Visual Acuity Results in School-Aged Children and Adults: Lea Symbols Chart Versus Bailey-Lovie Chart

Motor-Based Application Process for Cerebral Visual Impairment-Related Questionnaires for School-Age Children with Cerebral Palsy

This study aims to examine the psychometric properties of questionnaires related to cerebral visual impairment (CVI) in school-age children with cerebral palsy (CP). Additionally, it proposes an application process based on motor functionality for occupational therapists. A total of 288 children with CP were recruited for the study and administered the CVI Motor Questionnaire (CVI-MQ). The children's daily visual performance was assessed using the CVI Inventory and the Functional Vision Questionnaire (FVQ) considering the children's ambulatory status. The FVQ and the two factors extracted from the CVI Inventory significantly predicted visual functioning. Specific questionnaires related to CVI, applied with gross motor function in mind, can be valuable tools for occupational therapists to assess daily visual performance.

The Freiburg Acuity Test in Preschool Children: Testability, Test-Retest Variability, and Comparison With LEA Symbols

Purpose

To determine the testability, performance, and test-retest variability (TRV) of visual acuity (VA) assessment using the Freiburg Visual Acuity Test (FrACT) compared to the LEA Symbols Test (LEA) in preschool children.

Methods

In 134 preschool children aged 3.0 to 6.8 years, monocular VA of each eye was measured twice with a four-orientation Landolt C version of the FrACT and once with the LEA. FrACT runs were preceded by a binocular run for explanatory purposes. Test order alternated between subjects. Optotypes were presented on a computer monitor (FrACT) or on cards (LEA) at a distance of 3 m.

Results

Overall, 68% completed the FrACT (91/134 children) and 88% completed the LEA (118/134 children). Testability depended on age: FrACT, 19% (<4 years) and 87% (≥4 years); LEA, 70% (<4 years) and 95% (≥4 years). Mean ± SD VA difference between tests was 0.11 ± 0.19 logarithm of the minimum angle of resolution [logMAR], with LEA reporting better acuity. The difference depended on age (0.27 ± 0.23 logMAR [<4 years], 0.09 ± 0.18 logMAR [≥4 years], P < 0.001) and on test sequence (higher age dependence of FrACT VAs for LEA first, P < 0.001). The 95% limits of agreement for the FrACT TRV were ±0.298 logMAR.

Conclusions

The examiner-independent FrACT, using international reference Landolt C optotypes, can be used to assess VA in preschool children aged ≥4 years, with reliability comparable to other pediatric VA tests.

Translational Relevance

Use of the automated FrACT for VA assessment in preschool children may benefit objectivity and validity as it is a computerized test and employs the international reference Landolt C optotype.

Discrimination of paediatric acuity test optotypes by 6-year-old children

PURPOSE

To compare the discrimination performance of 6-year-old children for optotypes from six paediatric visual acuity tests and to fit Luce's Biased Choice Model to the data to estimate the relative similarities and bias for each optotype.

METHODS

Full data sets were collected from 20 typically developing 6-year-olds who had passed a vision screening. They were presented with single optotypes labelled 6/12 at a distance of 9 m and were asked to identify the optotype using a matching task containing all optotypes from the relevant test. The data were combined to form a confusion matrix for each test and a biased choice model was fitted to the data.

RESULTS

Median correct performance varied from 40% to 100% across optotypes, with the HOTV test having the highest values. Estimates of the similarity of each pair of optotypes indicated equal values for all pairs in the Landolt C, HOTV, Lea numbers and Tumbling E tests. The values differed for the picture tests, that is Lea Symbols and Allen figures. The estimates of bias for each individual optotype also indicated different values with the picture tests.

CONCLUSIONS

Previous studies of the threshold acuity of young children and adults have indicated differences in acuity estimates across paediatric tests. A recognition acuity task typically requires resolving the difference information between optotypes. The performance of the 6-year-olds here reveals variance in similarity and bias values for picture tests, particularly for the Allen figures when compared with the Lea Symbols. Ideally, this analysis should be performed when designing new tests, and these results motivate progression from the use of current picture tests to well calibrated letter or number tests at the earliest possible age.

Agreement between Lea Symbols and Patti Pics visual acuity in children and adults

BACKGROUND

Patti Pics (PP) and Lea Symbols (LS) are commonly used by eye care practitioners worldwide. Although the relationship between the two tests is fairly well understood, the availability of different chart designs (single optotypes, multiple optotypes, multiple optotypes with crowding box) merits futher understanding. The purpose of this study is to explore the agreement between the acuity measures obtained with Patti Pics and Lea Symbols in children and adults and compare their performance with the Sloan Letter (SL) chart in adults.

METHODS

Monocular visual acuity was obtained from ninety-three 3 to 5-year-old children using Patti Pics and Lea Symbols. Acuities were also obtained from 113 adults using the same tests under identical conditions. Acuity results obtained with the pediatric tests were compared with the gold-standard Sloan Letter chart in adults. The Bland-Altman method was implemented to compare the level of agreement between tests.

RESULTS

Patti Pics yielded worse visual acuity than the Lea Symbols by approximately half a logMAR line in both children (mean difference: -0.07 ± 0.07 logMAR, p <0.01) and adults (Mean difference: -0.05 ± 0.06 logMAR, p <0.01). The 95% limits of agreement between Lea Symbol acuity and Patti pics acuity in children was ± 0.14 logMAR. Mean difference between the Sloan Letter chart and Lea Symbols acuity was not statistically significant (p = 0.08) in adults but the difference was statistically significant between PP and SL (p<0.001). The 95% limits of agreement between LS and SL and between PP and SL was ± 0.19 logMAR and ± 0.22 logMAR, respectively.

CONCLUSION

Patti Pics consistently underestimated visual acuity as compared to Lea Symbols both in children and adults although the differences were not clinically significant. The LS and PP did not yield clinically significant differences in acuities when compared with Sloan letters in adults.

Vision Screening, Vision Disorders, and Impacts of Hyperopia in Young Children: Outcomes of the Vision in Preschoolers (VIP) and Vision in Preschoolers - Hyperopia in Preschoolers (VIP-HIP) Studies

ABSTRACT

This review summarizes clinically relevant outcomes from the Vision in Preschoolers (VIP) and VIP-Hyperopia in Preschoolers (VIP-HIP) studies. In VIP, refraction tests (retinoscopy, Retinomax, SureSight) and Lea Symbols Visual Acuity performed best in identifying children with vision disorders. For lay screeners, Lea Symbols single, crowded visual acuity (VA) testing (VIP, 5-foot) was significantly better than linear, crowded testing (10-foot). Children unable to perform the tests (<2%) were more likely to have vision disorders than children who passed and should be referred for vision evaluation. Among racial/ethnic groups, the prevalence of amblyopia and strabismus was similar while that of hyperopia, astigmatism, and anisometropia varied. The presence of strabismus and significant refractive errors were risk factors for unilateral amblyopia, while bilateral astigmatism and bilateral hyperopia were risk factors for bilateral amblyopia. A greater risk of astigmatism was associated with Hispanic, African American, and Asian race, and myopic and hyperopic refractive error. The presence and severity of hyperopia were associated with higher rates of amblyopia, strabismus, and other associated refractive error. In the VIP-HIP study, compared to emmetropes, meaningful deficits in early literacy were observed in uncorrected hyperopic 4- and 5-year-olds [≥+4.0 diopter (D) or ≥+3.0 D to ≤+6.0 D associated with reduced near visual function (near VA 20/40 or worse; stereoacuity worse than 240")]. Hyperopia with reduced near visual function also was associated with attention deficits. Compared to emmetropic children, VA (distance, near), accommodative accuracy, and stereoacuity were significantly reduced in moderate hyperopes, with the greatest risk in those with higher hyperopia. Increasing hyperopia was associated with decreasing visual function.

Visual Status in a Portuguese Population with Intellectual Disability

BACKGROUND

Neurosensory deprivation associated with vision is a well-known fact in people with intellectual disability (ID). This work aims to report the visual status of a population with ID in Portugal.

METHODS

A vision screening protocol was conducted during two Special Olympics events. The vision protocol included personal medical history, ocular health evaluation, and clinical measures, such as visual acuity (VA), binocular vision, colour vision, refractive error, and intraocular pressure. This protocol was administered to 134 subjects.

RESULTS

Half of the subjects reported that they had never attended or they did not remember having attended a previous eye exam. Additionally, 10% of them had not attended an eye exam in the immediate past three years. Half the subjects failed the VA test and 13% presented moderate Visual Impairment (VI) (VA worse than 0.5 logMAR in the best eye). Manifest ocular deviation was found in 25% of the subjects and the most common ocular health dysfunction conditions were conjunctiva hyperaemia, meibomian gland dysfunction, and lens anomalies. Refractive error correction allowed a reduction in the level of moderate VI to 3.7%.

CONCLUSIONS

The population analysed showed a poor eye care attendance rate and vision-related conditions are in agreement with previous reports. The development of national strategies to promote the awareness for routine eye care in people with ID and improving accessibility to eye care services may mitigate many of the most prevalent conditions encountered.

Retinal Function in X-Linked Juvenile Retinoschisis

Purpose

To assess retinal function in young patients with X-linked juvenile retinoschisis (XLRS), a disorder that is known to alter ERG postreceptor retinal components and also possibly photoreceptor components.

Methods

ERG responses to full-field stimuli were recorded under scotopic and photopic conditions in 12 XLRS patients aged 1 to 15 (median 8) years. A- and b-wave amplitudes and implicit times were examined over a range of stimulus intensities. Rod and cone photoreceptor (SROD, RROD, SCONE, RCONE) and rod-driven postreceptor (log σ, VMAX) response parameters were calculated from the a- and b-waves. Data from XLRS patients were evaluated for significant change with age.

Results

A- and b-wave amplitudes were smaller in XLRS patients compared with controls under both scotopic and photopic conditions. Saturated photoresponse amplitude (RROD), postreceptor b-wave (log σ), and saturated b-wave amplitude (VMAX) were significantly lower in XLRS patients than in controls; SROD did not differ between the two groups. SCONE and RCONE values were normal. In XLRS patients, neither a- and b-wave amplitudes nor calculated parameters (SROD, RROD, log σ, VMAX,SCONE, and RCONE) changed with age.

Conclusions

In these young XLRS patients, RROD and a-wave amplitudes were significantly smaller than in controls. Thus, in addition to XLRS causing postreceptor dysfunction, an effect of XLRS on rod photoreceptors cannot be ignored.

Eyelid squinting improves near vision in against-the-rule and distance vision in with-the-rule astigmatism in pseudophakic eyes: an eye model experimental study

Background

To elucidate whether eyelid squinting improves near and distance vision in against-the-rule (ATR) and with-the-rule (WTR) simple myopic astigmatism in pseudophakic eyes.

Methods

A refraction-model eye was mounted on a wavefront analyzer. The eyelid fissure was simulated using a slit placed horizontally in front of the model eye. Four different refractive statuses [− 1.50 diopters (D) and − 3.00 D of both WTR and ATR simple myopic astigmatism] were set using cylindrical lenses. For each refractive status (emmetropia, − 1.50 D WTR, − 1.50 D ATR, − 3.00 D WTR, and − 3.00 D ATR astigmatism), wavefront aberrations were measured, both with and without the slit, 40 times each.

Results

The 2 mm horizontal slit caused a hyperopic focus shift (+ 6.69 μm) in − 1.50 D WTR astigmatism, whereas, in − 1.50 D ATR astigmatism, it caused a myopic focus shift (− 2.01 μm). The astigmatism was decreased in the ATR astigmatism groups and increased in the emmetropia and WTR astigmatism groups, respectively. Total aberrations were decreased in the emmetropia and WTR astigmatism groups and increased in the ATR astigmatism groups. When the reference plane was set to the near plane, total aberrations were decreased in the ATR astigmatism groups.

Conclusion

As the horizontal slit was placed in front of the model eye, the focus moves nearer in ATR astigmatism and farther in WTR astigmatism. These effects of eyelid cause improvement of near vision of pseudophakic eyes with ATR astigmatism.

Validity of the +1.50 plus lens screening test as a predictor of uncorrected moderate hyperopia

PURPOSE

Screening for uncorrected hyperopia in school children is important given its association with poorer visual function and academic performance. However, standard distance visual acuity screening may not detect low to moderate hyperopia. The plus lens test is used to screen for hyperopia in many school screening protocols, but has not been well validated. The current study investigated the effectiveness of the plus lens test to identify hyperopia in school children.

METHODS

Participants included Grade 2 school children. Monocular distance visual acuity (logMAR letter chart) was measured unaided, and then through a +1.50D lens, known as the plus lens test. Cycloplegic refraction was undertaken to classify moderate hyperopia (≥+2.00D). Sensitivity, specificity, positive predictive values (PPV) and negative predictive values (NPV) were calculated for commonly used cut-offs for the plus lens test: 6/6, 6/9 and less than two lines difference between unaided acuity and acuity through the plus lens test.

RESULTS

The sample included 59 children (mean age 7.2 ± 0.4 years). Fourteen (24%) children were classified as having uncorrected hyperopia. The sensitivity and specificity of the +1.50 plus lens test for identifying hyperopia were 0% and 98% respectively for a 6/6 cut-off, 29% and 91% for 6/9 cut-off, and 50% and 76% for a <2 line reduction between unaided acuity and acuity through the plus lens test. Receiver Operating Curve (ROC) analysis revealed area under curves of 0.69 based on acuity through the plus lens test, and 0.65 for a reduction in acuity through the plus lens test.

CONCLUSIONS

The plus lens test has low sensitivity for detecting uncorrected hyperopia using traditional cut-offs of 6/9 or better. This raises questions about the role of the plus lens test in school screening batteries.

Do picture-based charts overestimate visual acuity? Comparison of Kay Pictures, Lea Symbols, HOTV and Keeler logMAR charts with Sloan letters in adults and children

Purpose

Children may be tested with a variety of visual acuity (VA) charts during their ophthalmic care and differences between charts can complicate the interpretation of VA measurements. This study compared VA measurements across four pediatric charts with Sloan letters and identified chart design features that contributed to inter-chart differences in VA.

Methods

VA was determined for right eyes of 25 adults and 17 children (4–9 years of age) using Crowded Kay Pictures, Crowded linear Lea Symbols, Crowded Keeler logMAR, Crowded HOTV and Early Treatment of Diabetic Retinopathy Study (ETDRS) charts in focused and defocused (+1.00 DS optical blur) conditions. In a separate group of 25 adults, we compared the VA from individual Kay Picture optotypes with uncrowded Landolt C VA measurements.

Results

Crowded Kay Pictures generated significantly better VA measurements than all other charts in both adults and children (p < 0.001; 0.15 to 0.30 logMAR). No significant differences were found between other charts in adult participants; children achieved significantly poorer VA measurements on the ETDRS chart compared with pediatric acuity tests. All Kay Pictures optotypes produced better VA (p < 0.001), varying from -0.38 ± 0.13 logMAR (apple) to -0.57 ± 0.10 logMAR (duck), than the reference Landolt C task (mean VA -0.19 ± 0.08 logMAR).

Conclusion

Kay Pictures over-estimated VA in all participants. Variability between Kay Pictures optotypes suggests that shape cues aid in optotype determination. Other pediatric charts offer more comparable VA measures and should be used for children likely to progress to letter charts.

Comparing Visual Acuity Measured by Lea Symbols and Patti Pics

INTRODUCTION

There is little data validating most illiterate eye charts. Lea Symbols®, however, have been well validated in numerous studies. In this study, we compare the assessment of visual acuity employing both the Lea Symbol hanging wall Early Treatment Diabetic Retinopathy Study (ETDRS)-style chart and a similar Patti Pics® ETDRS-style chart in order to determine whether the two charts provide clinically similar data.

METHODS

We tested the vision of the right eyes of fifty-two consecutive patients. Patients were cooperative children or adults between the ages of 3 and 88 years (mean 58 years). We alternated the order of the chart used first. Patients were also categorized by age and by visual acuity.

RESULTS

The visual acuities measured by the two charts were equal for 83% of the measurements (forty-three eyes). In 8% of eyes (four eyes), the visual acuity measured with the Lea Symbols was one line better than that measured by the Patti Pics; in 9% of eyes (five eyes), the acuity from the Patti Pics chart measured one line better than the Lea Symbols. There was no difference in measurements for either adults or children or among patients with different visual acuities.

CONCLUSION

We believe this study will serve to provide useful information when choosing an eye chart to assess visual acuity in a clinic setting. Patti Pics performed similarly to Lea Symbols in adults and children tested in a multi-specialty ophthalmology practice. We suspect that it would also perform similarly in the primary care and school settings.

Test Re-Test Reliability and Validity of Different Visual Acuity and Stereoacuity Charts Used in Preschool Children

BACKGROUND

Preschool vision screenings are cost effective ways to detect children with vision impairments. The use of any vision tests in children must be age appropriate, testable, repeatable and valid.

AIM

To compare the test re-test reliability, sensitivity and specificity of different visual acuity and stereo acuity charts used in preschool children.

MATERIALS AND METHODS

Monocular visual acuity of 90 subjects (180 eyes) of age 36 to 71 months was assessed with HOTV, Lea and E-chart in a preschool located in a semi urban area, Manipal, Karnataka. After the vision assessment, stereo acuity was recorded using Frisby and Titmus stereo charts followed by comprehensive eye examination. Repeated measurements of visual acuity and stereo acuity were done one week after the initial assessment.

RESULTS

Mean age of children was 53± 10 months with equal gender distribution. Intra class correlation (ICC) of Lea, HOTV, E-chart, Frisby and Titmus charts were 0.96, 0.99, 0.92, 1.0 and 1.0 respectively. The area under receiver operating curve (ROC) for Lea and E-chart was 0.892 and 0.776. HOTV was considered as the gold standard as it showed the least difference on repeated measurements. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of E-chart was 99, 15, 45, 94 and 21.8 percent, and Lea was 93, 56, 59 and 92 percent. The sensitivity, specificity, PPV and NPV of Frisby was 75, 27, 9, 92 percent were as of Titmus was 75, 13, 8 and 85 percent respectively.

CONCLUSION

HOTV chart can be used as the gold standard for measuring visual acuity of pre-schoolers in a semi urban area. Lea chart can be used in the absence of HOTV chart. Frisby and Titmus charts are good screening tools, but with poor diagnostic criteria.

Comparison of visual acuity results in preschool children with lea symbols and Bailey-Lovie E chart

Purpose:

To compare visual acuity with two visual acuity charts in preschool children.

Materials and Methods:

Visual acuity measurement with Lea symbols and Bailey-Lovie tumbling E chart was performed on children between 3 and 6 years of age. Visual acuity data from the two charts were analyzed with Bland-Altman plot to determine the limits of agreement. The Wilcoxon signed test was performed in children aged 3-4 years and in children aged 5-6 years separately to evaluate the influence of age. The inter-eye difference between the two charts were further analyzed with the paired t-test. A p value > 0.05 was considered statistically significant.

Results:

A total of 47 children were enrolled for the study. The average logarithm of the Minimum Angle of Resolution (LogMAR) monocular visual acuity with Lea symbols (0.17 ± 0.13) was better than the Bailey-Lovie tumbling E chart (0.22 ± 0.14). The mean difference between Bailey-Lovie tumbling E chart and Lea symbol chart was 0.05 ± 0.12 in logMAR units. A second analysis eliminating outliers showed the same result but lower differences (n = 43, 0.05 ± 0.05 logMAR units). Visual acuity results between the two charts in children aged 3-4 years showed a significant difference (p = 0.000), but not for children aged 5-6 years (p = 0.059). Inter-eye differences between the two charts was not statistically significant (p = 0.77).

Conclusion:

Bailey-Lovie tumbling E chart is comparable to the Lea symbols chart in pre-school children. But preference should be given to Lea symbols for children aged 3-4 years as the symbols are more familiar than a directional test for this age group.

The handy eye chart: a new visual acuity test for use in children

OBJECTIVE

To design a simple matching acuity test based on hand gestures that is minimally dependent on familiarity with symbols and letters. The visual acuity results obtained from children using the Handy Eye Chart were compared with results obtained with the Early Treatment Diabetic Retinopathy Study (ETDRS) chart.

DESIGN

Evaluation of diagnostic test or technology.

PARTICIPANTS

Sixty children aged 6 to 16 years were recruited consecutively from the Pediatric Ophthalmology section of the Emory Eye Center.

METHODS

Monocular visual acuity was tested using both the new eye chart and the ETDRS chart, alternating the order of administration between subjects. Testing was performed on the subject's eye with the poorest acuity.

MAIN OUTCOME MEASURES

Outcome measures were monocular logarithm of the minimum angle of resolution (logMAR) visual acuity scores for each chart.

RESULTS

The acuities were shown to have a strong linear correlation (r = 0.95) and a mean difference in acuity of -0.03 (95% confidence interval, -0.05 to -0.01) logMAR, equivalent to approximately 1.5 letters, with the new eye chart underestimating the vision as determined by the ETDRS chart. The 95% limits of agreement were ±1.6 lines.

CONCLUSIONS

This study supports the validity of the new eye chart as a measure of visual acuity in pediatric patients aged 6 to 18 years with vision ranging from 20/16 to 20/200.

Validation of printed and computerised crowded Kay picture logMAR tests against gold standard ETDRS acuity test chart measurements in adult and amblyopic paediatric subjects

AIMS

The impression exists that picture acuity scores may overestimate function when subjects are switched to letter charts. This has not been systematically investigated. The aims of this study were to validate both printed crowded Kay picture (pCKP) and computerised CKP (cCKP) logMAR test acuity measurements against gold standard ETDRS letter chart scores.

METHODS

A total of 30 adult subjects with various ophthalmic disease and 40 amblyopic children underwent test and re-test visual acuity measurements using the ETDRS chart, the pCKP logMAR test, and the cCKP acuity scores taken, using the COMPlog visual acuity measurement system. Bland and Altman methods were employed.

RESULTS

Computerised and printed Kay picture acuity scores agreed well. Both Kay picture test measurements were systematically biased when compared with ETDRS chart measurements. No significant proportional bias was found. The test retest variability (TRV) of all three tests was found to be similar between ± 0.14 and 0.16 logMAR in both groups.

CONCLUSIONS

All three tests were similarly replicable and computerised Kay pictures appear to be a valid alternative to hard copy Kay pictures. Kay picture acuity measurements were systematically biased when compared with the gold standard ETDRS. Measurement error means that differences of up to 0.16 logMAR may be observed in clinically stable patients when re-measured using the same technique. A combination of TRV and systematic bias can however lead to differences of up to 0.40 logMAR in stable amblyopic patients when switched from CKPs to ETDRS chart acuity measurements.

Development of human visual function

By 1985 newly devised behavioral and electrophysiological techniques had been used to track development of infants' acuity, contrast sensitivity and binocularity, and for clinical evaluation of developing visual function. This review focus on advances in the development and assessment of infant vision in the following 25 years. Infants' visual cortical function has been studied through selectivity for orientation, directional motion and binocular disparity, and the control of subcortical oculomotor mechanisms in fixation shifts and optokinetic nystagmus, leading to a model of increasing cortical dominance over subcortical pathways. Neonatal face processing remains a challenge for this model. Recent research has focused on development of integrative processing (hyperacuity, texture segmentation, and sensitivity to global form and motion coherence) in extra-striate visual areas, including signatures of dorsal and ventral stream processing. Asynchronies in development of these two streams may be related to their differential vulnerability in both acquired and genetic disorders. New methods and approaches to clinical disorders are reviewed, in particular the increasing focus on paediatric neurology as well as ophthalmology. Visual measures in early infancy in high-risk children are allowing measures not only of existing deficits in infancy but prediction of later visual and cognitive outcome. Work with early cataract and later recovery from blinding disorders has thrown new light on the plasticity of the visual system and its limitations. The review concludes with a forward look to future opportunities provided by studies of development post infancy, new imaging and eye tracking methods, and sampling infants' visual ecology.

An analysis of vision screening data from New York City public schools

OBJECTIVE

This study compares different vision screening batteries and documents the failure rates of different vision tests in children who receive periodic vision screenings.

METHODS

Vision screenings were conducted on 1,992 preschool through fifth grade children attending schools in lower socioeconomic areas in New York City. The screening battery incorporated visual acuity, retinoscopy, cover test, stereopsis, near point of convergence, ocular motility, accommodation, color vision, and ocular health.

RESULTS

Slightly less than one third (30%) of the children screened failed the State University of New York (SUNY) battery and were referred for a comprehensive examination, of which 249 (41%) children actually passed distance visual acuities. The referral rate for distance visual acuity alone was 19%. The referral rate for the Modified Clinical Technique (MCT) was 22%. A greater percentage (33%) of the children in grades kindergarten through fifth were referred compared with the preschoolers (20%). Only a small percentage (8%) of the children wore corrective lenses at the time of testing. There was a significant increase in the prevalence of binocular vision problems found in children from grades kindergarten through 5.

CONCLUSIONS

Poor visual acuity and binocular vision problems exist in schoolchildren despite ongoing vision screenings. The results provide evidence for the necessity of periodic rescreening starting in kindergarten and the importance of screening for hyperopia and binocular vision problems in addition to distance visual acuities.

Effect of age using Lea Symbols or HOTV for preschool vision screening

PURPOSE

To compare the effectiveness of the Lea Symbols and the HOTV distance visual acuity tests, presented monocularly in linear, crowded formats at 3 m, as vision screening tests to identify 3- to 5-year-old children in need of eye care.

METHODS

Subjects were 1,142 3- to 5-year-old Head Start children who completed a comprehensive eye examination, used to determine if the child had one or more targeted conditions: amblyopia, strabismus, significant refractive error, or unexplained reduced visual acuity. Each child was tested on both tests by masked examiners, with test order determined randomly. The optotype sizes administered were age-based according to the child's age at school entry on September 1. Children of age 3 were tested with 10/100, 10/32, 10/25, and 10/20 optotypes whereas those who were 4 were tested with 10/100, 10/25, 10/20, and 10/16 optotypes.

RESULTS

Most children (>95%) completed both tests, with no statistically significant differences. Pass/fail cut-offs were set to yield specificities as close as possible to 90%. The largest sensitivity differences observed were in the 3-year-old group (mean age, 45.3 months), where the sensitivity for detection of > or =1 targeted conditions was 61% for the Lea Symbols and was 46% for the HOTV letters (difference 15%, 95% confidence interval: -0.01 to 0.30) and the sensitivity for detection of group 1 conditions was 83% for the Lea Symbols and 57% for the HOTV letters (difference 26%, 95% confidence interval: -0.01 to 0.49). However, neither these differences nor any of the other age group sensitivity differences were statistically significant. For the 3-year-old children, the pass/fail criterion was one line larger for the HOTV letters than for the Lea Symbols.

CONCLUSIONS

Most children completed both tests. Although the 3-year-old children achieved better acuity scores with the Lea Symbols test, there were no statistically significant differences in sensitivity between tests for any age group.

A comparison of Lea Symbol vs ETDRS letter distance visual acuity in a population of young children with a high prevalence of astigmatism

PURPOSE

To compare visual acuity results obtained by use of the Lea Symbols chart with results obtained with Early Treatment Diabetic Retinopathy Study (ETDRS) charts in young children who are members of a population with a high prevalence of astigmatism.

METHODS

Subjects were 438 children ages 5 through 7 years who were enrolled in kindergarten or first grade on the Tohono O'odham Reservation: 241 (55%) had astigmatism >or=1.00 D in one or both eyes (range, 0.00-6.75 D). While wearing best correction, each child had right eye visual acuity tested with the 62 cm by 65 cm Lea Symbols chart at 3 m and with the 62 cm by 65 cm ETDRS chart at 4 m. Visual acuity was scored as the smallest optotype size at which the child correctly identified 3 of a maximum of 5 optotypes. ETDRS visual acuity also was scored based on the total number of letters that the child correctly identified.

RESULTS

Correlation between Lea Symbols visual acuity and ETDRS visual acuity was 0.78 (p < 0.001). Mean Lea Symbols visual acuity was one-half line (0.04-0.06 logMAR) better than mean ETDRS visual acuity (p < 0.001). The difference between Lea Symbols and ETDRS visual acuity was not correlated with the mean of the Lea Symbols and ETDRS visual acuity scores, which ranged from -0.3 logMAR (20/10) to 0.74 logMAR (20/110).

CONCLUSIONS

In this population of young children, in whom the primary source of reduced visual acuity is astigmatism-related amblyopia, the Lea Symbols chart produced visual acuity scores that were about 0.5 line better than visual acuity scores obtained with ETDRS charts.

Prevalence of decreased visual acuity among preschool-aged children in an American urban population: the Baltimore Pediatric Eye Disease Study, methods, and results

OBJECTIVE

To determine the age- and ethnicity-specific prevalence of decreased visual acuity (VA) in white and black preschool-aged children.

DESIGN

Cross-sectional study.

PARTICIPANTS

The Baltimore Pediatric Eye Disease Study is a population-based evaluation of the prevalence of ocular disorders in children 6 through 71 months of age in Baltimore, Maryland, United States. Among 4132 children identified, 3990 eligible children (97%) were enrolled and 2546 children (62%) were examined. This report focuses on 1714 of 2546 examined children (67%) who were 30 through 71 months of age.

METHODS

Field staff identified 63 737 occupied dwelling units in 54 census tracts. Parents or guardians of eligible participants underwent an in-home interview, and eligible children underwent a comprehensive eye examination including optotype visual acuity (VA) testing in children 30 months of age and older, with protocol-specified retesting of children with VA worse than an age-appropriate standard.

MAIN OUTCOME MEASURES

The proportion of children 30 through 71 months of age testable for VA and the proportion with decreased VA as defined by preset criteria.

RESULTS

Visual acuity was testable in 1504 of 1714 children (87.7%) 30 through 71 months of age. It was decreased at the initial test (wearing glasses if brought to the clinic) in both eyes of 7 of 577 white children (1.21%; 95% confidence interval [CI], 0.49-2.50) and 13 of 725 black children (1.79%; 95% CI, 0.95-3.08), a difference that is not statistically significant. Decreased VA in both eyes after retesting was found in 3 of 598 white children (0.50%; 95% CI, 0.10-1.48) and in 8 of 757 black children (1.06%, 95% CI = 0.45, 2.10), also not statistically significantly different. Uncorrected ametropia explained the decreased VA on initial testing in 10 of the 20 children.

CONCLUSIONS

Decreased VA in both eyes of children 30 through 71 months of age at presentation in urban Baltimore was 1.2% among white children and 1.8% among black children. After retesting within 60 days of the initial examination and with children wearing best refractive correction, the rate of decreased VA in both eyes was 0.5% among white children and 1.1% among black children.

The Sonksen logMAR Test of Visual Acuity: I. Testability and reliability

PURPOSE

To develop a standardized logMAR test of visual acuity for young children and establish testability and reliability.

METHODS

Two thousand nine hundred ninety-one children, aged 2 to 8 years 6 months, from a population sample of 4671 were recruited from schools and preschool facilities and tested. Ability to name or match letters, accept occlusion, and achieve binocular single and binocular and monocular measures of linear visual acuity were recorded. Inter- and intratester reliability was assessed for a random selection of 215 children.

RESULTS

Two thousand nine hundred seventy-four (99.4%) matched or named letters, 2966 (99%) achieved binocular single, 2940 (98%) achieved binocular linear, and 2807 (94%) achieved monocular linear (for both eyes) measures. Binocular linear measures were achieved in 50% aged less than 3 years, 80% aged 3 to 3(1/2), 92% aged 3(1/2) to 4, and 99% aged 4 years and over. Binocular linear measures were achieved in 86% of 2- to 3-year-olds and 96% of 3- to 3(1/2)-year-olds who matched or named letters; monocular linear measures were achieved in 86 and 95%, respectively, of these age groups who then accepted occlusion. The median time for completion of the test (binocular and monocular) was 3 minutes 55 seconds. The 95% limits of agreement for the same observer and for different observers were +/-0.13 and -0.19, +0.15 for binocular linear and -0.16, +0.15, and -0.17, +0.13 for monocular linear measures, respectively.

CONCLUSIONS

The Sonksen logMAR Test provides reliable binocular and monocular measures of linear visual acuity in a high proportion of children from the age of 2.5 years.

Sensitivity and specificity of a visual acuity screening protocol performed with the Lea Symbols 15-line folding distance chart in preschool children

PURPOSE

The aim of this study was to assess the feasibility of a visual acuity (VA) test using the Lea Symbols 15-line folding distance chart and its diagnostic validity in detecting VA deficiency in preschool children.

METHODS

A group of 149 children aged 38-54 months underwent VA examination performed with the Lea 15-line folding optotype at a distance of 3 metres, according to a test protocol described in the Methods section. After the VA test, a complete ophthalmological examination, including cycloplegic retinoscopy, a cover test and examination of the anterior and posterior segments, was performed on each child in order to detect any VA-threatening ocular abnormality. The Lea Symbols test's sensitivity, specificity, positive and negative likelihood ratios (LR +, LR -) and the receiver operating characteristic (ROC) curve were calculated by means of standard procedures using each VA level of the chart from 0.1 to 1 (1-0 logMAR) as a cut-off point.

RESULTS

The Lea Symbols test could be successfully used in 95.9% of the population. The most useful cut-off points for screening preschool children were found to be 0.8 (LR + 5.73, LR - 0.05) or 0.63 (LR + 11.7, LR - 0.23).

CONCLUSION

The Lea Symbols test proved to be clinically useful in detecting VA deficiency in preschool children. The choice between the two best performing cut-off levels should be made according to the expected cost-effectiveness of the screening programme.

Visual Acuity in Simple Myopic Astigmatism: Influence of Cylinder Axis

PURPOSE

The relationship between astigmatic refractive errors and their associated visual acuity has been studied in recent years in the context of refractive power space. The influence of the axis of astigmatism remains a matter of controversy. Our goal in this study is to provide additional experimental evidence to clarify this subject. The influence of the simulated axis orientation was compared with other factors that affect visual acuity such as the particular design of the test and the differences between eyes.

METHODS

Simple myopic astigmatism from 0 to -3.00 D, in steps of -0.25 D, and with five different axes between 0 degrees and 90 degrees , were simulated on four healthy eyes of young observers. In each case, visual acuity was recorded for three different tests. Refractions were expressed in the form of vectors and visual acuity was represented as a function of strength.

RESULTS

No significant differences in visual acuity were found for astigmatism of the same power but different axes. In fact, our results show these differences are even less important than those recorded for the same astigmatism induced in different eyes. The highest discrepancies in visual acuity were found when different charts were used to test the same astigmatic error.

CONCLUSIONS

The strength of the vector representing the astigmatic refractive state describes very accurately the performance of visual acuity across simple myopic astigmatic errors. In these cases, visual acuity can be associated with a single refractive parameter. This fact could be useful, especially in statistical studies involving visual performance.

Comparison of the HOTV and Lea symbols visual acuity tests in patients with amblyopia

PURPOSE

To determine whether the Lea symbols visual acuity test, compared with the HOTV visual acuity test, overestimates visual acuity in patients with amblyopia.

PATIENTS AND METHODS

Fifty-nine patients with amblyopia or a history of amblyopia treatment had visual acuity measurements in both eyes with the HOTV and Lea symbols tests. Crowding bars, separated by a width of 1 optotype, and the original pilot-testing protocol in the Amblyopia Treatment Study were used to quantify visual acuity.

RESULTS

The patients' ages ranged from 4 to 35 years (mean age, 10.1 years). Visual acuity in the amblyopic eyes ranged from 20/20 to 20/250. The mean visual acuity difference (HOTV scores vs Lea symbols scores) was -0.056 logMAR units (P < .001), slightly more than half of a line. The negative value indicates that patients performed better on the HOTV test. In nonamblyopic eyes, the mean difference was -0.05 logMAR units (P < .001). Patients with strabismic amblyopia had a mean difference of -0.05 logMAR units (P = .08); those with anisometropic amblyopia had a mean difference of -0.07 logMAR units (P = .002). Patients 8 years and younger had a mean difference of -0.04 logMAR units (P = .05); those older than 8 years had a mean difference of -0.06 logMAR units (P = .002).

CONCLUSIONS

In both amblyopic and nonamblyopic eyes, visual acuity measurements were better on HOTV testing compared with Lea symbols testing. The differences persisted regardless of patient age and the cause and severity of amblyopia. Overestimation of visual acuity by the Lea symbols test was not found.

Amblyopia characterization, treatment, and prophylaxis

Amblyopia has a 1.6-3.6% prevalence, higher in the medically underserved. It is more complex than simply visual acuity loss and the better eye has sub-clinical deficits. Functional limitations appear more extensive and loss of vision in the better eye of amblyopes more prevalent than previously thought. Amblyopia screening and treatment are efficacious, but cost-effectiveness concerns remain. Refractive correction alone may successfully treat anisometropic amblyopia and it, minimal occlusion, and/or catecholamine treatment can provide initial vision improvement that may improve compliance with subsequent long-duration treatment. Atropine penalization appears as effective as occlusion for moderate amblyopia, with limited-day penalization as effective as full-time. Cytidin-5'-diphosphocholine may hold promise as a medical treatment. Interpretation of much of the amblyopia literature is made difficult by: inaccurate visual acuity measurement at initial visit, lack of adequate refractive correction prior to and during treatment, and lack of long-term follow-up results. Successful treatment can be achieved in at most 63-83% of patients. Treatment outcome is a function of initial visual acuity and type of amblyopia, and a reciprocal product of treatment efficacy, duration, and compliance. Age at treatment onset is not predictive of outcome in many studies but detection under versus over 2-3 years of age may be. Multiple screenings prior to that age, and prompt treatment, reduce prevalence. Would a single early cycloplegic photoscreening be as, or more, successful at detection or prediction than the multiple screenings, and more cost-effective? Penalization and occlusion have minimal incidence of reverse amblyopia and/or side-effects, no significant influence on emmetropization, and no consistent effect on sign or size of post-treatment changes in strabismic deviation. There may be a physiologic basis for better age-indifferent outcome than tapped by current treatment methodologies. Infant refractive correction substantially reduces accommodative esotropia and amblyopia incidence without interference with emmetropization. Compensatory prism, alone or post-operatively, and/or minus lens treatment, and/or wide-field fusional amplitude training, may reduce risk of early onset esotropia. Multivariate screening using continuous-scale measurements may be more effective than traditional single-test dichotomous pass/fail measures. Pigmentation may be one parameter because Caucasians are at higher risk for esotropia than non-whites.