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Wednesday, April 28, 8:30 - 10:30 AM Hall BC Poster Session Program Number/Board # Range: 4314-4320 / B775-B781
466. Pediatric Refractive Error Organizing Section: VI
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Variability of Autorefractor Measurement in Infants, Children and Adults:The Welch Allyn
SureSight
M.Courage, S.M. Drodge, M.E. Mercer, R.J. Adams. Depts. of Psychology & Pediatrics,
Faculties of Science & Medicine, Memorial Univ of Newfoundland, St John’s, NF,
Canada.
Purpose:In recent years, several hand-held, portable and user friendly autorefractors have emerged to
provide rapid measurements of spherical and cylindrical refractive error for a wide variety of clinical
patients. The Welch Allyn SureSight is perhaps the most flexible and user/patient friendly of these
devices as it is targeted for very young pediatric patients and is calibrated for use without cycloplegia.
To date, there has been little evaluation of the effectiveness of this device, in particular, the consistency
of non-cycloplegic measurements and comparability to those obtained with formal clinical techniques.
Methods:Within a single session, we used the SureSight to obtain two measurements of the
right eye in infants (5-19 mo, n=86), preschoolers (2-5 yr, n=87), school-age children (7-10 yr,
n=102) and young adults (19-25 yr, n=112). The adults, (range = -10 to +7.75D sph; 0 to 3.5 cyl)
were also tested on two separate occasions over the next month. Adult data were compared to
non-cycloplegic measurements obtained with formal clinical autorefractive instrumentation.
Results: In general, age and the variability of refractive measurements were inversely related. The
mean absolute test-retest difference for sphere was 0.26D (SD=0.21D) for adults compared to 0.40D (SD
=0.44D) for school children, 0.61D (SD = 0.66D) for preschoolers and 0.78D (SD = 0.52D) for infants.
The trend for cylinder was similar but with less variability within each group (Mean diff. = 0.31D,
0.22D, 0.18D, and 0.12D for infants, preschoolers, school children and adults, respectively). One way
ANOVA revealed that for both cylinder and sphere, the developmental trend was significant (both p <
0.01). For adults, measurement variability increased over time (e.g., spherical estimates separated by a
month differed by 0.60D compared to 0.26D within a session, p< .001). Finally, comparison with clinical
measurements revealed that the autorefractor underestimated sphere by 0.80D and cylinder by 0.24D.
Conclusions:The Welch Allyn SureSight autorefractor likely provides reasonable first estimates of refractive
error for a broad patient population. However, estimates are much less stable in younger patients, are more
variable over sessions in older subjects and appear to underestimate spherical error somewhat. Nonetheless,
given these shortcomings (likely due to accommodation-related factors), the SureSight’s efficiency and
flexibility make it, for many patients, (e.g. young infants), perhaps the only practical option for estimating
refractive error.
CR: M. Courage, None; S.M. Drodge, None; M.E. Mercer, None; R.J. Adams, None.
Support: NSERC 03-372
Refractive Error and the Early Development of Visual Acuity
R.J. Adams, S.M. Drodge, J.R. Drover, S.Dalton, M.L. Courage. Departments
of Psychology & Pediatrics, Faculties of Science & Medicine, Memorial Univ of
Newfoundland, St John’s, NF, Canada.
Purpose: In previous work (ARVO 2001, 2002, 2003) we have reported that among individual
infants and young children, there is substantial variation in the development of both spatial
vision (visual acuity, contrast sensitivity) and refractive error. However, despite significant
scientific and clinical interest, the relationship between early optical error and early visual
development is very poorly understood, no doubt due to the methodological and technical
difficulties involved in obtaining accurate refractive estimates from individual infants and
toddlers. In the present work, we employ newly developed refractive technology in an attempt to
better quantify how much the early spatial limitations are accounted for by optical immaturities.
Methods: Left eyes from 6-month-old (n=28) and 12-month-old (n=30) infants
were refracted twice with the Welch Allyn SureSight autorefractor (without
cycloplegia) and within the same session, assessed with the Teller acuity cards. For
comparison, left eyes from 3-4-year-old preschoolers (n=56), 7-8-year-old children
(n= 44) and young adults (n=59) were refracted, and acuity assessed (uncorrected)
with either Snellen letters (adults and children) or LEA symbols (preschoolers).
Results: Calculations of total absolute refractive error [|Sph| + |Cyl|], spherical equivalent, and
other linear models of aggregate refractive error all revealed consistent results. As expected from
traditional work, levels of visual acuity in both adults and school-age children were predicted well
from the magnitude of uncorrected refractive error (all r > 0.59, all p < 0.01). However, although
preschool children showed the same trend as older subjects, there was absolutely no relationship
between visual acuity and refractive error in both groups of infants (range of r = -0.08 to +0.06).
Conclusions: Our study is the first to examine systematically, the relationship between
spatial vision and refractive error in young infants and preschoolers. In preschool children,
like adults and older children, visual acuity is predicted well by optical factors. Conversely,
almost none of the variation in visual acuity among individual infants is accounted for by
differences in optics. Consistent with current neurological and psychophysical models of
early visual development, our results suggest that infants’ spatial vision is constrained almost
entirely by photoreceptoral and neural immaturities.
CR: R.J. Adams, None; S.M. Drodge, None; J.R. Drover, None; S. Dalton, None; M.L.
Courage, None. Support: NSERC 03-372
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An Evaluation of the Accuracy of Estimation Retinoscopy
D.S. Carlin, D.K. Wallace, J.D. Wright. Pediatric Ophthalmology and Strabismus,
University of North Carolina, Chapel Hill, NC.
Introduction: One of the daily challenges of a pediatric ophthalmology practice is
retinoscopy of an uncooperative child. For those children who object most strongly to the
placement of lenses in front of their eyes, it would be ideal to obtain an accurate estimate
of refractive error without using lenses. One technique of estimation retinoscopy involves
sliding the sleeve of the Copeland retinoscope downward until a neutral red reflex is
achieved. The purpose of this study was to evaluate the accuracy of this technique by
comparing it to results from standard cycloplegic retinoscopy in cooperative children.
Methods: A Copeland retinoscope was calibrated using a schematic eye and 3 healthy adult
volunteers who received cycloplegic eye drops. A scale was created adjacent to the sleeve
of the retinoscope which allowed an estimate of refractive error based on the position of
the top of the sleeve. Seventy eyes of 35 children had cycloplegic estimation retinoscopy
done by one examiner who was blinded to refractive errors, and accuracy was defined as
one diopter within the refractive error obtained by standard retinoscopy with loose lenses.
Results: Estimation retinoscopy was accurate in: 34 of 37 eyes (92%) with spherical
equivalence between -1.50 D and +1.50 D, 13 of 33 eyes (39%) with spherical equivalence
between +1.75 D and +6.00 D, 12 of 13 eyes (92%) with cylindrical power between +1.00
D and +2.00 D, and 3 of 9 eyes (33%) with cylindrical power between +2.25 D and +5.00
D. None of 37 eyes with an estimated spherical equivalent less than +1.50 had an actual
spherical equivalent greater than +4.25 D, and one of 26 eyes (4%) with an estimated
cylinder power of +1.00 D or less had an actual cylinder power of greater than +2.25 D.
Conclusions: The technique of estimation retinoscopy done by sliding the sleeve of the
Copeland retinoscope downward is very sensitive for eyes with very mild myopia or hyperopia,
but it has poor sensitivity for eyes with higher degrees of hyperopia or astigmatism. However,
when this estimation technique indicates a spherical equivalent between -1.50 D and +1.50
D, with +1.00 D of cylinder power or less, the examiner can be assured that an amblyogenic
refractive error is almost never present.
CR: D.S. Carlin, None; D.K. Wallace, None; J.D. Wright, None.
Support:
Maximizing Refractive Error Detection in Preschool Vision Screening
A.M. Hickson1, P.P. Schmidt2. 1Pediatric Optometry, The Ohio State College of Optometry,
Eagan, MN; 2The Ohio State College of Optometry, Columbus, OH.
Pur pose: Sig n if icant ref ract ive er ror, hy peropia, an isomet ropia, and
astigmatism,in early childhood is the most frequent cause of amblyopia. To
compare refracting methods for detect significant refractive error when receiver
operating characteristic (ROC) curve analysis is used to maximize performance.
Methods: 48 preschool children (Mean Age: 4.4 yrs + 1.0 yr) had refractive error
measured in a pre-determined order by cycloplegic (C) retinoscopy, noncycloplegic (NC)
retinoscopy (Ret), and autorefraction (Nikon Retinomax K-plus (Retmax) and 2 Welch
Allyn (WA) autorefractors [Prototype (WAP) & SureSight (SS) 1.22 Child Mode]). All
testers were masked; C retinoscopy was the gold standard. ROC curve analysis was
conducted for each refracting method. For each refractive error type, specificity (Sp)
levels were set at 0.85, 0.90, and 0.95; sensitivity (Se) and cut points (CP) were determined.
Results: Hyperopia- Sp=0.85, Se: 0.42 (WAP) - 1.00 (NC Ret); CP=3.44D, 1.37D.
Sp=0.90, Se: 0.62 (NC Retmax) - 1.00 (NC Ret); CP=1.37D, 1.37D. Sp=0.95, Se: 0.17
(WAP) - 0.70 (SS 1.22); CP=3.95D, 3.87D. Anisometriopia- Sp=0.85, Se:0.0 (SS 1.22)
- 0.50 (NC Ret); CP=1.13D, 0.62D. Sp=0.90, Se:0.0 (SS 1.22) - 0.50 (NC Ret); CP=1.38D,
0.88D. Sp=0.95, Se: 0.0 (SS 1.22, Retmax) - 0.25 (NC Ret, WAP); CP=1.25D - 2.06D.
Astigmatism- Sp=0.85, Se:1.00 for all instruments; CP=0.88D - 1.63D. Sp=0.90, Se:1.00 for
all instruments; CP=1.13D - 1.88D. Sp=0.95, Se: 1.00 for all instruments; CP=1.75D - 2.50D.
Conclusions: Hyperopic cut points and sensitivity vary across methods. Anisometropia
cut points vary; sensitivity is poor. Astigmatic cut points and sensitivity are similar across
methods. ROC curve analysis enhances the potential usefulness of NC retinoscopy, Retinomax,
and SureSight 1.22 method of screening preschool children for significant refractive error.
CR: A.M. Hickson, None; P.P. Schmidt, None.
Support: Ruth Morris Fund, Welch Allyn Inc.
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Hyperopia and the emergent literacy skills of young children
S.Shankar1, M.A. Evans2, K.Ball1, J.Saad3, A.Butler1, W.R. Bobier1. 1School of Optometry,
University of Waterloo, ON, Canada; 2Psychology, University of Guelph, ON, Canada;
3
University of Western Ontario, London, ON, Canada.
Pur pose: To measu re emergent literacy skills in u ncor rected hy peropic child ren.
Methods: Eighty one children were recruited from a vision study and tested for visual acuity (VA;
Cambridge Crowding cards, single optotypes and crowded letters) and then administered three standardized
psychological tests to test phonological awareness, letter and word reading skills, and receptive vocabulary,
and an experimental test of visual orthographic skills. Parents completed a survey of family demographics
and the child’s home literacy experiences. As dry refractions underestimated hyperopia, results presented
are for 27 children with current cycloplegic data. When participants were classified on their cycloplegic
refraction as hyperopes (≥ 2D OU; N=9; aged 64.6±11 m) or emmetropes (≤ 1.75 D OU; N=18; aged
57.7±10 m) performance differences in vision testing and literacy were found. This division showed no
statistically significant differences between the two groups for age, and family variables that are known
to contribute to emergent literacy skills such as birth order, number of children in family, mother’s or
father’s education and reading skills, shared reading time, number of children’s books at home, etc.
Results: Vision: The crowding effect was larger for hyperopes than for emmetropes for the left eye
(χ2 (3) =12.82, p=.005), and approached significance for the right eye (χ 2 (3) =7.18, p=.06). There were
no significant differences for VA for single optotypes between hyperopes and emmetropes. Literacy:
Hyperopes had lower scores than emmetropes for visual-orthographic discrimination (Mann-Whitney
U=43.5, p=0.05), phonological awareness (Mann-Whitney U =35.5, p=0.02) and verbal ability and receptive
vocabulary (Mann-Whitney U=40.5, p=0.04). They did not differ in letter and word recognition ability.
While 4 of the emmetropes had received professional help for parental concerns (speech/language),
only one hyperopes’ parent had speech/language concerns but had not consulted a professional.
Conclusions: 1. Children who are hyperopic (≥2D) and have increased crowding effects also show reduced
performance on tests of visual-orthographic discrimination, phonological awareness, and verbal ability. 2.
Differences between hyperopes and emmetropes may represent developmental deficits in the visuocognitive
domain1, but the parental questionnaire revealed no significant concerns for any of the hyperopes.
1
Atkinson, J, Anker, S, Nardini, M, Braddick, O. 2002. Strabismus, 10, 187-98
CR: S. Shankar, None; M.A. Evans, None; K. Ball, None; J. Saad, None; A. Butler, None; W.R. Bobier,
None.
Support: Canadian Language and Literacy Research Network
DEVELOPMENT OF SPHERICAL EQUIVALENT AND ACUITY IN CHILDREN
WITH OCULOCUTANEOUS ALBINISM (OCA)
N.Couture1A, R.M. Hansen1A, A.Moskowitz1A, A.Gee1A, J.LeMoine1A, B.-L.Wu1B, A.B.
Fulton1A. AOphthalmology, BLaboratory Medicine, 1Children’s Hospital, Boston, MA.
Purpose: Study the development of spherical equivalent and acuity in infants and young
children with OCA. Broad distributions of refractive error and letter acuity are recognized
in mature subjects with OCA
Methods: Longitudinal measures of refractive error and acuity were obtained in 16 children
starting at age 1 month. Each were followed for up to 8 years. Each demonstrated physical
features of OCA and had tyrosinase gene and P-gene testing. Before age 3 years, binocular
grating acuities were measured with the Teller Acuity Card procedure. At older ages, symbol
acuities were obtained using established clinical tests (including LEA, HOTV, EDTRS).
Spherical equivalents were derived from results of cycloplegic retinoscopy. Spherical
equivalents and grating acuities were compared to the 95% prediction interval (PI) for healthy
infants and children. Data within the PI was defined as normal, and outside the PI as abnormal.
Results: The course of grating acuity was abnormal in 9 and normal in 7 of the 16 subjects. The
course of spherical equivalent was abnormal in 8 and normal in 8 subjects, but no significant
association between grating acuity and spherical equivalent was found. The abnormal courses
of spherical equivalent were characterized by persistent, moderate (N=2) or high (N=6)
hyperopia, or significant myopia that increased until 2 years of age (N=2). Six of the seven
subjects with normal grating acuity developed abnormal spherical equivalents and low symbol
acuity (20/100 or poorer). Among subjects with normal refractive development and good
symbol acuity (20/50 or better), only one had a history of abnormal grating acuity. Genotype
did not predict acuities or refraction. Consistent with previous reports, Summer’s indices of
ocular hypopigmentation did not predict acuity, nor did the indices predict refractive error.
Conclusions: Abnormal refractive development was associated with low symbol acuity in
these subjects with OCA. The determinants of refractive development and acuity in OCA
remain to be elucidated.
CR: N. Couture, None; R.M. Hansen, None; A. Moskowitz, None; A. Gee, None; J.
LeMoine, None; B. Wu, None; A.B. Fulton, None.
Support: NIH Grant EY10597
Copyright 2004 by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. For permission to reproduce any abstract, contact the ARVO Office at [email protected].
Commercial Relationships are noted at the end of each abstract by “None” or with codes.
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Wednesday, April 28, 8:30 - 10:30 AM Hall BC Poster Session Program Number/Board # Range: 4314-4320 / B775-B781
466. Pediatric Refractive Error Organizing Section: VI
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Objective Optical Function Evaluation in a Child with Crystalline Lens Dislocation
Using a Point Spread Function Analysis System
M.A. Goto1, T.Tachikawa1, M.Matsubara1, M.Shibutani2, K.Kobayashi2, G.Takeuchi2,
K.Negishi3, K.Ohnuma4, K.Ohno5, T.Noda5. 1Department of Ophthalmology, Tokyo
Women’s Medical University Daini Hospital, Tokyo, Japan; 2Topcon Corporation, Tokyo,
Japan; 3Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan;
4
Faculty of Engineering, Chiba University, Chiba, Japan; 5Department of Ophthalmology,
National Institute of Sensory Organs, Tokyo, Japan.
Purpose: To objectively estimate the optical f unction in a child with
crystalline lens dislocation using a new point spread function (PSF) analyzer.
Methods: Bilateral visual function in a 6-year-old boy with lens dislocation associated
with Marfan’s syndrome was evaluated by PSF analysis. Double-pass PSFs were
obtained and the optical status was objectively analyzed. The retinal images were
simulated and evaluated objectively by convoluting the PSFs to Landolt’s ring images.
Results: The subjective best-corrected visual acuities (BCVAs) were 30/20 (20/15 × sph. -2.00
D, cyl. -2.50 D, ax. 160ﾟ) in the right eye and 20/50 (20/30 × sph. -2.75 D, cyl. -5.00 D, ax. 55ﾟ)
in the left eye. Autorefractometry showed 3.75 D of astigmatism in the right eye; the left eye
was unmeasurable. Using PSF analysis, the anterior and posterior focal lines in the left eye were
identified objectively and the estimated astigmatism was calculated as 9.0 D. Simulated retinal
images of Landolt’s rings were synthesized, and it was theorized that astigmatic correction should
substantially improve optical function. After prescribing glasses based on PSF analysis data,
the BCVA improved to 20/22. In the right eye, although the presumed amount of astigmatism
was less than in the left eye, asymmetrical components of aberration were recognized in
the aerial images and simulated retinal images that seemed uncorrectable with spectacles.
Conclusions: In eyes with lens dislocation, marked oblique astigmatism occurred according
to the degree of the dislocation. The PSF analysis system can objectively evaluate the
characteristics of the optical function in pediatric eyes in which subjective examinations
are difficult to perform.
CR: M.A. Goto, None; T. Tachikawa, None; M. Matsubara, None; M. Shibutani, Topcon
Corporation E; K. Kobayashi, Topcon Corporation E; G. Takeuchi, Topcon Corporation
E; K. Negishi, None; K. Ohnuma, None; K. Ohno, None; T. Noda, None.
Support:
Copyright 2004 by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. For permission to reproduce any abstract, contact the ARVO Office at [email protected].
Commercial Relationships are noted at the end of each abstract by “None” or with codes.
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