Kay`s PowerPoint Presentation - West Virginia School Based Health

Vision Screening:
Getting to the Nitty-Gritty of How to Screen…
What to Use…and What to Avoid
P. Kay Nottingham Chaplin, EdD
Disclaimer
•
Former Director/Lead Trainer – Vision Initiative for Children – WVU Eye
Institute
• Trained >1,600 individuals, 178 workshops
•
Current Director – Vision and Eye Health Initiatives
•
Member of the national Advisory Committee to the National Center for
Children’s Vision and Eye Health, an initiative at Prevent Blindness
America, tasked to implement recommendations of the National Expert
Panel for a universal preschool vision screening strategy (i.e., vision
screening training/certification program)
•
Will see “great” and “really awful” eye charts manufactured by The GoodLite Company and marketed through Good-Lite and School Health
Corporation, but focus is not to push product from the podium
• Focus is to use power of podium to encourage appropriate and
evidence-based vision screening
2
5Learning Objectives
1. Describe 5 components of a standardized visual
acuity eye chart according to national and
international eye chart design guidelines.
2. List 3 challenges to common eye charts, even the
“Snellen” and “Sailboat” charts.
3. List 2 eye chart designs to avoid even when
optotypes are appropriate.
4. Describe 1 evidence-based method for quicker
vision screening when using an eye chart.
5. Describe 3 devices for instrument-based
screening.
3
Importance of Standardized Eye
Charts
• “Visual acuity scores can be significantly
affected by the chart design.” (p. 1248)
 Bailey, I.L. (2012). Perspective: Visual acuity – Keeping it
clear. Optometry and Vision Science, 89(9), 1247-1248.
• Visual acuity: Smallest optotypes that can just be
read satisfactorily.
• Visual task should be same on each line.
• Line size should be sole factor affecting visual
acuity test task.
 Bailey, I. L., & Lovie, J. E. (1976). New design principles
for visual acuity letter charts. American Journal of
Optometry & Physiological Optics, 53(11), 740-745.
4
• Standardized eye charts meeting
national and international eye chart
design guidelines offer equal test
task.
• Many commonly used eye charts do
not.
• What can happen if you use a nonstandardized eye chart?
5
Child does not pass vision screening
Screener uses
poorly designed
chart
Eye care
professional uses
standardized eye
chart – child
passes
Screener’s overreferral rate of
children with
normal vision
increases
Over time, eye care
professional may
mistrust Screener’s
referrals
Children who
actually have
vision disorders
could be underreferred
Parent takes time
off from work for
unnecessary eye
exam
Over-referral results in increased health care costs (Hered et al., 1997)
6
National and International Distance Visual Acuity
Eye Chart Recommendations
• 1980 - National
Academy of SciencesNational Research
Council (NAS-NRC)
• Recommended Standard
Procedures for the
Clinical Measurement
and Specification of
Visual Acuity
•
Committee on Vision. (1980).
Recommended standard procedures
for the clinical measurement and
specification of visual acuity. Report
of working group 39. Assembly of
Behavioral and Social Sciences,
National Research Council, National
Academy of Sciences, Washington,
DC. Advances in Ophthalmology,
41:103–148.
• 1984 - International
Council of
Ophthalmology (ICO)
• Visual acuity
measurement
standard.
• www.icoph.org/dynamic/at
tachments/resources/icovi
sualacuity1984.pdf
7
National and International Distance Visual Acuity
Eye Chart Recommendations
• 2003 - World Health
Organization
Prevention of
Blindness &
Deafness (WHO)
•
Consultation on
Development of Standards
for Characterization of
Vision Loss and Visual
Functioning
• Prevention of blindness and
deafness. Consultation on
development of standards
for characterization of
vision loss and visual
functioning. Geneva:
WHO;2003
(WHO/PBL/03.91).
• 2010 – American
National Standards
Institute, Inc.
• ANSI Z80.21-1992
(R2004) Approved
May 27, 2010
• Performance
standard for the
optical design of
optotypes used in
clinical visual acuity
measurement
systems
8
Optotypes approximately equal
in legibility
Similar recommendations across
guidelines
Horizontal between-optotype
spacing = 1 optotype width
Vertical between-line spacing =
height of next line down
Geometric progression of
optotype sizes of 0.1 log units
(logMAR, ETDRS)
5 optotypes per line
Optotypes black on white
background with luminance
between 80 cd/m2 and 160 cd/m2
Design guidelines = “ETDRS Design”
9
Importance of 5 Optotypes Per Line
• Smaller lines as move
down chart
• More letters to read on
non-standardized chart
• 5 optotypes per line =
identifying majority is
same throughout chart
Ferris, F., L., Kassoff, A., Bresnick, G. H., & Bailey, I. (1982). New visual acuity charts
for clinical research. American Journal of Ophthalmology, 94, 91-96
10
Importance of Legibility
• “Equal sizes of different letters and different
letter designs, therefore, do not imply equal
recognizability.”
• ICO – 1984 – p. 7
11
World Health Organization:
• “Regular training was
recommended for those
administering visual acuity
skill of
the tester affects
tests, as the
very significantly the validity
and variability of the
outcome.” p.6
12
Do the following eye charts fit
national/international eye chart
design guidelines?
Yes or
No?
___
13
Challenges With Common Eye Charts
Snellen Letters
Allen
Pictures
Kindergarten Test
Chart
Tumbling E
Lighthouse
or “House,
Apple,
Umbrella”
14
Challenges with “Snellen Charts”
• Does not meet
national/international
eye chart design
guidelines
• Is not standardized
Kaiser, P. K. (2009). Prospective evaluation of visual acuity assessment: A comparison of
Snellen versus ETDRS charts in clinical practice (An AOS thesis). Transactions of the
American Ophthalmological Society, 107, 311-324.
15
“Sailboat” Chart Lacks Scientific Evidence
• Does not meet national/international eye
chart design guidelines
• Optotypes of different sizes on same line
• Some optotypes in black “blobs”
• Found only 3 studies
• Only 1 looked at visual acuity, but with colored
optotypes
• Only 1 study pertains to current chart and the
goal was to determine whether children liked the
chart
Fink, W. H. (1944). An evaluation of visual acuity symbols. Transactions of the American
• Deemed “too complicated” for 3- and 4-yr-olds
Ophthalmological Society, 42, 49-99.
Lippmann, O. Vision screening of young children. (1971). American Journal of Public
Health, 61(8), 1586-1601.
Savitz, R. A., Reed R. B., & Valadian I. (1964). Vision screening of the preschool child:
report of a study. US Department of Health, Education, and Welfare. Welfare
Administration. Children’s Bureau. Washington, DC: US Government Printing Office. 16
Overarching Challenge with “Sailboat”
Chart: Lacks Scientific Evidence
•
Not on recommended list
of eye charts in 2003Policy Statement from:
• Chart’s history and
developer unknown
• American Academy of
Pediatrics
• American Association
of Certified
Orthoptists
• American Association
for Pediatric
Ophthalmology and
Strabismus
• American Academy of
Ophthalmology
• Earliest photograph:
August 1935
American Optical
Company catalog
Eye examination in infants, children, and
young adults by pediatricians. (2003).
Pediatrics, 111(4), 902-907.
17
2 Challenges with Tumbling E
1. Children’s orientation
and direction
challenges with
directional optotypes
a. Emerging cognitive
skill
b. Up/down emerges
before left/right
c. Usually in place by
ages 8 or 10
Elkind, D. (1961). Children’s conceptions
of right and left: Piaget replication study
IV. The Journal of Genetic Psychology, 99,
269-276.
2. Ability to guess
optotype at
threshold
Hyvärinen, L., Näsänen, R., &
Laurinen, P. (1980). New visual
acuity test for pre-school children.
Acta Ophthalmologica
(Copenhagen), 58(4), 507-11. 18
“Since horizontal direction
sense develops later than
vertical direction sense,
recognition of horizontally
pointing E’s by younger
children is particularly
unreliable.
Test symbols, not depending
on the direction sense,
improve testability, testing
time and visual acuity
scores.” (p. 70)
Lippmann, O. (1974). Choice of preschool vision test. The Eye, Ear, Nose
and Throat Monthly, 53(5): 68-73.
19
Challenges to Allen Pictures
1. Asking young children to
make a “whole” picture from
“parts”
2. Cultural bias
3. Calibrated against Snellen
30-ft E, not Landolt C
(international standard)
4. Dr. Allen: “The test is not
intended to replace existing
tests like the illiterate E and
the Sjögren hand. It is
recognized that the latter
tests are undoubtedly
superior and better
standardized for children
who can use them.”
20
Allen, H. F. (1957). A new
picture series for preschool
vision testing. American
Journal of Ophthalmology,
44(1), 38-41.
21
Lighthouse Chart
• Optotypes easy
to guess
• Poor visual acuity
results when
compared with
international
Landolt C
standard.
• Not on list of charts
recommended by:
• American Academy of
Pediatrics
• American Association
of Certified
Orthoptists
• American Association
for Pediatric
Ophthalmology and
Strabismus
• American Academy of
Ophthalmology
Candy, T. R., Mishoulam, S. R., Nosofsky, R. M., & Dobson, V. (2011). Adult
discrimination performance for pediatric acuity test optotypes. Investigative
Ophthalmology & Visual Science, 52(7), 4307-4313.
Eye examination in infants, children, and young adults by pediatricians. (2003).
Pediatrics, 111(4), 902-907.
22
Option for Snellen chart
Sloan Letters
Ferris, F., L., Kassoff, A., Bresnick, G. H., & Bailey, I. (1982). New visual acuity charts
for clinical research. American Journal of Ophthalmology, 94, 91-96
23
Pediatric Eye Charts
LEA Symbols
HOTV
24
LEA Symbols and HOTV Letters
• Candy et al. (2011) looked at discriminability of
optotypes within the same test to determine whether
some optotypes of same size were easier than others to
identify
• LEA Symbols, LEA Numbers, Tumbling E, and
Landolt C were similar to each other in ability to
identify
• Validated blur factor of LEA Symbols
• HOTV, Allen Figures, and Lighthouse tests had
significant differences in similarity or discriminability
of optotypes
• HOTV, Allen Figures, and Lighthouse could be
improved in how well visual acuities matched visual
acuities with the reference optotype, Landolt C.
25
What Does This Mean?
• “ . . . differences in acuity estimates resulting
from basic differences in optotype design and
combination are likely to have a significant
impact on children’s performance” p. 4312.
Candy, T. R., Mishoulam, S. R., Nosofsky, R. M., & Dobson, V. (2011).
Adult discrimination performance for pediatric acuity test optotypes.
Investigative Ophthalmology & Visual Science, 52(7), 4307-4313.
26
LEA Symbols
• Only pediatric eye
chart with
optotypes that blur
equally at threshold
• Culturally neutral
• Children call
optotypes what
they want
27
Screening Distance
• Young children: 10 feet from chart to child’s
eyes
• New, standardized charts will be at 10 feet
• 10/xx on left side of chart with 20/xx on right
side
28
“Linear-Spaced” Eye Charts
• 100% spacing between
optotypes (1 optotypewidth)
• Unequal spacing
BETWEEN lines – not
geometric progression
of 0.1 log (logMAR)
• Arbitrary and nonstandardized betweenline spacing
29
“Wide-Spaced” Eye Charts
• Between-optotype
spacing >100%
• Unequal spacing
BETWEEN lines – not
geometric progression
of 0.1 log (logMAR)
• Between-line spacing
is arbitrary
• Basically contains lines
of single optotypes
30
No Single Symbols or Flashcards
• Unless child has
disabilities and cannot
do full lines
• And want idea of what
child can see
• Youngson (1975) found:
• Visual acuity scores
of 30 children with
amblyopia were, on
average, 3 lines
worse on chart with
lines vs. single
optotypes
Youngson, R. M. (1975). Anomaly in visual acuity
testing in children. British Journal of
Ophthalmology, 59(3), 168-170.
31
Want “Proportional” Spacing
• a.k.a. ETDRS
• a.k.a. logMAR
32
More Info: No Need to Read Each
Optotype on Every Line
World Health
Organization (2003)
says:
• May be less tedious
for children to read
1st optotype on leftside of chart until
missing one and then
moving up a line and
reading entire line
• Camparini et al. found:
ETDRS-Fast (reading 1
letter per row until a
mistake is made) yields
accurate results
compared with standard
method of reading each
optotype on every line.
• Also – significantly
reduced test time
33
Camparini, M., Cassinari, P., Ferrigno, L., & Macaluso, C.
(2001). ETDRS-Fast: Implementing psychophysical adaptive
methods to standardized visual acuity measurement with
ETDRS charts. Investigative Ophthalmology & Visual
Science, 42(6), 1226-1231.
34
NEW Kits From AAPOS
(American
Association for Pediatric Ophthalmology and Strabismus)
AAPOS Vision Screening Kit
AAPOS Vision Screening
Kit: Supplemental
Screening Package
35
Vision Initiative for Children LEA Symbols/Sloan
Letters Kit
36
Older Children
Sloan Letters
ESV1200
Sloan
Letters for
ESV1200
37
Pediatric Eye Charts
LEA Symbols 10-Line
LEA Symbols
for ESV1200
HOTV
HOTV for
ESV1200
38
5-Foot Screening
LEA Symbols for
ESV1200
39
5-Foot Screening
Vision in Preschoolers
Vision in Preschoolers
with PASS 2
40
PC Software
VSS – Free 1-day
trial
41
iPad App
Near/Distance Vision
Screening and Testing
• Includes:
• LEA Symbols, LEA
Numbers, HOTV,
and Sloan Letters
• Distance and near
screening
• Continuous text
reading for near
vision.
42
iPad App
AAPOS Vision
Screening App
• Includes:
• LEA Symbols and
Sloan Letters
• Threshold and
critical line
formats
• Distance and near
screening
43
Devices
44
Welch Allyn SureSight Vision
Screener: School Health Version 2.23
•
Measures refractive error
monocularly
•
14” testing distance
•
Screen as young as 3 months of
age
•
Simple pass/fail reading
• Asterisk beside S (sphere) or C
(cylinder) suggests referral
• (S-) Myopia
• (S+) Hyperopia
• (C)
Astigmatism
• Shows 2-line difference
between eyes
• (D)
Anisometropia
45
Spot Vision Screener VS100
•
Screens both eyes same time
•
Screening distance about 3 feet
•
Capture time 1 second or less
•
Screen reads pass or eye exam
recommended
•
Screens for:
• Hyperopia - farsightedness
• Myopia - nearsightedness
• Astigmatism – blurred vision both eyes
• Anisometropia – unequal refraction
• Gaze – eye alignment
• Anisocoria – unequal pupil size
46
Vision Screener plusoptiX S09 or S12
• Both eyes are screened
simultaneously
• Screening is performed at 3.3
feet
• A "pass" or "refer" screening
result is displayed
automatically
• Screening takes 0.8 seconds
• Interfaces with EMR
• Anisometropia compares refraction of
both eyes
• Astigmatism - checks
corneal irregularities
• Hyperopia - checks
farsightedness
• Myopia - checks
nearsightedness
• Corneal reflexes checks symmetric eye
alignment
• Anisocoria - compares
pupil sizes of both
eyes
47
48
Current Recommendations
Miller, J. M., Lessin, H. R., American Academy of Pediatrics Section on
Ophthalmology, Committee on Practice and Ambulatory Medicine, American
Academy of Ophthalmology, American Association for Pediatric
Ophthalmology and Strabismus, & American Association of Certified
Orthoptists. (2012). Instrument-based pediatric vision screening policy
statement. Pediatrics, 130(5), 983-986. Retrieved from
http://pediatrics.aappublications.org/content/130/5/983.full.pdf+html
49
Current Recommendations
• Children aged 4 to 5 years:
• Instrument-based screening has not been
shown to be superior or inferior to eye
charts.
Schmidt, P., Maguire, M., Dobson, V., Quinn, G., Ciner, E., Cyert, L., . . .
Vision in Preschoolers Study Group. (2004). Comparison of preschool vision
screening tests as administered by licensed eye care professionals in the
Vision in Preschoolers Study. Ophthalmology, 111(4), 637-650. Retrieved from
http://download.journals.elsevierhealth.com/pdfs/journals/01616420/PIIS0161642004001629.pdf
50
Current Recommendations
• Children aged >5 years:
• Eye-chart or optotype-based screening
can be used reliably and should be
performed every 1 to 2 years.
American Academy of Pediatrics, Committee on Practice and Ambulatory
Medicine, Section on Ophthalmology; American Association of Certified
Orthoptists, American Association for Pediatric Ophthalmology and
Strabismus, & American Academy of Ophthalmology. (2003). Eye examination
in infants, children, and young adults by pediatricians. Pediatrics, 111(4 Pt. 1),
902-907. doi: 10.1542/peds.111.4.902. Retrieved from
http://pediatrics.aappublications.org/content/111/4/902.full.pdf+html?sid=19db
48d2-7312-4fb4-aef5-4997c5fde1c7
51
More Info: Pointing from World Health
Organization
•
Pointing to each optotype to
help children know where
they are on the chart is
permissible.
True or False?
_________
•
1.8 “Line-by-line isolation or
pointing may be used, but
not letter by letter.”
52
More Info: Referral Criteria
• 2003-Policy Statement
from:
• American Academy
of Pediatrics
• American
Association of
Certified Orthoptists
• American
Association for
Pediatric
Ophthalmology and
Strabismus
• American Academy
of Ophthalmology
•
Ages 3-5:
• Majority of optotypes (3
of 5) on 20/40 line
• Or 2-line difference
between eyes even if
difference is in passing
lines (i.e., 20/25 and
20/40)
•
Ages 6 and older
• Majority of optotypes (3
of 5) on 20/30 (20/32)
line
• Or 2-line difference
between eyes even if
difference is in passing
lines (i.e., 20/20 and
20/32)
Eye examination in infants, children, and young adults by pediatricians. (2003).
Pediatrics, 111(4), 902-907.
53
Nottingham
Chaplin, P. K., &
Bradford, G. E.
(2011). A
historical review
of distance vision
screening eye
charts: What to
toss, what to
keep, and what to
replace. NASN
School Nurse,
26(4), 221-228.
http://nas.sagepu
b.com/content/26
/4/221.abstract
54
55
Thank You for
Your Time and Attention!
P. Kay Nottingham Chaplin, Ed.D.
kay@good-lite.com
304-906-2204 304-376-9988
56