Leveraging neural plasticity for the treatment of amblyopia

Amblyopia is a form of visual cortical impairment that arises from abnormal visual experience early in life. Most often, amblyopia is a unilateral visual impairment that can develop as a result of strabismus, anisometropia, or a combination of these conditions that result in discordant binocular experience. Characterized by reduced visual acuity and impaired binocular function, amblyopia places a substantial burden on the developing child. Although frontline treatment with glasses and patching can improve visual acuity, residual amblyopia remains for most children. Newer binocular-based therapies can elicit rapid recovery of visual acuity and may also improve stereoacuity in some children. Nevertheless, for both treatment modalities full recovery is elusive, recurrence of amblyopia is common, and improvements are negligible when treatment is administered at older ages. Insights derived from animal models about the factors that govern neural plasticity have been leveraged to develop innovative treatments for amblyopia. These novel therapies exhibit efficacy to promote recovery, and some are effective even at ages when conventional treatments fail to yield benefit. Approaches for enhancing visual system plasticity and promoting recovery from amblyopia include altering the balance between excitatory and inhibitory mechanisms, reversing the accumulation of proteins that inhibit plasticity, and harnessing the principles of metaplasticity. Although these therapies have exhibited promising results in animal models, their safety and ability to remediate amblyopia need to be evaluated in humans.

Motion-Defined Form Perception in Deprivation Amblyopia

Purpose

The purpose of this study was to assess motion-defined form perception, including the association with clinical and sensory factors that may drive performance, in each eye of children with deprivation amblyopia due to unilateral cataract.

Methods

Coherence thresholds for orientation discrimination of motion-defined form were measured using a staircase procedure in 30 children with deprivation amblyopia and 59 age-matched controls. Visual acuity, stereoacuity, fusion, and interocular suppression were also measured. Fixation stability and fellow-eye global motion thresholds were measured in a subset of children.

Results

Motion-defined form coherence thresholds were elevated in 90% of children with deprivation amblyopia when viewing with the amblyopic eye and in 40% when viewing with the fellow eye. The deficit was similar in children with a cataract that had been visually significant at birth (congenital) and in children for whom the cataract appeared later in infancy or childhood (developmental). Poorer motion-defined form perception in amblyopic eyes was associated with poorer visual acuity, poorer binocular function, greater interocular suppression, and the presence of nystagmus. Fellow-eye deficits were not associated with any of these factors, but a temporo-nasal asymmetry for global motion perception in favor of nasalward motion suggested a general disruption in motion perception.

Conclusions

Deficits in motion-defined form perception are common in children with deprivation amblyopia and may reflect a problem in motion processing that relies on binocular mechanisms.

Risk of recurrence after cessation of dichoptic, binocular treatment of amblyopia

Contrast-rebalanced dichoptic games and videos have been shown to be an effective treatment for childhood amblyopia. Whether the visual acuity gains achieved with these binocular treatments are long-lasting has not been determined. In this prospective cohort study of 100 consecutive amblyopic children who improved by ≥0.2 logMAR or obtained ≤0.2 logMAR amblyopic eye visual acuity during a binocular treatment clinical trial, risk of recurrence was 24% (95% CI, 16%-35%) at up to 3 years' follow-up according to Kaplan-Meier survival analysis, which accounts for censored, truncated, and missing data. Risk of recurrence was similar among children who required additional treatment for residual amblyopia after 4-8 weeks of dichoptic treatment (n = 62 [19%]; 95% CI, 10%-34%) and those who did not (n = 38 [32%]; 95% CI, 18%-52%; P = 0.12). There was no association between recurrence and age, visual acuity at the end of binocular treatment, stereoacuity, or ocular alignment. In a secondary analysis to compare rates of recurrence with published data, risk of recurrence in the subset of children who had no additional treatment for residual amblyopia (28%) was similar to the reported recurrence after cessation of successful patching and atropine (24%) at 12 months. Children with successful binocular treatment of amblyopia require monitoring for recurrence of amblyopia.

Objective assessment of control compared with clinical triple office control score in children with intermittent exotropia

Poor control of intermittent exotropia may be used as an indication for surgery. However, control fluctuates during the day and from day to day. The standardized triple office control score (mean of three scores on a 6-point ordinal scale) is representative of repeated assessments throughout the day, but lacks validation against an objective measure of eye movements. We report the agreement between the triple office control score measured by the referring eyecare professional and lab-measured vergence instability using an EyeLink video eye tracker. Near and distance triple office control scores were moderately correlated with vergence instability. Near, but not distance, triple office control score was moderately correlated with the percentage of time intermittent exotropia was manifest during EyeLink recording. Larger triple office control scores for intermittent exotropia provide a meaningful description of larger vergence instability, supporting its use in clinical decisions and as a measure in clinical trials.

Slow Binocular Reading in Amblyopic Children Is a Fellow Eye Deficit

SIGNIFICANCE

Amblyopic children read 25% slower than their peers during binocular silent reading.

PURPOSE

We compared binocular reading to fellow eye reading to determine whether slow reading in amblyopic children is due to binocular inhibition; that is, the amblyopic eye is interfering during binocular reading.

METHODS

In a cross-sectional study, 38 children with amblyopia and 36 age-similar control children who completed grades 1 to 6 were enrolled. Children silently read grade-appropriate paragraphs during binocular reading and fellow eye reading while wearing ReadAlyzer eye-tracking goggles (Compevo AB, Stockholm, Sweden). Reading rate, number of forward saccades, number of regressive saccades, and fixation duration were analyzed between groups and between viewing conditions. We also examined whether sensory factors (amblyopia severity, stereoacuity, suppression) were related to slow reading.

RESULTS

For amblyopic children, binocular reading versus fellow eye reading did not differ for reading rate (176 ± 60 vs. 173 ± 53 words per minute, P = .69), number of forward saccades (104 ± 35 vs. 97 ± 33 saccades/100 words, P = .18), number of regressive saccades (21 ± 15 vs. 22 ± 13 saccades/100 words, P = .75), or fixation duration (0.31 ± 0.06 vs. 0.32 ± 0.07 seconds, P = .44). As expected, amblyopic children had a slower reading rate and more forward saccades than control children during binocular reading and fellow eye reading. Slow reading was not related to any sensory factors.

CONCLUSIONS

Binocular reading did not differ from fellow eye reading in amblyopic children. Thus, binocular inhibition is unlikely to play a role in slow binocular reading and is instead a fellow eye deficit that emerges from a disruption in binocular visual experience during development.

Amblyopia and the whole child

Amblyopia is a disorder of neurodevelopment that occurs when there is discordant binocular visual experience during the first years of life. While treatments are effective in improving visual acuity, there are significant individual differences in response to treatment that cannot be attributed solely to difference in adherence. In this considerable variability in response to treatment, we argue that treatment outcomes might be optimized by utilizing deep phenotyping of amblyopic deficits to guide alternative treatment choices. In addition, an understanding of the broader knock-on effects of amblyopia on developing visually-guided skills, self-perception, and quality of life will facilitate a whole person healthcare approach to amblyopia.

Binocular amblyopia treatment improves manual dexterity

PURPOSE

To determine whether deficits in manual dexterity in children with amblyopia improve after binocular amblyopia treatment and whether improvements are related to age at treatment, baseline sensory status, or amount of improvement in sensory status with treatment.

METHODS

Manual dexterity (Movement Assessment Battery for Children-2), visual acuity, fusion, suppression, and stereoacuity were measured at baseline and after 4-8 weeks of binocular amblyopia in 134 children with amblyopia, including 75 children in the "younger group" (aged 3 to <7 years) and 59 in the "older group" (aged 7-10 years), and in 40 age-similar control children.

RESULTS

Baseline manual dexterity standard scores of amblyopic children were significantly below those of controls in both the younger (8.81 ± 0.33 vs 11.80 ± 0.60 [P < 0.0001]) and older groups (7.19 ± 0.34 vs 9.75 ± 0.57 [P = 0.00013]). After 4-8 weeks of binocular amblyopia treatment, the younger group standard score improved to 9.85 ± 0.35 and the older group improved to 8.08 ± 0.39, but both groups remained significantly lower than controls (P = 0.03 and P = 0.01, resp.). Improvement in manual dexterity standard score was not associated with any baseline factors but was weakly correlated with the amount of visual acuity improvement (rs = 0.26; 95% CI, 0.09-0.41) CONCLUSIONS: Manual dexterity impairments are common among children with amblyopia. In our study cohort, binocular amblyopia treatment improved visual acuity and manual dexterity.

Dichoptic and Monocular Visual Acuity in Amblyopia

PURPOSE

Standard-of-care assessment for children with amblyopia includes measuring amblyopic eye best-corrected visual acuity (AE BCVA) with the fellow eye occluded. By definition, this abolishes the interocular suppression fundamental to amblyopia. Thus, measured AE BCVA may not accurately represent that eye's contribution to natural binocular viewing. We compared dichoptic and monocular AE BCVA and examined whether any differences were associated with eye-hand coordination or reading speed.

DESIGN

Cross-sectional study.

METHODS

Dichoptic and monocular AE BCVA of children aged 6-12 years (42 with amblyopia, 24 with recovered normal AE BCVA, 30 control) were measured. Stereoacuity, suppression, eye-hand coordination, and reading speed were also assessed.

RESULTS

Overall, 81% of amblyopic children had worse dichoptic than monocular AE BCVA (mean difference=0.15±0.11 logMAR; P < .0001), and 71% of children with recovered normal AE BCVA had worse dichoptic than monocular AE BCVA (mean difference = 0.20±0.17 logMAR, P < .0001). Controls had no significant difference. The difference between dichoptic and monocular AE BCVA was correlated with performance in standardized aiming/catching (r = -0.48, 95% CI -0.72, -0.14) and manual dexterity tasks (r = -0.37, 95% CI -0.62, -0.06), and with reading speed (r = -0.38, 95% CI -0.65, -0.03).

CONCLUSIONS

Dichoptic AE BCVA deficits were worse than monocular AE BCVA deficits and were associated with reduced stereoacuity and suppression, consistent with the hypothesis that binocular dysfunction plays a role. Further, impaired eye-hand coordination and slow reading were associated with dichoptic, but not monocular, AE BCVA. Some children with amblyopia may benefit from extra time for school tasks requiring eye-hand coordination or reading.

Applying Normal PedEyeQ Thresholds to Assess Eye-related Quality of Life among Children with Strabismus

PURPOSE

To determine proportions of children with strabismus with below-normal Pediatric Eye Questionnaire (PedEyeQ) scores.

METHODS

Ninety-eight children with strabismus (70 aged 5-11 years; 28 aged 12-17 years) were evaluated. Children completed the Child 5-11 or 12-17 PedEyeQ (Functional Vision, Bothered by Eyes/vision, Social, and Frustration/worry domains). Parents completed the Proxy (same domains plus Eye Care) and Parent PedEyeQ (Impact on Parent and Family, Worry about Child's Eye Condition, Worry about Child's Self-perception and Interactions, and Worry about Functional Vision domains). Previously published normal (5th percentile) thresholds were applied to calculate proportions with below-normal scores for each domain.

RESULTS

For the Child PedEyeQ more than 20% of 5- to 11-year-olds scored below normal, on all but the Social domain, whereas more than 50% of 12- to 17-year-olds scored below normal on all domains. On the Proxy PedEyeQ, more than 50% scored below normal on all domains when parents reported on 5- to 11-year-olds and 12- to 17-year-olds. For the Parent PedEyeQ, more than 50% of the parents of both 5- to 11-year-olds and 12- to 17-year-olds scored below normal on all domains.

CONCLUSIONS

The majority of children with strabismus have below-normal PedEyeQ scores, particularly children aged 12-17 years.

Plasma Levels of Bevacizumab and Vascular Endothelial Growth Factor After Low-Dose Bevacizumab Treatment for Retinopathy of Prematurity in Infants

Importance

Intravitreal bevacizumab effectively treats severe retinopathy of prematurity (ROP), but it enters the bloodstream and may reduce serum vascular endothelial growth factor (VEGF), potentially causing detrimental effects on developing organs in the premature infant.

Objective

To evaluate the association of intravitreal bevacizumab with plasma bevacizumab and VEGF concentrations at 2 and 4 weeks after predefined, de-escalating doses of intravitreal bevacizumab were administered to infants with severe ROP.

Design, Setting, and Participants

This phase 1 dose de-escalation case series study was conducted at 10 US hospitals of ophthalmology institutions from May 21, 2015, to May 7, 2019. Blood samples were collected 2 and 4 weeks after intravitreal bevacizumab injection. Participants included 83 premature infants with type 1 ROP in 1 or both eyes and no previous ROP treatment. Data were analyzed from April 2017 to August 2021.

Interventions

Study eyes received a single bevacizumab injection of 0.250 mg, 0.125 mg, 0.063 mg, 0.031 mg, 0.016 mg, 0.008 mg, 0.004 mg, or 0.002 mg. When the fellow eye required treatment, one dose higher was administered. Total dose administered at baseline was defined as the sum of doses given to each eye within 3 days of initial study-eye injection.

Main Outcomes and Measures

Plasma bevacizumab concentration at 2 and 4 weeks after injection and the percentage change in plasma VEGF concentrations from pretreatment levels.

Results

A total of 83 infants (mean [SD] age, 25 [2] weeks; 48 boys [58%]) were included in this study. Higher doses of bevacizumab administered at baseline were associated with higher plasma bevacizumab concentrations at 2 weeks (ρ, 0.53; 95% CI, 0.31-0.70) and 4 weeks (ρ, 0.44; 95% CI, 0.18-0.64). Plasma VEGF concentrations decreased by 50% or more from pretreatment levels in 40 of 66 infants (61%) at 2 weeks and 31 of 61 infants (51%) at 4 weeks, but no association was observed between the total dose of bevacizumab administered at baseline and percentage change in plasma VEGF concentrations 2 weeks (ρ, -0.04; 95% CI, -0.28 to 0.20) or 4 weeks (ρ, -0.17; 95% CI, -0.41 to 0.08) after injection.

Conclusions and Relevance

Results of this phase 1 dose de-escalation case series study revealed that bevacizumab doses as low as 0.002 mg were associated with reduced plasma VEGF levels for most infants at 2 and 4 weeks after intravitreal administration; however, no association was observed between total bevacizumab dose administered and reductions in plasma VEGF levels from preinjection to 2 weeks or 4 weeks. Additional studies are needed to evaluate the long-term effects of low-dose bevacizumab on neurodevelopment and retinal structure.

Web-based visual acuity testing for children

PURPOSE

To evaluate a newly developed, web-based system for at-home pediatric visual acuity testing and to compare results with standard in-office visual acuity test results.

METHODS

Children aged 3-12 years with and without visual deficits were enrolled (N = 65; 130 eyes). Monocular visual acuity was tested in-office using the ATS-HOTV (ages 3-6) or E-ETDRS (ages 7-12) protocol. Each child's family was emailed a link to a web-based version of the same visual acuity test for at-home testing. Equivalence was evaluated by using a linear mixed model to estimate the mean difference between in-office and at-home visual acuity test results and the corresponding two-sided 95% confidence interval.

RESULTS

For children tested with the ATS-HOTV protocol, the mean difference between in-office and at-home visual acuity test results was 0.01 log MAR (95% CI, -0.06 to 0.09). For children tested with the E-ETDRS protocol, the mean difference was 0.04 log MAR (95% CI, -0.06 to 0.14).

CONCLUSIONS

At-home, web-based ATS-HOTV and E-ETDRS visual acuity test results had excellent concordance with in-office visual acuity testing. If the burden of travel is significant, at-home testing of children's visual acuity may provide the information needed to continue care when it might otherwise be discontinued or delayed.

Recent Advances in Screening and Treatment for Amblyopia

Amblyopia is the most common cause of monocular visual impairment in children, with a prevalence of 2-3%. Not only is visual acuity reduced in one eye but binocular vision is affected, fellow eye deficits may be present, eye-hand coordination and reading can be affected, and self-perception may be diminished. New technologies for preschool vision screening hold promise for accessible, early, and accurate detection of amblyopia. Together with recent advances in our theoretical understanding of amblyopia and technological advances in amblyopia treatment, we anticipate improved visual outcomes for children affected by this very common eye condition. This article is based on previously conducted studies and does not contain any new studies with human participants or animals performed by any of the authors.

Diplopic versus nondiplopic strabismus: effects on functional vision and eye-related quality of life in adolescents

Twenty adolescents (12-17 years old) with diplopic strabismus and 20 with nondiplopic strabismus (matched to diplopic subjects for direction and magnitude of ocular deviation) completed the Pediatric Eye Questionnaire (PedEyeQ). Children completed the Child PedEyeQ, and one parent for each child completed the Proxy PedEyeQ and Parent PedEyeQ. PedEyeQ Rasch domain scores were calculated and converted to a scale of 0 (worst) to 100 (best). Distributions of domain scores were compared between diplopic and nondiplopic cohorts using Wilcoxon tests. Diplopic adolescents had significantly lower Child PedEyeQ scores on Functional Vision (72 vs 90; P = 0.008), Bothered by Eyes/Vision (65 vs 90; P = 0.009), and Frustration/Worry (53 vs 75; P < 0.001) domains. There was no difference on the Child Social domain (85 vs 90; P = 0.22). Proxy and Parent PedEyeQ scores were similar between diplopic and nondiplopic cohorts (P > 0.06 for each comparison). These findings highlight the importance of addressing diplopia when managing childhood strabismus.

Applying normal PedEyeQ thresholds to define reduced quality of life

Patient-reported outcome measures such as the Pediatric Eye Questionnaire (PedEyeQ) are increasingly recognized as important in healthcare assessment. Defining normal PedEyeQ thresholds would allow classification of individual children as having reduced versus normal domain scores. We prospectively enrolled visually normal children (aged 0-17 years; n = 310) to calculate normal PedEyeQ domain thresholds. In addition, 48 children with bilateral visual impairment (VI; best-eye acuity worse than 20/70 or 20/70 or better with limited visual fields) were enrolled for validation. The Child PedEyeQ (four domains) was completed by 5- to 17-year-olds. Parents completed Proxy (five domains) and Parent PedEyeQ (four domains). Each domain was Rasch scored (converted to 0-100); normal thresholds were defined as the 5th percentile of scores in visually normal controls. For Child 5-11 PedEyeQ, 39%-78% of VI children had reduced domain scores, and 88%-100% for 12- to 17-year-olds. For Proxy PedEyeQ, proportions ranged from 55% to 100% and for Parent PedEyeQ ≥83% had reduced scores. High prevalence of reduced PedEyeQ domain scores in the VI cohort, validates the use of normal thresholds. Nevertheless, variability in child self-reporting creates challenges for identifying individual 5- to 11-year-olds with reduced scores.

Longitudinal Development of Refractive Error in Children Treated With Intravitreal Bevacizumab or Laser for Retinopathy of Prematurity

Purpose

To compare the patterns of longitudinal refractive error development during the first 3.5 years in children with severe retinopathy of prematurity (ROP) treated with intravitreal bevacizumab (IVB) or laser photocoagulation.

Methods

This prospective cohort study enrolled extremely preterm infants (birth weight < 1000 g, gestational age 23-27 weeks) with type 1 ROP from multiple hospitals in Dallas between 1999 and 2017; IVB group (N = 22); laser group (N = 26). Cycloplegic retinoscopy was conducted from 0.04 years corrected age and every 0.5 to 1.0 years thereafter until 3.5 years old. Right eye spherical equivalent (SEQ) and astigmatism, anisometropia, and better-eye visual acuity were analyzed over time.

Results

In all children, both eyes were treated with the same modality. At the final visit, the prevalence of myopia (SEQ ≤ -1D) was 82.7% in the laser group and 47.7% in the IVB group (P < 0.05) with a mean SEQ of -8.0D ± 5.8D in the laser group versus -2.3D ± 4.2D in the IVB group (P < 0.001). Longitudinal SEQ were best fit with a bilinear model. Before one year, the rate of SEQ change was -5.0D/year in the laser group, but only -3.5D/year in the IVB group (T = -5.14, P < 0.001); after one year, there was a significant flattening of these slopes (T = 6.23, P < 0.001). Anisometropia in the IVB group was significantly less than in the laser group (P < 0.05). Final visual acuity in both groups was similar at 0.47 logMAR (∼ 20/60).

Conclusions

Children with severe ROP treated with IVB developed less myopic refractive error than those treated with laser largely because of a slower rate of refractive change during the first year of life.

Translational Relevance

These findings may inform decisions regarding ROP treatment timing and modality.

Normative pediatric visual acuity using electronic early treatment for diabetic retinopathy protocol

There is a lack of normative data for children tested with the electronic Early Treatment for Diabetic Retinopathy Study (E-ETDRS) protocol. In the current cross-sectional study, the mean best-corrected normal and 95% lower tolerance limit for E-ETDRS visual acuity by year in children 7-12 years of age was measured. Our objective was to provide a large normative data set for E-ETDRS visual acuity in children for use in clinical management and clinical trials.

Association of Visual Acuity with Eye-Related Quality of Life and Functional Vision Across Childhood Eye Conditions

PURPOSE

We evaluated relationships between visual acuity (VA) and eye-related quality of life and functional vision in children, across a spectrum of pediatric eye conditions, using the Pediatric Eye Questionnaire (PedEyeQ).

DESIGN

Cross-sectional study.

METHODS

Three hundred ninety-seven children (5-11 years of age) with an eye condition and 104 visually normal control subjects completed the Child PedEyeQ (functional vision, bothered by eyes/vision, social, and frustration/worry domains). One parent for each child completed the Proxy PedEyeQ (same domains as child plus eye care) and parent PedEyeQ (impact on parent and family, worry about child's eye condition, worry about child's self-perception and interactions, and worry about functional vision domains). Each domain was Rasch-scored and Spearman rank correlations were calculated to evaluate relationships between better-seeing-eye and worse-seeing-eye VA and PedEyeQ domain score.

RESULTS

There was a significant relationship between poorer better-seeing-eye VA and lower (worse) PedEyeQ score on 2 of 4 child domains (e.g., functional vision, r = -0.1474; P = .005), on 2 of 5 proxy PedEyeQ domains (e.g., functional vision, r = -0.2183; P < .001), and on 2 of 4 parent PedEyeQ domains (e.g., impact on parent and family, r = -0.1607; P = .001). Worse-seeing-eye VA was associated with lower PedEyeQ scores across all child, proxy and parent domains (P < .01 for each) with the exception of the child social domain (P = .15).

CONCLUSIONS

Both better-seeing-eye and worse-seeing-eye VA were associated with functional vision and eye-related quality of life in children, assessed using the PedEyeQ, although other factors may also influence relationships. These data further validate using the PedEyeQ across pediatric eye conditions.

Normative Values, Testability, and Validity for a New Preferential Looking Stereoacuity Test

Introduction: Age norms and testability for 3-5 year old children have been reported for the PASS III stereotest using a pointing response. We aimed to expand the normative data to children as young as 6 months, assess testability, and evaluate validity use of the PASS III as a preferential-looking test for younger children and children with special needs. Methods: 68 control children, 362 children with eye conditions, and 167 children with special needs were tested with the PASS III. Percent testable was calculated for children with and without special needs, normal tolerance limits were determined, and test validity was assessed. Results: In controls, mean PASS III stereoacuity improved from 371 arcsec at 12 months to 174 arcsec at 24 months, and 87 arcsec at 36 months. Testability in the 12, 24, and 36 months age groups were 81%, 87%, and 97% respectively and 92% for special needs children. Comparison to previously published norms and testing in a known nil stereoacuity cohort supported PASS III test validity. Compared to gold standard stereoacuity tests, accuracy of the PASS was 89%. Conclusion: Overall, preferential-looking tests using the PASS III provide a sensitive and specific measure of stereoacuity with high testability for young children and children with special needs.

Association of Strabismus With Functional Vision and Eye-Related Quality of Life in Children

Importance

Strabismus is common, affecting 2% to 4% of children, but how children and their families are affected in everyday life is poorly understood.

Objective

To evaluate the association of strabismus with functional vision and eye-related quality of life in children and their families using the Pediatric Eye Questionnaire (PedEyeQ).

Design, Setting, and Participants

This cross-sectional study was conducted between December 2017 and October 2019 and included 91 children with strabismus and 166 visually normal controls across 3 age groups (0-4, 5-11, and 12-17 years) who were enrolled at Mayo Clinic, Rochester, Minnesota, and Retina Foundation of the Southwest, Dallas, Texas.

Exposures

Children completed the child PedEyeQ (5 to 11- and 12 to 17-year versions: functional vision, bothered by eyes/vision, social, and frustration/worry domains); parents completed the proxy (0 to 4-, 5 to 11-, and 12 to 17-year versions: functional vision, bothered by eyes/vision, social, frustration/worry, and eye care domains) and the parent PedEyeQ (impact on parent and family, worry about child's eye condition, worry about child's self-perception and interactions, and worry about child's functional vision domains). Rasch-calibrated PedEyeQ scores were calculated for each domain and converted to 0 (worst) to 100.

Main Outcomes and Measures

PedEyeQ domain scores.

Results

Of 91 participants with strabismus, 41 (45.1%) were girls, 74 (81.3%) were white, 4 (4.4%) were Asian, 5 (5.5%) were more than 1 race, 5 (5.5%) were African American, and 2 (2.2%) were American Indian/Alaska Native. Child PedEyeQ domain scores were lower with strabismus vs visually normal controls among children ages 5 to 11 years and the greatest mean (SD) difference was in functional vision (12 [14] points; 95% CI, 6-18; P = .001), and among children ages 12 to 17 years, the greatest mean (SD) difference was in frustration/worry (27 [13] points; 95% CI, 18-36; P < .001). Proxy PedEyeQ domain scores were also lower with strabismus. The greatest difference among children ages 0 to 4 years was in functional vision (13 [9] points; 95% CI, 9-16; P < .001), among children ages 5 to 11 years was in functional vision (26 [10] points; 95% CI, 22-30; P < .001); and among children ages 12 to 17 years was in functional vision (21 [12] points; 95% CI, 12-30; P < .001), social (21 [13] points; 95% CI, 12-30; P < .001), and frustration/worry (21 [13] points; 95% CI, 12-30; P < .001). Parent PedEyeQ domain scores were lower with strabismus; the greatest difference was in worry about child's eye condition (38 [14] points; 95% CI, 34-42; P < .001).

Conclusions and Relevance

Strabismus is associated with reduced functional vision and eye-related quality of life in children. Parents of children with strabismus also experience a reduced quality of life. These findings advance our understanding of how strabismus affects children and their families and should be considered when defining patient management goals.

Factors Associated with Impaired Motor Skills in Strabismic and Anisometropic Children

Purpose

We evaluated motor skills in children diagnosed with strabismus and anisometropia, with or without amblyopia, and explored factors associated with impairments.

Methods

A total of 143 strabismic and anisometropic children 3 to 13 years of age (96 amblyopic, 47 nonamblyopic) and a group of age-similar 35 control children completed Manual Dexterity, Aiming and Catching, and Balance tasks from the Movement Assessment Battery for Children, Second Edition. Raw scores were converted to standardized scores, and amblyopic and nonamblyopic children were compared to controls. Clinical and sensory factors associated with motor performance were also evaluated.

Results

Overall, amblyopic and nonamblyopic children were three to six times more likely than controls to be at risk for or to have a total motor impairment (≤15th percentile). Although amblyopic children scored lower than controls for the Manual Dexterity, Aiming and Catching, and Balance tasks, nonamblyopic children scored lower on Manual Dexterity only. Factors related to manual dexterity deficits include the presence of amblyopia and binocularity deficits typical of these eye conditions. Aiming, catching, and balance deficits were most pronounced in children with an infantile onset of the eye condition, a history of strabismus, and reduced binocularity.

Conclusions

Amblyopia and strabismus disrupt the development of motor ability in children. These findings highlight the widespread effects of discordant binocular input early in life and the visual acuity and binocularity deficits typical of these eye conditions.

Self-perception in Preschool Children With Deprivation Amblyopia and Its Association With Deficits in Vision and Fine Motor Skills

Importance

Although the development of self-perception and self-esteem has been investigated in children with strabismic and anisometropic amblyopia, we know little about how self-perception is affected in deprivation amblyopia. Deprivation amblyopia from a dense, unilateral cataract is the least common and typically most severe form of amblyopia. After cataract extraction, optical correction, and patching treatment for amblyopia, visual acuity almost always remains abnormal, and except in rare cases, stereoacuity is nearly always nil.

Objective

To determine whether deprivation amblyopia is associated with altered self-perception in preschool children and to determine whether any differences in self-perception are associated with vision or motor skill deficits.

Design, Setting, and Participants

Cross-sectional study conducted from 2016 to 2019 at a pediatric vision research laboratory. Children aged 3 to 6 years were enrolled, including 15 children with deprivation amblyopia and 20 control children.

Main Outcomes and Measures

Self-perception was assessed using the Pictorial Scale of Competence and Acceptance for Young Children, which includes 4 specific domains: cognitive competence, peer acceptance, physical competence, and maternal acceptance. Fine motor skills were evaluated with the Manual Dexterity and Aiming & Catching Scales of the Movement ABC-2 test. Visual acuity and stereoacuity also were assessed.

Results

Of the 35 children included, 13 of 35 were girls (37%) and 28 of 35 were non-Hispanic White (80%). Children with deprivation amblyopia had significantly lower peer acceptance and physical competence scores compared with control children (mean [SD], 2.80 [0.44] vs 3.25 [0.33]; mean difference, 0.45; 95% CI for difference, 0.19-0.71; P = .002 and 2.94 [0.45] vs 3.41 [0.37]; mean difference, 0.47; 95% CI for difference, 0.19-0.75; P = .002, respectively). Among children with amblyopia, moderate associations were found between self-perception domain scores and motor skills, including peer acceptance and manual dexterity (r = 0.68; 95% CI, 0.26-0.89; P = .005), peer acceptance and aiming (r = 0.54; 95% CI, 0.03-0.82; P = .03), and physical competence and aiming (r = 0.55; 95% CI, 0.06-0.83; P = .03).

Conclusions and Relevance

Lower self-perception of peer acceptance and physical competence were associated with early visual deprivation in children in their everyday life.

A pilot randomized trial of contrast-rebalanced binocular treatment for deprivation amblyopia

BACKGROUND

Binocular neural architecture may be preserved in children with deprivation amblyopia due to unilateral cataract. The purpose of this study was to investigate whether a contrast-rebalanced binocular treatment, recently used with success to treat the interocular suppression and amblyopia in strabismic and anisometropic children, can contribute to rehabilitation of visual acuity in children with deprivation amblyopia secondary to monocular cataract.

METHODS

In a pilot randomized trial, 15 children (4-13 years of age) were enrolled and randomized to continue with their current treatment only (n = 7) or to continue with their current treatment and add contrast-rebalanced binocular iPad game play 5 hours/week for 4 weeks (n = 8). The primary outcome was change in visual acuity at 4 weeks.

RESULTS

Although 10 of 15 participants were patching, there was little change in visual acuity during the 3 months prior to enrollment. At the 4-week primary outcome visit, the mean improvement in visual acuity for the binocular game group was significantly greater than that for the current-treatment group (0.08 ± 0.10 logMAR vs -0.03 ± 0.05 logMAR [t_10.2 = 2.53, P = 0.03]). None of the children who had dense congenital cataract achieved improved visual acuity with binocular treatment.

CONCLUSIONS

In this study cohort, visual acuity improved over 8 weeks in children with unilateral deprivation amblyopia who played a binocular contrast-rebalanced binocular iPad game.

A randomized clinical trial of contrast increment protocols for binocular amblyopia treatment

BACKGROUND

Most clinical trials of contrast-rebalanced binocular amblyopia treatment used a contrast increment protocol of 10% daily with successful play. Paired with a definition of success requiring only 15-30 min/day of gameplay, this increment protocol could allow children to reach 100% fellow eye contrast in 3-9 hours; however, this may not provide adequate therapeutic time with reduced fellow eye contrast. The purpose of this study was to compare the original protocol against three alternative contrast increment protocols designed to increase the number of treatment hours.

METHODS

In this prospective study, 63 amblyopic children (4-10 years; amblyopic eye visual acuity, 20/40-125) were randomly assigned one of four daily contrast increment protocols for 4 weeks, all starting with 20% fellow eye contrast: 10%, 5%, 0%, or 10% for first 4 weeks then reset to 20% and repeat 10% increment for the final 4 weeks. Children played contrast-rebalanced games for 1 hour/day, 5 days/week. Best-corrected visual acuity, stereoacuity, and suppression were assessed at baseline and every 2 weeks until the 8-week outcome visit.

RESULTS

At baseline, mean amblyopic eye best-corrected visual acuity was 0.47 ± 0.14 logMAR (20/60), improving overall 0.14 ± 0.08 logMAR (1.4 lines; P < 0.0001) at 8 weeks. All four protocols resulted in similar improvement in visual acuity (0.13-0.16 logMAR; all Ps < 0.0002). Stereoacuity and suppression also improved (all Ps < 0.05).

CONCLUSIONS

None of the new protocols resulted in less improvement than the original 10% contrast increment protocol. Contrast-rebalanced binocular games yielded significant improvements in visual acuity, stereoacuity, and suppression with or without daily contrast increments.

Associations of Eye-Related Quality of Life With Vision, Visuomotor Function, and Self-Perception in Children With Strabismus and Anisometropia

Purpose

To evaluate associations between eye-related quality of life (ER-QOL) assessed by the Child Pediatric Eye Questionnaire (Child PedEyeQ) and functional measures (vision, visuomotor function, self-perception) in children with strabismus, anisometropia, or both. Our hypothesis was that children with functional deficits would have lower ER-QOL, and if so, these associations would support the convergent construct validity of the Child PedEyeQ.

Methods

We evaluated 114 children (ages 5-11 years) with strabismus, anisometropia, or both. Each child completed the Child PedEyeQ to assess four Rasch-scored domains of ER-QOL: Functional Vision, Bothered by Eyes/Vision, Social, and Frustration/Worry. In addition, children completed one or more functional tests: visual acuity (n = 114), Randot Preschool Stereoacuity (n = 92), contrast balance index (suppression; n = 91), Readalyzer reading (n = 44), vergence instability (n = 50), Movement Assessment Battery for Children-2 manual dexterity (n = 57), and Pictorial Scale of Perceived Competence and Social Acceptance for Young Children (n = 44).

Results

Child PedEyeQ Functional Vision domain scores were correlated with self-perception of physical competence (rs = 0.65; 95% confidence interval [CI], 0.35-0.96) and reading speed (rs = 0.47; 95% CI, 0.16-0.77). Bothered by Eyes/Vision domain scores were correlated with self-perception of physical competence (rs = 0.52; 95% CI, 0.21-0.83). Moderate correlations were observed between Social domain scores and vergence instability (rs = -0.46; 95% CI, -0.76 to -0.15) and self-perception of physical competence (rs = 0.43; 95% CI, 0.12-0.73) and peer acceptance (rs = 0.49; 95% CI, 0.18-0.80). Frustration/Worry domain scores were moderately correlated with self-perception of physical competence (rs = 0.41; 95% CI, 0.10-0.71) and peer acceptance (rs = 0.47; 95% CI, 0.16-0.77).

Conclusions

Strong and moderate correlations were observed between functional measures and Child PedEyeQ domain scores. These associations provide supporting evidence that the Child PedEyeQ has convergent construct validity.

Eye-related quality of life and functional vision in children wearing glasses

PURPOSE

To evaluate eye-related quality of life (ER-QOL) and functional vision in children wearing glasses using the Pediatric Eye Questionnaire (PedEyeQ).

METHODS

Children 5-17 years of age with normal visual acuity who wore glasses for correction of refractive error and with no other eye condition or treatment and control subjects who did not wear glasses, along with 1 parent for each child, were prospectively enrolled. Children completed the Child 5-11 or 12-17 PedEyeQ (four domains); parents completed the Proxy 5-11 or 12-17 questionnaires (perceived effect on child; five domains) and also the Parent questionnaire (effect on parent themselves; four domains). Each domain was Rasch-scored (converted to 0-100), and scores between groups were compared.

RESULTS

A total of 40 subjects and 99 non-glasses-wearing controls, along with 1 parent for each child, were included. Children 5-11 and 12-17 years of age who wore glasses had lower PedEyeQ scores across all domains compared with controls (mean differences, -6 to -15; P ≤ 0.04 for each domain). Proxy scores were also lower for glasses wearers across age groups and domains (mean differences, -4 to -18; P ≤ 0.02), and Parent scores were lower for parents of children wearing glasses (mean differences, -6 to -18; P < 0.001 for each domain).

CONCLUSIONS

In this study, glasses wearers had reduced ER-QOL and functional vision compared with control subjects. Parents of children wearing glasses also experience reduced quality of life.

Worth 4 Dot App for Determining Size and Depth of Suppression

Purpose

To describe and evaluate an iOS application suppression test, Worth 4 Dot App (W4DApp), which was designed and developed to assess size and depth of suppression.

Methods

Characteristics of sensory fusion were evaluated in 25 participants (age 12–69 years) with normal (n = 6) and abnormal (n = 19) binocular vision. Suppression zone size and classification of fusion were determined by W4DApp and by flashlight Worth 4 Dot (W4D) responses from 33 cm to 6 m. Measures of suppression depth were compared between the W4DApp, the flashlight W4D with neutral density filter bar and the dichoptic letters contrast balance index test.

Results

There was high agreement in classification of fusion between the W4DApp method and that derived from flashlight W4D responses from 33 cm to 6 m (α = 0.817). There were no significant differences in success rates or in reliability between the W4DApp or the flashlight W4D methods for determining suppression zone size. W4DApp suppression zone size strongly correlated to that determined with the flashlight W4D (rho = 0.964, P < 0.001). W4DApp depth of suppression measures showed significantly higher success rates (χ² = 5.128, P = 0.043) and reliability (intraclass correlation analysis = 0.901) but no significant correlation to the depth of suppression calculated by flashlight W4D and neutral density bar (rho = 0.301, P = 0.399) or contrast balance index (rho = −0.018, P = 0.958).

Conclusions

The W4DApp has potential clinical benefit in measuring suppression zone size; however, further modifications are required to improve validity of suppression depth measures.

Translational Relevance

W4DApp iOS application will be a convenient tool for clinical determination of suppression characteristics.

Self-perception in Children Aged 3 to 7 Years With Amblyopia and Its Association With Deficits in Vision and Fine Motor Skills

Importance

Deficits in fine motor skills and slow reading speed have been reported in school-aged children and adults with amblyopia. These deficits were correlated with lower self-perception of athletic and cognitive competence. Although perceived competence and social acceptance are key determinants of developing self-perception in young children, the association of amblyopia with self-perception and the association of altered self-perception with fine motor skills to date have not been reported for young children aged 3 to 7 years.

Objectives

To investigate whether amblyopia is associated with altered self-perception in young children and to assess whether any differences in self-perception are associated with deficits in vision and fine motor skills.

Design, Setting, and Participants

In this cross-sectional study, conducted at a pediatric vision laboratory from January 10, 2016, to May 4, 2018, healthy children aged 3 to 7 years (preschool to second grade) were enrolled, including 60 children with amblyopia; 30 children who never had amblyopia but had been treated for strabismus, anisometropia, or both; and 20 control children.

Main Outcomes and Measures

Self-perception was assessed using the Pictorial Scale of Perceived Competence and Social Acceptance for Young Children, which includes the following 4 specific domains: cognitive competence, peer acceptance, physical competence, and maternal acceptance (total score range, 1-4; higher scores indicate higher perceived competence or acceptance). Fine motor skills were evaluated with the Manual Dexterity and Aiming and Catching scales of the Movement Assessment Battery for Children, second edition (score range, 1-19; higher scores indicate better skill performance). Visual acuity and stereoacuity also were assessed.

Results

Children with amblyopia (28 girls and 32 boys; mean [SD] age, 6.3 [1.3] years) had significantly lower mean (SD) peer acceptance and physical competence scores compared with the control children (peer acceptance, 2.74 [0.66] vs 3.11 [0.36]; mean difference, 0.37; 95% CI for difference, 0.06-0.68; P = .04; and physical competence, 2.86 [0.60] vs 3.43 [0.52]; mean difference, 0.57; 95% CI for difference, 0.27-0.87; P = .009). Among the children with amblyopia, self-perception of physical competence was significantly correlated with aiming and catching skills (r = 0.43; 95% CI, 0.10-0.67; P = .001) and stereoacuity (r = -0.39; 95% CI, -0.05 to -0.65; P = .02). Children treated for strabismus or anisometropia, but who never had amblyopia, also had significantly lower mean (SD) physical competence scores compared with control children (2.89 [0.54] vs 3.43 [0.52]; 95% CI for difference, 0.23-0.85; P = .03).

Conclusions and Relevance

These findings suggest that lower self-perception of peer acceptance and physical competence identify the broad effects of altered visual development in the everyday life of children with amblyopia.

Validation of the Pediatric Eye Questionnaire in Children with Visual Impairment

PURPOSE

To evaluate the recently developed Pediatric Eye Questionnaire (PedEyeQ) in visually impaired and visually normal children, as an initial validation of the PedEyeQ.

DESIGN

Questionnaire validation study.

METHODS

A total of 48 children with visual impairment (retinal, cortical, and corneal conditions) and 59 visually normal controls were enrolled at 2 centers. Five- to 17-year-old children completed the Child PedEyeQ (5-11- and 12-17-year-old versions), and parents completed the Proxy PedEyeQ (0-4-, 5-11-, and 12-17-year-old versions) and the Parent PedEyeQ. Rasch scores were calculated by age group for each distinct domain within each age-specific PedEyeQ (converted to 0-100 for interpretation). Domains for the Child PedEyeQ are functional vision, bothered by eyes/vision, social, and frustration/worry. Proxy PedEyeQ domains are functional vision, bothered by eyes/vision, social, frustration/worry, and eye care. Parent PedEyeQ domains are impact on parent and family, worry about child's eye condition, worry about child's self-perception/interactions, and worry about child's functional vision. For each domain, median PedEyeQ scores were compared between visually impaired and visually normal cohorts.

RESULTS

Child 5-11 and 12-17 PedEyeQ scores were significantly lower (worse) for visually impaired children than for controls for each domain (P < .007), except for the social domain in 5-11-year-old children (P = .13). In addition, Proxy 0-4-, 5-11-, and 12-17-year-old PedEyeQ scores, and Parent PedEyeQ scores, were lower for visually impaired children across all domains (P < .001).

CONCLUSIONS

Visually impaired children and their parents had significantly lower (worse) PedEyeQ scores than visually normal controls, across functional vision and eye-related quality of life domains, demonstrating known-group validity of the PedEyeQ in children with visual impairment.

Self-perception of School-aged Children With Amblyopia and Its Association With Reading Speed and Motor Skills

Importance

Reading and eye-hand coordination deficits in children with amblyopia may impede their ability to demonstrate their knowledge and skills, compete in sports and physical activities, and interact with peers. Because perceived scholastic, social, and athletic competence are key determinants of self-esteem in school-aged children, these deficits may influence a child's self-perception.

Objective

To determine whether amblyopia is associated with lowered self-perception of competence, appearance, conduct, and global self-worth and whether the self-perception of children with amblyopia is associated with their performance of reading and eye-hand tasks.

Design, Setting, and Participants

This cross-sectional study was conducted from January 2016 to June 2017 at the Pediatric Vision Laboratory of the Retina Foundation of the Southwest and included healthy children in grades 3 to 8, including 50 children with amblyopia; 13 children without amblyopia with strabismus, anisometropia, or both; and 18 control children.

Main Outcomes and Measures

Self-perception was assessed using the Self-perception Profile for Children, which includes 5 domains: scholastic, social, and athletic competence; physical appearance; behavioral conduct; and a separate scale for global self-worth. Reading speed and eye-hand task performance were evaluated with the Readalyzer (Bernell) and Movement Assessment Battery for Children, 2nd Edition. Visual acuity and stereoacuity also were assessed.

Results

Of 50 participants, 31 (62%) were girls, 31 (62%) were non-Hispanic white, 6 (12%) were Hispanic white, 3 (6%) were African American, 4 (8%) were Asian/Pacific Islander, and 3 (6%) were more than 1 race/ethnicity, and the mean [SD] age was 10.6 [1.3] years. Children with amblyopia had significantly lower scores than control children for scholastic (mean [SD], 2.93 [0.74] vs 3.58 [0.24]; mean [SD] difference, 0.65 [0.36]; 95% CI, 0.29-1.01; P = .004), social (mean [SD], 2.95 [0.64] vs 3.62 [0.35]; mean [SD] difference, 0.67 [0.32]; 95% CI, 0.35-0.99] P < .001), and athletic (mean [SD], 2.61 [0.65] vs 3.43 [0.52]; mean [SD] difference, 0.82 [0.34]; 95% CI, 0.48-1.16; P = .001) competence domains. Among children with amblyopia, a lower self-perception of scholastic competence was associated with a slower reading speed (r = 0.49, 95% CI, 0.17-0.72; P = .002) and a lower self-perception of scholastic, social, and athletic competence was associated with worse performance of aiming and catching (scholastic r = 0.48; 95% CI, 0.16-0.71; P = .007; social r = 0.63; 95% CI, 0.35-0.81; P < .001; athletic r = 0.53; 95% CI, 0.21-0.75; P = .003). No differences in the self-perception of physical appearance (mean [SD], 3.32 [0.63] vs 3.64 [0.40]), conduct (mean [SD], 3.09 [0.56] vs 3.34 [0.66]), or global self-worth (mean [SD], 3.42 [0.42] vs 3.69 [0.36]) were found between the amblyopic and control groups.

Conclusions and Relevance

These findings suggest that lower self-perception is associated with slower reading speed and worse motor skills and may highlight the wide-ranging effects of altered visual development for children with amblyopia in their everyday lives.

Impaired Fellow Eye Motion Perception and Abnormal Binocular Function

Purpose

Binocular discordance due to strabismus, anisometropia, or both may result in not only monocular visual acuity deficits, but also in motion perception deficits. We determined the prevalence of fellow-eye deficits in motion-defined form (MDF) perception, the ability to identify a two-dimensional (2D) shape defined by motion rather than luminance contrast. We also examined the following: the causative role of reduced visual acuity and binocularity, associations with clinical and sensory factors, and effectiveness of binocular amblyopia treatment in alleviating deficits.

Methods

Participants included 91 children with residual amblyopia (strabismic, anisometropic, or both; age, 9.0 ± 1.7 years), 79 nonamblyopic children with treated strabismus or anisometropia (age, 8.5 ± 2.1 years), and 20 controls (age, 8.6 ± 1.5 years). MDF coherence thresholds, visual acuity, stereoacuity, and interocular suppression were measured.

Results

MDF deficits, relative to controls, were present in the fellow eye of 23% of children with residual amblyopia and 20% of nonamblyopic children. Stereoacuity and age first patched were correlated with MDF threshold (r = 0.29, 95% CI: 0.09–0.47; r = −0.33, 95% CI_: −0.13 to −0.50, respectively). MDF deficits were more common in children treated with patching alone than in those receiving contrast-rebalanced binocular treatment with games or movies (t₈₉ = 3.46; P = 0.0008). The latter was associated with a reduction in mean fellow eye MDF threshold (t₂₆ = 6.32, P < 0.0001).

Conclusions

Fellow eye MDF deficits are common and likely reflect abnormalities in binocular cortical mechanisms that result from early discordant visual experience. Binocular amblyopia treatment, which is effective in improving amblyopic eye visual acuity, appears to provide a benefit for the fellow eye.

Fellow Eye Deficits in Amblyopia

Amblyopia is a neurodevelopmental disorder of the visual system, as a result of discordant visual experience during infancy or early childhood. Because amblyopia is typically defined as monocularly reduced visual acuity accompanied by one or more known amblyogenic factors, it is often assumed that the fellow eye is normal and sufficient for tasks like reading and eye-hand coordination. Recent scientific evidence of ocular motor, visual, and visuomotor deficits that are present with fellow eye monocular viewing and with binocular viewing calls this assumption into question. This clinical update reviews the research that has revealed fellow ocular motor and visual deficits and the effect that these deficits have on an amblyopic child's visuomotor and visuocognitive skills. We need to understand how to prevent and rehabilitate the effects of amblyopia not only on the nonpreferred eye but also on the fellow eye.

Binocular amblyopia treatment with contrast-rebalanced movies

BACKGROUND

Binocular amblyopia treatments promote visual acuity recovery and binocularity by rebalancing the signal strength of dichoptic images. Most require active participation by the amblyopic child to play a game or perform a repetitive visual task. The purpose of this study was to investigate a passive form of binocular treatment with contrast-rebalanced dichoptic movies.

METHODS

A total of 27 amblyopic children, 4-10 years of age, wore polarized glasses to watch 6 contrast-rebalanced dichoptic movies on a passive 3D display during a 2-week period. Amblyopic eye contrast was 100%; fellow eye contrast was initially set to a lower level (20%-60%), which allowed the child to overcome suppression and use binocular vision. Fellow eye contrast was incremented by 10% for each subsequent movie. Best-corrected visual acuity, random dot stereoacuity, and interocular suppression were measured at baseline and at 2 weeks.

RESULTS

Amblyopic eye best-corrected visual acuity improved from 0.57 ± 0.22 at baseline to 0.42 ± 0.23 logMAR (t₂₆ = 8.09; P < 0.0001; 95% CI for improvement, 0.11-0.19 logMAR). Children aged 3-6 years had more improvement (0.21 ± 0.11 logMAR) than children aged 7-10 years (0.11 ± 0.06 logMAR; t₂₅ = 3.05; P = 0.005). Children with severe amblyopia (≥0.7 logMAR) at baseline experienced greater improvement (0.24 ± 0.12 logMAR) than children with moderate amblyopia at baseline (0.12 ± 0.06 logMAR; t₂₅ = 3.49; P = 0.002).

CONCLUSIONS

In this cohort, passive viewing of contrast-rebalanced dichoptic movies effectively improved visual acuity in amblyopic subjects. The degree of improvement observed was similar to that previously reported for 2 weeks of binocular games treatment and with 3-4 months of occlusion therapy.

Development of Pediatric Eye Questionnaires for Children With Eye Conditions

PURPOSE

To develop patient-derived Pediatric Eye Questionnaires (PedEyeQ) to separately assess eye-related quality of life (ER-QOL) and functional vision in children with eye conditions.

DESIGN

Questionnaire development study.

METHODS

A total of 444 children (0 to <18 years old), across 10 diagnostic categories, were enrolled at 2 sites. All parents (n = 444) and 277 children (5 to <18 years old) completed master questionnaires, developed from patient-derived concerns. Factor analysis was performed to identify unidimensional domains (eigenvalue >1.0) and Rasch analyses (differential item functioning, targeting, fit) to reduce items (separate analyses for subjects aged 0-4, 5-11, and 12-17 years and for each factor).

RESULTS

The Child 5- to 11-year-old PedEyeQ consisted of 4 unidimensional domains/questionnaires: functional vision, bothered by eyes/vision, social, frustration/worry (10 items each). The Child 12- to 17-year-old PedEyeQ consisted of the same 4 domains (total 39 items). The Proxy 0- to 4-year-old PedEyeQ consisted of 3 questionnaires/domains: functional vision, bothered by eyes/vision, social (total 29 items). The Proxy 5- to 11-year-old PedEyeQ consisted of 5 questionnaires/domains: functional vision, bothered by eyes/vision, social, frustration/worry, eye care (total 39 items), as did the Proxy 12- to 17-year-old PedEyeQ (total 42 items). The Parent PedEyeQ consisted of 4 questionnaires/domains: impact on parent/family, worry regarding child's eye condition, worry regarding child's self-perception and interactions, worry regarding child's visual function (total 35 items). Rasch look-up tables were created for scoring.

CONCLUSIONS

By following a rigorous approach, we have developed Pediatric Eye Questionnaires for separately assessing functional vision and ER-QOL domains in children of any age and with any eye condition.

From suppression to stereoacuity: a composite binocular function score for clinical research

PURPOSE

This study aimed to validate a binocular function score that is based on common clinical measures of visual function, providing a more complete analysis of binocular outcomes, against laboratory-based dichoptic tests of threshold stereoacuity and depth of suppression.

METHODS

Scores on a composite binocular function (BF) score derived from clinical stereoacuity measures (Randot Preschool Stereoacuity Test and Randot Butterfly) and the Worth 4 Dot test were determined in adults (n = 20; age 24.8 ± 7.2 years) and children (N = 77; age 8.3 ± 1.7 years) with abnormal binocular vision from strabismus or amblyopia. Adults had threshold stereoacuity measured with a novel, computerised dichoptic psychophysical test of stereopsis. Depth of suppression (dichoptic eye chart inter-ocular contrast balance test) was determined in both adults and children.

RESULTS

Clinical Randot stereoacuity was measurable in 50% of adult and 61% of child participants. Threshold stereoacuity was measurable in 65% of the adult participants. The presence of suppression or simultaneous perception (flat fusion or diplopia) was measurable in all participants, enabling assignment of a BF score to all participants in both groups. In adults, the BF score was highly correlated with the psychophysical threshold stereoacuity measure (ρ = 0.71; p < 0.001). In both adults and children, there was also a high correlation between the BF score and inter-ocular contrast balance (adult ρ = 0.90; child ρ = 0.86; p < 0.001).

CONCLUSIONS

The composite BF score is a convenient and valid scale of binocularity that can be used to extend the stereoacuity measure in cohorts where nil stereoacuity is common and thus could be considered as an outcome measure in clinical trials.

Improved Binocular Outcomes Following Binocular Treatment for Childhood Amblyopia

Purpose

Childhood amblyopia can be treated with binocular games or movies that rebalance contrast between the eyes, which is thought to reduce depth of interocular suppression so the child can experience binocular vision. While visual acuity gains have been reported following binocular treatment, studies rarely report gains in binocular outcomes (i.e., stereoacuity, suppression) in amblyopic children. Here, we evaluated binocular outcomes in children who had received binocular treatment for childhood amblyopia.

Methods

Data for amblyopic children enrolled in two ongoing studies were pooled. The sample included 41 amblyopic children (6 strabismic, 21 anisometropic, 14 combined; age 4–10 years; ≤4 prism diopters [PD]) who received binocular treatment (20 game, 21 movies; prescribed 9–10 hours treatment). Amblyopic eye visual acuity and binocular outcomes (Randot Preschool Stereoacuity, extent of suppression, and depth of suppression) were assessed at baseline and at 2 weeks.

Results

Mean amblyopic eye visual acuity (P < 0.001) and mean stereoacuity improved (P = 0.045), and mean extent (P = 0.005) and depth of suppression (P = 0.003) were reduced from baseline at the 2-week visit (87% game adherence, 100% movie adherence). Depth of suppression was reduced more in children aged <8 years than in those aged ≥8 years (P = 0.004). Worse baseline depth of suppression was correlated with a larger depth of suppression reduction at 2 weeks (P = 0.001).

Conclusions

After 2 weeks, binocular treatment in amblyopic children improved visual acuity and binocular outcomes, reducing the extent and depth of suppression and improving stereoacuity. Binocular treatments that rebalance contrast to overcome suppression are a promising additional option for treating amblyopia.

Multiple-Choice Answer Form Completion Time in Children With Amblyopia and Strabismus

Importance

Abnormal binocular experience during infancy or childhood from strabismus and/or anisometropia results in visual acuity deficits (eg, amblyopia) and impaired stereoacuity. These pediatric eye conditions have also been linked to slow reading and fine motor impairment.

Objective

To assess an academic-related fine motor outcome-multiple-choice answer form completion time-in children with amblyopia and strabismus.

Design, Setting, and Participants

In this cross-sectional study completed between May 2014 and November 2017 at a nonprofit eye research institute, 47 children with amblyopia treated for strabismus, anisometropia, or both, 18 children with nonamblyopic strabismus, and 20 normal controls were enrolled.

Exposures

Children were asked to transfer the correct answers from a standardized reading achievement test booklet to a multiple-choice answer form as quickly as possible without making mistakes or reading the text.

Main Outcomes and Measures

The time to complete the task was recorded and analyzed between groups.

Results

Of the 85 included children, 40 (47%) were female, the mean (SD) age was 10.09 (0.91) years, and the last mean (SD) grade completed was 3.42 (0.92). Compared with children in the control group (mean [SD] time to completion, 230 [63] seconds), children with amblyopia (mean [SD] time to completion, 297 [97] seconds; difference, 63 seconds; 95% CI, 24-102; P = .001) and children with nonamblyopic strabismus (mean [SD] time to completion, 293 [53] seconds; difference, 68 seconds; 95% CI, 21-115; P = .002) required approximately 28% (95% CI, 20-37) more time to fill out a multiple-choice answer form. Completion time was not associated with etiology, visual acuity, or stereoacuity.

Conclusions and Relevance

Multiple-choice answer forms typically accompany standardized testing in schools in the United States. Longer completion time in children with amblyopia or strabismus may affect a child's performance on tests using multiple-choice answer forms and may hinder academic success.

Pediatric ophthalmology and childhood reading difficulties: Amblyopia and slow reading

Reading is a major life activity, as recognized by the US Congress in the Americans with Disabilities Act Amendments Act of 2008, and the education code of most US states requires schools to evaluate reading and implement reading programs to addresses students' reading difficulties. Currently, such legislation is employed to identify accommodations needed for children with bilateral visual impairment and for children with dyslexia and/or related learning disabilities. Yet recent research has shown that children with the most common form of monocular visual impairment-amblyopia-read slowly. Slow reading can be detrimental to academic performance and learning, which in turn may affect self-esteem. Parents and educators can work together to implement accommodations (eg, extra time) to help amblyopic students succeed in their daily school tasks, and improve their performance on the timed, standardized tests that are critical for promotion and admission to magnet schools, TAG programs, high schools, and colleges. Children with other visual disorders that cause visual impairment in one eye (eg, glaucoma, cataract, trauma, etc) should also be considered for academic accommodations.

Slow reading in children with anisometropic amblyopia is associated with fixation instability and increased saccades

BACKGROUND

Previous studies show slow reading in strabismic amblyopia. We recently identified amblyopia, not strabismus, as the key factor in slow reading in children. No studies have focused on reading in amblyopic children without strabismus. We examined reading in anisometropic children and evaluated whether slow reading was associated with ocular motor dysfunction in children with amblyopia.

METHODS

Anisometropic children (7-12 years) with or without amblyopia were compared to age-similar normal controls. Children silently read a grade-appropriate paragraph during binocular viewing. Reading rate (words/min), number of forward and regressive saccades (per 100 words) and fixation duration were recorded with the ReadAlyzer. Binocular fixation instability was also evaluated (EyeLink 1000).

RESULTS

Amblyopic anisometropic children read more slowly (n = 25; mean with standard deviation, 149 ± 42 words/min) than nonamblyopic anisometropic children (n = 15; 196 ± 80 words/min; P = 0.024) and controls (n = 25; 191 ± 65 words/min; P = 0.020). Nonamblyopic anisometropic children read at a comparable rate to controls (P = 0.81). Slow reading in amblyopic anisometropic children was correlated with increased forward saccades (r = -0.84, P < 0.001), increased regressive saccades (r = -0.85, P < 0.001), and fellow eye instability during binocular viewing (r = -0.52, P = 0.019).

CONCLUSIONS

Slow reading in school-age children with anisometropic amblyopia is related to increased frequency of saccades and fixation instability of the fellow eye. Further research should consider the effects of slower reading on academic performance.

Relationship among clinical factors in childhood intermittent exotropia

PURPOSE

To determine the relationships between stereoacuity, control of exotropia, and angle of deviation in children with intermittent exotropia (IXT).

METHODS

Data collected for 652 participants 3 to <11 years of age with IXT meeting eligibility criteria for enrollment into one of two multicenter, randomized clinical trials were used to evaluate relationships between stereoacuity, control, and angle of deviation at enrollment.

RESULTS

Any level of stereoacuity and angle of deviation could be accompanied by any level of control. Worse distance exotropia control was weakly associated with poorer distance stereoacuity (R = 0.26; 99% CI, 0.17-0.36) and larger angles of deviation at distance (R = 0.27; 99% CI, 0.17-0.36). Worse near exotropia control was weakly associated with poorer near stereoacuity (R = 0.17; 99% CI, 0.07-0.27) and moderately associated with larger angles of deviation at near (R = 0.37; 99% CI, 0.28-0.45). There was no association between stereoacuity and angle of deviation at distance (R = 0.07; 99% CI, -0.03 to 0.17) or at near (R = 0.02; 99% CI, -0.08 to 0.12).

CONCLUSIONS

Although weak and moderate associations were found between stereoacuity, control, and angle of deviation, a child may exhibit any combination of stereoacuity, control, and angle of deviation. The specific roles of control, stereoacuity, and angle of deviation in the diagnosis, management, and pathogenesis of IXT are unclear, and each appears to yield somewhat independent information.

Congenitally Impaired Disparity Vergence in Children With Infantile Esotropia

Purpose

We examined whether congenital impairment of disparity vergence in infantile esotropia (ET) exists in children with short duration ET (≤3 months) compared with long-duration ET and healthy controls. A short duration of misalignment would allow for a substantial amount of balanced binocular input during the critical period of binocular disparity development.

Methods

A total of 19 children aged 5 to 12 years and treated for infantile ET with a short (≤3 months; n = 10) or long (≥5 months; n = 9) duration of constant misalignment before alignment were enrolled. A total of 22 healthy control children were enrolled as a comparison group. Eye movements during disparity vergence and accommodative vergence were recorded using an EyeLink 1000 binocular eye tracker. Mean response gain was compared between and within groups to determine the effect of duration of misalignment and viewing condition.

Results

Compared with controls, children with short (P = 0.002) and long (P < 0.001) duration infantile ET had reduced response gains for disparity vergence, but not for accommodative vergence (P = 0.19).

Conclusions

Regardless of duration of misalignment, children with infantile ET had reduced disparity vergence, consistent with a congenital impairment of disparity vergence in infantile ET. Although early correction of misalignment increases the likelihood that some level of binocular disparity sensitivity will be present, normal levels may never be achieved.

Bilateral childhood visual impairment: child and parent concerns

PURPOSE

To identify specific health-related quality of life and visual function concerns affecting children with bilateral visual impairment as expressed by children or one of their parents (proxy) and concerns affecting the parents themselves.

METHODS

A total of 37 children <16 years of age with visual impairment (visual acuity worse than 20/70 in the better eye) and one parent for each child were prospectively enrolled. Semistructured individual interviews were performed with children 5-15 years of age (n = 16) and with one parent for each child (ages 0-15 years, N = 37). Interview transcripts were analyzed using NVivo software. Categories of concern were identified from both child and parent interviews, from which broad themes were identified. The frequencies of the themes and specific categories of concerns were calculated.

RESULTS

Regarding the child's experience, categories of concern were grouped into 6 themes: visual function (expressed by 13 of 16 children [81%] and 33 of 37 parents [89%]), treatment (63% and 54%), emotions (50% and 68%), social (50% and 70%), physical discomfort (50% and 22%), and worry (38% and 8%). Concerns expressed regarding the parents' own experience were grouped into 5 themes: worry (100%), compensate-adjust for condition (89%), treatment (84%), emotions (81%), and affects family (46%).

CONCLUSIONS

Individual interviews identified a wide spectrum of concerns in children with visual impairment and their parents, affecting functional, emotional, social and physical domains. Specific concerns will be used to develop patient-derived questionnaires for quantifying the effects of visual impairment on children and parents in everyday life.

Assessing Suppression in Amblyopic Children With a Dichoptic Eye Chart

Purpose

Suppression has a key role in the etiology of amblyopia, and contrast-balanced binocular treatment can overcome suppression and improve visual acuity. Quantitative assessment of suppression could have a role in managing amblyopia. We describe a novel eye chart to assess suppression in children.

Methods

We enrolled 100 children (7–12 years; 63 amblyopic, 25 nonamblyopic with strabismus or anisometropia, 12 controls) in the primary cohort and 22 children (3–6 years; 13 amblyopic, 9 nonamblyopic) in a secondary cohort. Letters were presented on a dichoptic display (5 letters per line). Children wore polarized glasses so that each eye saw a different letter chart. At each position, the identity of the letter and its contrast on each eye's chart differed. Children read 8 lines of letters for each of 3 letter sizes. The contrast balance ratio was the ratio at which 50% of letters seen by the amblyopic eye were reported.

Results

Amblyopic children had significantly higher contrast balance ratios for all letter sizes compared to nonamblyopic children and controls, requiring 4.6 to 5.6 times more contrast in the amblyopic eye compared to the fellow eye (P < 0.0001). Amblyopic eye visual acuity was correlated with contrast balance ratio (r ranged from 0.49–0.57 for the 3 letter sizes). Change in visual acuity with amblyopia treatment was correlated with change in contrast balance ratio (r ranged from 0.43–0.62 for the 3 letter sizes).

Conclusions

Severity of suppression can be monitored as part of a routine clinical exam in the management of amblyopia in children.

Effect of a Binocular iPad Game vs Part-time Patching in Children Aged 5 to 12 Years With Amblyopia: A Randomized Clinical Trial

Importance

A binocular approach to treating anisometropic and strabismic amblyopia has recently been advocated. Initial studies have yielded promising results, suggesting that a larger randomized clinical trial is warranted.

Objective

To compare visual acuity (VA) improvement in children with amblyopia treated with a binocular iPad game vs part-time patching.

Design, Setting, and Participants

A multicenter, noninferiority randomized clinical trial was conducted in community and institutional practices from September 16, 2014, to August 28, 2015. Participants included 385 children aged 5 years to younger than 13 years with amblyopia (20/40 to 20/200, mean 20/63) resulting from strabismus, anisometropia, or both. Participants were randomly assigned to either 16 weeks of a binocular iPad game prescribed for 1 hour a day (190 participants; binocular group) or patching of the fellow eye prescribed for 2 hours a day (195 participants; patching group). Study follow-up visits were scheduled at 4, 8, 12, and 16 weeks. A modified intent-to-treat analysis was performed on participants who completed the 16-week trial.

Interventions

Binocular iPad game or patching of the fellow eye.

Main Outcomes and Measures

Change in amblyopic-eye VA from baseline to 16 weeks.

Results

Of the 385 participants, 187 were female (48.6%); mean (SD) age was 8.5 (1.9) years. At 16 weeks, mean amblyopic-eye VA improved 1.05 lines (2-sided 95% CI, 0.85-1.24 lines) in the binocular group and 1.35 lines (2-sided 95% CI, 1.17-1.54 lines) in the patching group, with an adjusted treatment group difference of 0.31 lines favoring patching (upper limit of the 1-sided 95% CI, 0.53 lines). This upper limit exceeded the prespecified noninferiority limit of 0.5 lines. Only 39 of the 176 participants (22.2%) randomized to the binocular game and with log file data available performed more than 75% of the prescribed treatment (median, 46%; interquartile range, 20%-72%). In younger participants (aged 5 to <7 years) without prior amblyopia treatment, amblyopic-eye VA improved by a mean (SD) of 2.5 (1.5) lines in the binocular group and 2.8 (0.8) lines in the patching group. Adverse effects (including diplopia) were uncommon and of similar frequency between groups.

Conclusions and Relevance

In children aged 5 to younger than 13 years, amblyopic-eye VA improved with binocular game play and with patching, particularly in younger children (age 5 to <7 years) without prior amblyopia treatment. Although the primary noninferiority analysis was indeterminate, a post hoc analysis suggested that VA improvement with this particular binocular iPad treatment was not as good as with 2 hours of prescribed daily patching.

Trial Registration

http://www.clinicaltrials.gov Identifier: NCT02200211.

Binocular iPad Game vs Patching for Treatment of Amblyopia in Children: A Randomized Clinical Trial

Importance

Fellow eye patching has long been the standard treatment for amblyopia, but it does not always restore 20/20 vision or teach the eyes to work together. Amblyopia can be treated with binocular games that rebalance contrast between the eyes so that a child may overcome suppression. However, it is unclear whether binocular treatment is comparable to patching in treating amblyopia.

Objectives

To assess the effectiveness of a binocular iPad (Apple Inc) adventure game as amblyopia treatment and compare this binocular treatment with patching, the current standard of care.

Design, Setting, and Participants

This investigation was a randomized clinical trial with a crossover design at a nonprofit eye research institute. Between February 20, 2015, and January 4, 2016, a total of 28 patients were enrolled in the study, with 14 randomized to binocular game treatment and 14 to patching treatment.

Interventions

Binocular game and patching as amblyopia treatments.

Main Outcomes and Measures

The primary outcome was change in amblyopic eye best-corrected visual acuity (BCVA) at the 2-week visit. Secondary outcomes were change in stereoacuity and suppression at the 2-week visit and change in BCVA at the 4-week visit.

Results

Among 28 children, the mean (SD) age at baseline was 6.7 (1.4) years (age range, 4.6-9.5 years), and 7 (25%) were female. At baseline, the mean (SD) amblyopic eye BCVA was 0.48 (0.14) logMAR (approximately 20/63; range, 0.3-0.8 logMAR [20/40 to 20/125]), with 14 children randomized to the binocular game and 14 to patching for 2 weeks. At the 2-week visit, improvement in amblyopic eye BCVA was greater with the binocular game compared with patching, with a mean (SD) improvement of 0.15 (0.08) logMAR (mean [SD], 1.5 [0.8] lines) vs 0.07 (0.08) logMAR (mean [SD], 0.7 [0.8] line; P = .02) after 2 weeks of treatment. These improvements from baseline were significant for the binocular game (mean [SD] improvement, 1.5 [0.8] lines; P < .001) and for patching (mean [SD] improvement, 0.7 [0.8] line; P = .006). Depth of suppression improved from baseline at the 2-week visit for the binocular game (mean [SD], 4.82 [2.82] vs 3.24 [2.87]; P = .03) and for patching (mean [SD], 4.77 [3.10] vs 2.57 [1.67]; P = .004). Patching children crossed over to binocular game treatment, and all 28 children played the game for another 2 weeks. At the 4-week visit, no group difference was found in BCVA change, with children who crossed over to the binocular games catching up with children treated with binocular games, for a mean (SD) improvement of 0.17 (0.10) logMAR (mean [SD], 1.7 [1.0] lines) for the binocular game vs a mean (SD) improvement of 0.16 (0.12) logMAR (mean [SD], 1.6 [1.2] lines) for the patching crossover (P = .73).

Conclusions and Relevance

A binocular iPad game was effective in treating childhood amblyopia and was more efficacious than patching at the 2-week visit. Binocular games that rebalance contrast to overcome suppression are a promising additional option for treating amblyopia.

Trial Registration

clinicaltrials.gov Identifier: NCT02365090.

Comparison of Rating Scales in the Development of Patient-Reported Outcome Measures for Children with Eye Disorders

BACKGROUND

A rating scale is a critical component of patient-reported outcome instrument design, but the optimal rating scale format for pediatric use has not been investigated. We compared rating scale performance when administering potential questionnaire items to children with eye disorders and their parents.

METHODS

Three commonly used rating scales were evaluated: frequency (never, sometimes, often, always), severity (not at all, a little, some, a lot), and difficulty (not difficult, a little difficult, difficult, very difficult). Ten patient-derived items were formatted for each rating scale, and rating scale testing order was randomized. Both child and parent were asked to comment on any problems with, or a preference for, a particular scale. Any confusion about options or inability to answer was recorded.

RESULTS

Twenty-one children, aged 5-17 years, with strabismus, amblyopia, or refractive error were recruited, each with one of their parents. Of the first 10 children, 4 (40%) had problems using the difficulty scale, compared with 1 (10%) using frequency, and none using severity. The difficulty scale was modified, replacing the word "difficult" with "hard." Eleven additional children (plus parents) then completed all 3 questionnaires. No children had problems using any scale. Four (36%) parents had problems using the difficulty ("hard") scale and 1 (9%) with frequency. Regarding preference, 6 (55%) of 11 children and 5 (50%) of 10 parents preferred using the frequency scale.

CONCLUSIONS

Children and parents found the frequency scale and question format to be the most easily understood. Children and parents also expressed preference for the frequency scale, compared with the difficulty and severity scales. We recommend frequency rating scales for patient-reported outcome measures in pediatric populations.