The amblyopia treatment study visual acuity testing protocol

General health-related quality of life in preschool children with strabismus or amblyopia

OBJECTIVE

To explore the associations of general health-related quality of life (GHRQOL) with strabismus or amblyopia in preschool children.

DESIGN

Population-based study.

PARTICIPANTS

Sample of children aged 25 to 72 months in the Multi-ethnic Pediatric Eye Disease Study (MEPEDS).

METHODS

The Pediatric Quality of Life Inventory (PedsQL), a measure of GHRQOL, was administered to the parents of the children.

MAIN OUTCOME MEASURES

The PedsQL consists of 4 subscales (physical, emotional, social, and school functioning) and 3 composite scores (physical summary, psychosocial summary, and total). Regression models were used to evaluate the associations of GHRQOL with strabismus (in children 25-72 months) or amblyopia (in children 30-72 months).

RESULTS

Of the 4218 children aged ≥25 months, 121 (2.9%) were diagnosed with strabismus. Significant differences were found in all 3 composite scores between children with and without strabismus, before and after controlling for gender, age, race, family income, systemic health conditions, and prior knowledge of strabismus diagnosis (P<0.05). These differences were present in esotropes, exotropes, children with intermittent strabismus, and children with constant strabismus. A total of 3318 children were aged ≥30 months, and 71 children (2.1%) had amblyopia. There were no significant differences in any PedsQL scores between children with and without amblyopia, even after adjusting for gender, age, race, and family income (P>0.05).

CONCLUSIONS

Strabismus was associated with significantly worse GHRQOL in preschool children. Although we did not find any detectable association between amblyopia and GHRQOL, further study using vision-specific instruments is required to explore the impact of both strabismus and amblyopia on pediatric quality of life.

Laterality of amblyopia

PURPOSE

To determine the frequency of unilateral amblyopia in right versus left eyes among children younger than 18 years.

DESIGN

Analysis of data collected in randomized clinical trials conducted by the Pediatric Eye Disease Investigator Group.

METHODS

The laterality of the amblyopic eye was analyzed in 2635 subjects younger than 18 years who participated in 9 multicenter prospective, randomized treatment trials. Eligibility criteria for these clinical trials included unilateral amblyopia associated with strabismus, anisometropia, or both, with visual acuity between 20/40 and 20/400. Logistic regression was used to assess the association of baseline and demographic factors with the laterality of amblyopia.

RESULTS

Among subjects with anisometropic amblyopia (with or without strabismus), amblyopia was present more often in left than right eyes, with a relative prevalence of 59% in left eyes (95% confidence interval, 57% to 62%; P < .001 from a test of proportion, 50%). However, among subjects with strabismic-only amblyopia, there was no laterality predilection (relative prevalence of 50% in left eyes; 95% confidence interval, 47% to 54%; P = .94).

CONCLUSIONS

Anisometropic amblyopia, with or without strabismus, occurs more often in left eyes than right eyes. This finding of amblyopia laterality may be related to microtropia, sighting dominance, or other forms of ocular dominance; developmental or neurological factors; laterality in the development of refractive error; or a combination thereof.

A pilot study evaluating the use of EyeSpy video game software to perform vision screening in school-aged children

PURPOSE

To compare the vision-screening results of school-aged children tested with EyeSpy software and those of children examined by a pediatric ophthalmologist. We also compared combined results of an electronic visual acuity (EVA) tester and stereopsis testing to the results of a professional eye examination.

METHODS

In this pilot study, all children were tested with an EyeSpy and ETDRS EVA tester, followed by ocular examination including stereopsis assessment and cyclopegic refraction. The order of presentation of the EVA and EyeSpy assessments was assigned randomly. The EyeSpy test was performed twice (with an occlusive eyepatch and red-blue dissociative goggles). EyeSpy registered pass or refer results for visual acuity testing at a threshold of 20/32 visual acuity and stereopsis of 300 arcsec. Similar threshold values were used in the EVA/stereopsis testing.

RESULTS

The average age of 72 subjects was 11.4 +/- 2.2 years. Prevalence of visual impairment was 25 (34.7%) of 72 as reported by the professional examination. The sensitivity, specificity, and conventional positive likelihood ratio were 88%, 87%, and 6.8 when EyeSpy was used with a patch; 88%, 74%, and 3.44 when EyeSpy was used with goggles; and 88%, 94%, and 13.79 for EVA/stereospsis, respectively, compared with the gold-standard professional eye examination. EyeSpy screening results using a patch were not significantly different than those of a professional examination (p = 0.508). The 2 results concurred in 63 (87.5%) of 72 subjects.

CONCLUSIONS

EyeSpy software has potential for use as a vision-screening device. The use of EyeSpy with an occlusive patch outperformed EyeSpy with dissociative glasses.

Impact of confidence number on accuracy of the SureSight Vision Screener

PURPOSE

To assess the relation between the confidence number provided by the Welch Allyn SureSight Vision Screener and screening accuracy, and to determine whether repeated testing to achieve a higher confidence number improves screening accuracy in pre-school children.

METHODS

Lay and nurse screeners screened 1452 children enrolled in the Vision in Preschoolers (VIP) Phase II Study. All children also underwent a comprehensive eye examination. By using statistical comparison of proportions, we examined sensitivity and specificity for detecting any ocular condition targeted for detection in the VIP study and conditions grouped by severity and by type (amblyopia, strabismus, significant refractive error, and unexplained decreased visual acuity) among children who had confidence numbers < or =4 (retest necessary), 5 (retest if possible), > or =6 (acceptable). Among the 687 (47.3%) children who had repeated testing by either lay or nurse screeners because of a low confidence number (<6) for one or both eyes in the initial testing, the same analyses were also conducted to compare results between the initial reading and repeated test reading with the highest confidence number in the same child. These analyses were based on the failure criteria associated with 90% specificity for detecting any VIP condition in VIP Phase II.

RESULTS

A lower confidence number category were associated with higher sensitivity (0.71, 0.65, and 0.59 for < or =4, 5, and > or =6, respectively, p = 0.04) but no statistical difference in specificity (0.85, 0.85, and 0.91, p = 0.07) of detecting any VIP-targeted condition. Children with any VIP-targeted condition were as likely to be detected using the initial confidence number reading as using the higher confidence number reading from repeated testing.

CONCLUSIONS

A higher confidence number obtained during screening with the SureSight Vision Screener is not associated with better screening accuracy. Repeated testing to reach the manufacturer's recommended minimum value is not helpful in pre-school vision screening.

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 randomized trial comparing Bangerter filters and patching for the treatment of moderate amblyopia in children

OBJECTIVE

To determine whether visual acuity improvement with Bangerter filters is similar to improvement with patching as initial therapy for children with moderate amblyopia.

DESIGN

Randomized, clinical trial.

PARTICIPANTS

We enrolled 186 children, 3 to <10 years old, with moderate amblyopia (20/40-20/80).

METHODS

Children were randomly assigned to receive either daily patching or to use a Bangerter filter on the spectacle lens in front of the fellow eye. Study visits were scheduled at 6, 12, 18, and 24 weeks.

MAIN OUTCOME MEASURES

Visual acuity in amblyopic eyes at 24 weeks.

RESULTS

At 24 weeks, amblyopic eye improvement averaged 1.9 lines in the Bangerter group and 2.3 lines in the patching group (difference in mean visual acuities between groups adjusted for baseline acuity = 0.38 line). The upper limit of a 1-sided 95% confidence interval was 0.76 line, which slightly exceeded a prespecified noninferiority limit of <0.75 line. Similar percentages of subjects in each group improved > or =3 lines (Bangerter group 38% vs patching group 35%; P = 0.61) or had > or =20/25 amblyopic eye acuity (36% vs 31%, respectively; P = 0.86). There was a lower treatment burden in the Bangerter group as measured with the Amblyopia Treatment Index. With Bangerter filters, neither a fixation switch to the amblyopic eye nor induced blurring in the fellow eye to worse than that of the amblyopic eye was required for visual acuity improvement.

CONCLUSIONS

Because the average difference in visual acuity improvement between Bangerter filters and patching was less than half a line, and there was lower burden of treatment on the child and family, Bangerter filter treatment is a reasonable option to consider for initial treatment of moderate amblyopia.

The infant aphakia treatment study: design and clinical measures at enrollment

OBJECTIVE

To compare the use of contact lenses and intraocular lenses (IOLs) for the optical correction of unilateral aphakia during infancy.

METHODS

In a randomized, multicenter (12 sites) clinical trial, 114 infants with unilateral congenital cataracts were assigned to undergo cataract surgery with or without IOL implantation. Children randomized to IOL treatment had their residual refractive error corrected with spectacles. Children randomized to no IOL treatment had their aphakia treated with a contact lens.

MAIN OUTCOME MEASURES

Grating acuity at 12 months of age and HOTV visual acuity at 4 1/2 years of age.

APPLICATION TO CLINICAL PRACTICE

This study should determine whether either treatment for an infant with a visually significant unilateral congenital cataract results in a better visual outcome.

RESULTS

Enrollment began December 23, 2004, and was completed January 16, 2009. The median age at the time of cataract surgery was 1.8 months. Fifty patients were 4 to 6 weeks of age at the time of enrollment; 32, 7 weeks to 3 months of age; and the remaining 32, more than 3 to less than 7 months of age. Fifty-seven children were randomized to each treatment group. Eyes with cataracts had shorter axial lengths and steeper corneas on average than the fellow eyes.

CONCLUSIONS

The optimal optical treatment of aphakia in infants is unknown. However, the Infant Aphakia Treatment Study was designed to provide empirical evidence of whether optical treatment with an IOL or a contact lens after unilateral cataract surgery during infancy is associated with a better visual outcome.

Visual acuity norms in pre-school children: the Multi-Ethnic Pediatric Eye Disease Study

PURPOSE

To provide population-based normative data for monocular visual acuity (VA) and interocular differences in VA (IOD) in Black and Hispanic children 30 to 72 months of age without visually significant refractive errors or ophthalmic abnormalities.

METHODS

In a population-based cohort of children in the Multi-Ethnic Pediatric Eye Disease Study, monocular HOTV VA measurements using the Amblyopia Treatment Study protocol were analyzed using continuous and dichotomous outcomes for VA and IOD, after excluding subjects with ophthalmic abnormalities or refractive error.

RESULTS

The analysis cohort consisted of 1722 Black and Hispanic children aged 30 to 72 months. Mean logMAR VA improved with age (p < 0.0001) and male gender (p = 0.0008). The proportion of children achieving VA 20/40 or better was associated with age (p < 0.0001), but not ethnicity or gender, and was 81, 94, 99, and virtually 100% in children aged 30 to 35, 36 to 47, 48 to 59, and 60 to 72 months of age, respectively. The most stringent VA threshold that excluded <5% of normal children was 20/63, 20/50, 20/32, and 20/32 for children aged 30 to 35, 36 to 47, 48 to 59, and 60 to 72 months, respectively. Children attending preschool or daycare achieved VA 20/32 more often than those not attending, after age adjustment (p = 0.01), as did children from higher-income families (p = 0.04). There was no association between mean absolute IOD and age (p = 0.45), ethnicity (p = 0.12), or gender (p = 0.19). The proportion of children with an IOD of 0 to 1 lines was higher in males than females (p = 0.02); it did not vary by age (p = 0.06) or ethnicity (p = 0.17). An IOD of 2 or more lines occurred in 6% of normal children.

CONCLUSIONS

VA test performance in normal pre-school children improves with age. We propose new age-specific thresholds for defining abnormal monocular VA using HOTV optotypes in children between 2 and 5 years of age, for use in screening, clinical practice, and research.

Course of development of global hyperacuity over lifespan

PURPOSE

Global visual integration is fundamental to shape and face recognition. Although the maturation of local visual function, such as resolution acuity, has been well documented, less is known about the changes in global visual function during development and with aging.

METHODS

Two hundred thirty-six normal subjects, ranging in age from 0.25- to 78-years old, participated in the study. Global hyperacuity (detection threshold for radial deformation) was obtained from 300 eyes using either a computerized testing or a chart testing protocol and spatial forced choice (preferential looking for <2.6-year old, pointing for young children, or verbal response for older children and adults). Resolution acuity was also measured. The developmental courses for global hyperacuity and resolution acuity were fit to a 3-segment curve to capture the initial rapid development, followed by a period of stable, adult-level visual function and, finally, the decline in visual function with aging.

RESULTS

Curve fitting revealed that global hyperacuity was 0.25 logMAR at 0.25 years of age, and improved rapidly to -0.56 logMAR at 5.4 years of age but did not reach the mean adult level (-0.86 logMAR) until 21 years of age. Global hyperacuity started to deteriorate from 55 years of age at the rate of 0.035 logMAR per decade. In comparison, resolution acuity reached 0.0 logMAR at 5 years of age, and reached the adult level of -0.1 logMAR at 11 years of age. Resolution acuity also started to decrease from 55 years of age at the rate of 0.058 logMAR per decade.

CONCLUSIONS

Similar to vernier alignment acuity, global hyperacuity improves rapidly during infancy and early childhood but takes longer to reach the adult level than resolution acuity. The delayed maturation of global hyperacuity suggests that further development to refine neural circuitry at the cortical level takes place in the second decade of life.

Prevalence of amblyopia and strabismus in white and African American children aged 6 through 71 months the Baltimore Pediatric Eye Disease Study

OBJECTIVE

To determine the age-specific prevalence of strabismus in white and African American children aged 6 through 71 months and of amblyopia in white and African American children aged 30 through 71 months.

DESIGN

Cross-sectional, population-based study.

PARTICIPANTS

White and African American children aged 6 through 71 months in Baltimore, MD, United States. Among 4132 children identified, 3990 eligible children (97%) were enrolled and 2546 children (62%) were examined.

METHODS

Parents or guardians of eligible participants underwent an in-home interview and were scheduled for a detailed eye examination, including optotype visual acuity and measurement of ocular deviations. Strabismus was defined as a heterotropia at near or distance fixation. Amblyopia was assessed in those children aged 30 through 71 months who were able to perform optotype testing at 3 meters.

MAIN OUTCOME MEASURES

The proportions of children aged 6 through 71 months with strabismus and of children aged 30 through 71 months with amblyopia.

RESULTS

Manifest strabismus was found in 3.3% of white and 2.1% of African American children (relative prevalence [RP], 1.61; 95% confidence interval [CI], 0.97-2.66). Esotropia and exotropia each accounted for close to half of all strabismus in both groups. Only 1 case of strabismus was found among 84 white children 6 through 11 months of age. Rates were higher in children 60 through 71 months of age (5.8% for whites and 2.9% for African Americans [RP, 2.05; 95% CI, 0.79-5.27]). Amblyopia was present in 12 (1.8%) white and 7 (0.8%) African American children (RP, 2.23; 95% CI, 0.88-5.62). Only 1 child had bilateral amblyopia.

CONCLUSIONS

Manifest strabismus affected 1 in 30 white and 1 in 47 African American preschool-aged children. The prevalence of amblyopia was <2% in both whites and African Americans. National population projections suggest that there are approximately 677,000 cases of manifest strabismus among children 6 through 71 months of age and 271 000 cases of amblyopia among children 30 through 71 months of age in the United States.

Testability of vision and refraction in preschoolers: the strabismus, amblyopia, and refractive error study in singaporean children

PURPOSE

To determine the testability of several vision and refraction tests in preschool-aged children.

DESIGN

Population-based study of Chinese preschool-aged children in Singapore.

METHODS

One thousand five hundred and forty-two Singaporean Chinese children aged 6 to 72 months were recruited through door-to-door screening of government-subsidized apartments in Singapore. Trained eye professionals administered all tests, including monocular logarithm of the minimum angle of resolution visual acuity with the Sheridan Gardiner chart, monocular Ishihara color testing (Richmond Products Inc, Albuquerque, New Mexico, USA), biometric measurements using IOLMaster (Carl Zeiss, Jena, Germany), and Randot stereoacuity (Stereo Optical Co, Chicago, Illinois, USA) for children 30 to younger than 72 months. Cycloplegic refraction and keratometry measurements also were determined using a table-mounted autorefractor (Canon Autorefractor RK-F1; Canon, Tokyo, Japan) in children 24 to younger than 72 months.

RESULTS

Testabilities were 84.8% for visual acuity (40.7% for age 30 to < 36 months, 70.8% for age 36 to < 42 months, 86.7% for age 42 to < 48 months, 94.8 for age 48 to < 54 months, 98.6 for age 54 to < 66 months, and 98.7% for age 66 to < 72 months), 81.1% for the Ishihara color test, 82.2% for Randot stereoacuity, 62.2% for table mounted autorefraction, and 91.7% for IOLMaster. All testabilities significantly increased with age (P < .0001). Girls had higher testability rates than boys for the autorefraction and Randot stereoacuity tests (P = .036 and .008, respectively).

CONCLUSIONS

The vision and refraction tests were testable in a high proportion of preschool-aged Chinese Singaporeans. Preschool children in older age groups are likely to complete these tests successfully, with important implications for determining age limits for screening in the community and clinic.

Prevalence and causes of visual impairment in African-American and Hispanic preschool children: the multi-ethnic pediatric eye disease study

PURPOSE

To determine the prevalence and causes of decreased visual acuity (VA) in a population-based study of minority preschool children.

DESIGN

Population-based, cross-sectional study.

PARTICIPANTS

Children 30 to 72 months of age in 44 census tracts in Los Angeles County.

METHODS

A population-based sample of children underwent comprehensive ophthalmic evaluation including monocular VA testing, cover testing, cycloplegic autorefraction, anterior segment and fundus evaluation, and VA retesting with refractive correction. The prevalence and etiology of decreased VA were determined, for both presenting and best-measured VA, and better eye and worse eye.

MAIN OUTCOME MEASURES

Prevalence of decreased presenting and best-measured VA with an identifiable ophthalmic etiology.

RESULTS

Presenting VA was assessed in 3207 children and best-measured VA in 3364 children. Although nearly one third of cases of worse-eye decreased presenting VA were without an identifiable ophthalmic etiology, this proportion decreased with increasing age. Decreased presenting VA that resolved with retesting and was associated with uncorrected refractive error was present in the worse eye of 4.3% of African-American children and 5.3% of Hispanic children, and in the better eye of 1.9% of African-American children and 1.7% of Hispanic children. Decreased best-measured VA that was not immediately correctable with spectacles and that was because of ocular disease, unilateral or bilateral amblyopia, or probable bilateral ametropic amblyopia, was seen in the worse eye of 1.5% of African-American and 1.9% of Hispanic children, and in the better eye of 0.8% of African-American and 0.6% of Hispanic children. Amblyopia related to refractive error was the most common cause.

CONCLUSIONS

More than 5% of African-American and Hispanic preschool children in Los Angeles County have either correctable visual impairment from uncorrected refractive error or visual impairment from amblyopia related to refractive error.

The Multi-Ethnic Pediatric Eye Disease Study: Design and Methods

PURPOSE

To summarize the study design of the Multi-Ethnic Pediatric Eye Disease Study (MEPEDS).

METHODS

The objectives of the MEPEDS are to: (1) estimate age- and ethnicity-specific prevalence of strabismus, amblyopia, and refractive error; (2) evaluate the association of selected risk factors with these ocular disorders; and (3) evaluate the association of ocular conditions on limitations in health-related functional status in a population-based sample of 12,000 children aged 6-72 months from four ethnic groups--African-American, Asian-American, Hispanics/Latinos and non-Hispanic White. Each eligible child undergoes an eye examination, which includes an interview with his/her parent. The interview includes an assessment of demographic, behavioral, biological, and ocular risk factors and health-related functional status. The examination includes fixation preference testing, visual acuity, stereoacuity, axial length measurement, cycloplegic refraction, keratometry, eye alignment, and anterior and posterior segment examination.

Treatment of severe amblyopia with weekend atropine: results from 2 randomized clinical trials

PURPOSE

To determine the effectiveness of weekend atropine for severe amblyopia from strabismus, anisometropia, or both combined among children 3 to 12 years of age.

METHODS

We enrolled children into 2 prospective, randomized multicenter clinical trials of amblyopia therapy. Herein we report the results for severe amblyopia, 20/125 to 20/400. In Trial 1, 60 children 3 to 6 years of age (mean, 4.4 years) were randomized to weekend atropine plus a plano lens or weekend atropine plus full spectacle correction for the sound eye. In Trial 2, 40 children 7 to 12 years of age (mean, 9.3 years) were randomized to weekend atropine or 2 hours of daily patching. The visual acuity outcome was assessed at 18 weeks in Trial 1 and 17 weeks in Trial 2.

RESULTS

In Trial 1, visual acuity improved by an average of 4.5 lines in the atropine plus correction group (95% CI, 3.2-5.8 lines) and 5.1 lines in the atropine plus plano lens group (95% CI, 3.7-6.4 lines). In Trial 2, visual acuity improved by an average of 1.5 lines in the atropine group (95% CI, 0.5-2.5 lines) and 1.8 lines in the patching group (95% CI, 1.1-2.6 lines).

CONCLUSIONS

Weekend atropine can improve visual acuity in children 3 to 12 years of age with severe amblyopia. Improvement may be greater in younger children.

Factors affecting development of motor skills in extremely low birth weight children

PURPOSE

The aim of this study is to analyze the impact of ophthalmic and neonatal factors on motor development in extremely low birth weight (ELBW) children.

METHODS

Sixty-four ELBW children at least 3 years of age were recruited. Visual acuity (VA) was assessed using the Teller acuity cards (TACs) and a letter test, if possible. A validated questionnaire assessing 25 fine (part A) and 20 gross motor (part B) skills was administered to the parents. Data were collected on retinopathy of prematurity (ROP) zone, intraventricular haemorrhage (IVH), length of stay in hospital, and number of days on oxygen.

RESULTS

Abnormal TAC acuity was associated with significantly lower scores on both parts A and B (part A: 21.5 versus 11.8, p < 0.001; part B: 17.5 versus 13.2, p < 0.001). Linear regression demonstrates a significant direct relationship between letter acuity and score A only (p = 0.03, r(2) = 0.179). Neither length of hospital stay, number of days ventilated, nor a history of IVH were associated with score A or B. However, the presence of ROP zone 1 was associated with a lower score A (p = 0.03).

CONCLUSION

In this ELBW cohort VA and ophthalmic factors were the only factors associated with scores of development, particularly fine motor development.

Infantile aperiodic alternating nystagmus

BACKGROUND

This study identifies the clinical and ocular motility characteristics of the periodic and aperiodic forms of infantile alternating nystagmus (IAPAN) and establishes the range of electrophysiological and clinical characteristics while providing clues to its presence and pathophysiology.

METHODS

Seventy-eight patients with ocular oscillations consistent with IAPAN were reported. Outcome variables were: age, follow-up in months, vision, strabismus, other eye and systemic abnormalities, head position, periodicity, cycle and null period duration, foveation time, waveforms, and cycle symmetry.

RESULTS

Age range was 1 to 67 years, 50% had pure periodic and aperiodic forms, 46% had albinism, 26% had binocular acuity of 20/40 or greater, 72% had strabismus, 35% had amblyopia, 31% had other eye disease, 14% had systemic disease, 87% had an anomalous head posture, and 65% had binocular directional asymmetry. The periodic cycle averaged 224 seconds and the aperiodic cycle ranged from 2 to more than 300 seconds. One in three patients with strabismus and nystagmus periodicity had a static head posture.

CONCLUSION

Fifteen percent of the infantile nystagmus syndrome population had either the periodic or aperiodic form. A changing null period is often clinically missed because of long or irregular cycles, decreased acuity, associated strabismus, and either a nonexistent or inconsistent head posture. The changing null period is easier to recognize using eye movement recordings or if the non-preferred eye is occluded and the preferred eye is examined with the head straight and gaze in primary position for at least 5 to 7 minutes. The recognition of this variant has profound treatment implications.

Comparison of the amblyopia treatment study HOTV and the electronic-early treatment of diabetic retinopathy study visual acuity protocols in amblyopic children aged 5 to 11 years

As part of the long-term follow-up of amblyopic children who were enrolled in the Amblyopia Treatment Study, we tested visual acuity in both eyes of 142 patients by using 2 established visual acuity protocols, the Amblyopia Treatment Study HOTV (ATS HOTV) visual acuity protocol and the Electronic-Early Treatment of Diabetic Retinopathy Study (E-ETDRS) protocol, at one of the annual visits. Mean age at the time of testing was 9.0 years (range, 5.6-11.9 years). The ATS-HOTV protocol resulted in a slight mean overestimate of visual acuity relative to the E-ETDRS protocol (0.68 lines for amblyopic eyes; 0.25 lines for fellow eyes). The overestimation occurred primarily when the E-ETDRS visual acuity was poorer than 0.3 logMAR. ATS-HOTV acuity also underestimated interocular visual acuity differences by 0.42 lines. When one uses the ATS-HOTV protocol, it may be wise to exercise caution when interpreting "near-normal" visual acuity or interocular differences as "within normal" because the ATS-HOTV method may have a slight bias toward better performance of amblyopic eyes than E-ETDRS.

The critical period for surgical treatment of dense congenital bilateral cataracts

INTRODUCTION

We examined the critical period for deprivation amblyopia in a cohort of patients with dense bilateral congenital cataracts to investigate the optimum timing for surgical treatment.

METHODS

Thirty-seven infants with dense bilateral congenital cataracts that were extracted by 31 weeks of age were enrolled prospectively. Visual acuity outcome was assessed at >/=5 years of age. We statistically evaluated which of 4 models provided the best fit to the data: (1) no change in visual acuity outcome with delay in surgery, (2) linear decline of outcome with delay, (3) a bilinear model in which a critical age exists after which outcome depends on delay, and (4) a bilinear model in which a critical age exists before which outcome depends on delay. In addition, we reviewed medical records for associated adverse outcomes, including strabismus, nystagmus, secondary membrane formation, and glaucoma.

RESULTS

A bilinear model with a critical age of 14 weeks fit the data better than a linear model (chi(2) = 14.7; p < 0.0006). During weeks 0-14, mean visual acuity decreased by 1 line with each 3 weeks' delay in surgery. From 14 to 31 weeks, visual acuity was independent the subject's age at surgery, averaging 20/80. Surgery after 4 weeks was associated with a greater prevalence of strabismus and nystagmus than surgery before 4 weeks, whereas surgery during the first 4 weeks was associated with a greater prevalence of secondary membrane formation and glaucoma.

CONCLUSIONS

We did not find a latent period for the treatment of children with dense bilateral congenital cataracts. Deprivation amblyopia may be minimized with early surgery for bilateral cataracts.

The visual status of children ages 3 to 6 years in the vision screening program in Taiwan

PURPOSE

To investigate the current status of myopia, amblyopia, and strabismus of preschoolers in Taiwan.

METHODS

The records of a vision screening performed in 2005 at 4 preschools by a tertiary referral medical center in Kaohsiung, Taiwan were reviewed. Cycloplegic refraction, visual acuity by E chart, stereopsis by Titmus and National Taiwan University tests, and ocular alignment were analyzed.

RESULTS

Most (97.7%) of the children (n = 618) were able to perform visual acuity testing. There was good correlation between the results of cycloplegic spherical equivalent obtained by autorefraction and by retinoscopy (r = 0.934, p < 0.001). The prevalence of amblyopia was about 5%. A trend was found between amblyopia morbidity and the 4 age groups when a single criterion (best-corrected visual acuity <0.7) was used for all ages (decreased amblyopia incidence with increased age; p = 0.028, chi(2) test for trend). The prevalence of myopia was 3.0%, 4.2%, 4.7%, and 12.2% at ages 3, 4, 5, and 6 years, respectively. There was a trend of increased myopia with increased age (p = 0.021, chi(2) test for trend).

CONCLUSIONS

The prevalence of myopia in children ages 3 to 6 years in Taiwan was high compared with the prevalence in other countries. Criteria for amblyopia based on age difference and on the types of visual acuity test are recommended.

Further validation of the Amblyopia Treatment Index parental questionnaire

BACKGROUND

The Amblyopia Treatment Index (ATI) is a parental questionnaire that has been used to assess the impact of patching or atropine treatment on the child and family in several amblyopia treatment studies. The 18-item parental questionnaire was designed with versions for treatment with patching or atropine. We pooled data across studies to further evaluate the validity of the ATI, to further assess the presence or absence of factors (subscales).

METHODS

A parent or guardian completed the ATI for 794 children who participated in 1 of 4 randomized clinical trials. Internal consistency reliability was assessed with Cronbach's alpha, and factor analysis was performed.

RESULTS

The ATI demonstrated high internal consistency reliability, with a Cronbach's alpha of 0.88 (95% CL = 0.87, 0.89). Factor analysis revealed the same 3 minimally overlapping factors found in the original validation study, which were again labeled "adverse effects," "treatment compliance," and "social stigma." Two of the 18 items did not load with any factor and could reasonably be omitted from future ATI administrations.

CONCLUSIONS

The ATI is a useful instrument for assessing the impact of patching or atropine treatment on the child and family.

Fixation preference and visual acuity testing in a population-based cohort of preschool children with amblyopia risk factors

PURPOSE

To compare the clinical assessment of fixation preference (FP) to visual acuity (VA) in a population-based sample of preschool children with amblyopia risk factors.

DESIGN

Evaluation of diagnostic test in a population-based study.

PARTICIPANTS

243 children with anisometropia and/or strabismus, aged 30 to 72 months, living in Los Angeles County, CA [corrected]

METHODS

Before measuring VA, FP testing was performed at near and usually without correction, using the binocular fixation pattern in children with strabismus >10 prism diopters (Delta), or the induced tropia test for children with strabismus <or=10Delta or without strabismus. We determined the sensitivity and specificity of FP testing for predicting unilateral amblyopia, defined by optotype VA, among children with amblyopia risk factors.

MAIN OUTCOME MEASURE

Grade of FP.

RESULTS

Sensitivity of FP testing for amblyopia among children with anisometropia was 20% (9/44) and specificity was 94% (102/109). Among strabismic children, sensitivity was 69% (9/13; worse in children 30-47 than 48-72 months old) and specificity was 79% (70/89), with similar findings for esotropia and exotropia.

CONCLUSION

The ability of FP testing to correctly identify amblyopia in preschool children with amblyopia risk factors is poor. Clinicians should be wary of using FP as a surrogate measure of interocular difference in VA in young children.

FINANCIAL DISCLOSURE(S)

The authors have no proprietary or commercial interest in any materials discussed in this article.

Lack of concordance between fixation preference and HOTV optotype visual acuity in preschool children: the Baltimore Pediatric Eye Disease Study

OBJECTIVE

To compare the results of fixation preference testing and standardized visual acuity testing in white and black children aged 30 through 71 months.

DESIGN

Cross-sectional study.

PARTICIPANTS

The Baltimore Pediatric Eye Disease Study is a population-based evaluation of the prevalence of vision disorders in children aged 6 through 71 months in Baltimore, Maryland, United States. A total 1714 children 30 through 71 months of age were eligible for inclusion in this report, with 1435 (83.7%) testable by both fixation preference and Amblyopia Treatment Study (ATS) visual acuity testing protocol.

METHODS

The vision of all children 30 through 71 months of age was tested using both the ATS visual acuity testing protocol (using single HOTV symbols with surround bars) and fixation preference testing (FPT).

MAIN OUTCOME MEASURES

The ability of fixation preference testing to identify children with clinically important interocular differences (IOD) in visual acuity (i.e., two or more logarithm of minimum angle of resolution units of difference or more).

RESULTS

Fifty-three children had 2 or more lines of IOD in visual acuity. Seven of them were graded as having momentary or no fixation (sensitivity = 13.2%; 95% confidence interval [CI], 5.3-27.2]), whereas 45 were graded as normal by FPT. In all 7 of the cases of poor FPT, the better-seeing eye was preferred. Low sensitivity and high specificity for detecting an IOD of 2 lines or more with FPT were seen for both white (33.3% sensitivity; 95% CI, 9.5-57.2; 99.6% specificity; 95% CI, 98.7-100) and black (6.5% sensitivity; 95% CI, 0.6, 23.2; 99.3% specificity; 95% CI, 98.3-99.8) children. When assessing FPT performance for 3 or more lines of IOD, only 5 of the 20 children (sensitivity, 25%; 95% CI, 6.0-44.0) had FPT grades of momentary or no fixation.

CONCLUSIONS

Fixation preference testing, when used as part of a population-based research project, does not identify accurately preschool children with 2 lines or more of IOD in presenting visual acuity. The clinical value of this test is poor and its use for diagnosis and monitoring interventions should be reconsidered.

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.

A randomized trial of near versus distance activities while patching for amblyopia in children aged 3 to less than 7 years

PURPOSE

To determine whether performing near activities while patching for amblyopia enhances improvement in visual acuity.

DESIGN

Randomized clinical trial.

PARTICIPANTS

A total of 425 children, aged 3 to <7 years, with amblyopia (20/40-20/400) that was caused by anisometropia, strabismus, or both, and that persisted after treatment with spectacles.

METHODS

Children were randomized to 2 hours of patching per day with near activities or 2 hours of patching per day with distance activities. Instruction sheets describing common near and distance activities were given to the parents. Study visits were scheduled at 2, 5, 8, and 17 weeks. In weeks without a visit, weekly telephone calls were made to the parent to monitor and encourage compliance during the first 8 weeks.

MAIN OUTCOME MEASURE

Masked assessment of visual acuity by isolated crowded HOTV optotypes at 8 weeks.

RESULTS

At 8 weeks, improvement in amblyopic eye visual acuity averaged 2.6 lines in the distance activities group and 2.5 lines in the near activities group (mean difference in acuity between groups, adjusted for baseline acuity, 0.0 lines 95% confidence interval, -0.3 to 0.3). The 2 groups also appeared statistically similar at the 2-, 5-, and 17-week visits. At the 17-week examination, children with severe amblyopia improved a mean of 3.6 lines with 2 hours of daily patching.

CONCLUSIONS

Performing common near activities does not improve visual acuity outcome when treating anisometropic, strabismic, or combined amblyopia with 2 hours of daily patching. Children with severe amblyopia may respond to 2 hours of daily patching.

A randomized trial of atropine vs patching for treatment of moderate amblyopia: follow-up at age 10 years

OBJECTIVE

To determine the visual acuity outcome at age 10 years for children younger than 7 years when enrolled in a treatment trial for moderate amblyopia.

METHODS

In a multicenter clinical trial, 419 children with amblyopia (visual acuity, 20/40-20/100) were randomized to patching or atropine eyedrops for 6 months. Two years after enrollment, a subgroup of 188 children entered long-term follow-up. Treatment after 6 months was at the discretion of the investigator; 89% of children were treated.

MAIN OUTCOME MEASURE

Visual acuity at age 10 years with the electronic Early Treatment Diabetic Retinopathy Study test.

APPLICATION TO CLINICAL PRACTICE

Patching and atropine eyedrops produce comparable improvement in visual acuity that is maintained through age 10 years.

RESULTS

The mean amblyopic eye acuity, measured in 169 patients, at age 10 years was 0.17 logMAR (logarithm of the minimum angle of resolution) (approximately 20/32), and 46% of amblyopic eyes had an acuity of 20/25 or better. Age younger than 5 years at entry into the randomized trial was associated with a better visual acuity outcome (P < .001). Mean amblyopic and sound eye visual acuities at age 10 years were similar in the original treatment groups (P = .56 and P = .80, respectively).

CONCLUSIONS

At age 10 years, the improvement of the amblyopic eye is maintained, although residual amblyopia is common after treatment initiated at age 3 years to younger than 7 years. The outcome is similar regardless of initial treatment with atropine or patching.

Results of ocular dominance testing depend on assessment method

PURPOSE

We developed a near ocular dominance test modeled after the distance hole-in-the-card test and assessed both test-retest reliability of four tests of ocular dominance and agreement between tests.

METHODS

Forty-six subjects aged 18 to 78 years with visual acuity 20/40 or better in each eye were enrolled from a primary care practice. All subjects had normal eye examinations, with the exception of refractive error, and were examined in their habitual correction. Subjects were tested twice each with the distance hole-in-the-card test, new near hole-in-the-card test, near convergence test, and the Pediatric Eye Disease Investigator Group fixation preference test.

RESULTS

There was excellent test-retest reliability for each ocular dominance test. Nevertheless, there was only moderate to slight agreement between each possible pairing of tests.

CONCLUSIONS

Results of ocular dominance tests vary depending on both the testing distance and the specific activity performed as part of the testing procedure.

Normative pediatric visual acuity using single surrounded HOTV optotypes on the Electronic Visual Acuity Tester following the Amblyopia Treatment Study protocol

PURPOSE

To provide normative pediatric visual acuity data using HOTV optotypes presented on the Electronic Visual Acuity Tester following the Amblyopia Treatment Study (ATS) protocol.

METHODS

Monocular testing was conducted on 384 healthy full-term children ranging from 3 to 10 years of age (mean, 5.4 years; SD, 1.8 years). A total of 373 children completed monocular testing of each eye. In addition, 23 adults (mean, 28.7 years; SD, 4.9 years) were tested for comparison. Both monocular visual acuity and interocular acuity differences were recorded.

RESULTS

Mean visual acuity improved by slightly more than one line (0.12 logMAR) from 3 years of age to adulthood, increasing from 0.08 logMAR to -0.04 logMAR (F(6,400) = 26.3, p < 2.0 x 10(-26)). At all ages, mean interocular acuity difference was less than one line on a standard acuity chart (overall mean difference = 0.04 logMAR; SD, 0.06 logMAR).

CONCLUSIONS

These results represent the first normative data reported for HOTV optotypes using the ATS protocol on the Electronic Visual Acuity Tester. These data may play an important role in clinical practice, screening, and clinical research.

The Sonksen logMAR test of visual acuity: II. Age norms from 2 years 9 months to 8 years

PURPOSE

To establish age norms and interocular differences in visual acuity between 2 years 9 months and 8 years for the Sonksen logMAR Test.

METHODS

Cross-sectional population-based study. Binocular measures of linear visual acuity were achieved in 2,940 children and monocular measures were achieved in 2,820 right eyes and 2,821 left eyes, respectively. Measures for both right and left eyes were achieved by 2,807. Asymmetric logistic models were used to construct smoothly changing age-related centile curves showing how visual acuity changes with age in a normative population sample.

RESULTS

All curves demonstrated an increase in visual acuity with age that was steepest between 2 years 9 months and 5 years 3 months. Equivalent centiles for linear visual acuity were better when viewed binocularly than monocularly; the difference was least between the 95th centiles (best levels) and greatest between the 5th centiles (worst levels). There were no clinically significant differences between group measures of visual acuity from right and left eyes-average within child difference 0.0095 logMAR units, 95% CI, 0.0059-0.013. Interocular differences did not vary significantly with age (p = 0.73). The 90th and 95th centiles for interocular difference were 0.125 and 0.175 log units, respectively.

CONCLUSIONS

This study demonstrates how visual acuity varied with age for the Sonksen logMAR Test and presents the findings in the clinically useful format of centile charts.

Predicting long-term visual outcome in children with birth weight under 1001 g

PURPOSE

To examine the visual acuity development of extremely low birth weight children and to determine factors that are predictive of long-term outcome.

METHODS

This is a prospective observational longitudinal cohort study of children with birth weight less than 1001 g. One hundred thirty-nine children were recruited. Retinopathy of prematurity (ROP) examinations were graded according to the International Classification for ROP. Grating acuity was assessed monocularly with Teller acuity cards. All children were assessed before 24 months corrected age; 123 of the cohort had a grating acuity assessment at over 3 years. For the children who were capable, an assessment of recognition acuity was measured with the Electronic Visual Acuity system.

RESULTS

Data are presented for the right eye and the ages reported are adjusted for prematurity to allow comparison with normative data. Initial grating acuity was compared with the late grating and recognition acuity, but in both cases analysis showed no statistically significant association. However, the relative risk analysis showed that, if the slope was abnormal, there was a 5.5 times higher risk of abnormal recognition acuity. Eyes with zone 1 disease were associated with a worse visual acuity outcome, but zone 1 disease also occurred more frequently in children with lower birth weight and gestational age.

CONCLUSIONS

Early measurements of visual acuity may be misleading in terms of the visual prognosis. The factor that was most predictive of a poor late visual acuity outcome was the rate of development, as calculated by the slope of the early visual acuity measurements.

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.

Visual acuity testability in African-American and Hispanic children: the multi-ethnic pediatric eye disease study

PURPOSE

To compare the age- and gender-specific testability rates for the Amblyopia Treatment Study (ATS) HOTV visual acuity testing protocol using the electronic visual acuity (EVA) tester in African-American and Hispanic preschool children.

DESIGN

Population-based, cross-sectional study.

METHODS

Measurement of presenting monocular distance visual acuity using the ATS HOTV protocol was attempted in all African-American and Hispanic children aged 30 to 72 months from the population-based Multi-Ethnic Pediatric Eye Disease Study (MEPEDS). Children able to be tested monocularly in both eyes were considered able. Age-, gender-, and ethnicity-specific testability rates were calculated. Comparisons of testability among different groups were performed using Chi-square analyses and the Cochran trend test.

RESULTS

Testing was attempted on 3,126 children (1,471 African-American, 1,655 Hispanic; 50% female). Overall, 84% (83% African-American, 85% Hispanic; 86% female, 82% male) were testable. Older children were more likely to complete testing successfully than younger children (P < .0001). Age-specific testability in children 30 to 36 months of age, 37 to 48 months of age, 49 to 60 months of age, and 61 to 72 months of age was 39%, 84%, 98%, and 100%, respectively. After stratifying by age, there were no ethnicity-related differences in children testable (P = .12). Girls (86%) were slightly more likely to be testable than boys (82%; P > .003).

CONCLUSIONS

Monocular threshold visual acuity testing using the ATS HOTV protocol on the EVA tester (Jaeb Center for Health Research, Tampa, Florida, USA) can be completed by most African-American and Hispanic preschool children, particularly those older than 36 months of age. This protocol therefore may be used in minority preschool children as an integral part of the diagnosis and management of amblyopia and other forms of visual impairment.

Prevalence of amblyopia and strabismus in African American and Hispanic children ages 6 to 72 months the multi-ethnic pediatric eye disease study

OBJECTIVE

To determine the age- and ethnicity-specific prevalences of strabismus in African American and Hispanic/Latino children ages 6 to 72 months and of amblyopia in African American and Hispanic/Latino children 30 to 72 months.

DESIGN

Cross-sectional study.

PARTICIPANTS

The Multi-ethnic Pediatric Eye Disease Study is a population-based evaluation of the prevalence of vision disorders in children ages 6 to 72 months in Los Angeles County, California. A comprehensive eye examination was completed by 77% of eligible children. This report focuses on results from 3007 African American and 3007 Hispanic/Latino children.

METHODS

Eligible children in all enumerated households in 44 census tracts were identified. Participants underwent an in-home interview and were scheduled for a comprehensive eye examination and in-clinic interview. The examination included evaluation of ocular alignment, refractive error, and ocular structures, as well as determination of optotype visual acuity (VA) in children 30 months and older.

MAIN OUTCOME MEASURES

The proportion of 6- to 72-month-olds with strabismus on ocular examination and proportion of 30- to 72-month-olds with optotype VA deficits and amblyopia risk factors consistent with predetermined definitions of amblyopia.

RESULTS

Strabismus was detected in 2.4% of Hispanic/Latino children and 2.5% of African American children (P = 0.81), and was more prevalent in older children than in younger children. Amblyopia was detected in 2.6% of Hispanic/Latino children and 1.5% of African American children, a statistically significant difference (P = 0.02), and 78% of cases of amblyopia were attributable to refractive error. Amblyopia prevalence did not vary with age.

CONCLUSIONS

Among Hispanic/Latino and African American children in Los Angeles County, strabismus prevalence increases with age, but amblyopia prevalence appears stable by 3 years of age. Amblyopia is usually caused by abnormal refractive error. These findings may help to optimize the timing and modality of preschool vision screening programs.

Treatment of bilateral refractive amblyopia in children three to less than 10 years of age

PURPOSE

To determine the amount and time course of binocular visual acuity improvement during treatment of bilateral refractive amblyopia in children three to less than 10 years of age.

DESIGN

Prospective, multicenter, noncomparative intervention.

METHODS

One hundred and thirteen children (mean age, 5.1 years) with previously untreated bilateral refractive amblyopia were enrolled at 27 community- and university-based sites and were provided with optimal spectacle correction. Bilateral refractive amblyopia was defined as 20/40 to 20/400 best-corrected binocular visual acuity in the presence of 4.00 diopters (D) or more of hypermetropia by spherical equivalent, 2.00 D or more of astigmatism, or both in each eye. Best-corrected binocular and monocular visual acuities were measured at baseline and at five, 13, 26, and 52 weeks. The primary study outcome was binocular acuity at one year.

RESULTS

Mean binocular visual acuity improved from 0.50 logarithm of the minimum angle of resolution (logMAR) units (20/63) at baseline to 0.11 logMAR units (20/25) at one year (mean improvement, 3.9 lines; 95% confidence interval [CI], 3.5 to 4.2). Mean improvement at one year for the 84 children with baseline binocular acuity of 20/40 to 20/80 was 3.4 lines (95% CI, 3.2 to 3.7) and for the 16 children with baseline binocular acuity of 20/100 to 20/320 was 6.3 lines (95% CI, 5.1 to 7.5). The cumulative probability of binocular visual acuity of 20/25 or better was 21% at five weeks, 46% at 13 weeks, 59% at 26 weeks, and 74% at 52 weeks.

CONCLUSIONS

Treatment of bilateral refractive amblyopia with spectacle correction improves binocular visual acuity in children three to less than 10 years of age, with most improving to 20/25 or better within one year.

Treatment of strabismic amblyopia with refractive correction

PURPOSE

To report data on the response of previously untreated strabismic amblyopia to spectacle correction.

DESIGN

Prospective, interventional case series.

METHODS

Twelve patients with previously untreated strabismic amblyopia were prescribed spectacles and examined at five-week intervals until visual acuity was not improved from the prior visit.

RESULTS

Amblyopic eye acuity improved by 2 lines or more from spectacle-corrected baseline acuity in nine of the 12 patients (75%), resolving in three (interocular difference <or=1 line). Mean change from baseline to maximum improvement was 2.2 +/- 1.8 lines. Improvement continued for up to 25 weeks.

CONCLUSIONS

These results support the suggestion from a prior study that strabismic amblyopia can improve and even resolve with spectacle correction alone. Larger studies with concurrent controls are needed to confirm or refute these findings.

Reliability of three different visual acuity testing procedures in school children

AIM

To evaluate the usability and reliability of three different visual acuity (VA) testing procedures using Landolt C's in 8 positions with a semi-automated computer program in school children.

METHODS

100 school children (median 7 years, 59 boys and 41 girls) were included; only the better eye was tested. We used the semi-automated computer program CORVIS.VT in a forced choice method. Three different test strategies were employed, each two times: A) DIN, B) Standard-Staircase and C) Best-PEST procedure with sequences A, B, C or A, C, B.

RESULTS

Average testing time was 100 s +/- 45 (DIN), 59 s +/- 36 (Staircase) and 77 s +/- 25 (Best-PEST). The mean VA estimated with DIN was equivalent to that with the Best-PEST procedure. However, the mean VA with Standard-Staircase was one line less. In DIN, 76% of the retest scores were within 0.1 logMAR unit of the initial test score (Staircase: 72%, Best-PEST 73%). The 95% confidence interval of test-retest reliability was calculated to be -0.05 +/- 0.24 logMAR in DIN, +0.02 +/- 0.32 logMAR in Staircase, and 0.00 +/- 0.29 logMAR in Best-PEST.

CONCLUSION

A high percentage of children aged 6 to 9 years (98%) can be tested with Landolt C's (8 positions). We found a decreasing test-retest reliability starting from DIN via Best-PEST to Staircase in this configuration.

Emergency management of corneal injuries

Corneal injuries account for a significant proportion of the ophthalmic workload of most emergency departments. Although the vast majority of cases are relatively minor, accurate diagnosis and appropriate management are vital to prevent potentially sight-threatening sequelae. We present a survey of corneal injury cases at a general emergency department.

INTRODUCTION

Corneal injuries are very common in both the adult and paediatric population and account for a significant proportion of the workload of most emergency departments. This survey assesses management of corneal injury cases at a general emergency department.

MATERIALS AND METHODS

A retrospective case study was performed of 100 patients consecutively diagnosed with a corneal abrasion by slit lamp examination at the emergency department of the Chelsea and Westminster Hospital, London. Each case was assessed to determine documentation of set criteria including visual acuity (VA), treatment and grade of examiner.

RESULTS

The commonest cause of injury was direct minor trauma (64% of cases) with contact lens related problems accounting for 12% of presentations. VA was documented correctly in 85 adult patients (90.4% of adults), incorrectly in 2 cases, and not documented at all in 7 adults (7.4%). VA was not recorded in paediatric cases. All cases were treated with topical chloramphenicol drops although frequency of treatment ranged from 2 to 5 times daily and duration of treatment ranged between 3 and 5 days and for 7 days. 6 cases (6%) were assessed by an emergency nurse practitioner and the remaining number were seen by a casualty officer.

DISCUSSION

VA must be accurately documented in all adult cases and should be documented in children of school age. A pinhole test should be performed in cases where VA is below 6/9. For analgesia, the use of topical nonsteroidal anti-inflammatory drugs, lubricants and bandage contact lens should be considered. Emergency nurse practitioners and general practitioners are ideally placed to follow-up uncomplicated cases.

Visual acuity and cognitive outcomes at 4 years of age in a double-blind, randomized trial of long-chain polyunsaturated fatty acid-supplemented infant formula

BACKGROUND

While there is a large body of data on the effects of long-chain polyunsaturated fatty acid supplementation of infant formula on visual and cognitive maturation during infancy, longterm visual and cognitive outcome data from randomized trials are scarce.

AIM

To evaluate docosahexaenoic acid (DHA) and arachidonic acid (ARA)-supplementation of infant formula on visual and cognitive outcomes at 4 years of age.

METHODS

Fifty-two of 79 healthy term infants who were enrolled in a single-center, double-blind, randomized clinical trial of DHA and ARA supplementation of infant formula were available for follow-up at 4 years of age. In addition, 32 breast-fed infants served as a "gold standard". Outcome measures were visual acuity and the Wechsler Preschool and Primary Scale of Intelligence--Revised.

RESULTS

At 4 years, the control formula group had poorer visual acuity than the breast-fed group; the DHA- and DHA+ARA-supplemented groups did not differ significantly from the breast-fed group. The control formula and DHA-supplemented groups had Verbal IQ scores poorer than the breast-fed group.

CONCLUSION

DHA and ARA-supplementation of infant formula supports visual acuity and IQ maturation similar to that of breast-fed infants.

New tests of distance stereoacuity and their role in evaluating intermittent exotropia

PURPOSE

Poor control of intermittent exotropia has been considered an indication for surgical intervention, and poor distance stereoacuity may be an indicator of poor control. Two new measures of distance stereoacuity, the Frisby-Davis Distance test (FD2) and Distance Randot test (DR), both of which have been validated in normal and strabismic subjects, were evaluated, and we compared stereoacuity with scores on a recently described control scale.

DESIGN

Prospective case series.

PARTICIPANTS

Twenty-five consecutive patients with intermittent exotropia.

METHODS

Office-based control was graded at distance and near on a 0 to 5 scale, and distance control ranged from 1 (recovery in 1-5 seconds after monocular occlusion) to 4 (>50% spontaneously tropic). Stereoacuity was measured using the FD2 and DR at distance and the Preschool Randot and Frisby tests at near.

MAIN OUTCOME MEASURE

Distance stereoacuity measured using the FD2 and DR.

RESULTS

Measurable distance stereoacuity thresholds in intermittent exotropia were poor with the DR and excellent with the FD2 (medians, nil and 40''; P<0.0001). Near stereoacuity was excellent with both the Preschool Randot and Frisby (medians, 60'' and 60''; P = 0.99). There was poor correlation between distance control score and either FD2 (r(s) = 0.1, P = 0.6) or DR (r(s) = 0.3, P = 0.2). Control scores correlated with magnitude of deviation at distance (r(s) = 0.5, P = 0.02) and near (r(s) = 0.5, P = 0.01).

CONCLUSIONS

The real-world contour-based targets of the new distance FD2 appear to stimulate fusion in intermittent exotropia, even when distance control is poor. In contrast, the new Polaroid vectograph-based DR is very sensitive to disturbances of binocularity. Two new distance stereoacuity tests appear sensitive to opposite ends of the intermittent exotropia spectrum; FD2 performance deteriorates when the patient is constantly tropic, whereas DR performance deteriorates at the earliest stages of intermittency.

Recurrence of amblyopia after occlusion therapy

PURPOSE

To determine the stability of visual acuity (VA) after a standardized occlusion regimen in children with strabismic and/or anisometropic amblyopia.

DESIGN

Retrospective, population-based, consecutive observational case series.

PARTICIPANTS

Four hundred forty-nine patients younger than 10 years who underwent an occlusion trial for amblyopia and were observed until there was a recurrence of amblyopia or for a maximum of 1 year after decrease or cessation of occlusion therapy.

METHODS

We performed a retrospective chart review of all patients treated by occlusion therapy for strabismic and/or anisometropic amblyopia at our institution over a 34-year period. Of the 1621 patients identified in our database, 449 met the eligibility criteria and were included in this study. Patients having at least a 2 logarithm of the minimum angle of resolution (logMAR)-level improvement in VA by optotypes or a change from unmaintained to maintained fixation preference during the course of occlusion therapy were included. A recurrence of amblyopia was defined as > or =2 logMAR levels of VA reduction or reversal of fixation preference within 1 year after a decrease or cessation of occlusion therapy.

MAIN OUTCOME MEASURE

Recurrence of amblyopia after a decrease or cessation of occlusion therapy and its relationship with patient age and VA of the amblyopic eye at the time of decrease or cessation of occlusion therapy.

RESULTS

Of 653 occlusion trials, 179 (27%) resulted in recurrence of amblyopia. The recurrence was found to be inversely correlated with patient age. There was no statistically significant association between the recurrence of amblyopia and VA of the amblyopic eye at the end of maximal occlusion therapy.

CONCLUSIONS

There is a clinically important risk of amblyopia recurrence when occlusion therapy is decreased before the age of 10 years. The risk of recurrence is inversely correlated with age (P<0.0001).

Assessment of a new Distance Randot stereoacuity test

PURPOSE

We sought to develop a new "Distance Randot" test, establish a normative data set for children and adults, and compare with established measures of stereoacuity.

METHODS

Distance Randot, distance Frisby-Davis 2 (FD2), and near Preschool Randot stereoacuity (Stereo Optical Co., Inc., Chicago, IL) were assessed in 23 normal children (ages 4-14 years), 21 normal adults (ages 20-36 years), and 131 patients with a variety of strabismic conditions (ages 4-85 years). For each test, stereoacuity was defined as the smallest disparity in which 2 targets were correctly identified. The simultaneous prism and cover test (SPCT) and the alternate prism and cover test (APCT) were used to assess misalignment.

RESULTS

For the new Distance Randot test, normative results were similar to published data obtained with established near and distance stereoacuity tests. In the patient cohort, comparing stereoacuity data obtained from Distance Randot stereoacuity test and the Near Preschool Randot stereoacuity test, most of the patients with discordant scores had poorer distance than near stereoacuity. Comparing the Distance Randot stereoacuity test and the Distance FD2, all of the patients with discordant scores had poorer Distance Randot than FD2 scores.

CONCLUSIONS

Distance Randot test is more likely to detect abnormalities in distance stereopsis and may provide a useful tool in measuring distance stereoacuity in patients with and without strabismus. However, further studies are needed to define the efficacy of the Distance Randot test in monitoring progression specific conditions such as intermittent exotropia, where it may prove useful as a guide to the timing of intervention.

Long-term motor and sensory outcomes after early surgery for infantile esotropia

PURPOSE

The proper timing of surgery for infantile esotropia remains controversial. Early surgery may yield better sensory outcomes whereas later surgery may result in better alignment. Several recent studies reported promising sensory outcomes in small groups of children that underwent surgery by 6 months of age. Here, we present motor and sensory outcomes of a cohort of 50 consecutive children enrolled in a prospective study who had surgery by 6 months of age and were followed for 4-17 years.

METHODS

Angle of deviation, subsequent surgeries, treatment with spectacles, amblyopia, fusion, and stereopsis were evaluated during follow-up. Outcomes from the early surgery group were compared with a concurrently recruited cohort who had surgery at 7-12 months (n=78).

RESULTS

On the initial visit, both cohorts had the same median angle of deviation (45(Delta)) and similar refractive error; the median angle of deviation increased by the final preop visit (55(Delta)). Postoperatively, both cohorts had alignment within 6(Delta) in 83-94% of cases on all visits. Both cohorts had similar rates of additional surgery, and 44-48% wore hyperopic correction postoperatively. Compared with the 7- to 12-month cohort, more children in the early-surgery cohort had peripheral fusion (78% vs 61%; p < 0.02), central fusion (15% vs 2%; p < 0.01), Randot stereopsis (38% vs 16%; p < 0.003), and Randot stereoacuity of 200 seconds or better (20% vs 9%; p < 0.05).

CONCLUSIONS

Early surgery was associated with a higher prevalence of fusion and stereopsis, without adverse motor outcomes.

Clinical and electrophysiological effects of extraocular muscle surgery on patients with Infantile Nystagmus Syndrome (INS)

The purpose of this report is to summarize clinical and electrophysiological effects of extraocular muscle surgery in patients with INS. Our hypothesis is that surgery on the extraocular muscles of patients with INS changes their nystagmus resulting in improved vision and visual functions. All patients had all four virgin horizontal recti operated on, either for strabismus alone, nystagmus alone, for a head posture due to an eccentric null zone alone or for a head posture due to an eccentric null zone plus strabismus. All patients have been followed for at least 12 months. Subjective outcome measures include the pre- and post-operative binocular best optically corrected null zone acuity (NZA) in 75 patients and gaze dependent acuity (GDA) in 12 patients. Objective outcome measure included null zone width (NZW) in 75 patients. The results are summarized as follows: NZA increased .1 LogMar or greater in 75% with those patients <or=8 years significantly better. Subjective GDA and NZW measured from eye movement recordings showed persistent, significant increases. This report adds to the evidence that surgery on the extraocular muscles in patients with INS has independent neurological and visual results, from simply reposition the head, eye(s) or visual axis.

Treatment of anisometropic amblyopia in children with refractive correction

OBJECTIVE

To evaluate the effectiveness of refractive correction alone for the treatment of untreated anisometropic amblyopia in children 3 to <7 years old.

DESIGN

Prospective, multicenter, noncomparative intervention.

PARTICIPANTS

Eighty-four children 3 to <7 years old with untreated anisometropic amblyopia ranging from 20/40 to 20/250.

METHODS

Optimal refractive correction was provided, and visual acuity (VA) was measured with the new spectacle correction at baseline and at 5-week intervals until VA stabilized or amblyopia resolved.

MAIN OUTCOME MEASURES

Maximum improvement in best-corrected VA in the amblyopic eye and proportion of children whose amblyopia resolved (interocular difference of < or =1 line) with refractive correction alone.

RESULTS

Amblyopia improved with optical correction by > or =2 lines in 77% of the patients and resolved in 27%. Improvement took up to 30 weeks for stabilization criteria to be met. After stabilization, additional improvement occurred with spectacles alone in 21 of 34 patients observed in a control group of a subsequent randomized trial, with amblyopia resolving in 6. Treatment outcome was not related to age, but was related to better baseline VA and lesser amounts of anisometropia.

CONCLUSION

Refractive correction alone improves VA in many cases and results in resolution of amblyopia in at least one third of 3- to <7-year-old children with untreated anisometropic amblyopia. Although most cases of resolution occur with moderate (20/40-20/100) amblyopia, the average 3-line improvement in VA resulting from treatment with spectacles may lessen the burden of subsequent amblyopia therapy for those with denser levels of amblyopia.

A randomized trial to evaluate 2 hours of daily patching for strabismic and anisometropic amblyopia in children

OBJECTIVE

To compare 2 hours of daily patching (combined with 1 hour of concurrent near visual activities) with a control group of spectacle wear alone (if needed) for treatment of moderate to severe amblyopia in children 3 to 7 years old.

DESIGN

Prospective randomized multicenter clinical trial (46 sites).

PARTICIPANTS

One hundred eighty children 3 to 7 years old with best-corrected amblyopic-eye visual acuity (VA) of 20/40 to 20/400 associated with strabismus, anisometropia, or both who had worn optimal refractive correction (if needed) for at least 16 weeks or for 2 consecutive visits without improvement.

INTERVENTION

Randomization either to 2 hours of daily patching with 1 hour of near visual activities or to spectacles alone (if needed). Patients were continued on the randomized treatment (or no treatment) until no further improvement was noted.

MAIN OUTCOME MEASURE

Best-corrected VA in the amblyopic eye after 5 weeks.

RESULTS

Improvement in VA of the amblyopic eye from baseline to 5 weeks averaged 1.1 lines in the patching group and 0.5 lines in the control group (P = 0.006), and improvement from baseline to best measured VA at any visit averaged 2.2 lines in the patching group and 1.3 lines in the control group (P<0.001).

CONCLUSION

After a period of treatment with spectacles, 2 hours of daily patching combined with 1 hour of near visual activities modestly improves moderate to severe amblyopia in children 3 to 7 years old.

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

Results from recent randomised clinical trials in amblyopia should change our approach to screening for and treatment of amblyopia. Based on the current evidence, if one screening session is used, screening at school entry could be the most reasonable time. Clinicians should preferably use age-appropriate LogMAR acuity tests, and treatment should only be considered for children who are clearly not in the typical range for their age. Any substantial refractive error should be corrected before further treatment is considered and the child should be followed in spectacles until no further improvement is recorded, which can take up to 6 months. Parents and carers should then be offered an informed choice between patching and atropine drops. Successful patching regimens can last as little as 1 h or 2 h a day, and successful atropine regimens as little as one drop twice a week. Intense and extended regimens might not be needed in initial therapy.

The treatment of amblyopia

Recent studies suggest that children with amblyopia associated with anisometropia, strabismus, or both should be treated initially with best refractive correction until visual acuity is stable. This may take several months, and a proportion of children will achieve equal visual acuity with glasses alone. For residual anisometropic and strabismic amblyopia, the initial choice of patching or atropine should involve the parent and the child. The dose of prescribed patching or atropine may initially be quite modest, such as 2 hours of patching a day or twice weekly atropine. Treatment should be offered to children until at least 12 years of age and possibly to teenagers. Ongoing studies are addressing the role of undertaking near activities while patched and the role of atropine for severe amblyopia and for older amblyopic children. Future studies are needed to investigate the best treatment strategies for residual amblyopia, whether weaning treatment is needed at the end of a course, and how compliance can be enhanced.