Computerized method of visual acuity testing: adaptation of the amblyopia treatment study visual acuity testing protocol

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.

Effect of age on response to amblyopia treatment in children

OBJECTIVE

To determine whether age at initiation of treatment for amblyopia influences the response among children 3 to less than 13 years of age with unilateral amblyopia who have 20/40 to 20/400 amblyopic eye visual acuity.

METHODS

A meta-analysis of individual subject data from 4 recently completed randomized amblyopia treatment trials was performed to evaluate the relationship between age and improvement in logMAR amblyopic eye visual acuity. Analyses were adjusted for baseline amblyopic eye visual acuity, spherical equivalent refractive error in the amblyopic eye, type of amblyopia, prior amblyopia treatment, study treatment, and protocol. Age was categorized (3 to <5 years, 5 to <7 years, and 7 to <13 years) because there was a nonlinear relationship between age and improvement in amblyopic eye visual acuity.

RESULTS

Children from 7 to less than 13 years of age were significantly less responsive to treatment than were younger age groups (children from 3 to <5 years of age or children from 5 to <7 years of age) for moderate and severe amblyopia (P < .04 for all 4 comparisons). There was no difference in treatment response between children 3 to less than 5 years of age and children 5 to less than 7 years of age for moderate amblyopia (P = .67), but there was a suggestion of greater responsiveness in children 3 to less than 5 years of age compared with children 5 to less than 7 years of age for severe amblyopia (P = .09).

CONCLUSIONS

Amblyopia is more responsive to treatment among children younger than 7 years of age. Although the average treatment response is smaller in children 7 to less than 13 years of age, some children show a marked response to treatment.

Stereoacuity in children with anisometropic amblyopia

PURPOSE

To determine factors associated with pretreatment and posttreatment stereoacuity in subjects with moderate anisometropic amblyopia.

METHODS

Data for subjects enrolled in seven studies conducted by the Pediatric Eye Disease Investigator Group were pooled. The sample included 633 subjects aged 3 to <18 years with anisometropic amblyopia, no heterotropia observed by cover test, and baseline amblyopic eye acuity of 20/100 or better. A subset included 248 subjects who were treated with patching or Bangerter filters and had stereoacuity testing at both the baseline and outcome examinations. Multivariate regression models identified factors associated with baseline stereoacuity and with outcome stereoacuity as measured by the Randot Preschool Stereoacuity test.

RESULTS

Better baseline stereoacuity was associated with better baseline amblyopic eye acuity (P < 0.001), less anisometropia (P = 0.03), and anisometropia due to astigmatism alone (P < 0.001). Better outcome stereoacuity was associated with better baseline stereoacuity (P < 0.001) and better amblyopic eye acuity at outcome (P < 0.001). Among 48 subjects whose amblyopic eye visual acuity at outcome was 20/25 or better and within one line of the fellow eye, stereoacuity was worse than that of children with normal vision of the same age.

CONCLUSIONS

In children with anisometropic amblyopia of 20/40 to 20/100 inclusive, better posttreatment stereoacuity is associated with better baseline stereoacuity and better posttreatment amblyopic eye acuity. Even if their visual acuity deficit resolves, many children with anisometropic amblyopia have stereoacuity worse than that of nonamblyopic children of the same age.

Optical treatment of strabismic and combined strabismic-anisometropic amblyopia

OBJECTIVE

To determine visual acuity improvement in children with strabismic and combined strabismic-anisometropic (combined-mechanism) amblyopia treated with optical correction alone and to explore factors associated with improvement.

DESIGN

Prospective, multicenter, cohort study.

PARTICIPANTS

We included 146 children 3 to <7 years old with previously untreated strabismic amblyopia (n = 52) or combined-mechanism amblyopia (n = 94).

METHODS

Optical treatment was provided as spectacles (prescription based on a cycloplegic refraction) that were worn for the first time at the baseline visit. Visual acuity with spectacles was measured using the Amblyopia Treatment Study HOTV visual acuity protocol at baseline and every 9 weeks thereafter until no further improvement in visual acuity. Ocular alignment was assessed at each visit.

MAIN OUTCOME MEASURES

Visual acuity 18 weeks after baseline.

RESULTS

Overall, amblyopic eye visual acuity improved a mean of 2.6 lines (95% confidence interval [CI], 2.3-3.0), with 75% of children improving ≥ 2 lines and 54% improving ≥ 3 lines. Resolution of amblyopia occurred in 32% (95% CI, 24%-41%) of the children. The treatment effect was greater for strabismic amblyopia than for combined-mechanism amblyopia (3.2 vs 2.3 lines; adjusted P = 0.003). Visual acuity improved regardless of whether eye alignment improved.

CONCLUSIONS

Optical treatment alone of strabismic and combined-mechanism amblyopia results in clinically meaningful improvement in amblyopic eye visual acuity for most 3- to <7-year-old children, resolving in at least one quarter without the need for additional treatment. Consideration should be given to prescribing refractive correction as the sole initial treatment for children with strabismic or combined-mechanism amblyopia before initiating other therapies.

FINANCIAL DISCLOSURE(S)

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

Risk factors for astigmatism in preschool children: the multi-ethnic pediatric eye disease and Baltimore pediatric eye disease studies

OBJECTIVE

To evaluate risk factors for astigmatism in a population-based sample of preschool children.

DESIGN

Population-based cross-sectional study.

PARTICIPANTS

Population-based samples of 9970 children ages 6 to 72 months from Los Angeles County, California, and Baltimore, Maryland.

METHODS

A cross-sectional study of children participating in the Multiethnic Pediatric Eye Disease Study and the Baltimore Eye Disease Study was completed. Data were obtained by clinical examination or by in-person interview. Odds ratios and 95% confidence intervals (CI) were calculated to evaluate potential associations between clinical, behavioral, or demographic factors and astigmatism.

MAIN OUTCOME MEASURES

Odds ratios (ORs) for various risk factors associated with astigmatism.

RESULTS

Participants with myopia (≤-1.0 diopters) were 4.6 times as likely to have astigmatism (95% CI, 3.56-5.96) than those without refractive error, whereas participants with hyperopia (≥+2.00 diopters) were 1.6 times as likely (95% CI, 1.39-1.94). Children 6 to <12 months of age were approximately 3 times as likely to have astigmatism than children 5 to 6 years of age (95% CI, 2.28-3.73). Both Hispanic (OR, 2.38) and African-American (OR, 1.47) children were as likely to have astigmatism than non-Hispanic white children. Furthermore, children whose mothers smoked during pregnancy were 1.46 times (95% CI, 1.14-1.87) as likely to have astigmatism than children whose mothers did not smoke.

CONCLUSIONS

In addition to infancy, Hispanic and African-American race/ethnicity and correctable/modifiable risk factors such as myopia, hyperopia, and maternal smoking during pregnancy are associated with a higher risk of having astigmatism. Although the prevalence of smoking during pregnancy is typically low, this association may suggest etiologic pathways for future investigation.

FINANCIAL DISCLOSURE(S)

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

Risk factors for decreased visual acuity in preschool children: the multi-ethnic pediatric eye disease and Baltimore pediatric eye disease studies

OBJECTIVE

To investigate risk factors associated with unilateral or bilateral decreased visual acuity (VA) in preschool children.

DESIGN

Population-based, cross-sectional prevalence study.

PARTICIPANTS

Population-based samples of 6504 children ages 30 to 72 months from California and Maryland.

METHODS

Participants were preschool African-American, Hispanic, and non-Hispanic white children from Los Angeles, California, and Baltimore, Maryland. Data were obtained by a parental interview and a detailed ocular examination. Logistic regression models were used to evaluate the independent associations between demographic, behavioral, and clinical risk factors with unilateral and bilateral decreased VA.

MAIN OUTCOME MEASURES

Odds ratios (ORs) for various risk factors associated with interocular difference (IOD) in VA of ≥2 lines with ≤20/32 in the worse eye, or bilateral decreased VA <20/40 or <20/50 if <48 months of age.

RESULTS

In multivariate logistic regression analysis, 2-line IOD with a VA of ≤20/32 was independently associated with Hispanic ethnicity (OR, 2.05), esotropia (OR, 8.98), spherical equivalent (SE) anisometropia (ORs ranging between 1.5 and 39.7 for SE anisometropia ranging between 0.50 to <1.00 diopters [D] and ≥2.00 D), and aniso-astigmatism in J0 or J45 (ORs ranging between 1.4 and ≥5.3 for J0 or J45 differences ranging between 0.25 to <0.50 D and ≥1.00 D). Bilateral decreased VA was independently associated with lack of health insurance (OR, 2.9), lower primary caregiver education (OR, 1.7), astigmatism (OR, 2.3 and 17.6 for astigmatism 1.00 to <2.00 D and ≥2.00 D), and SE hyperopia ≥4.00 D (OR, 10.8).

CONCLUSIONS

Anisometropia and esotropia are risk factors for IOD in VA. Astigmatism and high hyperopia are risk factors for bilateral decreased VA. Guidelines for the screening and management of decreased VA in preschool children should be considered in light of these risk associations.

FINANCIAL DISCLOSURE(S)

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

Risk factors associated with childhood strabismus: the multi-ethnic pediatric eye disease and Baltimore pediatric eye disease studies

OBJECTIVE

To investigate risk factors associated with esotropia or exotropia in infants and young children.

DESIGN

Population-based cross-sectional prevalence study.

PARTICIPANTS

Population-based samples of 9970 children 6 to 72 months of age from California and Maryland.

METHODS

Participants were preschool African-American, Hispanic, and non-Hispanic white children participating in the Multi-Ethnic Pediatric Eye Disease Study and the Baltimore Eye Disease Study. Data were obtained by parental interview and ocular examination. Odd ratios and 95% confidence intervals were calculated to evaluate the association of demographic, behavioral, and clinical risk factors with esotropia and exotropia.

MAIN OUTCOME MEASURES

Odds ratios (ORs) for various risk factors associated with esotropia or exotropia diagnosis based on cover testing.

RESULTS

In multivariate logistic regression analysis, esotropia was associated independently with prematurity, maternal smoking during pregnancy, older preschool age (48-72 months), anisometropia, and hyperopia. There was a severity-dependent association of hyperopia with the prevalence of esotropia, with ORs increasing from 6.4 for 2.00 diopters (D) to less than 3.00 D of hyperopia, to 122.0 for 5.00 D or more of hyperopia. Exotropia was associated with prematurity, maternal smoking during pregnancy, family history of strabismus, female sex, astigmatism (OR, 2.5 for 1.50 to <2.50 D of astigmatism, and 5.9 for ≥2.5 D of astigmatism), and anisoastigmatism in the J0 component (OR, ≥2 for J0 anisoastigmatism of ≥0.25 D).

CONCLUSIONS

Prematurity and maternal smoking during pregnancy are associated with a higher risk of having esotropia and exotropia. Refractive error is associated in a severity-dependent manner to the prevalence of esotropia and exotropia. Because refractive error is correctable, these risk associations should be considered when developing guidelines for the screening and management of refractive error in infants and young children.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Distance versus near visual acuity in amblyopia

PURPOSE

There are conflicting reports about whether distance and near visual acuity are similar in eyes with amblyopia. The purpose of this study is to compare monocular distance visual acuity with near visual acuity in amblyopic eyes of children.

METHODS

Subjects 2 to 6 years of age were evaluated in a randomized trial of amblyopia therapy for moderate amblyopia (20/40 to 20/80) due to anisometropia, strabismus, or both. Prior to initiating the protocol-prescribed therapy, subjects had best-corrected visual acuity measured with standardized protocols at 3 meters and 0.4 meters using single-surrounded HOTV optotypes.

RESULTS

A total of 129 subjects were included. The mean amblyopic eye visual acuity was similar at distance and near (mean, 0.45 logMAR at distance versus 0.45 logMAR at near; mean difference, +0.00, 95% CI, -0.03 to 0.03). Of the 129 subjects, 86 (67%) tested within 1 line at distance and near; 19 (15%) tested more than 1 logMAR line better at distance, and 24 (19%) tested more than 1 logMAR line better at near. The mean visual acuity difference between distance and near did not differ by cause of amblyopia, age, or spherical equivalent refractive error.

CONCLUSIONS

We found no systematic difference between distance and near visual acuity in 2- to 6-year-old children with moderate amblyopia associated with strabismus and/or anisometropia. Individual differences between distance and near visual acuity are likely due to test-retest variability.

Evidence-based medicine and levels of evidence

Evidence-based medicine is the practice of making medical decisions based on evidence gained from applying the scientific method. Published studies are evaluated using three key questions: "Are the results valid?"; "What are the results?"; and "Can the results be applied to my patients?" The hierarchy of study methods for obtaining evidence is, in order from least to most useful: laboratory research, editorials, case reports and series, case-control studies, cohort studies, and randomized clinical trials. Retrospective case series can suffer from problems such as selection of a biased sample, mixing of treatment effects, and lack of control group. Randomized clinical trials (and meta-analyses of multiple trials) provide the highest level of evidence because randomization limits confounding and prevents bias of treatment assignment. In addition, randomized trials have standardization of interventions, prospective data collection, and masked outcome measures. Although every question cannot be addressed by a randomized clinical trial, the best available evidence should be sought and used to guide treatments.

Prevalence and risk factors for visual impairment in preschool children the sydney paediatric eye disease study

PURPOSE

To assess the prevalence and associations of visual impairment (VI) in preschool children.

DESIGN

Cross-sectional, population-based study.

PARTICIPANTS

A total of 2461 children (73.8% participation rate), aged 6 to 72 months, were examined in the Sydney Paediatric Eye Disease Study during 2007-2009; of whom 1188, aged 30 to 72 months, with complete visual acuity (VA) data in both eyes, were included in this report.

METHODS

Measurement of VA was attempted on all children using the Electronic Visual Acuity (EVA) system or a logarithm of the minimum angle of resolution (logMAR) chart. Visual impairment was defined as presenting VA <20/40 in children aged ≥48 months and <20/50 in those aged <48 months. Post-cycloplegic refraction was measured, and myopia was defined as spherical equivalent (SE) ≤-0.50 diopters (D), hyperopia was defined as SE ≥2.00 D, astigmatism was defined as cylinder ≥1.00 D, and anisometropia was defined as SE difference ≥1.00 D between 2 eyes. Ethnicity, birth parameters, and sociodemographic information were collected in questionnaires completed by parents.

MAIN OUTCOME MEASURES

Visual impairment prevalence and its associations with child demographic factors and birth parameters.

RESULTS

Visual impairment was found in 6.4% of the worse eye and 2.7% of the better eye in our sample. Refractive errors (69.7%) and amblyopia (26.3%) were the principal causes of VI in the worse eye. Astigmatism (51.3%) and hyperopia (28.9%) were the main refractive errors causing VI. In regression analysis controlling for other factors, VI was independently associated with low birthweight of <2500 g (odds ratio 2.4, 95% confidence interval, 1.1-5.3), but not with age, gender, ethnicity, or measures of socioeconomic status (P > 0.05).

CONCLUSIONS

Visual impairment in at least 1 eye was found in 6.4% of Australian preschool children, with bilateral VI found in 2.7%. Uncorrected refractive errors and amblyopia were the principal ocular conditions associated with VI. Low birthweight was a significant risk factor independent of age, gender, and ethnicity.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Visual acuity development of children with infantile nystagmus syndrome

PURPOSE

Infantile nystagmus syndrome (INS) can be idiopathic or associated with ocular or systemic disease. The ocular oscillation of INS directly contributes to loss of visual acuity. In this study, visual acuity development in patients with INS was examined.

METHODS

Children with INS were classified as having idiopathic INS (n = 84) or INS with an associated sensory deficit: INS and albinism (n = 71), bilateral optic nerve hypoplasia (ONH; n = 23), or congenital retinal disorder (n = 36). Visual acuity was assessed with Teller cards and/or optotypes, and the data were analyzed for three age groups (<24 months, 24-48 months, and >48 months).

RESULTS

Patients with idiopathic INS showed mildly reduced visual acuity early in life and gradual maturation with age that paralleled a normative curve. Patients with albinism also showed a mild visual deficit early in life but failed to keep pace with the normative curve, showing a gradual increase in visual acuity deficit. Patients with ONH and congenital retinal disorders exhibited more severe visual acuity deficits during infancy. The ONH group displayed slow improvement of visual acuity with a plateau at 24 months through >48 months, with a small increase in visual acuity deficit. The congenital retinal disorder group had no significant change in visual acuity across age and had a rapid increase in visual acuity deficit.

CONCLUSIONS

The pattern of visual acuity development differs among children with INS, depending on the presence or absence of associated sensory system deficits. Careful characterization of visual system differences in patients with INS is important if visual acuity is an outcome in clinical trials.

Vernier acuity cards: examination of development and screening validity

PURPOSE

Because vernier acuity seems to be limited by the visual cortex, it possesses excellent potential as a clinical/screening tool to detect amblyopia in infants and toddlers. Thus, we developed the vernier acuity cards specifically for this age group. We compared developmental data gathered using this new test and the Teller Acuity Cards. In addition, we compared the clinical/screening validity of the two tests by testing children old enough to complete optotype acuity testing (6.2 ± 2.5 years).

METHODS

Vernier acuity and grating acuity were assessed in 98 children and 18 adults with normal vision (age range = 2.8 months to 35.8 years). The developmental time course of the two visual functions was compared. In addition, vernier acuity and grating acuity were measured in 43 children with amblyopia and 30 nonamblyopic children with an amblyogenic condition. Each child's grating acuity and vernier acuity were classified as normal/abnormal based on age-appropriate norms. These classifications were compared with amblyopia diagnoses by crowded HOTV or Early Treatment Diabetic Retinopathy Study (ETDRS) testing.

RESULTS

Vernier acuity and grating acuity follow different developmental time courses in normal infants and children. Vernier acuity is initially poorer than grating acuity but surpasses it by the age 5 years and is adult-like by the age 8 years. Compared with the Teller Acuity Cards, the vernier acuity cards yielded higher sensitivity (81 vs. 44%) and similar specificity (73 vs. 93%) and were more sensitive to all amblyopia subtypes/levels of severity.

CONCLUSIONS

The developmental time course of vernier acuity differed from that of grating acuity, implying that it is not mediated by the retina. Also, the impressive validity of the vernier acuity cards suggests that they are an effective tool for detecting amblyopia.

Retinal nerve fiber layer thickness in children with optic pathway gliomas

PURPOSE

To determine the relationship of high-contrast visual acuity (VA) and low-contrast letter acuity with retinal nerve fiber layer (RNFL) thickness in children with optic pathway gliomas.

DESIGN

Cross-sectional convenience sample, with prospective data collection, from a tertiary care children's hospital of patients with optic pathway gliomas associated with neurofibromatosis type 1, sporadic optic pathway gliomas, and neurofibromatosis type 1 without optic pathway gliomas.

METHODS

Patients underwent best-corrected VA testing using surrounded H, O, T, V optotypes and low-contrast letter acuity (5%, 2.5%, and 1.25% low-contrast Sloan letter charts). Mean RNFL thickness (micrometers) was measured by a Stratus optical coherence tomography device (Carl Zeiss Meditec) using the fast RNFL thickness protocol. Eyes were classified as having abnormal vision if they had high-contrast VA of more than 0.1 logarithm of the minimal angle of resolution units or visual field loss. The association of subject age, glioma location, and RNFL thickness with both VA and low-contrast letter acuity scores was evaluated by 1-way analysis of variance and linear regression, using the generalized estimating equation approach to account for within-patient intereye correlations.

RESULTS

Eighty-nine eyes of patients with optic pathway gliomas were included, and 41 were classified as having abnormal VA or visual field loss. Reduced RNFL thickness was associated significantly with higher logarithm of the minimal angle of resolution scores for both VA (P < .001) and all low-contrast letter acuity charts (P < .001) when accounting for age and glioma location.

CONCLUSIONS

Eyes of most children with optic pathway gliomas and decreased RNFL thickness had abnormal VA or visual field loss.

Visual acuity testing using autorefraction or pinhole occluder compared with a manual protocol refraction in individuals with diabetes

PURPOSE

To compare visual acuity (VA) scores obtained after autorefraction or using a pinhole occluder to scores obtained after refraction according to a standard clinical research protocol.

DESIGN

Prospective, comparative case series.

PARTICIPANTS

One hundred ten study participants (209 eyes) with diabetes mellitus and a broad range of diabetic retinopathy severity and VA.

METHODS

We measured VA after autorefraction by a Topcon KR-8000 autorefractor as well as after a Diabetic Retinopathy Clinical Research Network (DRCR.net) protocol manual refraction. The order of testing was randomized and examiners were masked to the source of each refraction. A second VA measurement, utilizing an identical DRCR.net manual refraction, was made in a subset of eyes (n = 144; 69%) to establish test-retest variability for comparison purposes. All eyes underwent VA testing using a pinhole occluder.

MAIN OUTCOME MEASURES

Best corrected VA as measured by the Electronic Early Treatment Diabetic Retinopathy Study Visual Acuity Test (E-ETDRS).

RESULTS

In all eyes, the median E-ETDRS VA letter score (EVA) obtained after manual refraction (MR-EVA) was 69 (Snellen equivalent 20/40), ranging from 4 to 93 (20/800 to 20/16). The median MR-EVA was slightly better than the median EVA obtained after autorefraction (AR-EVA), with a median difference (AR-EVA - MR-EVA) of -1 letter (25th, 75th percentiles, -4, 2 letters). The absolute difference between AR-EVA and MR-EVA was similar to the test-retest variability of MR-EVA alone. In contrast, MR-EVA was better than EVA obtained using a pinhole occluder (PH-EVA; median PH-EVA - MR-EVA, -4 letters [-9, 0]), and had significantly less test-retest variability (P<0.001). Generally, the spherical equivalent of autorefraction was slightly more hyperopic (or less myopic) than the spherical equivalent of manual refraction (median difference, +0.25 diopters [0, +0.63]).

CONCLUSIONS

Given the substantial time and effort required for training and certification of study protocol refractionists, and the similarity between AR-EVA and MR-EVA, further evaluation of autorefraction, but not pinhole occluder testing, as an alternative to the current clinical research gold standard of ETDRS protocol manual refraction in study participants with diabetic retinopathy is warranted.

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.

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.

Effect of long-chain polyunsaturated fatty acid supplementation on neurodevelopmental outcome in full-term infants

It takes more than 20 years before the human brain obtains its complex, adult configuration. Most dramatic developmental changes occur prenatally and early postnatally. During development, long-chain polyunsaturated fatty acids (LCPUFA) such as doxosahexaenoic acid (DHA) and arachidonic acid (AA) are accreted in the brain. Since breastfeeding is associated with a better developmental outcome than formula feeding, and human milk in contrast to traditional standard formula contains LCPUFA, the question arose whether LCPUFA supplementation of infant formula may promote the neurodevelopmental outcome. The current paper reviews the evidence available in full-term infants. It concludes that postnatal supplementation of formula with LCPUFA is associated with a beneficial effect on short-term neurodevelopmental outcome. However, no evidence is available that LCPUFA supplementation enhances neurodevelopmental outcome in full-term infants beyond the age of four months. Nevertheless, it should be realized that very limited information is available on the effect of LCPUFA supplementation on neurodevelopmental outcome at school age or later. It is conceivable that effects of LCPUFA supplementation first emerge or re-emerge at school age when more complex neural functions are expressed.

Oral reading after treatment of dense congenital unilateral cataract

BACKGROUND

Good long-term visual acuity outcomes for children with dense congenital unilateral cataracts have been reported after early surgery and good compliance with postoperative amblyopia therapy. However, treated eyes rarely achieve normal visual acuity, and there has been no formal evaluation of the utility of the treated eye for reading.

METHODS

Eighteen children previously treated for dense congenital unilateral cataract were tested monocularly with the Gray Oral Reading Test, 4th edition (GORT-4) at 7 to 13 years of age with the use of 2 passages for each eye, one at grade level and one at +1 above grade level. In addition, right eyes of 55 normal children age 7 to 13 served as a control group. The GORT-4 assesses reading rate, accuracy, fluency, and comprehension.

RESULTS

Visual acuity of treated eyes ranged from 0.1 to 2.0 logMAR and of fellow eyes from -0.1 to 0.3 logMAR. Treated eyes scored significantly lower than fellow and normal control eyes on all scales at grade level and at +1 above grade level. Monocular reading rate, accuracy, fluency, and comprehension were correlated with visual acuity of treated eyes (r(s) = -0.575 to -0.875, p < 0.005). Treated eyes with 0.1-0.3 logMAR visual acuity did not differ from fellow or normal control eyes in rate, accuracy, fluency, or comprehension when reading at grade level or at +1 above grade level. Fellow eyes did not differ from normal controls on any reading scale.

CONCLUSIONS

Excellent visual acuity outcomes after treatment of dense congenital unilateral cataracts are associated with normal reading ability of the treated eye in school-age children.

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.

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.

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.

Overcoming barriers to pediatric visual acuity screening through education plus provision of materials

PURPOSE

The American Academy of Pediatrics (AAP) recommends that LEA and HOTV optotypes be used for vision screening and that adhesive tape be used to occlude one eye during testing. We have developed an educational program designed to improve the quality and efficiency of vision screening. The purpose of this study was to ascertain the effectiveness of this program.

METHODS

All 672 pediatric doctors and nurses in the state of Alaska were surveyed by mail to assess their screening protocol and the number of patients cared for annually. Respondents received educational material, including an instructional video, eye patches for visual acuity testing, and a critical line HOTV test box. Subjects were resurveyed 3 months later to determine whether the instructional intervention altered their established protocol.

RESULTS

Of the 672 practitioners contacted for the survey, 239 (35.6%) responded, representing 31,000 patients, or 62% of all preschool children in Alaska. Use of recommended optotypes was rare (Lea, 3%, HOTV, 7%) compared with the use of nonrecommended optotypes (including use of the E test by 40% of respondents). The postintervention survey was answered by 107 (16%) practitioners. Of these, 24 (23%) reported that they had begun using an adhesive patch for visual acuity testing, whereas 19 (18%) had begun using AAP-recommended testing optotypes.

CONCLUSIONS

In-office video education and provided adhesive eye patches increased the use of patches in primary care preschool vision screening. Mail delivery was less effective than anticipated.

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.

Patching vs atropine to treat amblyopia in children aged 7 to 12 years: a randomized trial

OBJECTIVE

To compare patching with atropine eyedrops in the treatment of moderate amblyopia (visual acuity, 20/40-20/100) in children aged 7 to 12 years.

METHODS

In a randomized, multicenter clinical trial, 193 children with amblyopia were assigned to receive weekend atropine or patching of the sound eye 2 hours per day. Main Outcome Measure Masked assessment of visual acuity in the amblyopic eye using the electronic Early Treatment Diabetic Retinopathy Study testing protocol at 17 weeks.

RESULTS

At 17 weeks, visual acuity had improved from baseline by an average of 7.6 letters in the atropine group and 8.6 letters in the patching group. The mean difference between groups (patching - atropine) adjusted for baseline acuity was 1.2 letters (ends of complementary 1-sided 95% confidence intervals for noninferiority, -0.7, 3.1 letters). This difference met the prespecified definition for equivalence (confidence interval <5 letters). Visual acuity in the amblyopic eye was 20/25 or better in 15 participants in the atropine group (17%) and 20 in the patching group (24%; difference, 7%; 95% confidence interval, -3% to 17%).

CONCLUSIONS

Treatment with atropine or patching led to similar degrees of improvement among 7- to 12-year-olds with moderate amblyopia. About 1 in 5 achieved visual acuity of 20/25 or better in the amblyopic eye.

CLINICAL RELEVANCE

Atropine and patching achieve similar results among older children with unilateral amblyopia.

TRIAL REGISTRATION

(clinicaltrials.gov) Identifier: NCT00315328.

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.

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.

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.

Automated determination of distance visual acuity: towards teleophthalmology services

PURPOSE

The aim of this study was to evaluate the visual acuity scores of a computer-based visual function testing (CVFT) system. The automated chart uses logMAR notation (logarithm of the minimum angle of resolution) and randomised tilting E as optotype. The test was conducted using a laptop computer.

METHODS

This prospective, clinic-based, test validation study was based on a model of repeatability in two observations. The right eyes of a total of 104 participants were randomly tested with both CVFT and the manual, gold standard Early Treatment of Diabetic Retinopathy Study (ETDRS) chart.

RESULTS

The mean difference between CVFT and ETDRS was -0.01+/-0.11 (SD) logMAR units. The Spearman Rank correlation coefficient (r) between the absolute difference and the average was 0.35. The average time for testing one eye was 54.7+/-11.89 seconds. The mean difference between two consecutive, repeated CVFT tests in the same eye was 0.02+/-0.07 logMAR units (paired t-test p=0.046).

CONCLUSIONS

A novel, automated visual acuity testing application is reported. This automated system should be a useful tool for mass screening of visual impairment in rural and remote regions with its ease of use and shorter testing time.

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: 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.

Validity and reliability of the Children's Visual Function Questionnaire (CVFQ)

PURPOSE

The Children's Visual Function Questionnaire (CVFQ) is a vision-specific quality-of-life instrument designed for use with children up to 7 years of age. The goal of this study was to assess the construct validity of CVFQ subscales by examining their sensitivity to four research questions commonly posed in ophthalmic clinical trials.

METHODS

CVFQ Competence, Personality, Family Impact, and Treatment Difficulty subscale scores were compared for groups of pediatric patients with unilateral versus bilateral disease (35 bilateral and 38 unilateral cataract), different severity of visual impairment (61 retinopathy of prematurity [ROP] grouped by acuity), difficulty of treatment regimen (22 optical, 44 surgery, 38 surgery with optical, and 35 surgery with optical and occlusion), and alternative treatments for the same condition (24 intraocular lenses, 37 aphakic contact lenses).

RESULTS

Patients treated for bilateral cataracts had significantly worse Competence subscale scores than patients treated for unilateral cataract, and patients with bilateral severe ROP (visual acuity 20/200 or poorer in both eyes) had significantly worse Competence subscale scores than other patients with ROP. Treatment Difficulty subscale scores were worse for patients with unilateral cataracts than for those with bilateral cataracts, worse for patients treated with occlusion therapy than for those treated with surgery or optical correction, and worse for those treated with an aphakic contact lens than for those treated with an intraocular lens. Family Impact subscale scores were worse for patients with unilateral cataracts than for those with bilateral cataracts, worse for patients treated with surgery than for those treated with optical correction, and worse for those with severe bilateral ROP than for any other patients with ROP.

CONCLUSIONS

The CVFQ subscales quantified meaningful differences among pediatric patient groups who were chosen to address key research questions commonly posed in ophthalmic clinical trials.

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.

Comparison of logMAR ETDRS chart and a new computerised staircased procedure for assessment of the visual acuity of children

The validity and repeatability of visual acuity measures are particularly important in the detection and monitoring of childhood visual anomalies such as amblyopia. The repeatability and sensitivity of a new computerised visual acuity test, 'Staircased Procedure' is compared with the now gold standard visual acuity test, the early treatment of diabetic retinopathy study (ETDRS). Twenty-seven visually normal children (mean age: 6.7 +/- 1.1 years) and 27 children with amblyopia (mean age: 6.1 +/- 0.7 years) were tested with the ETDRS and Staircased Procedure. A retest was administered 4-5 weeks later and 30 min later for the visually normal and the amblyopic children, respectively. The staircased procedure produced significantly better visual acuity than the ETDRS for visually normal and amblyopic children. Repeatability was similar for both tests (ETDRS: 0.11 log units; staircased procedure: 0.13 log units). In conclusion, the Staircased Procedure was an acceptable test with high repeatability and validity.