coherence
tomography images (Uhlhorn et al, Vis Res 2008). An anatomical
model of the accommodating lens was created by averaging the
unstretched radii of curvature, unstretched thickness, unstretched
power, accommodation, curvature-power slope, and thicknesspower slope of the 7 lenses. The values were entered in a paraxial
lens model with continuous index gradient (Manns et al, ARVO
2008). The gradient is modeled as a set of spherical iso-indicials
with radius that varies linearly from the equator to the surface. The
refractive index at the lens center and surface are set to be equal to
1.429 and 1.375 independent of accommodation (De Castro et al,
IOVS, 2013). A power-dependence is assumed for the axial index
variation: n(z)=1.429-0.054 zb/tb, where t is the anterior or posterior
half-thickness. The power coefficient b was calculated so that the
accommodative response predicted by the optical model matches that
of the anatomical model.
Results: Unstretched radius: Anterior = 4.28+/-0.43 mm and
posterior = 3.23+/-0.11 mm; unstretched thickness = 3.91+/-0.12
mm; unstretched power = 49.2+/-3.6D; accommodation = 20.1+/6.1D; curvature-power slope: Anterior = 0.00646+/-0.00102 mm-1/D
and posterior = 0.00525+/-0.00097mm-1/D; thickness-power slope =
0.042+/-0.002 mm/D. The power coefficient increased non-linearly
from b=5.0 in the relaxed state to b=5.8 in the accommodated state.
The corresponding average/equivalent indices are approximately
independent of accommodation: 1.420/1.440 for the relaxed and
1.421/1.438 for the accommodated lens. The power coefficient,
average and equivalent index and their changes with accommodation
are consistent with results obtained using a gradient reconstruction
algorithm (De Castro et al, IOVS 2013).
Conclusions: The model with continuous gradient accurately predicts
the anatomical and optical accommodative response of cynomolgus
lenses.
Commercial Relationships: Fabrice Manns, None; Bianca Maceo
Heilman, None; Arthur Ho, None; Jean-Marie A. Parel, None
Support: NEI Grants: R01EY14225, R01EY021834, F31EY021444
(Maceo), P30EY14801 (Center Grant); Australian Federal
Government CRC Program (Vision CRC); Research to Prevent
Blindness; the Florida Lions Eye Bank; Drs. KR Olsen and ME
Hildebrandt; the Henri and Flore Lesieur Foundation (JMP)
Experimental Protocols for Ex-Vivo Lens Stretching Tests to
Investigate the Biomechanics of the Human Accommodation
Apparatus
Ralph Michael1, Laura Pinilla Cortés1, Gustavo A. Montenegro1,
Justin C. D’Antin1, Marek Mikielewicz1, Rafael I. Barraquer1,
Harvey J. Burd2. 1Institut Universitari Barraquer, Barcelona, Spain;
2
Department of Engineering Science, University of Oxford, Oxford,
United Kingdom.
Purpose: To explore alternative experimental protocols to investigate
the biomechanical behavior of the crystalline lens and zonules using
ex-vivo stretching.
Methods: Radial stretching tests were conducted on the anterior
segment (consisting of lens, zonules, ciliary body and sclera) of four
pairs of presbyopic human donor eyes. A simple mechanical model is
used to describe the behavior of the anterior segment when tested in
this way. Each pair of samples was initially stretched with the ciliary
body intact. One sample was re-tested after cutting the ciliary body
radially and the other sample was re-tested after removing the lens.
Results: The external forces needed to stretch the sample with the
ciliary body intact were significantly greater than for the tests in
which the ciliary body had been cut. The forces measured with the
ciliary body intact and lens in-situ, were comparable to the sum of the
forces measured in the tests where the ciliary body had been cut (lens
in-situ) and the forces measured in the tests on the intact ciliary body,
with the lens removed.
Conclusions: When stretching tests are conducted on the anterior
segment, significant circumferential tensions develop in the ciliary
body. This means that the forces applied to the lens and zonules
cannot be related directly to the forces applied by the external loading
system. If radial cuts are introduced in the ciliary body prior to
testing, however, then this difficulty does not arise.
Commercial Relationships: Ralph Michael, None; Laura Pinilla
Cortés, None; Gustavo A. Montenegro, None; Justin C. D’Antin,
None; Marek Mikielewicz, None; Rafael I. Barraquer, None;
Harvey J. Burd, None
Isolated human lens shape determined by tridimensional digital
shadowphotogrammetry: A pilot study
Ashik Mohamed1, 2, Heather A. Durkee3, Fabrice Manns3, 4, Arthur
Ho2, 5, Virender S. Sangwan1, 5, Jean-Marie A. Parel3, 5, Robert C.
Augusteyn2, 5. 1Prof. Brien Holden Eye Research Centre, L V Prasad
Eye Institute, Hyderabad, India; 2School of Optometry and Vision
Science, The University of New South Wales, Sydney, NSW,
Australia; 3Ophthalmic Biophysics Center, Bascom Palmer Eye
Institute, University of Miami Miller School of Medicine, Miami, FL;
4
Biomedical Optics and Laser Laboratory, Department of Biomedical
Engineering, University of Miami College of Engineering, Miami,
FL; 5Vision Cooperative Research Centre, Brien Holden Vision
Institute, Sydney, NSW, Australia.
Purpose: To examine the curvature of the anterior and posterior
surfaces of isolated human crystalline lenses using a digital minishadowphotogrammetric system.
Methods: Crystalline lenses (n = 103, aged 1 month to 88 years,
median post-mortem time 26 hours) were isolated from eyes received
from the Ramayamma International Eye Bank, Hyderabad, India.
Axial thickness, equatorial diameter and surface curvatures (central
3 mm) were calculated from coronal and sagittal profiles of the
lenses imaged using a custom-built shadowphotogrammetric system
(Mohamed et al, IOVS 2014;55: E-Abstract 747) (Fig. 1). The data
were analyzed as a function of age using regression analysis.
Results: For the younger lenses (aged 1 month to 5 years), the
anterior (3.99 ± 0.61 mm) and posterior (4.16 ± 0.74 mm) radii
of curvature (R) were independent of age (p>0.05). There was no
significant difference between the anterior and posterior radii of
curvature in young lenses (p = 0.71, Paired t-test). For older lenses
(aged 14 to 88 years), the anterior radius (8.74 ± 2.22 mm) was
independent of age (p>0.05), whereas the posterior radius showed
a significant increase with age (R = 4.94 + 0.02*Age, p = 0.0003).
In these lenses, the anterior radius was significantly larger than the
posterior radius (p<0.0001, Wilcoxon signed-rank test). The ratio
of anterior radius to posterior radius showed no age dependency
(p>0.05) in both young (0.99 ± 0.24) and adult (1.51 ± 0.37) lenses,
the difference between the two groups being significant (p = 0.001,
Mann-Whitney test) (Fig. 2). Thickness (T) decreases from ~5.4 mm
during infancy to ~4.2 mm by 5 years, and increases significantly
with age from 14 to 88 years (T = 3.79 + 0.01*x, p<0.0001). The
diameter shows an exponential relationship with age (y = 7.21x0.07).
Conclusions: The human crystalline lens anterior and posterior
surface curvatures are quasi equal in very young isolated lenses. Lens
curvatures stabilize around age 14.
Representative Coronal and Sagittal Images
The ratio of anterior radius to posterior radius as a function of age
Commercial Relationships: Ashik Mohamed, None; Heather A.
Durkee, None; Fabrice Manns, None; Arthur Ho, None; Virender
S. Sangwan, None; Jean-Marie A. Parel, None; Robert C.
Augusteyn, None
Support: NIH R01EY021834, R01EY014225 and P30EY14801,
the Australian Federal Government CRC Scheme through the Vision
Cooperative Research Centre, Florida Lions Eye Bank, and Henri and
Flore Lesieur Foundation (JMP). Raksha Urs, Victor Hernandez and
Andres Bernal provided technical support.
Performance of the crystalline lens in the accommodated eye of
myopia
Jennifer Bruhns, Ji C. He. New England College of Optometry,
Boston, MA.
Purpose: Accommodation of the eye is performed by deformation of
the crystalline lens, and deficiency of the accommodation is believed
to be a factor associated with myopia development. However, the lens
performance during accommodation in the myopic eyes has not been
well investigated. The purpose of this study was to measure optical
and structural changes in the accommodated lens of myopic eyes.
Methods: A custom developed Hartmann-Shack wavefront sensor,
integrated with a custom developed spectral domain optical coherent
tomography (SD-OCT) system, was used to measure accommodative
responses (AR) for 17 young adults (aged 21 to 39 yrs old, Rx from
-0.75 D to -8.50D with a mean of -4.50±2.44D). The wavefront
sensor measured Zernike aberrations up to 7th order for the right eye
when accommodative stimulation (AS) was presented for the same
eye at 0.0, 2.0, 4.0 and 6.0D with a Badal system. The 840nm SDOCT system, co-axially aligned with the wavefront sensor, was used
to image the cornea and the lens.
Results: When accommodating 6D, the mean accommodative
changes were 5.40±0.48D in refractive power and -0.03±0.04micron
in spherical aberration. With 6D accommodation, the mean anterior
chamber depth (ACD) was shortened by 0.28±0.06mm while the lens
thickness (LT) was thicken by 0.313±0.07mm, and thus resulting in
a backward movement of the posterior lens surface of 0.04±0.04mm.
The mean anterior lens radius changed from 12.68±1.91mm at 0D to
8.99±1.69mm at 6D of accommodation. Whereas, the mean posterior
lens surface was more curved. It ranged from 6.90±1.09 mm in radius
at 0D to 6.30±1.02mm at 6D accommodation. There was a significant
correlation between the LT change and the ACD change (R2 = 0.76,
p<0.001).
Conclusions: Compared to a forward movement of the lens in the
accommodated eye of emmetropia, as we reported in last ARVO, the
lens moves backward more in the accommodated eye of myopia. The
relatively more backward movement of the lens might contribute
to the deficiency of accommodation in myopic eye and thus be
associated with myopia development.
Commercial Relationships: Jennifer Bruhns, None; Ji C. He,
None
Support: 1R21EY021336
Impact of scattering on accommodation responses
Alexandros Pennos1, Emmanuel Chirre1, Pedro M. Prieto1, Ulrich
Wildenmann2, Frank Schaeffel2, Pablo Artal1. 1Laboratorio de Óptica,
Universidad de Murcia, Murcia, Spain; 2Ophthalmic Research
Institute, Universitat Tübingen, Tübingen, Germany.
Purpose: Increased intraocular scattering degrades vision due to a
reduction of contrast in the retinal images. This may also have an
impact on accommodation. The aim of this study is to investigate
the relationship between increased scatter and accommodation
performance.
Methods: An open-view binocular sensor [Chirre et al., Opt. Lett.,
39, 4773, (2014)] operating in real time (25Hz) with an invisible
infrared beam (1050 nm) was used to measure accommodation, pupil
size and aberrations in both eyes simultaneously. Six young subjects
(29.5 ±2.6 years old) without any known ocular anomaly were
measured while accommodating monocularly with their dominant
eye from far (3 m) to a near (0.3 m) target through scattering
diffusers. Accommodation was measured in the contralateral eye,
not covered with the diffuser nor exposed to the stimuli. Six diffuser
conditions were tested: no filter (baseline), 0.1 and 0.6 Bangerter foils
(Ryser Optik, St. Gallen, Switzerland), BlackProMist 2, ProMist 1,
and the combination of ProMist1 and ProMist2 (Tiffen Company,
Hauppauge, NY, USA). All of them were characterized by means of a
single-pass optical integration method [Ginis et al., J. Vis. 12(3), 20,
(2012)].
Results: A very good correlation (R2 = 0.94) was found between
the scatter coefficient induced by each filter and the average lag
of accommodation. For the densest filter (0.1 Bangerter foil), the
average loss of accommodative response was 0.64±0.62 D, with
values close to 1.5 D for one subject. The increase in the lag of
accommodation is mainly produced by under-accommodation to the
near stimulus although for the 0.1 Bangerter foil most subjects also
found difficulties to relax their accommodation when the stimulus is
placed at far.
Conclusions: Intraocular scattering, which is known to reduce
the contrast of the retinal images, impairs the performance of the
accommodation response. We have found a high correlation between
the amount of induced scattering and the increase in the lag of
accommodation. In early presbyopic subjects with elevated scatter,
this effect could be a factor in age-related loss of accommodation.
Commercial Relationships: Alexandros Pennos, None; Emmanuel
Chirre, None; Pedro M. Prieto, None; Ulrich Wildenmann, None;
Frank Schaeffel, None; Pablo Artal, None
Support: Supported by the SEIDI, Spain (grant FIS2013-41237-R),
ITN-OPAL (supported by European Commission’s Seventh
Framework Programme under the Marie Curie Actions) and Seecat
(Advanced Research Grant of the European Research Council).
Effect of Orthokeratology on the dynamics of ocular
accommodation
Yimin Yuan, Yilei Shao, Weigen Zhu, Meixiao Shen, Fan Lu. School
of Ophthalmology & Optometry, Wenzhou Medical University,
Wenzhou, China.
Purpose: To investigate the pattern of dynamic accommodative
response of myopic eyes after orthokeratology.
Methods: Ten myopic children (mean ± SD age: 10.1 ± 2.4 years)
who fitted orthokeratology lenses in both eyes were recruited.
The right eye of each subject was investigated before dispensing,
and 1 month, 3 month and 6 month after Orthokeratology. For
each visit, accommodative stimuli was given by a Badal system.
Meanwhile, dynamic accommodation was continuously recorded
using Grandseiko WAM-5500 auto-refractor. Real-time imaging of
the anterior segment was simultaneously performed using a custombuilt ultra-long scan depth OCT based on CMOS camera. The values
of accommodative response (AR), as well as anterior chamber depth
(ACD), pupil diameter (PD), lens thickness (LT), anterior (LAC) and
posterior (LPC) surfaces curvatures of the lens were obtained. Then
custom algorithms were developed to fit curves and to yield dynamic
aspects (latency, peak velocity, and amplitude) for the changes of the
above parameters.
Results: The latency of AR decreased and the peak velocity of AR
increased at 3 months and 6 month after orthokerotology compared
to baseline (Re-ANOVA and post hoc test, P < 0.01). The amplitude
of AR increased at 6 month after orthokerotology (P < 0.01). For
non-accommodative condition, ACD, and the radii of ASC were
found significantly decreased at 1 month, 3 month and 6 month after
Orthokeratology compared to baseline (P < 0.01). Meanwhile, the LT
was found significantly increased (P < 0.01).
Conclusions: Dynamic accommodation was improved in myopic
children after Orthokeratology. The morphology of anterior eye
seemed to be more “accommodative” at relax status. This may
suggest that the improvement of accommodation is a key factor for
myopia control using Orthokeratology.
Commercial Relationships: Yimin Yuan, None; Yilei Shao, None;
Weigen Zhu, None; Meixiao Shen, None; Fan Lu, None
Support: National Natural Science Foundation of China (Grant No.
81170869)
Accommodative changes of the wavefront aberration, lens shape
and ciliary muscle in the emmetropic eyes of young adults
Ji C. He1, Jianhua Wang2, Mian C. Wei1, Jing C. Mao1. 1New England
College of Optometry, Boston, MA; 2Bascom Palmer Eye Institute,
Miami, FL.
Purpose: Accommodation of the human eye involves a loop of
biological and optical processes, including the ciliary muscle
contraction, the lens shape deformation, and the change of ocular
wavefront aberrations. But, inter-relationship of the accommodative
changes between different accommodative components within the
loop has not been well explored. The purpose of this study was to
study the inter-relationship between the different components by in
vivo measuring accommodative changes of the wavefront aberration,
lens shape and ciliary muscle for emmetropic young adults.
Methods: A Hartmann-Shack wavefront sensor, integrated with
two OCT systems, was developed to measure wavefront aberrations
for 15 subjects (aged 22 to 27 yrs old; Rx from -0.50 to +1.00D)
during accommodation. One OCT system was used to image the lens
deformation while the other was aligned for imaging ciliary muscle
contraction.
Results: Over a 6D accommodation, mean accommodative changes
were: 5.43±0.26D in refractive power; -0.083±0.027 micron in
spherical aberration, 44.4±7.5 and 24.0.1±21.3 (m-1) in curvature of
the anterior and posterior lens surfaces respectively, 0.38±0.03mm
in lens thickness (LT), and 0.065±0.048mm in the difference of
ciliary thickness between 1.0mm and 3.0mm from the scleral
spur. For individual eye, the change in anterior lens curvature
was significantly correlated to the refractive power change (mean
correlation coefficient r=0.97) and also to the change in the difference
of ciliary thickness (mean r=0.81). The LT was negatively correlated
to spherical aberration for every eye (mean r=-0.95).
Conclusions: For emmetropic eye, accommodative change in
refractive power is in proportion to the changes in lens curvatures,
which are in turn proportionally related to the change of ciliary
muscle thickness. The results provide basic information for
characterizing accommodation performance and also for designing
accommodative intraocular lens.
Commercial Relationships: Ji C. He, None; Jianhua Wang, None;
Mian C. Wei, None; Jing C. Mao, None
Support: NEI 1R21EY021336
Accommodative response to electrical stimulation of the sclera of
peripheral cornea in cats and porcines
Toshifumi Mihashi1, Yoko Hirohara2, 4, Tomomitsu Miyoshi3,
Suguru Miyagawa4, 5, Hiroyuki Kanda4, Hajime Sawai3, Takashi
Fujikado4, Thomas Drew6, James S. Wolffsohn6. 1Innovative
Research Initiatives, Tokyo Institute of Technology, Yokohama,
Japan; 2Product Technology Sec., Topcon Corp., Itabashi, Japan;
3
Department of Integrative Physiology, Osaka University Graduate
School of Medicine, Suita, Japan; 4Department of Applied Visual
Science, Osaka University Graduate School of Medicine, Suita,
Japan; 5Fundamental Technology Sec., Topcon Corp., Itabashi, Japan;
6
School of Life and Health Sciences, Aston University, Birmingham,
United Kingdom.
Purpose: We have reported that the changes in the accommodative
response to electrical stimulation of the branches of the ciliary
nerves in cats. (Miyagawa et al, PLoS One, 2014). We have also
reported that no robust accommodative responses to the electrical
stimulations of the sclera of peripheral cornea (SSPC) were observed
in enucleated porcine eyes (Mihashi et al, VPOptics, 2014). In this
study, accommodative responses to SSPC stimulation in cats and
porcines were investigated.
Methods: Two eyes of two cats under anesthesia and after they were
sacrificed were studied. Three enucleated porcine eyes obtained
from a local slaughterhouse were also studied. Trains of biphasic
pulses (current, 3 mA; duration, 2 ms/phase; frequency, 40 Hz)
were applied using a tungsten electrode (0.3mm diameter) from
several orientations. Wavefront sensing with a compact wavefront
aberrometer (Uday et al J Cataract Refract Surg, 2013) were
performed before and 4 s (cat) and 10 s (pig) after the stimulations
and wavefront aberrations including spherical errors were analyzed
over a 4-mm pupil area.
Results: In the first cat under anesthesia, at three out of seven
stimulus positions, 0.2 D hyperopic accommodative responses were
observed and in two orientations, myopic responses were observed.
For the other cat, weak accommodative responses including
astigmatic changes were observed. In the sacrificed condition of the
second cat, 0.1 D myopic response was observed for one stimulus
orientation and the smaller responses were observed at six out of
eight stimulus positions. No accommodative responses were elicited
for the enucleated porcine eyes.
Conclusions: In the anesthetized cats, electrical stimulation
of the SSPC induced accommodative responses; the responses
were unstable and weaker than the responses by the ciliary
nerve stimulations we observed in our previous study. Small
accommodative responses were observed after one of two cats had
been sacrificed, but no accommodative responses were detected in
the enucleated porcine eyes. Further studies are needed to confirm
difference in the accommodation functions in the two species.
Commercial Relationships: Toshifumi Mihashi, Topcon CorpÔºé
(F); Yoko Hirohara, Topcon Corp. (E); Tomomitsu Miyoshi, None;
Suguru Miyagawa, Topcon Corp. (E); Hiroyuki Kanda, None;
Hajime Sawai, None; Takashi Fujikado, None; Thomas Drew,
Johnson and Johnson (F); James S. Wolffsohn, Johnson and Johnson
(F)
Comparison of three methods to measure objective amplitude of
accommodation
Yunyun Chen1, 2, Wanqing Jin1, 2, Zhili Zheng1, Bjorn Drobe3, 2,
Hao Chen1, 2. 1School of Ophthalmology and Optometry, Wenzhou
Medical University, WenZhou, China; 2WEIRC, WMU-Essilor
International Research Centre, WenZhou, China; 3R&D Optics Asia,
Essilor International, WenZhou, China.
Purpose: To compare objective amplitudes of accommodation
measured by autorefraction associated with a motorized Badal system
in static and dynamic conditions and objective minus lens technique.
Methods: Thirty-one young adults (age 23.35 ± 2.04 years) were
enrolled in the study. Subjects’ refraction ranged from +0.25 to
-6.00DS with astigmatism less than 0.50DC. Refractive errors
were corrected by contact lenses. Accommodative response was
measured using Grand Seiko WAM-5500 open field autorefractor.
Accommodation was stimulated using a static (SB) or dynamic (DB)
(speed 0.25D/s) Badal system with a high contrast distance fixation
target or using minus lens technique (ML), the fixation target placed
at 33 cm. Objective amplitude of accommodation was defined as
difference between maximum and minimum responses for SB and
DB, and as difference between maximum response and distance
autorefraction for ML.
Results: Objective amplitudes of accommodation measured using
SB and DB were similar (respectively 5.58 ±0.85D and 5.62 ±1.34D;
p=0.80 Fisher LSD). Mean interdevice difference was SB-DB=
-0.05D with 95% limits of agreement of [-1.12; 1.02] D. ML gave
significantly higher accommodative responses compared to SB and
DB (6.17±0.90D, p<0.05 Fisher LSD). Mean interdevice difference
were ML-SB=+0.60D and ML-DB=+0.55D with 95% limits of
agreement of respectively [-0.06; 1.47D] D and [-0.34; 1.44] D.
Conclusions: Static and dynamic Badal techniques underestimated
objective amplitude of accommodation by approximately 10%,
compared to minus lens technique. Minification of minus lenses
and proximal cues of fixation target may be responsible for this
difference.
Commercial Relationships: Yunyun Chen, Essilor Int. (F);
Wanqing Jin, Essilor Int. (F); Zhili Zheng, Essilor Int. (F); Bjorn
Drobe, Essilor Int. (E); Hao Chen, Essilor Int. (F)
Support: International S&T Cooperation Program of China (Grant
No. 2014DFA30940)
The effect of longitudinal chromatic aberration on the lag of
accommodation and depth of field
Mateusz T. Jaskulski2, 1, Ivan Marin-Franch1, Paula BernalMolina1, Norberto Lopez-Gil2, 1. 1Universidades de Murcia y
Valencia, Laboratorio Interuniversitario de Investigación en Visión
y Optometría, Murcia, Spain; 2Universidad de Murcia, Instituto
Universitario de Investigación en Envejecimiento, Murcia, Spain.
Purpose: Recently it has been proven that spherical aberration has
influence over the depth of field (DOFi) and the accommodation
lag (Bernal-Molina et al., OVS, 2014). We study if the longitudinal
chromatic aberration (LCA) also plays a role in increasing the DOFi
during accommodation, thus providing an effectively larger range of
accommodation.
Methods: Wavefront aberration maps for three accommodative
demands (AD) 0D, 2D, 4D were measured in 4 subjects using
a custom-made adaptive optics system equipped with a ShackHartmann sensor, a deformable mirror (Mirao 52-e, Imagine Eyes),
and a Badal system controlled by the subject. The accommodation
was paralyzed with 2 drops of cyclopentolate (1%). The deformable
mirror was then set to cancel out the paralyzed aberrations and add
the ones obtained for each AD, to the end that the system simulated
the optics of the accommodated eye. Subjects looked through
the system including the mirror and a 5.7 mm artificial pupil at a
target on an OLED microdisplay. The target consisted of 5 Sloan
letters (0.1 logMAR) shown in sequence in B&W, red (R, 650nm),
green (G, 550nm) and blue (B, 468nm). The luminance was in all
cases constant at 12 cd/m2. By means of the Badal system, subjects
indicated near and far borders of the perceived DOFi based upon the
objectionable blur criterion. The DOFi of the cycloplegic eyes with
all the aberrations corrected (VA < -0.3 logMAR) was also obtained
in all color conditions.
Results: Intersubject mean values of DOFi were similar between
different color conditions: for the AD of 0D we obtained 0.90±0.15D
for B&W, 1.10±0.14D for R, 0.95±0.25D for G, and 0.91±0.12D
for B. The mean DOFi was also stable between different simulated
accommodation conditions, for example the B&W DOFi was
0.9±15D for 0D, 1.0±15D for 2D and 0.8±0.28D for 4D, and
1.0±0.10D for the fully corrected eye. The DOFi due to the chromatic
aberration (the dioptric span between the outer limits of the R and B
DOFi) was on average 1.9 times larger than the DOFi found for the
B&W condition, for each of the AD’s.
Conclusions: The values of the B&W and monochromatic DOFi are
similar and practically do not change for any of the simulated AD’s.
However the DOFi due to the full range of LCA is nearly twice as
large as the one obtained for the B&W. These results indicate that the
presence of an accommodative lag should not be influenced by the
presence of chromatic aberration.
Commercial Relationships: Mateusz T. Jaskulski, None; Ivan
Marin-Franch, None; Paula Bernal-Molina, None; Norberto
Lopez-Gil, None
Support: This work was supported by the Marie Curie ITN grant
“AGEYE” 608049. Founded by an European grant ERC-2012-StG
309416-SACCO.
Relationship between the subjective measurement of
accommodative facility and the objective assessment of the
dynamic accommodative response
Nicola Szostek1, Hetal Buckhurst1, Christine Purslow1, 2, Avril
Collinson1, Phillip J Buckhurst1. 1Faculty of Health and Human
Sciences, Plymouth University, Plymouth, United Kingdom; 2School
of Optometry and Vision Sciences, Cardiff University, Cardiff,
United Kingdom.
Purpose: The dynamic accommodative response can be assessed
objectively using a modified open field autorefractor. Previous
studies have utilised the results of autorefraction to describe
accommodative latency and lag. Accommodative facility is a
subjective method, used in clinical practice for the assessment of the
speed of accommodative change. This study proposes new metrics
for assessing accommodative dynamics and relates these metrics to
the measurement of accommodative facility.
Methods: Accommodative dynamics were measured using the Grand
Seiko WAM 5500 autorefractor (RyuSyo, Japan) on 42 healthy
adults (mean 30±8yrs, range 19-47yrs). A 4.00D accommodative
stimulus was presented in 5-second cycles using the DynaWAM
Badal adaption. A 4-parameter sigmoidal regression curve function
was fitted to each data set and used to determine: time taken to
full accommodation (SoA) and disaccomodation (SoD), latency
of accommodation (LoA) and disaccommodation (LoD). The total
objective speed of accommodative change (oSoAC) was defined
as the sum of SoA and SoD. In addition LoA was calculated again
using a data smoothing method used in previous studies (sLoA).
Accommodative facility (AF) with a 4.00D stimulus change was
assessed via the number of cycles achieved per minute (CPM).
Spearman’s Rho test was conducted to examine the correlation
between accommodative dynamics metrics, AF and age.
Results: The mean SoA: 2.45s±1.32; SoD: 1.88s±0.56; AF: 11.5±6.5;
oSoAC: 4.36s±1.42; LoD: 1.04s±0.50; LoA: 1.17s±0.4; and sLoA:
0.93s±0.41. The age of the subject was found to correlate with the
measures of SoA (r=0.339, p<0.028), SoD (r=0.415, p<0.06), AF
(r=-0.611, p<0.001), and total oSoAC (r=0.661, p<0.001). However,
neither metric for determining accommodative latency correlated
with age (p>0.05). AF showed a significant, inverse correlation with
SoD (r =-0.454, p<0.03), LoD (r =-0.325, p <0.36) and oSoAC (r
=-0.390, p <0.11) but failed to show any significant association with
SoA and both measures of accommodative latency (p>0.05).
Conclusions: The traditional assessment of accommodative latency
via accommodative dynamics did not correlate with age or AF.
The novel metrics of SoD, LoD and SoAC proposed in this study
correlated with both AF and age and may provide additional insight
into accommodative dynamics that relate to clinical measurements
and patient symptoms.
Commercial Relationships: Nicola Szostek, Bausch and Lomb (F);
Hetal Buckhurst, None; Christine Purslow, None; Avril Collinson,
None; Phillip J Buckhurst, Bausch and Lomb (C)
Support: Baulsh and Lomb: Unrestricted PhD grant
Calculating Accommodative Optical Response in Young and Prepresbyopic Eyes using Paraxial Schematic Eye Models
Viswanathan G. Ramasubramanian, Adrian Glasser. College of
Optometry, University of Houston, Houston, TX.
Purpose: Ultrasound biomicroscopy (UBM) studies on young
and pre-presbyopic subjects show that the accommodative optical
response (AOR) can be predicted in a population from each UBM
measured biometry parameter using linear relationships between
AOR and accommodative biometric changes, with standard
deviations of less than 0.55 D. Here, ocular biometry parameters
measured for different accommodative states were used to construct
accommodating paraxial schematic eyes (SE) to predict the AOR.
Methods: The ocular parameters measured were corneal thickness,
anterior and posterior corneal radii of curvature (from OCT), anterior
chamber depth, lens thickness, anterior and posterior lens radii of
curvature (from UBM) and axial length (from A-scan ultrasound).
UBM parameters were measured while subjects accommodated to
different stimulus demands. The AOR to the same stimulus demands
was measured objectively with a Grand-Seiko (GS) autorefractor.
Subjects included 24 young and 24 pre-presbyopes. Paraxial SE
models were constructed for all subjects for all accommodative
states. Standard and iteratively calculated lens equivalent refractive
index values were used. Individual SE models were also constructed
for all subjects using the average change in each UBM parameter
for each stimulus demand from the baseline unaccommodated state
in each subject population. The AOR calculated from the SE models
were compared with the GS measured AOR from each subject.
Results: The slopes and r2 values of the linear regressions between
individual schematic eye calculated and GS measured AOR for
the young subjects were 0.77 and 0.86 and for the pre-presbyopic
subjects were 0.64 and 0.55. The mean difference in AOR (GS individual SEs) was -0.27 D for the young subjects and 0.33 D for
the pre-presbyopic subjects. In the individual eyes, the mean ± SD
of the absolute differences in AOR between the GS and SEs for the
young and pre-presbyopic subjects was 0.50 ± 0.39 D and 0.50 ±
0.37 D, respectively. For average SEs, the mean ± SD of the absolute
differences in AOR between the GS and the SEs for the young
and pre-presbyopic subjects was 0.77 ± 0.88 D and 0.51 ± 0.49 D,
respectively.
Conclusions: Individual paraxial SE models calculated from
measured ocular biometry parameters offer better prediction of
AOR than from individual biometry parameters in young and prepresbyopic subject populations.
Commercial Relationships: Viswanathan G. Ramasubramanian,
None; Adrian Glasser, None
Support: NIH R01 EY017076, NIH P30 EY07551
Measurement of Accommodation with High Dynamic Range
Using a Shack-Hartmann Wavefront Sensor and Dual Channel
Accommodation Stimulus
Victor M. Hernandez1, 2, Marco Ruggeri1, Fabrice Manns1, 2, JeanMarie A. Parel1, 3. 1Ophthalmic Biophysics Center, Bascom Palmer
Eye Institute, Miami, FL; 2Department of Biomedical Engineering,
University of Miami, Biomedical Optics and Lasers Laboratory,
Coral Gables, FL; 3Vision Cooperative Research Centre, Sydney,
NSW, Australia.
Purpose: To develop a combined Shack-Hartmann wavefront sensor
and modified extended range dual-channel Badal optometer stimulus
for the dynamic refractive measurement of accommodation with high
dynamic range without refractive correction, and with a long working
distance to allow coupling with an Optical Coherence Tomography
system for simultaneous lens biometry.
Methods: We designed a system that combines a superluminescent
diode emitting at 750 nm and a Shack-Hartmann wavefront sensor
(WFS150-5C, Thorlabs; Newton, NJ) equipped with a 4-f relay
system via a hot mirror to a two channel (far/near) accommodation
stimulus (Figure 1). The 4f relay system uses f=100 mm lenses to
provide a working distance sufficient to allow future combination
with an anterior segment OCT system. The accommodation stimulus
was designed to present a 10 D stimulus in subjects with refractive
error ranging from –10 D to +6 D. The far target channel is used
as a baseline and adjusted to provide a stimulus at the far point of
the subject. The near target channel is adjusted manually to provide
the desired amount of accommodation stimulus. The stimulus is
presented via a microprocessor-controlled 1.8” liquid crystal display.
Switching the displays on/off provides a step-stimulus that allows
measurement of the dynamic accommodative response. The system
was mounted on an adjustable motorized slit-lamp table. Preliminary
experiments were performed on 4 subjects (age range: 24-49,
refractive error range: -8 D-+1.75 D) following an IRB-approved
protocol. The accommodative response to a stimulus ranging from 0
D to -6 D in 2 D was measured for the right eye of each subject.
Results: The system was able to measure the accommodative
response in all subjects when the stimulus was switched from far to
near.
Conclusions: The preliminary experiments demonstrate the
feasibility of the design.
Figure 1: Profile image of the device mounted to a motorrized
examination table with a chin rest.
Commercial Relationships: Victor M. Hernandez, None; Marco
Ruggeri, None; Fabrice Manns, None; Jean-Marie A. Parel, None
Support: NEI Grants: R01EY14225, P30EY14801 (Center Grant);
Australian Federal Government CRC Program (Vision CRC);
Research to Prevent Blindness; the Florida Lions Eye Bank; Drs. KR
Olsen and ME Hildebrandt; the Henri and Flore Lesieur Foundation
(JMP)
Uniformity of Accommodation across the Visual Field
Tao Liu, Vidhyapriya Sreenivasan, Larry N. Thibos. School of
Optometry, Indiana University, Bloomington, IN.
Purpose: Optical blur due to accommodative error in peripheral
vision has been implicated in myopia development and progression.
We investigated the uniformity of focusing errors over central retina
as a function of accommodation demand in young adult and juvenile
subjects.
Methods: A laboratory scanning wavefront aberrometer (Wei &
Thibos, Opt Express. 2010;18/2:1134-43) uses rotating mirrors to
pivot a laser probe beam (850 nm) about the pupil center to place a
“retinal beacon” at a random sequence of 37 retinal locations over
the central 27° of visual field. For each retinal location, beacon
light reflected out of the eye is de-scanned by the same mirrors and
then directed to a conventional Shack-Hartmann wavefront sensor
for analysis. The visual stimulus was displayed on an achromatic
micro-display in a Badal configuration. Aberrations were measured
at 8 levels of accommodative demand (1D steps of target vergence
starting 1D beyond the estimated far point). Accommodative error is
the difference between target vergence and the eye’s refractive state
as measured by defocus Zernike coefficient C20 (in diopters).
Results: For most adult subjects, ocular refractive state changed
uniformly over the central visual field as the eye accommodated.
Visual field maps of accommodative error reveal subtle patterns of
deviation on the order of ±0.5 D that are unique to the individual and
relatively invariant to changes in accommodative state. Population
mean maps for accommodative error are remarkably uniform across
the central visual field, indicating the retina of the hypothetical
“average eye” is conjugate to a sphere of constant target vergence
for all states of accommodation, even though individual eyes might
deviate from the mean due to random variations. This result confirms
and extends previous work on adults (Mathur, Atchison, & Charman,
2009. J Vis 9, 20 1-11). Similar results were observed also for
children. No systematic difference between emmetropic and myopic
eyes was evident.
Conclusions: Ocular refractive state changes uniformly over
the central visual field as the eye accommodates. Accuracy of
accommodation across the visual field is similar to that measured in
the fovea. Thus loss of image quality due to accommodative errors,
which potentially drives myopia, will be similar across the central
retina.
Commercial Relationships: Tao Liu, None; Vidhyapriya
Sreenivasan, None; Larry N. Thibos, None
Support: P30EY019008
Effect of Age on Amplitude of Accommodation in a Swedish
Population
Baskar Theagarayan, Yelene Sorman. Department of Medicine and
Optometry, Linnaeus University, Kalmar, Sweden.
Purpose: The purpose of this study was to determine the relationship
between age and amplitude of accommodation in a Swedish
population and also to investigate the age of onset of Presbyopia in
this population.
Methods: All the measurements were performed in a Eye Clinic
in Sweden. Subjects living in and around southern part of Sweden
were recruited for this study. All the subjects had at least 20/20 best
corrected visual acuity and normal binocular vision. The sample size
was 103 subjects aged between 9 and 68 years. The amplitude of
accommodation was measured using the push-up and the push-down
method with a Royal Air Force (RAF) ruler. The ruler has both a
metric scale in centimeters and a dioptric scale. The subjects were
asked to read letters of N5 print size and report first sustained blur in
push-up method and first sustained clear in push-down method. The
subjects had their best correction in place during the measurements.
All the measurements were done both monocularly (Right eye-OD
and Left eye-OS) and binocularly (OU).
Results: Regression analysis showed a significant decrease in the
amplitude of accommodation with age (p < 0.05). Age of onset of
presbyopia (less than 5 D amplitude) was 39 and 41 years based on
monocular and binocular values respectively in this sample. There
was no significant difference in the amplitude values between OD
and OS (p > 0.05). Binocular amplitude values were higher than
monocular values. There was a significant difference between
push-up and push-down values (p < 0.05). Compared to Hofstetter’s
results, this study showed lower values than expected.
Conclusions: Amplitude of accommodation decreased with age as
suggested by previous studies. At the age of 54 years, the amplitude
reached around 0.85 D and remained constant after that. Age of
onset of presbyopia in this Swedish population was similar to other
European population.
Commercial Relationships: Baskar Theagarayan, None; Yelene
Sorman, None
A pilot study on effects of sustained accommodation on the optics
of the human eye
Jason Shen, Frank Spors, Don Egan, Chunming Liu, Xiangyun Liu.
College of Optometry, Western Univ of Hlth Sciences, Pomona, CA.
Purpose: Myopia often presents and progresses throughout the
school years and it has been hypothesized that high levels of near
work may contribute to its development. The optics change during
near work; for example, lag of accommodation might be related to
myopia progression. This study is to investigate the possible changes
of the optics of the eye during the sustained near work.
Methods: A commercial Shack-Hartmann aberrometer was modified
to be an open field instrument in order to achieve unrestricted visual
field. Twenty-one low myopes were recruited into the study with only
their left eyes being measured. Subjects were instructed to watch a 15
minutes long video displayed on a computer screen placed 50 cm in
front of the eyes. Measurements were taken at one minute intervals
while the subjects were directed to fixate on a central Maltese Cross
target. Up to six-order Zernike coefficients were recorded and
analyzed. Both a small sample non-parametric signed rank test and
paired t-test were used for statistical data analysis.
Results: The averaged mean spherical equivalent (MSE) refractive
error decreased in the first 9 minutes at the rate of 0.06 D per
minute. After 9 minutes, MSE showed more fluctuation with time.
Changes of 3rd-order coma were more pronounced than changes in
other higher order aberration terms. 4th order spherical aberration
consistently decreased during the first 7 minutes. Compared to 2nd
order defocus change, higher order aberrations had no significant
impact to the changes of the optics of the measured eyes within 15
minutes of accommodation (p > 0.05).
Conclusions: The accommodation of the eye decreases first, but later
shows more fluctuation with sustained near work. Optical changes
in the eye with prolonged near work appear to be mainly caused by
the changes in the 2nd order defocus term rather than by higher order
wavefront errors in the eye.
Commercial Relationships: Jason Shen, None; Frank Spors,
None; Don Egan, None; Chunming Liu, None; Xiangyun Liu,
None
Pseudoaccommodation in children after congenital cataract
surgery and implanted with monofocal intraocular lens :
incidence and mechanisms
Charlotte Marie Dénier1, Pascal Dureau2, Catherine Edelson2,
Georges Caputo2. 1Hôpital Necker, Paris, France; 2Fondation
Rothschild, Paris, France.
Purpose: Some pseudophakic patients implanted with monofocal
intraocular lens (IOL) have good near visual acuity with their
distance correction. This apparent accommodation has been called
“pseudo-accommodation”. The objective of this study was to evaluate
the prevalence of pseudo-accommodation in children after bilateral
congenital cataract surgery, without amblyopia, and to define its
mechanisms.
Methods: We included 40 eyes of 23 children aged 6 to 18, with
a corrected distance visual acuity above 8/10 and a normal near
visual acuity (P2) with +3 addition. We also included a group of
14 pseudophakic adults, with a corrected distance visual acuity
superior to 8/10 and a normal near visual acuity (P2) with +3
addition. Pseudo-accomodation was defined as a near visual acuity
better than P4 with the distance correction and without addition.
Prevalence of pseudo-accommodation was calculated in each
group. In order to determine the factors accounting for pseudoaccommodation in children, we compared the group of children
with pseudo-accommodation with to that of adults without pseudoaccommodation under several parameters : refraction, axial length,
corneal topography, aberrometry, pupillary diameter, implant’s shift
after cyclopentolate mesured with OCT-SD.
Results: In the children group, 36 (90%) had a near visual acuity at
equal to P4 without addition. Among the 28 included adults eyes,
2 (7%) had pseudo-accommodation. When we compared the 36
children eyes with pseudo-accommodation and the 26 adults eyes
without pseudo-accommodation, we found that spherical equivalent,
implant’s power, corneal multifocality and corneal higher-order
aberrations (mainly coma and trefoil) were significantly higher in
the group with pseudo- accommodation, while pupil diameter and
implant’s shift were statistically the same in both groups. Axial length
was smaller in the pseudo-accommodation group.
Conclusions: Pseudo-accommodation in pseudophakic children is
a poor known phenomenon. With this study, we have highlighting
its high prevalence among non-amblyopic children. In children no
mechanism has ever really been identified. This study found several
possible mechanisms to explain pseudo-accommodation in children
: a high power of the IOL and a small axial length, maximizing the
effect of the IOL’s shift, corneal multifocality and corneal higherorder aberrations.
Commercial Relationships: Charlotte Marie Dénier, None; Pascal
Dureau, None; Catherine Edelson, None; Georges Caputo, None
Accommodation in young adults wearing multifocal soft contact
lenses under long- and short- wavelength lighting
Manbir Nagra1, Christine F. Wildsoet2. 1Aston University,
Birmingham, United Kingdom; 2UC Berkeley, Berkeley, CA.
Purpose: Several studies have suggested accommodative lags may
serve as a stimulus for myopic growth, and while a blurred foveal
image is believed to the main stimulus for accommodation, spectral
composition of the retinal image is also believed to influence
accommodative accuracy. Of particular interest is how altering
spectral lighting conditions influences accommodation in the
presence of soft multifocal contact lenses, which are currently being
used off-label for myopia control.
Methods: Accommodative responses were assessed using a Grand
Seiko WAM-5500 autorefractor for four target distances: 25, 33, 50,
and 100cm for 30 young adult subjects (14 myopic, 16 emmetropic;
mean refractive errors (±SD, D) -4.22±2.04 and -0.15±0.67
respectively). Measurements were obtained with four different
soft contact lenses, Single vision distance (SVD), Single vision
near (SVN), Centre-Near (CN) and Centre-Distance (CD) (+1.50
add), and three different lighting conditions: red (peak λ 632nm),
blue (peak λ 460nm), and white (peak λ 560nm). Corrections for
chromatic differences in refraction were made prior to calculating
accommodative errors.
Results: The size of accommodative errors was significantly affected
by lens design (p<0.001), lighting (p=0.027), and target distance
(p=0.009). Mean accommodative errors were significantly larger with
the SV lenses compared to the CD and CN designs (p<0.001). Errors
were also significantly larger under blue light compared to white
(p=0.004) and a significant interaction noted between lens design and
lighting (p<0.001). Blue light generally decreased accommodative
lags and increased accommodative leads relative to white and red
light, the opposite was true of red light (p≤0.001). Lens design also
significantly influenced direction of accommodative error (i.e. lag or
lead) (p<0.001). Interactions with or between refractive groups were
not found to be statistically significant for either the magnitude or
direction of accommodative error (p>0.05 for all).
Conclusions: Accuracy of accommodation is affected by both lens
design and by wavelength of lighting. These accommodative lag
data lend some support to recent speculation about the potential
therapeutic value of lighting with a spectral bias towards blue during
near work for myopia, although such treatment effects are likely to be
more subtle under broad compared to the narrow spectrum lighting
conditions used here.
Commercial Relationships: Manbir Nagra, Coopervision (R);
Christine F. Wildsoet, None
Support: Part-funded by an internal Aston University grant
Relationship between the subjectively and objectively determined
depth of focus of the human eye using defocus curves
Alexander Leube1, Arne Ohlendorf1, Juan Tabernero2, Siegfried
Wahl1. 1Ophthalmic Research Institut, University Tuebingen,
Tuebingen, Germany; 2Laboratorio de Óptica, Universidad Murcia,
Murcia, Spain.
Purpose: The study compared the depth of focus (DoF) of the human
eye, calculated from objective image quality metrics (IQM) and
subjectively measured defocus curves.
Methods: 15 subjects with a mean age of 25.5±3.3 years and a mean
spherical equivalent refractive error of M=-0.45D±2.46D participated
and mydrias was assessed using three drops of 1% cyclopentolat
(assessed three times with 10 min between applications). Monocular
subjective defocus curves (range: ±1.5D in 0.5D steps) were
measured in a distance of 5m in the fully corrected dominate eye
using a 4mm artificial pupil. The DoF was calculated as the dioptric
range under the defocus curve at the threshold “maximum visual
acuity [logMAR] + 0.1”. A commercial aberrometer (i.Profilerplus,
ZEISS, Germany) was used to assess the ocular wavefront. The
point spread function (PSF) and the optical transfer function (OTF)
were analyzed of the single wavefront aberrations for a 4mm pupil,
using Matlab (MathWorks, Natick, USA). The DoF was calculated
using the augmented visual Strehl-Ratio of the OTF (VSOTFa) at
the thresholds 80% and 50% of the maximum value as well as the
visual Strehl-Ratio of the PSF (VSPSF) at a threshold of 50% of the
maximum value. A two-tailed Student’s t-test was used for statistical
analysis.
Results: Using the VSOTFa, the DoF was 0.41±0.08D for the
80% and 0.76±0.11D for the 50% threshold, while the DoF was
0.71±0.12D for the VSPSF at the 50% threshold. Subjective
assessment of the DoF gave a mean value of 0.70±0.23D and showed
a correlation to the individual RMS of the higher order aberrations
(RMS HOA) (r=0.677, p=0.006). DoF was significantly different for
80% VSOTFa (p<0.001) and 80% VSPSF (p<0.001) compared to the
subjective DoF, while the DoF at 50% VSOTFa (p=0.349) and 50%
VSPSF (p=0.730) was not. Nevertheless, there was no significant
relationship between the metrics and subjective measurements
of DoF (50% VSOTFa r=0.20; 50% VSPSF r= 0.24). Individual
thresholds for VSOTFa showed a significant correlation with the
RMS-value of the HOA (r=-0.621, p=0.013).
Conclusions: The estimation of the DoF using the VSOTFa and the
VSPSF at a 50% threshold showed no significant difference to the
subjectively measured DoF, but lacked a significant correlation. To
predict the DoF from objective wavefront measurements, we propose
the use of the VSOTFa at an individual threshold that is estimated
from the RMS HOA.
Commercial Relationships: Alexander Leube, None; Arne
Ohlendorf, ZEISS Vision international GmbH (E); Juan Tabernero,
None; Siegfried Wahl, ZEISS Vision international GmbH (E)
WAVEFRONT ANALYSIS OF HIGHER-ORDER
ABERRATIONS IN PATIENTS WITH HIGH MYOPIA
Santiago Delgado-Tirado, Yazmin Báez-Peralta, Lucia GonzalezBuendia, Iztiar Fernandez, Miguel José Maldonado, Rosa Coco.
Ophthalmology, IOBA, Valladolid, Spain.
Purpose: We performed a prospective, observational and analytical
study to elucidate the correlation between axial length (AXL) and
higher-order aberrations (HOAs) in patients with high myopia
(<-6D). It is believed that an increase in HOAs is correlated with a
significant decrease in quality of vision, especially under scotopic
conditions.
Methods: We analysed 95 eyes from 51 high myopic patients, with
a median age of 43 years. Patients presenting any corneal or lens
disease that could interfere in their aberrometry values, and those
suffering any macular disease evidenced by OCT (3D OCT-2000
FA plus, Topcon) were excluded. Wavefront analysis of corneal,
internal and ocular aberrations was performed with a HartmannShack aberrometer (Wavefront® Analyzer KR-1W, Topcon). In
order to assess the relationship between both variables the Spearman
correlation coefficient was used.
Results: A statistically significant positive correlation between AXL
and internal spherical aberration was detected for the whole sample.
Besides, a statistically significant positive correlation between AXL
and internal tetrafoil aberration, was observed.
Conclusions: According to our results, patients with high myopia
show greater values of HOAs. Thus, it appears to be a positive
correlation between AXL and internal aberrometry. This findings
may help to understand why patients with high myopia reiteratedly
complain about its poor quality of vision, despite of having an
optimum correction of their refractive error and a good visual acuity.
Commercial Relationships: Santiago Delgado-Tirado, None;
Yazmin Báez-Peralta, None; Lucia Gonzalez-Buendia, None;
Iztiar Fernandez, None; Miguel José Maldonado, None; Rosa
Coco, None
Numerical simplification of ray tracing for non-circularly
symmetric models of the human eye
Danilo Andrade de Jesus, D Robert Iskander. Wroclaw University of
Technology, Wroclaw, Poland.
Purpose: To simplify numerical analysis of ray tracing techniques in
application to models of the human eye.
Methods: Recently a method that simplifies calculation of
geometrical points spread function has been proposed for circularly
symmetric systems (Gagnon et al., App. Opt. 2014). The method is
based on Chebyshev polynomials and it is realized with the help of
Matlab Chebfun toolbox – a new tool for computing with functions
developed at Oxford University (www.chebfun.org). An extension of
this method to 2D non-circularly symmetric systems is proposed. In
this method, surfaces, rays, and refractive indices are all represented
in functional forms being approximated by Chebyshev polynomials.
Although generalization from one dimensional to two dimensional
Chebyshev polynomials is not trivial (i.e., not all properties of 1D
Chebyshev polynomials are present in their 2D representations),
there are many benefits of using them including the ease of surface
representation, manipulation of multiple surface designs, and the
ability to represent gradient index (GRIN) type lenses. Such a
representation appears to be an ideal tool for performing ray tracing
in anatomically correct eye models such as the one proposed by Liou
and Brenner (JOSA A, 1997).
Results: A two-dimensional Chebyshev function based ray tracing
procedure for an arbitrary number of surfaces and arbitrary surface
shapes has been developed. The Liou and Brenner anatomically
accurate model of the human eye has been used for evaluating the
method (Figure 1). Computational complexity (assessed as the CPU
time) increases with the addition of each surface in a linear form
indicating that the method has a great computational potential to
be used for more intricate eye models in which, for example, the
crystalline lens is described with multiple surfaces.
Conclusions: Performing ray tracing with Chebfun toolbox
substantially simplifies calculations as it is based on object oriented
programming with handle functions. Realization of the ray tracing
technique in Matlab is particularly attractive among researchers for
whom other ray tracing optical engineering packages such as those
employed in Zemax are more cumbersome and sometimes difficult to
acquire.
An example of chebfun-based ray tracing using the anatomically
correct eye model of Liou and Brenner (JOSA A, 1997) where all the
distances corresponds to millimeters.
Commercial Relationships: Danilo Andrade de Jesus, None; D
Robert Iskander, None
Support: FP7-PEOPLE-2013-ITN, AGEYE 608049
Wide-field schematic model of the Human Eye with
Asymmetrically Tilted and Decentered Lens
James Polans1, Bart Jaeken2, Ryan P. McNabb3, 1, Lucia Hervella2,
Pablo Artal4, Joseph A. Izatt1, 3. 1Biomedical Engineering, Duke
University, Durham, NC; 2R&D, VOPTICA SL, Murcia, Spain;
3
Ophthalmology, Duke University, Durham, NC; 4Laboratorio de
Optica, Universidad de Murcia, Murcia, Spain.
Purpose: More accurate schematic eye models would aid in the
design of advanced ophthalmic instrumentation, including OCT,
SLO, fundus cameras and fluorescence imagers. Since the aberrations
of the human eye vary strongly with retinal eccentricity, it becomes
increasingly important to have an optically accurate eye model for
the design of instruments requiring a wide field-of-view. We propose
a schematic eye that reproduces the aberrations of the human eye
across a wide visual field.
Methods: The model eye was built to reproduce the experimentally
measured wavefront aberrations for 4-mm pupil recorded for the
central 80° of the horizontal meridian (101 eyes) and 50° of the
vertical meridian (10 eyes). These data were acquired using a custom
scanning Shack-Hartmann wavefront sensor [1]. Optical modeling
software (Zemax) and a reverse building eye modeling technique
were used to optimize a merit function. We developed a custom
surface in order to allow the model to be more easily incorporated
into the design of imaging instruments.
Results: Across the entire field-of-view, the eye model shows
excellent agreement with the measured data both comprehensively
and for low-order and high-order aberrations (Fig. 1). In comparison
to previous eye models (Fig. 2), our schematic eye excels at
reproducing the aberrations at the peripheral retinal. Tilt and
decentration of the crystalline lens permits our model to mimic the
asymmetries of the aberrations found in real eyes.
Conclusions: Our proposed model shows great promise towards the
design of wide-field imaging instruments, and it has the potential to
provide further insights in the study of the peripheral optics of the
human eye. Also, we outline a robust eye modeling technique that is
capable of predicting trends beyond those defined explicitly in the
optimization routine.
1. B. Jaeken, L. Lundstrom, and P. Artal, Opt Express 19, 7903
(2011).
2D grid of measured wavefront data (left) compared with the
aberrations calculated for the newly proposed eye model (right) in the
pupil plane.
Plots showing Zernike aberrations versus retinal eccentricity across
the horizontal meridian: oblique astigmatism (a), defocus (b),
vertical astigmatism (c), horizontal coma (d), oblique trefoil (e),
spherical aberration (f), mean sphere (g), and cylinder (h). Error bars
correspond to the standard deviation in the measured data (101 eyes).
Commercial Relationships: James Polans, None; Bart Jaeken,
Voptica (E); Ryan P. McNabb, None; Lucia Hervella, Voptica (E);
Pablo Artal, Voptica (I), Voptica (P), Voptica (S); Joseph A. Izatt,
Bioptigen Inc (I), Bioptigen Inc (P), Bioptigen Inc (S)
Support: National Science Foundation (CBET-1-03905); European
Research Council Advanced Grant (SEECAT, ERC-2013AdG-339228); SEIDI, Spain (FIS2013-41237-R)
Higher order statistical eye model for normal eyes
Jos J. Rozema1, 2, Pablo Rodriguez Perez3, Rafael Navarro3, MarieJose B. Tassignon1, 2. 1Ophthalmology, Antwerp University Hospital,
Edegem, Belgium; 2Medicine and Health Sciences, University of
Antwerp, Antwerp, Belgium; 3Facultad de Ciencias, ICMA Consejo
Superior de Investigaciones Científicas-Universidad de Zaragoza,
Zaragoza, Spain.
Purpose: This work presents a stochastic model capable of
generating an unlimited number of random, but realistic biometry
sets, including the corneal elevation, intraocular distances and
wavefronts, with the same statistical and epidemiological properties
as the original data it is based on.
Methods: One cohort of 312 eyes of 312 healthy Caucasian subjects
(aged 20 – 60 years) was measured with an autorefractometer,
Scheimpflug imaging (Oculus Pentacam), optical biometer (Haag–
Streit Lenstar) and an aberrometer (Tracey iTrace). The corneal
elevation maps, represented by Zernike coefficients, were compressed
using Principal Component Analysis, leaving a total of 17 parameters
to describe the variability of the ocular biometry. These data were
then fitted with a linear combination of three multivariate Gaussians
through an Expectation Maximization algorithm, which has been
shown to give a good representation of the ocular biometry in
a population. Based on this fit a stochastic model was built that
generates an unlimited number of random biometry sets, from which
total wavefronts and other ocular parameters can be calculated.
Equality between the original and the synthetic data was assessed
using non-parametric “two one-sided” tests.
Results: The wavefronts calculated using the measured biometry
were significantly equal to the originally measured wavefronts (two
one-sided Wilcoxon test, p < 0.05), confirming the accuracy of the
ray tracing algorithm. Subsequently, the stochastic model was used
to randomly generate the biometry of 1000 eyes and calculate the
associated wavefronts by ray tracing. For both the biometry and the
wavefront this synthetic data were significantly equal to the originally
measured data (two one-sided Mann-Witney test, p < 0.05), thus
making them statistically indistinguishable.
Conclusions: The statistical eye model is able to produce synthetic
biometry data that is indistinguishable from actual biometry. As such
this model may be an interesting alternative to static eye models for
researchers in visual optics that do not have access to biometry data.
Commercial Relationships: Jos J. Rozema, None; Pablo
Rodriguez Perez, None; Rafael Navarro, None; Marie-Jose B.
Tassignon, None
Support: Flemish Agency for Innovation by Science and Technology,
grant IWT/110684
(Sarkar et al., IERG, 2014). This study modeled the effects of
inter-ocular differences in phase noise and contrast induced by these
wavefront errors on stereo-acuity in keratoconus.
Methods: Lower-order aberrations (LOAs) and HOAs were
measured in 9 keratoconus cases and 5 control subjects, postcycloplegia with 6 mm diameter pupils, either unaided or through
RGP contact lenses (CLs), using a Shack-Hartmann irx3™ wavefront
aberrometer. Refractive data and stereo-depth thresholds were
measured through spectacles and CLs under the same conditions
to compare low and high magnitudes of HOAs. Phase effects were
modeled from the horizontal cross-correlation functions of random
dot patterns convolved with point-spread functions of right and left
eyes. Contrast effects were modeled with retinal image quality (IQ)
metrics computed for each eye using aberrations scaled to 4 mm
diameter pupils. Analyses of variance were performed to investigate
the contribution of inter-ocular differences in phase noise and
contrast to the empirical stereo-depth thresholds.
Results: Stereo-thresholds ranged from 56 – 872 arc sec in cases and
from 29 – 134 arc sec in controls. Some of the variance seen in the
empirical stereo-thresholds in keratoconus obtained with spectacles
(i.e. with HOAs uncorrected) was explained by the signal to noise
ratio derived from the cross-correlation functions (r = -0.59; R2 =
0.36; p < 0.05). The width of the cross-correlation function, estimated
from the standard deviation, was moderately correlated with stereothresholds obtained with spectacles (r = 0.43; R2 = 0.18; p = 0.13).
Inter-ocular differences in IQ metrics chosen to highlight contrast
differences due to HOAs (VSOTF, VSMTF), showed little or no
relationship to the stereo-thresholds.
Conclusions: Inter-ocular HOA differences in keratoconus subjects
introduce phase noise in the disparity domain that affect the fidelity
of disparity signals for stereo-depth perception. The contribution of
contrast differences from HOAs is small in comparison. However,
small residual LOAs could have a larger contrast-difference effect on
stereopsis.
Commercial Relationships: Sangeetha Metlapally, None; Vinay
K. Nilagiri, None; Tiffanie T. Yu, None; Shrikant R. Bharadwaj,
None; Clifton M. Schor, None
A Cross-correlation Model of the Effect of Higher and Lowerorder Aberrations on Stereopsis in Keratoconus
Sangeetha Metlapally1, Vinay K. Nilagiri2, Tiffanie T. Yu1, Shrikant R.
Bharadwaj2, Clifton M. Schor1. 1Optometry, University of California,
Berkeley, Berkeley, CA; 2L V Prasad Eye Institute, Hyderabad, India.
Purpose: Inter-ocular differences and averages of higher-order
aberrations (HOAs) both co-vary with stereo-acuity in keratoconus

Visual Psychophysics / Physiological Optics 106 Retinal

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