Summer 2009 - School of Optometry

Summer 2009
Volume 12, Numbers 1/2
FACULTY PROFILE: Kevin Houston
FEATURED REVIEW: Bioptic Update
CLINICAL REVIEW AND RESEARCH: Relation of Height to Refractive
Error and Ocular Optical Components. Literature Review and
Additional Data
OPTOMETRY HISTORY: IU Alumnus Gary Campbell Produces
Monograph on the History of American Phoropters.
ARTICLE OF INTEREST: Mirror Symmetry of Astigmatic Axes
BOOK REVIEW: Proust was a Neuroscientist
In This Issue
Profiled in this issue is a faculty member relatively new to the IU faculty, Kevin Houston.
Dr. Houston is an alumnus of Indiana University School of Optometry. For the featured
review, he provides an update of bioptic systems for persons with reduced visual acuity.
Work by another alumnus, Gary Campbell, is also discussed in this issue. He has
produced a monograph on the history of American phoropters. Also in this issue are a
literature review on the relation of height and refractive error, a review of an article on
interocular symmetry of astigmatic axes, and a review of a book on the relation of art
and science.
David A. Goss
Editor
ON THE COVER: Figure 10 (page 4) in Kevin Houston’s Bioptic Update article
shows the view with the Conforma Bi-Level Telescope Apparatus.
Correspondence and manuscripts submitted for publication should be sent to the Editor: David A.
Goss, School of Optometry, Indiana University, Bloomington, IN 47405 USA (or
dgoss@indiana.edu). Business correspondence should be addressed to the Production Manager:
J. Craig Combs, School of Optometry, Indiana University, Bloomington, IN 47405 USA (or jocombs
@indiana.edu). Address changes or subscription requests should be sent to Sue Gilmore, School
of Optometry, Indiana University, Bloomington, IN 47405 USA (or sgilmore@indiana.edu).
Our appreciation is extended to Essilor of America for
financial support of this publication.
Varilux® is a registered trademark of Essilor International, S.A
Summer 2009
Volume 12, Numbers 1/2
Table of Contents
Indiana University School of
Optometry Administration:
P. Sarita Soni, M.S., O.D.,
Interim Dean
Clifford W. Brooks, O.D.,
Director,
Optician/Technician Program
Joseph A. Bonanno, Ph.D.,
Associate Dean for Academic
Affairs
Rowan Candy, Ph.D.,
Associate Dean for Research
William Swanson,, Ph.D.,
Associate Dean for
Graduate Programs
Sandra L. Pickel, B.G.S., A.S.,
Opt.T.R., Associate Director,
Optician/Technician Program
Cindy Vance,
Director of Student
Administration
Indiana Journal of Optometry
Editor:
David A. Goss, O.D., Ph.D.
Editorial Board:
Arthur Bradley, Ph.D.
Clifford W. Brooks, O.D.
Daniel R. Gerstman, O.D., M.S.
Victor E. Malinovsky, O.D.
Neil A. Pence, O.D.
Production and Layout
J. Craig Combs, M.H.A.
TABLE OF CONTENTS
FACULTY PROFILE: Kevin Houston
by Todd Peabody ……………………………………….…… 2
FEATURED REVIEW: Bioptic Update
by Kevin Houston ………………..........................………… 4.
CLINICAL REVIEW AND RESEARCH:
Relation of Height to Refractive Error and Ocular Optical
Components. Literature Review and Additional Data
by David A. Goss and Vernon Dale Cox …….................... 7
OPTOMETRY HISTORY:
IU Alumnus Gary Campbell Produces Monograph on the
History of American Phoropters
David A. Goss ………………………………….......……….. 13
ARTICLE OF INTEREST:Mirror Symmetry of Astigmatic Axes,
by David A. Goss ………………..................................….. 14
BOOK REVIEW: Proust was a Neuroscientist
Reviewed by David A.Goss ...................................……… 16
Statement of Purpose: The Indiana Journal of Optometry is published by the
Indiana University School of Optometry to provide members of the Indiana
Optometric Association, Alumni of the Indiana University School of Optometry, and
other interested persons with information on the research and clinical expertise at
the Indiana University School of Optometry, and on new developments in
optometry/vision care.
The Indiana Journal of Optometry and Indiana University are not responsible for
the opinions and statements of the contributors to this journal. The authors and
Indiana University have taken care that the information and recommendations
contained herein are accurate and compatible with the standards generally
accepted at the time of publication. Nevertheless, it is impossible to ensure that all
the information given is entirely applicable for all circumstances. Indiana
University disclaims any liability, loss, or damage incurred as a consequence,
directly or indirectly, of the use and application of any of the contents of this
journal. This journal is also available on the world wide web at:
http://www.opt.indiana.edu/IndJOpt/home.html
Faculty Profile: KEVIN HOUSTON, O.D.
BY
TODD PEABODY, O.D.
K
evin Houston was born in Phoenixville,
Pennsylvania, but grew up in Lansing, IL, a
southern suburb of Chicago. Despite his
upbringing on the Southside of Chicago,
traditionally considered White Sox territory, Kevin
is a lifelong Cubs fan. In high school, Kevin was a
musician and an athlete,
excelling both on the baseball
diamond and on the French
horn in the high school band.
He went on to attend school
downstate at Eastern Illinois
University. He excelled in
Army ROTC there, earning his
Black Beret qualification. At
EIU, he earned his Bachelor
degree in Zoology and
Chemistry. Upon graduation,
Kevin spent a year teaching
kids about dinosaur fossils and
ecology as a Conservation Educator at Disney’s
Animal Kingdom in Orlando, FL.
Kevin gained admission to Indiana University
School of Optometry in fall 1999. As a student at
IUSO, Kevin was heavily involved in service, an
active member of Indiana University Optometric
Student Association, Volunteer Optometric
Services to Humanity, and Beta Sigma Kappa
Optometric Honor Society.
After graduating from optometry school in 2003,
Kevin worked in private practice in Mitchell,
Indiana. Influenced by his multiply handicapped
brother, Kevin found his niche working with special
populations. This eventually led him to Atlanta
Georgia to work at Gottlieb Vision Group, a clinic
internationally recognized for rekindle™, a
treatment for visual field loss. Here he gained
experience treating patients with vision loss due to
acquired brain injury and stroke, ocular disease,
and developmental disabilities. In 2006, he earned
fellowship in the American Academy of Optometry.
In January 2007 Kevin left private practice to teach
clinical low vision rehabilitation at IUSO.
The University clinics are specially equipped to
allow thorough evaluation of patients with serious
vision disturbance resulting from degenerative eye
conditions, congenital eye conditions, degenerative
neurological conditions, stroke, brain tumors,
automobile accidents, and aneurysm. These
patients typically have moderate to severe
reduction in visual acuity, glare disability,
constricted visual fields, visual spatial distortions,
visual processing disorders, color vision deficits,
double vision, poor balance and mobility, and
inability to perform activities of daily living. Kevin
also provides inpatient vision rehabilitation at the
Rehabilitation Hospital of Indiana.
In addition to his work in the clinic, Kevin has
developed a reputation for his speaking and his
research. He has given 26 lectures to various
groups in the professional community and has
been steadily working on cutting edge low vision
research. His current investigations include
prescribing trends of BiOptic telescope systems for
driving, minimum vision requirements for cell
phone use, and prism adaptation therapy for
unilateral spatial neglect. Throughout his time at
IU, Kevin has served as the Indianapolis Director of
Low Vision Services for IUSO as well as the
Director of Inpatient Optometric Services at the
Rehabilitation Hospital of Indiana.
In time away from the School, Kevin enjoys
photography, jogging as a member of the Indiana
University School of Optometry Running Team,
and spending time with family and friends. He and
his wife Lindsey treasure spending time with their
21 month old son Maddox Houston.
Page 1 ... Vol. 12, Nos. 1/2 ... Summer 2009 ... Indiana Journal of Optometry ..........................................
Bioptic Update
BY
KEVIN HOUSTON, O.D.
Abstract
Forty-five states in the United States currently permit visually impaired people with moderately
reduced visual acuity to drive with the aid of a bioptic telescope. A review of the major types of
bioptics prescribed are discussed in detail with fitting pearls. A review of the literature pertaining
to visual risk factors for motor vehicle crashes is presented and a protocol for the assessment of
potential driver rehabilitation patients is presented based on the latest research. Training
procedures are also outlined with an introduction to the use of a new computer aided training
software and discussion of the potential role for immersive driving simulators to improve the
safety of bioptic drivers.
Key words/phrases: Bioptics, driving, dynamic driver software, low vision
Introduction
Forty-five states in the United States currently
permit people with moderately reduced visual
acuity to drive with the aid of a bioptic telescope
system (BTS).1 The driver will have reduced
central vision with full peripheral vision and use a
2x-5.5x telescope mounted on the top of the frame
or drilled and cemented into the spectacle lens.
The telescope allows the driver to quickly glance
between their regular
lens, termed the carrier,
and the magnified view
of the telescope in
order to see signs and
other road hazards.
The median estimated
time spent viewing
through the telescope is
only 5% of the time with
the most common tasks
being spotting road
Figure 1
signs, traffic lights, and
identifying road hazards.2
Galilean telescopes consist of a plus lens
objective and a minus eyepiece, creating an
upright image with a relatively short tube length, as
seen in Figure 1. The drawback is the relatively
small field of view due to an internal exit pupil. The
exit pupil is the image of the entrance pupil, in this
case the objective lens at the front of the scope, as
seen through the eyepiece. Field of view in any
telescope design is maximized by having the eye
as close as possible to the exit pupil. In Galilean
style bioptics, minimizing the eye to eyepiece
distance is essential. The small field of view
makes Galilean telescopes significantly more
challenging to fit properly. Pupillary distance,
telescope location, and angle of tilt must all be
precisely measured after adjusting the frame. The
cosmetically appealing small size of these devices
motivates doctors
and patients to
tolerate their
inconveniences.
Keplerian
telescopes have the
downfall of being
much larger and
heavier than their
Galilean cousins,
but are much easier
Figure 2
to fit and use. They
consist of a plus objective, and plus eyepiece.
This results in a longer focal length and an inverted
image, as seen in Figure 2. An inverting prism is
needed to create an upright image, further
increasing the weight. The exit pupil is a virtual
image outside the telescope, and can actually be
observed by looking at the bioptic from the rear
and rocking it side to side. The clinician should
see the exit pupil as though it is floating out of the
eyepiece, moving against the direction of the
telescope as it is slightly
tilted left to right. When the
bioptic is worn, this virtual
image allows the exit pupil
of the telescope to align
with the entrance pupil of
the eye, thereby
maximizing the field of
Figure 3
view. Higher powers up to
10x can realistically be used if the patient has good
dexterity and understands the limitations in the
visual field.
Keplerian Bioptics
Ocutech VES®-II has been around for many
years and is still a favorite of many of my patients.
The characteristic design that has made this model
and the generations after it popular was the
.................................................... Indiana Journal of Optometry ... Summer 2009 ... Vol. 12, Nos. 1/2... page 2
periscope type design
allowing the telescope to sit
length wise against the
frame rather than
protruding out (Figure 3).
The VES II is still fit by
practitioners when the
patient requires the
Figure 4
telescope to sit up higher.
This model is mounted on top of the frame and is
not drilled through the lens, requiring a larger head
tilt forward to enter the bioptic. The half-eye frame
is the only frame choice for this device.
Ocutech VES-K
is similar to the VESII with the difference
being the mounting
of the telescope
(Figure 4). Frame
options include the
aviator style Ocutech
K and the oval unisex
styles only. Drilling
Figure 5
the eyepiece through
the carrier lens increases the field of view by
getting it closer to the eye. The degree of head-tilt
required is less, facilitating quicker spotting.
Ocutech VES-Autofocus is currently still the
only commercially available autofocus bioptic
telescope (Figure 5). This device is useful when
hands free focusing is required. The convenience
of autofocus is literally outweighed by the size of
the device at 2.5 ounces and the hassle of the
battery pack. The autofocus mechanism is
relatively outdated and contains some of the
glitches common to older autofocus cameras. With
prudent foresight, the engineers fashioned the
device with an
autofocus lock to
prevent misfocusing during
driving. The
autofocus is only
available in 4x with
the standard 12
degree field of view.
Ocutech plans to
Figure 6
release a new
autofocus telescope in the summer of 2009 which
they promise will provide significant advancements
in this type of technology.
Ocutech VES Mini, as its name indicates, is a
new compact design. It is optically similar to the
other VES models being a Keplerian with the
periscope type design. However, instead of
attaching to the top of
the frame, it is drilled
into the carrier lens
(Figure 6). The major
advantage has been
the 15 degree field of
view and the ability to
do a binocular mount.
Despite its smaller
Figure 7
size, most patients
consider it less cosmetically appealing than the
other VES models. Ocutech is planning to
introduce a smaller and cosmetically superior
Galilean model sometime in the next 12 months.
Ocutech VES Sport is the newest addition to
the bioptic telescope market (Figure 7). It is most
similar to the VES-K, with several improvements.
1) The optics are noticeably sharper and brighter,
2) the housing is more sleek and comes in different
colors, 3) the near focus of the 4x is 7 inches
compared to 9 inches on the VES-K, 4) there is a
parallax correction for image shift that occurs when
using the device at near, and 5) refractive
compensation without an eyepiece lens is also
better, up to +/-15. The field of view, frame
options, and weight are the same. I have a couple
patients who use the device for near and
intermediate tasks in addition to the traditional
distance use. However, most patients who choose
to upgrade do so for the cleaner optics and
appearance.
Designs for Vision Expanded field spiral
telescope systems (EFTS) is a series of Keplerian
scopes that have been a mainstay in the field of
bioptics for years. The optics are very crisp; some
of the best available. A wide range of powers are
possible up to 10x. Downfalls include their weight
at 4 ounces compared to the VES at 0.9 ounces,
smaller 4x field of view at 9 degrees compared to
the VES’s 12.5 degrees, and poor cosmesis. The
telescope protrudes directly out of the lens making
for a front
heavy system.
As the device
ages the weight
will commonly
cause the
mounting to
loosen or crack Figure 8
the carrier lens. The large size also occludes
much of the driver’s visual field. The nice optics of
this device persuades many of my patients who do
not mind the weight to stick with this design.
The Beecher Mirage is a set of head-mounted
binoculars (Figure 8). Brightness and field of view
Page 3 ... Vol. 12, Nos. 1/2 ... Summer 2009 ... Indiana Journal of Optometry .....................................................
is the best on the market with 15 degrees in the 4x.
Unlike most bioptics, it is not drill mounted into a
carrier lens. If carrier lens prescription is needed,
the bridge can be adjusted to allow a frame to fit
under the bioptic. The eyepieces can be easily
adjusted for PD allowing a technician to fit and
adjust the device. The clinician can prescribe this
binocular bioptic without having to be concerned
that it will come out of alignment and cause the
patient to see double, as is the case with other
models. The wide field of view makes it an
excellent option for older patients who might have
problems adapting to the smaller field of view of
other bioptics. The mirage is also available in a
5.5x with a field of view comparable to most 4x
models. This is likely why Indiana amended its
bioptic driving law to allowing patients to drive with
the 5.5x Mirage, whereas 4x is the magnification
limit for all other devices. Eschenbach introduced
a new mounting for the Mirage last year that looks
more like a glasses frame and provides more
stability than the old strap design seen in Figure 8.
The disadvantage of the Mirage is its 3 oz weight,
large size, and poor cosmesis; which many
patients will find tolerable in exchange for its ease
of use and superior optics. Powers available up to
8x are not eligible to use for driving, but
nonetheless it works well to improve orientation
and mobility in the severely and profoundly visually
impaired.
Galilean Bioptics
Conforma’s Bi-Level Telescopic Apparatus
(BITA) is a miniature Galilean telescope and has
been available since the 1980's. I still find it to be
the best of the microgalilean bioptics. It comes in a
3/8ths and 1/2 inch sizes from 2.5x-6x (Figure 9).
The field of view will discourage some patients, but
I have not found it to
be an issue once it is
mounted in its carrier
lens. The telescope is
not cemented into the
carrier and can be slid
back to minimize the
vertex distance and
increase the field of
Figure 9
view. The clinician can
specify whether the focusing apparatus is in the
front of the carrier lens, or in the rear. Peripheral
vision is not obstructed due to the small size of the
telescope, creating a magnified image
superimposed on top of the normal field (Figure
10). This allows the patient to retain full peripheral
vision, depth perception, and spatial orientation
while looking
through the
telescope. The
telescopes can
be mounted in
the bioptic
position or on
the visual axis; a
method called
simulvision. I
have fit this both
ways and either Figure 10
way seems to work well. With a good fit the 4x
gets a 10.5 degree field of view; significantly less
than Keplerian models, but tolerable for many
patients when weighed against its cosmetic upside.
Designs for vision (DFV) also makes a
telescope
comparable to
the BITA called
the microspiral
galilean,
although I have
Figure 11
not ever
attempted fit this
device. The visual field of the 4x is 5 degrees and
it can be mounted in the bioptic position or on the
visual axis, similar to the BITA’s simulvision.
Eagle Eye II by Designs for Vision is probably
the most cosmetically appealing bioptic currently
available (Figure 11). The objective sits flush with
the carrier lens, hiding most of the telescope
behind the lens. I often tint the carrier and have
used mirrored clip-ons to completely cover the
scope. Unfortunately it only comes in 2.2x, limiting
it to only the most mildly visually impaired drivers.
Because of the proximity of the eyepiece to the eye
and the relatively large objective and eyepiece
diameter, the field of view is relatively good at 11
degrees. The difference between this telescope
and the Model II bioptic is the mounting. The
Model II protrudes 2-3 mm out of the front of the
lens, but is still a very cosmetically acceptable
option. The Eagle Eye II has a ball and socket
mounting that allows the telescope to be adjusted
to maximize alignment.
We still have some patients in the DFV
focusable (spiral) and fixed focus Galilean
systems. This is one of the most popular designs
for bioptic driving. It is very durable, has fixed
focus preventing the potential hazard of driving
with a defocused telescope, can be mounted
binocularly, and is easily compatible with filters. It
does, however, have limitations of visual field at 6
degrees in the 4x, and relatively poor cosmesis
................................................... Indiana Journal of Optometry ... Summer 2009 ... Vol. 12, Nos. 1/2... page 4
compared to other Galileans.
Vision Requirements for Bioptic Driving in
Indiana
In order to be a candidate for bioptic driving, a
patient must have:
• 20/200, better eye
• Visual Acuity must reach 20/40 with
telescope (4x or less)
• Visual field no less than 120 degrees
horizontal
• Color vision adequate for traffic lights and
signs; red, yellow, green
• Stable eye condition
• No other co-morbidities
• 30 hours on-the-road training with certified
driving rehab specialist (CDRS)
• Approval of BMV medical advisory board
• Annual review must be done by OD &
reported to BMV
• Renewal every 4 years done by OD &
reported to BMV
Identifying High Risk Drivers
Not all patients who will meet the Indiana
vision requirements for the bioptic program will be
able to successfully complete the program and
obtain their license. The 30 hour on road training
allows sufficient time for the driving specialist to
discover which patients will not be safe drivers.
Unfortunately, this step comes at the end of the
program after significant time and money has been
spent. Accurately predicting which patients have a
poor prognosis for driver rehabilitation early in the
process is a benefit to the patient both
psychologically and fiscally. Recent research
studies have allowed clinicians to better predict on
road performance.
The Salisbury Eye Evaluation (SEE) Study
The Salisbury Eye Evaluation Study was
conducted in Salisbury, Maryland from 1993-1995
and the data on driving risk was published in April,
2007. Salisbury is a semi-rural town of 24,000
which is relatively grid-locked with four lane roads
and intersections with traffic signals. The driving
situation in Salisbury is probably most similar to
towns like Terre Haute and Kokomo, Indiana. This
was a retrospective study looking at 1801 driver
records of individuals aged 65-84. It was the first
study to look at multiple measures of visual
function including Visual Acuity (VA), Contrast
Sensitivity, Glare, Stereo, Humphrey Visual Field
(HVF), and Useful Field of View (UFOV). They
looked for correlations between visual measures
and at-fault motor vehicle crashes. Results
showed that visual field was the most important
measure, followed by contrast sensitivity, and glare
sensitivity. Greater than 20 points missed in the
entire binocular field or greater than 10 points
missed in the inferior binocular field on the full-field
81-point test translated to increased risk. Accident
rates likewise began to increase with contrast
sensitivity measures less than 1.6 Log on the PeliRobson test.3 The SEE study supports other
studies that found contrast sensitivity to be a risk
factor for crash involvement.4
Other Important Studies
Several other studies have impacted the way
we evaluate patients in our clinics. Tests of
divided attention have been found to be a good
predictor of crash risk including both the Useful
Field of View (UFOV) and the Trail-Making Test
Part-B (TMT-B). We use the TMT-B because of its
long associated correlation to driving performance
and ease of administration. It is an extravagant
version of connect the dots, where the patient must
connect number one to letter A, A to 2, 2 to B, and
so on; alternating between numbers and letters.
Studies have repeatedly shown the predictive
value of this test for driving. Times were strongly
associated with recent crash involvement in a
study of 1,700 drivers, on-road driving performance
in a study with 105 drivers,5 and future at-fault
crash risk in a study with 2,508 drivers.6 The large
sample sizes and strong statistical correlations
from these studies demonstrate the predictive
power of this test.
Recommended Bioptic Driver Protocol
Evaluation
The aforementioned research has lead to a
new protocol for the evaluation of drivers that
includes Full-Field 81 point field, contrast
sensitivity using the Peli-Robson chart, glare acuity
testing, and TMT-B in addition to traditional vision
tests. Data are analyzed and risk factors are
tallied as 1) bioptic Snellen acuity worse than
20/30, 2) contrast sensitivity less than 1.6, 3) >10
points missing in the inferior binocular field or >20
points missed on the entire binocular field, 4) large
bilateral macular scotomata, 5) significant color
deficiency, and 6) glare disability greater than 2
lines. Unstable or progressive vision conditions
are a separate risk factor that can carry more
weight at the examiner’s discretion. Prognosis is
determined based on number of risk factors; 1
being good, 2-moderate, 3-guarded, or 4-poor.
With greater than 5 risk factors, the patient does
Page 5 ... Vol. 12, Nos. 1/2 ... Summer 2009 ... Indiana Journal of Optometry ...................................................
not a receive bioptic fitting for driving. This
protocol has been useful to help make objective
and evidence based decisions in a situation where
an emotional patient may affect the clinician’s
decision. Without a set protocol, the practitioner
may be pressured to move forward with training
when it is not in the best interest of the patient.
Training
An evidence-based protocol cannot be
developed at this time for bioptic training due to
insufficient research. Systematic and uniform
training on the use of the bioptic is important to
allow these techniques to be studied and taught to
future OD’s and driving specialists. New computer
programs and driver simulators offer opportunities
to improve a patient’s skill with their bioptic. In our
clinic we are doing 3 to 4 one-hour visits using
standard approaches such as stationary target
spotting on paper charts as well as novel
computer-aided training using a projected
animation program that has dynamic and
translating targets in motion such as letters,
arrows, and traffic signs. The program is called
Dynamic Driver, Bioptic Training Program7 and
can be downloaded at
https://www.indiana.edu/~opt2/lvtrain/login.htm
We also use a projected video driving simulation in
an attempt to achieve generalization of the skills
learned to the task of driving. More realistic
immersive simulators where the patient sits in a car
cab that is interfaced with a video display are
already available. One such apparatus is the
DriveSafety DS-600c. The patient sits in an actual
car cab with full driver controls including steering
wheel torque feedback and mirrors with integrated
LDCs. It sits on a motion platform that provides
inertial cues when the driver turns or brakes.
Software allows for the creation of customized
driving scenarios. While computerized training
cannot replace on-road training, this type of
technology may prove useful in maximizing skills in
a safe environment. Control over the driving
scenario ensures that patients can be evaluated
and trained for the most important situations that
they cannot be guaranteed to encounter during
their 30-hours on the road with the driving
specialist. Trouble spots can be identified and
repeatedly practiced safely.
reality technology offers new possibilities for
improving safety in this high risk population.
Disclosures
The author has no financial interest in the
products or techniques discussed in this article.
Acknowledgements
The author thanks Ocutech, Conforma, and
Designs for Vision for providing technical
specifications and photographs of their products for
use in this article.
References
1. Nolan J. An overview of bioptic driving: history,
regulations, and practical experiences. Visibility,
News and Research from the Envision Low Vision
Rehabilitation Center 2009; 3(2): 5-7.
2. Bowers AR, Apfelbaum DH, Peli E. Bioptic
telescopes meet the needs of drivers with
moderate visual acuity loss. Invest Ophthalmol Vis
Sci 2005;46:66-74.
3 Rubin GS, Ng ES, Bandeen-Roche K, Keyl PM,
Freeman EE, West SK. A prospective, populationbased study of the role of visual impairment in
motor vehicle crashes among older drivers: the
SEE study. Invest Ophthalmol Vis Sci
2007;48:1483-1491.
4. Owsley C, Stalvey BT, Wells J, Sloane ME,
McGwin G Jr. Visual risk factors for crash
involvement in older drivers with cataract. Arch
Ophthalmol 2001: 119:881-887.
5. Wang C, Kosinski C, Schwartzberg J, Shanklin
A. AMA’s Physician's Guide to Assessing and
Counseling Older Drivers. Washington, DC:
National Highway Traffic Safety Admin; 2003.
www.ama-assn.org/ama/pub/category/10791.html
6. Vance DE, Roenker DL, Cissell GM, Edwards
JD, Wadley VG, Ball KK. Predictors of driving
exposure and avoidance in a field study of older
drivers from the state of Maryland. Accid Anal
Prev 2006;38:823-831. Epub 2006 Mar 20.
7. Houston, K. Dynamic Driver, Bioptic. 2007.
https://www.indiana.edu/~opt2/lvtrain/login.htm.
Conclusion
The bioptic market continues to see slow but
steady improvements in technology. Use of
traditional devices and training techniques in
combination with novel computerized and virtual
............................................Indiana Journal of Optometry ... Summer 2009 ... Vol. 12, Nos. 1/2... page 6
Relation of Height to Refractive Error and
Ocular Optical Components: LITERATURE
REVIEW AND ADDITIONAL DATA
BY DAVID A. GOSS, O.D., PH.D. AND VERNON DALE COX, PH.D.
M
any theories of myopia development and
emmetropization involve various aspects of
ocular growth.1-7 According to some of these
theories, metrics of general body growth, such as
height, could be expected to be correlated with
refractive error and ocular optical components,
such as axial length. The purpose of this paper is
to review studies of the relation of height to
refractive error and ocular components. In
addition, some previously unpublished data will be
presented.
Literature Review
Johansen8 reported on the heights of 527
boys, ages 12 to 15 years, from seven different
schools in Denmark. Forty-three of the boys had
myopia, which ranged from -0.50 to -7.00 D, and
which averaged -2.6 D. Mean heights were
numerically greater among the myopes than the
non-myopes at each age: 2.1 cm greater among
the 12 year olds, 1.8 cm greater at 13 years old,
3.4 cm at 14 years, and 5.2 cm at 15 years. The
difference in means was statistically significant
only for the 15 year olds. Heights varied
considerably within both refractive groups, with
standard deviations in the separate refractive and
age groups generally being between 6.5 and 7.5
cm.
Two graduate thesis projects at Indiana
University studied the relationships between axial
length and height and other anthropometric
measurements. Mohindra9 found a statistically
significant correlation of axial length and stature in
35 males born in India. Subjects were 20 to 38
years of age. Eighteen of the subjects were
myopic. The correlation coefficient of axial length
and height was r = 0.57. Baldwin10 studied 40
male myopes and 40 female myopes between the
ages of 17 and 36 years. Their myopia ranged
from -0.50 to -13.50 D. Correlation coefficients of
axial length with height were not statistically
significant: r = 0.12 in males and r = 0.01 in
females.
Goldschmidt11 reviewed a 1938 German study
(Francke) that found that myopes under 6 D
averaged about 4 cm taller than emmetropes, but
that myopes over 6 D were not taller than
emmetropes. He also described a 1958 French
study (Benoit) which reported statistically
significant greater height in myopes than nonmyopes. However, in Benoit’s study, when
subjects were divided into “peasants” and
students, the differences in mean heights between
myopes and non-myopes were no longer
statistically significant.
Goldschmidt11 presented data for 3,511 men
called up for military service examination in
Denmark in the spring of 1964. Most of the men
were 18 to 20 years of age. Men who had myopia
of at least -0.50 D in at least one eye were
considered myopic; they numbered 491 of the
3,511. The mean height of the myopic men was
1.6 greater than the mean height of the nonmyopic men (p<0.001). Goldschmidt divided the
study population into six occupational categories
(pupils and undergraduates, business men and
office workers, advanced school or trade school
training, craftsmen, skilled workers, laborers and
seamen). Myopic persons were not found to be
taller than non-myopic persons in the same
occupational groups. Students on average were
about 5 cm taller than laborers, and myopia was
much more common among students than among
laborers.
Another study of Danish military recruits was
performed some 20 years later with the data from
7,950 males in 1985 in eastern Denmark.12
Refractive data were taken from the power of
habitual spectacles, or from contact lens
prescriptions, or from refractive examination. The
mean heights (with standard deviations in
parentheses) for different refractive groups were
as follows: -5.75 to -8.00 D, 179.9 cm (6.4); -2.75
to -5.50 D, 180.8 cm (6.4); -0.25 to -2.50 D, 180.4
cm (6.7); 0 D, 179.6 cm (6.6); +0.25 to +2.50 D,
180.9 (7.3); +2.75 to +8.00 D, 177.9 cm (5.4). All
together, myopes averaged 0.8 cm taller than
emmetropes and 1.0 cm taller than hyperopes.
In a study of 11 year old children in the United
Kingdom, Peckham et al.13 presented data for a
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large group of children, of which 189 boys and 214
girls had myopia. Children with myopia were
significantly taller than children without myopia, the
difference being 1.0 cm. They noted that myopia
was more common in families with higher social
status and in families with fewer children. In an
analysis of variance the difference in height
between myopes and non-myopes was almost
entirely accounted for by differences in social
status and family size.
Johnson et al.14 presented data for members
of a small Labrador community. They reported
statistically significant correlations of height with
refractive error for subjects over the age of 20
years. The correlation coefficients were: r = 0.42
for Caucasian males (n = 30; p<0.025); r = 0.53 for
Inuit and mixed race males (n = 104; p<0.001); r =
0.38 for Caucasian females (n = 15; p<0.1); r =
0.28 for Inuit and mixed race females (n = 97;
p<0.01). They did not give data for the relation of
height and refractive error, but they stated that
“The younger age groups who have the highest
incidence of myopia tend to be taller than the older
population…” They speculated that “It could be
that better hygiene and a higher calorie diet has
resulted in the younger population growing taller
than their parents, with the penalty that their eyes
are longer and therefore more likely to become
myopic.”
Teikari15 reported on the relationship of
refractive error and height in 690 twins in Finland.
Subjects were surveyed to determine if they wore
glasses. If they did, they were asked for a copy of
their current prescription or the address of the eye
care provider. Those who were found to have
spherical equivalent prescriptions of -0.25 D or
more minus were classified as myopes. Those
who reported that they did not wear glasses and
that their vision was normal at far and near were
classified as non-myopes. Height was obtained
from a questionnaire filled out by the subjects, who
were 30 or 31 years old at the time of the
questionnaire. The average height for myopic
males was 1.9 cm greater than for non-myopic
males, a difference which was statistically
significant (p=0.03). The mean height for myopic
females was 1.0 cm more than for non-myopic
females, but the difference was not significant
(p=0.41). There were 43 twin pairs that had one
myope and one non-myope. In the twin pairs
discordant for myopia, myopes were taller than
non-myopes among males, but no difference was
observed among females.
Rosner et al.16 reviewed the computerized
examination records of 106,926 consecutive male
17 to 19 year old military recruits in Israel. Myopia
was found when all recruits with less than 6/7.5
unaided visual acuity in either eye had noncycloplegic refractions performed. Non-myopes
had a mean height of 173.7 cm (n = 85,763; SD =
6.7). Subjects with myopia of -0.25 to -3.00 D had
a mean height of 173.2 cm (n = 10,315; SD = 6.9).
For subjects with 3.25 to 6.00 D of myopia, the
mean height was 173.3 cm (n = 5,423; SD = 6.9),
and for those with more than 6 D of myopia, it was
172.8 cm (n = 1,637; SD = 7.1). Heights were
significantly less for each of the myopia groups
than for the non-myopes when statistically adjusted
for intelligence quotient, education, and ethnic
origin.
Wong et al.17 studied 951 Chinese adults
between the ages of 40 and 79 years (mean age,
58.1 years). The correlation coefficient of height
with spherical equivalent refractive error from
subjective refraction was only r = -0.04. However,
the correlations of height with axial length and
corneal radius were much higher (r = 0.33 for axial
length and r = 0.30 for corneal radius), and both
were statistically significant (p<0.001). Being taller
was still correlated with longer axial lengths and
flatter corneas after controlling for age, sex,
education, occupation, income, housing type, and
weight.
A study of 1,449 Singapore Chinese children,
ages seven to nine years, was published by Saw et
al.18 Refractive error data used for analysis were
the right eye spherical equivalents from
autorefraction after instillation of cyclopentolate.
Children with myopia of at least 3.00 D had a mean
height of 130.6 cm (SD = 7.2), while children with
myopia of 0.50 to 3.00 D had a mean height of
127.6 cm (SD = 7.6). In children with emmetropia,
the mean height was 126.5 cm (SD = 7.1),
compared to 124.4 cm (SD = 7.2) for those with
hyperopia. The difference between heights for
higher myopes and for emmetropes was
statistically significant (p=0.042). The authors also
separated the data into quartiles by height. When
the means were adjusted for age, gender, parental
myopia, books read per week, school attended,
and weight, the children in the tallest quartile had
0.46 mm longer axial lengths, 0.1 mm flatter
corneas, and 0.47 D more myopia than the children
in the shortest quartile. Statistical significance was
found for the trends of longer axial length
(p<0.001), flatter cornea (p<0.001), and more
myopia (p=0.002) with increasing height by quartile
analysis.
A study of Mongolian adults19 included
refraction by non-cycloplegic autorefraction. There
...............................................................Indiana Journal of Optometry ... Summer 2009 ... Vol. 12, Nos. 1/2 ... page 8
were 615 subjects on whom both refraction and
height data were obtained. Subjects ranged in age
from 40 to over 70 years of age. The mean
heights for different refractive errors levels were
(with standard deviations in parentheses): more
than 5.0 D of myopia, 157.4 cm (7.8); -3.1 to -5.0
D, 156.8 cm (10.8); -1.1 to -3.0, 156.7 cm (9.3); 0.1 to -1.0, 158.0 cm (7.5); 0 to +1.0 D, 158.7 cm
(9.1); more than 1.0 D of hyperopia, 155.1 cm
(8.7). The authors did not present a statistical test
of relation of refractive error and height. Using
their means and standard deviations to perform ttests, it was found that none of the separate
myopia group means differed significantly from the
mean for the emmetropia (0 to +1.0 D) group. The
mean height for the low myopia group (-0.1 to -1.0
D) was significantly greater than the mean height
for the hyperopes (p<0.02), and the mean height
for the emmetropes was significantly greater than
that for the hyperopes (p<0.001).
Khandekar et al.20 studied a number of
variables in Omani children in 7th grade and again
in 10th grade. Subjective refractions were done,
and spherical equivalents were used for analysis.
In the 7th grade, 503 male myopes averaged 1.9
cm taller than 647 male non-myopes, and 937
female myopes averaged 0.9 cm taller than 766
female non-myopes. Differences were statistically
significant. In the 10th grade, the male myopes
were significantly taller than the male non-myopes
by an average of 1.4 cm, and the female myopes
were significantly taller than the female nonmyopes by an average of 1.0 cm.
Ojaimi et al.21 reported data from a study of six
to seven year old children in Sydney, Australia.
Included were 859 girls and 881 boys. Refractive
data used in the analysis were right eye spherical
equivalents from autorefraction after instillation of
cyclopentolate. Pearson correlation coefficients
were determined for the relation of height with the
following variables: with refractive error, r = 0.008;
with axial length, r = 0.25 (p<0.0001); with steepest
corneal radius, r = 0.18 (p<0.0001); with flattest
corneal radius, r = 0.21 (p<0.0001). The authors
also separated the data by height quintiles. In the
quintile analysis, being taller was also significantly
associated with longer axial length (p<0.0001) and
flatter corneal radii (p<0.0001). Those
associations remained highly statistically significant
when data were adjusted for age, gender, weight,
and parental myopia.
Another study in Australia22 examined the
relationship of height to refractive error in 690
monozygotic twins and 534 dizygotic twins.
Subject ages ranged from 18 and 86 years, with a
mean of 52 years. There were 823 females and
401 males. Refractive error data were right eye
spherical equivalents from autorefraction after the
use of tropicamide. Height showed a low but
statistically significant correlation with refractive
error, r = -0.15 (p<0.01). Increasing height was
correlated with greater axial length, with the
correlation coefficient being r = 0.32. Height was
also divided into quartiles. The tallest quartile was
1.36 times more likely to be myopic, defined as a
spherical equivalent refractive error of -0.50 D or
more minus, than the shortest quartile.
A few studies have reported longitudinal data.
In a study of English children, Gardiner23,24
observed that rates of increase in height tended to
be greater in myopes than in non-myopes and
greater in progressing myopes than in stationary
myopes. Sorsby et al.25 reported that children
who had great increases in axial length did not
have exceptionally large increases in height in the
same period of time. Khandekar et al.26 found
that myopes who progressed more than 0.50 D/yr
from 7th to 10th grade had an average increase in
height of 12.5 cm compared to a 10.5 cm average
increase in height in myopes who progressed 0.50
D/yr or less during the same years.
Additional Data
Additional data to examine correlations of
height with refractive error and the ocular optical
components were compiled from subjects in
Oklahoma in various studies conducted at
Northeastern State University27-30 and from the
Myopia Clinic at the W.W. Hastings Indian Health
Service Hospital in Tahlequah, Oklahoma.31
Subjects ranged in age from 7 to 40 years, but
most were between the ages of 8 and 30 years.
The vast majority of subjects were Caucasian,
Cherokee or other American Indian, or mixed
Caucasian and American Indian. Corneal powers
were obtained from manual keratometry with either
a Bausch & Lomb keratometer or a Marco
keratometer. Axial length was measured by
ultrasonography, using one of three ultrasound
units, Sonometrics Ocuscan 400, Cooper Vision
Ultrascan Digital AII, and Humphrey Ultrasonic
Biometer model 810. Refractive data were derived
as described in the individual studies. Right eye
data were used for analysis, except in cases where
left eye data were more complete. Data for males
and females were considered separately because
several studies have found greater axial lengths
and lesser corneal powers in males than in
females.25,28,30,32,33
Page 9 ... Vol. 12, Nos. 1/2 ... Summer 2009 ... Indiana Journal of Optometry ..........................................
Pearson correlation coefficients were as follows in
males:
Height and refractive error: r = -0.37, n = 911,
p<0.0001
Height and axial length: r = 0.42, n= 883, p<0.0001
Height and keratometry: r = -0.06, n = 898,
p=0.0915
Axial length and refractive error: r = -0.73, n =
1031, p<0.0001
Keratometry and refractive error: r = -0.10, n =
1046, p = 0.0009
Axial length and keratometry: r = -0.36, n = 1017,
p<0.0001
Pearson correlation coefficients were as follows in
females:
Height and refractive error: r = -0.28, n = 1049,
p<0.0001
Height and axial length: r = 0.37, n= 1022,
p<0.0001
Height and keratometry: r = -0.10, n = 1033,
p=0.0017
Axial length and refractive error: r = -0.71, n =
1183, p<0.0001
Keratometry and refractive error: r = -0.11, n =
1203, p<0.0001
Axial length and keratometry: r = -0.38, n = 1167,
p<0.0001
Increasing axial length was associated with
more minus refractive error, greater axial length,
and lesser keratometer power. However, myopia,
axial length, and height all increase with age, so
age could be a confounding variable. Age was
factored out using partial correlation coefficients.34
The partial correlations supported weak
correlations of taller height with more minus
refractive error, greater axial length, and flatter
corneas. The partial correlation coefficients were
as follows:
Males, height and refractive error, r = -0.12,
p<0.0005
Females, height and refractive error, r = -0.08,
p<0.01
Males, height and axial length, r = 0.21, p<0.0001
Females, height and axial length, r = 0.18,
p<0.0001
Males, height and keratometry, r = -0.12, p<0.0005
Females, height and keratometry, r = -0.09,
p<0.005
For subjects 20 years of age or more, mean
height was significantly greater for myopic (defined
as any minus refractive error) males than for nonmyopic (zero or plus refractive errors) males
(p<0.05), but there was not a significant difference
in mean heights between myopic females and nonmyopic females. For males 20 years of age and
older, the mean heights were 181.2 cm (n = 88; SD
= 6.3) for the myopes and 177.8 cm (n = 27; SD =
7.1) for the non-myopes. For the females, the
mean heights were 164.6 cm (n = 52; SD = 7.6) for
the myopes and 165.7 cm (n = 18; SD = 7.9) for the
non-myopes.
Comments
Most studies found greater average height in
persons with myopia than in persons without
myopia, but there were several studies that found
no difference and one study that found lesser
height in myopia. It is possible that differences in
results from study to study may be related to
different ages and populations studied, as well as
different refractive measurement methods and
differing classifications of myopia. Some studies
found emmetropes and myopes to be taller than
hyperopes, but some studies grouped emmetropes
and hyperopes together as non-myopes. The
majority of studies found a correlation of greater
height with greater axial length and lesser corneal
power.
Current theories of refractive development
suggest an important role of ocular growth. Some
theories suggest a relationship of general body
growth and refractive development. For example,
substances regulating ocular growth could be
synergistic with substances regulating general body
growth. And some hypotheses positing a role for
diet in myopia etiology suggest greater height
would be associated with myopia.5 Undoubtedly
numerous variables affect both refractive
development and growth in stature, and there may
be some confounding variables. For example,
higher socioeconomic status may be associated
with both higher prevalence of myopia and greater
height. Some studies continued to find an
association of myopia with greater height when
controlled for socioeconomic status. As with most
areas of refractive error investigation, definitive
answers await further study.
References
1. Baldwin WR. A review of statistical studies of
relations between myopia and ethnic, behavioral,
and physiological characteristics. Am J Optom
Physiol Opt 1981;58:516-527.
2. Bock GR, Widdows K, eds. Myopia and the
Control of Eye Growth. Chichester: Wiley, 1990.
3. Grosvenor T, Flom MC, eds. Refractive
Anomalies: Research and Clinical Applications.
Boston: Butterworth-Heinemann, 1991.
................................................. Indiana Journal of Optometry ... Summer 2009 ... Vol. 12, Nos. 1/2... page 10
4. Goss DA, Wickham MG. Retinal-image mediated
ocular growth as a mechanism for juvenile onset
myopia and for emmetropization – a literature
review. Doc Ophthalmologica 1995;90:341-375.
5. Cordain L, Eaton SB, Miller JB, Lindeberg S,
Jensen C. An evolutionary analysis of the aetiology
and pathogenesis of juvenile-onset myopia. Acta
Ophthalmologica Scand 2002;80:125-135.
6. Gilmartin B. Myopia: precedents for research in
the twenty-first century. Clin Exp Ophthalmol
2004;32:305-324.
7. Wallman J, Winawer J. Homeostasis of eye
growth and the question of myopia. Neuron
2004;19:447-468.
8. Johansen EV. Simple myopia in schoolboys in
relation to body height and weight. Acta
Ophthalmologica 1950;28:355-361.
9. Mohindra I. The Relationship between axial
length and certain anthropometric data, M.S.
thesis, Indiana University, 1962.
10. Baldwin WR. The relationship between axial
length of the eye and certain other anthropometric
measurements of myopes. Am J Optom Arch Am
Acad Optom 1964;41:513-522.
11. Goldschmidt E. Myopia and height. Acta
Ophthalmologica 1966;44:751-761.
12. Teasdale TW, Goldschmidt E. Myopia and its
relationship to education, intelligence and height:
preliminary results from an on-going study of
Danish draftees. Acta Ophthalmologica
1988;66(supplement 185):41-43.
13. Peckham CS, Gardiner PA, Goldstein H.
Acquired myopia in 11-year-old children. Br Med J,
Feb 26,1977;542-544.
14. Johnson GJ, Matthews A, Perkins ES. Survey
of ophthalmic conditions in a Labrador community.
I. Refractive errors. Br J Ophthalmol 1979;63:440448.
15. Teikari JM. Myopia and stature. Acta
Ophthalmologica 1987;65:673-676.
16. Rosner M, Laor A, Belkin M. Myopia and
stature: Findings in a population of 106,926 males.
Eur J Ophthalmol 1995;5:1-6.
17. Wong TY, Foster PJ, Johnson GJ, Klein BEK,
Seah SKL. The relationship between ocular
dimensions and refraction with adult stature: The
Tanjong Pagar Survey. Invest Ophthalmol Vis Sci
2001;42:1237-1242.
18. Saw SM, Chua WH, Hong CY, Wu HM, Chia
KS, Stone Ram Tan D. Height and its relationship
to refraction and biometry parameters in Singapore
Chinese children. Invest Ophthalmol Vis Sci
2002;43:1408-1413.
19. Wickremasinghe S, Foster PJ, Uranchimeg D,
Lee PS, Devereux JG, Alsbirk PH, Machin D,
Johnson GJ, Baasanhu J. Ocular biometry and
refraction in Mongolian adults. Invest Ophthalmol
Vis Sci 2004;45:776-783.
20. Khandekar R, Al Harby S, Mohammed AJ.
Ophthal Epidemiol 2005;12:207-213.
21. Ojaimi E, Morgan IG, Robaei D, Rose KA,
Smith W, Rochtchina E, Mitchell P. Effect of stature
and other anthropometric parameters on eye size
and refraction in a population-based study of
Australian children. Invest Ophthalmol Vis Sci
2005;46:4424-4429.
22. Dirani M, Islam A, Baird PN. Body stature and
myopia – the Genes in Myopia (GEM) Twin Study.
Ophthal Epidemiol 2008;15:135-139.
23. Gardiner PA. The relation of myopia to growth.
Lancet 1954;266(6810):476-479.
24. Gardiner PA. Physical growth and the progress
of myopia. Lancet 1955;269(6897):952-953.
25. Sorsby A, Benjamin B, Sheridan M. Refraction
and its components during growth of the eye from
the age of three. Medical Research Council
Special Report Series no. 301. London: Her
Majesty’s Stationery Office, 1961.
26. Khandekar R, Kurup P, Mohammed AJ.
Determinants of the progress of myopia among
Omani school children: A historical cohort study.
Eur J Ophthalmol 2007;17:110-116.
27. Goss DA, Cox VD, Herrin-Lawson GA, Dolton
WA. Refractive error, axial length, and height as a
function of age in young myopes. Optom Vis Sci
1990;67:332-338.
28. Goss DA, Jackson TW. Cross-sectional study
of changes in the ocular components in school
children. Applied Optics 1993;32:4169-4173.
29. Goss DA, Jackson TW. Clinical findings before
the onset of myopia in youth: I. Ocular optical
components. Optom Vis Sci 1995;72:870-878.
30. Goss DA, VanVeen HG, Rainey BB, Feng B.
Ocular components measured by keratometry,
phakometry, and ultrasonography in emmetropic
and myopia optometry students. Optom Vis Sci
1997;74:489-495.
31. Schmitt EP. Vision care to Indian people in
Northeastern Oklahoma: History and development
of Northeastern State University College of
Optometry vision services. In: Goss DA,
Edmondson LL, eds. Eye and Vision Conditions in
the American Indian. Yukon, OK: Pueblo
Publishing, 1990:191-203.
32. Stenstrom S. Investigation of the variation and
correlation of the optical elements of human eyes –
Part III. Am J Optom Arch Am Acad Optom
1948;25:340-350.
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33. Francois J, Goes F. Ultrasonographic study of
100 emmetropic eyes. Ophthalmologica
1977;175:321-327.
34. Edwards AL. An Introduction to Linear
Regression and Correlation, 2nd ed. New York:
W.H. Freeman, 1984:43-45.
David Goss was a faculty member at
Northeastern State University College of
Optometry in Tahlequah, Oklahoma, where the
data discussed in this paper were collected,
from 1980 to 1992. He has been Professor of
Optometry at Indiana University since 1992.
Dale Cox is a retired physicist. His
professional positions included Professor of
Physics at Northeastern State University in
Oklahoma and Research Scientist at Conoco,
Inc., in Ponca City, Oklahoma.
................................................. Indiana Journal of Optometry ... Summer 2009 ... Vol. 12, Nos. 1/2... page 12
IU Alumnus Gary Campbell Produces
Monograph on the History of American
Phoropters
BY DAVID A. GOSS, O.D., PH.D.
G
ary L. Campbell, member of the IU School of Optometry Class of 1977, has authored and selfpublished a monograph entitled “Phoroptors: Early American Instruments of Refraction and Those
who Used Them.” He produced the paperback booklet of 99 pages in a 22 cm high by 14 cm wide format.
In the title and throughout the book, he used the spelling phoroptor, an early spelling of the word, rather
than phoropter, a common spelling today.
The production of this book in 2008 is timely, because 2008 marks the 100th anniversary of the
submission of the patent application for the instrument that could be recognized as the first phoropter.
Henry DeZeng received the patent in 1909. The DeZeng phoropter, which he called
an Optometer, included spherical and cylindrical lenses, rotary prisms, Maddox rods,
and an adjustable interpupillary distance setting.
In the foreword to the book, Campbell explained that as a collector of phoropters,
he was disappointed to learn that there was no single source that he could use to find
information about most historical phoropters. Instead, information was scattered over
many sources and had to be researched one phoropter at a time. As a
consequence, he decided to produce this monograph.
The front matter of the book includes a glossary of terms for persons not familiar
with the terminology used in the book. Chapters 1 through 3 (pages 21 to 30)
provide a historical overview of the optical business and state of refraction just before
phoropters were developed.
Chapters 4 through 6 (pages 33 to 59) discuss
instruments which were precursors to phoropters, such as trial lenses, trial frames,
optometers, and phorometers.
Chapters 7 through 11 (pages 61 to 89) are devoted specifically to phoropters. After a brief introduction
to phoropters in Chapter 7, chapters 8 through 10 are organized to illustrate the evolution of particular lines
of instruments made in the United States. In chapter 7, Charles Sheard is quoted as saying the following in
1923 about Henry DeZeng’s 1909 phoropter patent: “From out of all this multiplicity of scientific ideals and
separate pieces of instrumentation – somewhat rough and crude and generally without calibration or optical
accuracy – the inventive mind of Mr. DeZeng brought forth this first complete combination, conveniently
and mechanically properly fitted and adjusted, for refractive and muscular eye work.”
Chapter 8 starts with Henry DeZeng’s phoropter patented in 1909 and proceeds through the PhoroOptometer to the No. 574, No.584, No. 588, No. 589, No. 593, and the AO Model 590 to the AO Rx Master.
The AO Rx Master was the direct precursor to the AO Ultramatic Rx Master commonly used today.
Chapter 9 discusses the Shigon/Woolf/General Optical/Shuron line of instruments. Patents received by
Nathan Shigon in 1910 and 1915 were transferred to the Woolf Instrument Corporation, which
subsequently produced the Ski-Optometer Models 215 and 205. The patents were later transferred to the
General Optical Company and the Shuron Optical Company, which produced the Genothalmic Refractor.
Chapter 10 deals with the Bausch & Lomb Greens and Greens II Refractors. The Greens Refractor was
introduced in 1933 based on a 1931 patent by Clyde L. Hunsicker and work by Aaron S., Louis D., and M.I.
Green. Chapter 11 briefly mentions some phoropters made outside the United States.
In an epilogue on page 91, Campbell notes that “Phoroptors have advanced significantly since the time
DeZeng, Woolf, General Optical, and the Greens first designed them. Improvements have been
substantial and the competition has been hardy. Eventually Woolf, Shuron, and Bausch & Lomb stopped
Page 13... Vol. 12, Nos. 1/2 ... Summer 2009 ... Indiana Journal of Optometry ........................................
making phoroptors. Only the line of DeZeng/American Optical prevailed and it has now achieved a
century of producing phoroptors in America.”
The monograph contains 31 figures, most of which are photographs or diagrams of phoropters. There
are also pictures or diagrams of optometers, phorometers, and other instruments. A five-page listing of
references can be found on pages 93 to 97.
On page 91, Campbell suggests that “for those engaged in collecting optical instruments perhaps this
small manual will be a helpful guide to identify and learn about phoroptors and other early America
instruments of refraction.” I think that is an accurate statement, but I also found this book to be enjoyable
reading. And it was interesting to read about some phoropters that I used extensively, but which our
current students may never have seen, such as the Bausch & Lomb Greens Refractor and the AO Rx
Master. Dr. Gary Campbell practices in Wheaton, Illinois. Copies of the book can be obtained for $10 by
contacting him at GaryLCampbell@gmail.com.
Mirror Symmetry of Astigmatic Axes
BY DAVID A. GOSS, O.D., PH.D.
I
can recall being taught in optometry school that astigmatic axes tended to be mirror symmetric in the
two eyes of an individual. In other words, if the axis for one eye was 105, the axis for the other eye
tended to be about 75. Or if the axis for one eye was 10, the axis for the other eye was usually about
170. In the intervening years, that notion has seemed to me to be correct more often than not. A recent
paper has provided statistical support for that idea.
Guggenheim et al.1 examined spectacle prescriptions at 19 optometry practices in northern England.
A total of 50,995 patients had an astigmatic component to their spectacle prescriptions for both eyes. For
patients examined more than once, only the most recent prescription was used in the analysis.
Astigmatism was specified in minus cylinder notation. The authors compared the relationship between
right eye and left eye axes to the differences expected for a direct symmetry model and a mirror
symmetry model. The direct symmetry model suggested that the exes were numerically about the same
in the two eyes; in other words, the direct symmetry model suggests that axis 105 in one eye would tend
to be found with axis 105 in the other eye, or if axis 10 was found in one eye the axis in the other eye
would usually be about 10.
The authors noted that axis 180 would essentially be the same as axis 0, with, for example, axis 180
in one eye being only two degrees away from axis 2, not 178 degrees. To test for symmetry of axes, it
would therefore be necessary to add 180 to the axis of one eye in some cases or subtract 180 from the
axis of one eye in other cases. So for the direct symmetry model the absolute value of one of the
following differences would be expected to be very close to zero:
OD axis – OS axis
OD axis – OS axis + 180
OD axis – OS axis – 180
In the mirror symmetry examples given in the first paragraph above, the axes in the two eyes add to
180. To test for mirror symmetry, one could see how far the sum is from 180. However, to take another
example, if the axes were 5 in one eye and 2 in the other eye, that individual would be 7 degrees away
from mirror symmetry (2 is 7 degrees away from 175), not 163 degrees (as would be suggested by 180
minus the sum of 5 and 2). So for the mirror symmetry model, the absolute value of one of the following
would be expected to be very close to zero:
.................................................... Indiana Journal of Optometry ... Summer 2009 ... Vol. 12, Nos. 1/2... page 14
OD axis – (180 – OS axis)
OD axis – (180 – OS axis) + 180
OD axis – (180 – OS axis) – 180
The median absolute value for difference from direct symmetry was 20 degrees and the median
absolute value for difference from mirror symmetry was 10 degrees. The difference in medians was
highly statistically significant by the Wilcoxon signed ranks test. The authors did separate analyses of the
data by amount of astigmatism (greater than or less than 1.00 D), type of astigmatism (with-the-rule,
against-the-rule, or oblique), and age decades (11-20 to 71-80). The median for difference from the
mirror symmetry model was significantly lower than the median for the direct symmetry model for both
amounts of astigmatism, for all three types of astigmatism, and for all seven age groups. These results
support the preponderance of mirror symmetry over direct symmetry.
Another way that the authors examined symmetry of right and left eye axes was by breaking the
astigmatism down into J0 and J45 vector components. Any cylinder can be broken down into 90-180
cross cylinder (J0) and 45-135 cross cylinder (J45) vector components. For axes of 90 and 180, J45
would be zero. For axes from 1 to 89, J45 would have a positive value. For axes from 91 to 179, J45
would be a negative number. So if J45 is the same sign in the two eyes, symmetry of axes to closer to
direct symmetry. If the signs of the J45 values are opposite in the two eyes, symmetry of axes is closer
to mirror symmetry.
Of the 50,995 subjects in the study, 18, 859 had a J45 of zero in one or both eyes. The number of
subjects with differing J45 signs in the two eyes was 22,963, while 9,173 subjects had J45 values with
the same sign in the two eyes. Dividing 22,963 by 9,173, we find that the ratio of subjects with mirror
symmetry of axes to subjects with direct symmetry of axes was 2.5 to 1.
The results of this study showed mirror symmetry of cylinder axes to be more common than direct
symmetry. This was true for both higher and lower amounts of astigmatism, for all types of astigmatism
(with-the-rule, against-the-rule, and oblique), and for all age decade groups from 11 to 80.
Reference
1. Guggenheim JA, Zayats T, Prashar A, To CH. Axes of astigmatism in fellow eyes show mirror rather
than direct symmetry. Ophthal Physiol Opt 2008;28:327-333.
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Book Review: PROUST WAS A NEUROSCIENTIST
REVIEWED BY DAVID A. GOSS
Proust was a Neuroscientist. Jonah Lehrer.
Boston: Houghton Mifflin, 2007. xii + 242 pages.
ISBN-10: 0-618-62010-9. ISBN-13: 978-0-61862010-4. Hardcover, $24.00.
I
n today’s world, we are often lead to believe that
science can solve every problem and answer
every question. In this book, author Jonah Lehrer
imaginatively illustrates how various artists and
non-scientist writers offered
insight into various aspects of
human existence decades
before science was able to
unravel explanations of related
neural function. In each of the
eight chapters, the author
discusses the work of an artist
(five writers, one painter, one
composer, and one chef) and
then neuroscience research
related to particular elements of
the artist’s work. The artists
discussed are Walt Whitman
(1819-1892), George Eliot
(1819-1880), Auguste Escoffier
(1846-1935), Marcel Proust (1871-1922), Paul
Cézanne (1839-1906), Igor Stravinsky (18821971), Gertrude Stein (1874-1946), and Virginia
Woolf (1882-1941).
In the chapter dealing with Proust, for
example, the author notes that Proust had
observed how memories change over time as they
are influenced by intervening events and had
incorporated examples of that in his novels.
Decades later, neuroscience seems to show that
memories are not represented as hard-wired
places in the brain, but rather as patterns of
synapses which are strengthened or modified by
experience: “As long as we have memories to
recall, the margins of those memories are being
modified to fit what we know now…” (page 87).
One of the most interesting chapters was the
one featuring famous chef Auguste Escoffier. At
the time Escoffier worked, it was thought that the
tongue was sensitive only to sweet, salty, bitter,
and sour. Escoffier developed delicious recipes
and promoted cooking that included little of those
four known tastes. It has been discovered that his
cooking emphasized glutamate, for which receptors
have been discovered and which enhances taste
and deliciousness. In another chapter, not quite as
well done but related to vision, Lehrer notes that
Cézanne painted an interpretation of what he saw,
rather than attempting to copy it. He goes on to
describe how an appreciation of Cézanne’s
paintings requires imagination and interpretation,
just as the visual cortex interprets input from the
retina.
Some chapters make a clearer connection
between art and science than others, but one can
easily conclude that the book provides a caution to
science against arrogance and condescension. In
a final concluding chapter, Lehrer notes a
“’communications gap’ between scientists and
artists.” And he observes that “Each side would
benefit from an understanding of the other…” (page
190). The author mentions that it is unfortunate
that many of the efforts of scientists to bring art and
science together have been characterized either by
an attempt to make the humanities more like
reductionist science, by an antagonism toward
anything non-scientific, or by a poor understanding
of the art being considered. In order to achieve a
re-integration of art and science, the “two existing
cultures must modify their habits….the humanities
must sincerely engage with the sciences…and not
ignore science’s inspiring descriptions of
reality…the sciences must recognize that their
truths are not the only truths….art is a necessary
counterbalance to the glories and excesses of
scientific reductionism, especially as they are
applied to human experience.” (page 197)
The author’s musings on the relation of art
and science are interesting in their own right, but I
couldn’t help but thinking that they have a parallel
in the relations of scientists and clinicians.
Scientists try to design their experiments with
control for variables that might affect the outcome
of the study so that they can attribute the outcome
solely to the variable being intentionally
manipulated. Clinicians must deal with all those
pesky variables as part of the package that each
patient represents. Just as art and science would
each “benefit from an understanding of the other,”
clinical care and research work would each benefit
if their practitioners strove to understand the goals,
approaches, and skills of their counterparts.
The author, Jonah Lehrer, is a graduate of
Columbia University and studied at Oxford
University as a Rhodes Scholar. He is an Editor at
Large for Seed Magazine and a Contributing Editor
for Scientific American Mind. He is also the author
of the book “How We Decide.”
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