Natural history of amblyopia untreated owing to lack of compliance

Do Socioeconomic Inequalities Exist Within Ophthalmology and Orthoptics in the UK?: A Scoping Review

Introduction

It is well documented that socioeconomic disadvantage adversely affects general health and ocular health worldwide. Within orthoptics, while clinicians recognise a relationship between socioeconomic situation and treatment outcome, no previous literature review was found to address this issue. Neither was a UK-specific literature review found to address the same issue for ophthalmology as a whole.

Aim

This literature review evaluates evidence for an association between socioeconomic situation and ophthalmic/orthoptic conditions and their treatment outcomes, specifically within the UK.

Methods

Keyword searches were conducted on Google Scholar and the University of Liverpool library catalogue. Results for the main analyses were limited to full papers, specific to the UK, written in English. Literature was only included from pre-2000 if more recent evidence was insufficient.

Results

There is evidence of socioeconomic disadvantage being associated with the following: reduced visual acuity; reduced attendance at diabetic retinopathy screening appointments; and delayed presentation of glaucoma, cataracts, and diabetic retinopathy. However, evidence linking socioeconomic disadvantage to AMD is mixed. There is limited evidence of the increased prevalence of amblyopia and subsequent barriers to its treatment for socioeconomically underserved children. There is also evidence of a reduction in quality of life for socioeconomically underserved adults with strabismus.

Conclusions

Health inequalities within ophthalmology and orthoptics are reported, but with confounding results for some conditions. Further research should explore the reasons behind the inequalities that are found and identify methods of reducing them.

Visual Acuity Outcomes and Loss to Follow-up in the Treatment of Amblyopia in Children From Lower Socioeconomic Backgrounds

PURPOSE

To compare visual acuity outcomes and loss to follow-up after initiation of treatment for unilateral amblyopia in children from different socioeconomic backgrounds.

METHODS

Medical records of children diagnosed as having unilateral amblyopia at an initial encounter between 2015 and 2018 were reviewed. Medicaid and private insurance were used as proxies for socioeconomic status (SES). Data points were collected at the patients' initial, follow-up, and final visits. Visual acuity improvement was the primary outcome variable in patients with at least one follow-up appointment. In a separate analysis, failure to attend a single follow-up appointment was examined for associations with SES, race, sex, and distance traveled to appointments.

RESULTS

Seventy-three patients met the inclusion criteria; of these, 28 had Medicaid and 45 had private insurance. Visual acuity improved by 2.86 lines in the Medicaid group and 2.98 lines in the private insurance group (P = .84). Number of missed appointments and distance traveled did not correlate with visual acuity improvement. In the loss to follow-up subanalysis, 40 of 141 (28.4%) patients with Medicaid and 11 of 107 (10.3%) patients with private insurance failed to attend a single follow-up visit (P = .001). No association was found between loss to follow-up and race, sex, or distance traveled.

CONCLUSIONS

Visual acuity outcomes of treatment for amblyopia did not differ between patients with Medicaid and patients with private insurance who followed up. However, patients with Medicaid were much more likely to be immediately lost to follow-up. Measures should be taken by eye care providers and pediatricians to increase follow-up in patients from low SES populations. [J Pediatr Ophthalmol Strabismus. 2022;59(2):110-117.].

Retinoblastoma and vision

The assessment of vision has a growing importance in the management of retinoblastoma in the era of globe-conserving therapy, both prior to and after treatment. As survival rates approach 98-99% and globe salvage rates reach ever-higher levels, it is important to provide families with information regarding the visual outcomes of different treatments. We present an overview of the role of vision in determining the treatment given and the impact of complications of treatment. We also discuss screening and treatment strategies that can be used to maximise vision.

Amblyopia treatment: an evidence‐based approach to maximising treatment outcome

The basis of treatment for amblyopia (poor vision due to abnormal visual experience early in life) for 250 years has been patching of the unaffected eye for extended times to ensure a period of use of the affected eye. Over the last decade randomised controlled treatment trials have provided some evidence on how to tailor amblyopia therapy more precisely to achieve the best visual outcome with the least negative impact on the patient and the family. This review highlights the expansion of knowledge regarding treatment for amblyopia and aims to provide optometrists with a summary of research evidence to enable them to better treat amblyopia. Treatment for amblyopia is effective, as it reduces overall prevalence and severity of visual loss in this population. Correction of refractive error alone significantly improves visual acuity, sometimes to the point where further amblyopia treatment is not required. Atropine penalisation and patch occlusion are effective in treating amblyopia. Lesser amounts of occlusion or penalisation have been found to be just as effective as greater amounts. Recent evidence has highlighted that occlusion or penalisation in amblyopia treatment can create negative changes in behaviour in children and impact on family life. These complications should be considered when prescribing treatment because they can negatively affect compliance. Studies investigating the maximum age at which treatment of amblyopia can still be effective and the importance of near activities during occlusion are ongoing.

Amblyopia: prevalence, natural history, functional effects and treatment

Amblyopia, defined as poor vision due to abnormal visual experience early in life, affects approximately three per cent of the population and carries a projected lifetime risk of visual loss of at least 1.2 per cent. The presence of amblyopia or its risk factors, mainly strabismus or refractive error, have been primary conditions targeted in childhood vision screenings. Continued support for such screenings requires evidence-based understanding of the prevalence and natural history of amblyopia and its predisposing conditions, and proof that treatment is effective in the long term with minimal negative impact on the patient and family. This review summarises recent research relevant to the clinical understanding of amblyopia, including prevalence data, risk factors, the functional impact of amblyopia and optimum treatment regimes and their justification from a vision and life skills perspective. Collectively, these studies indicate that treatment for amblyopia is effective in reducing the overall prevalence and severity of visual loss from amblyopia. Correction of refractive error alone has been shown to significantly reduce amblyopia and less frequent occlusion can be just as effective as more extensive occlusion. Occlusion or penalisation in amblyopia treatment can create negative changes in behaviour in children and impact on family life, and these factors should be considered in prescribing treatment, particularly because of their influence on compliance. Ongoing treatment trials are being undertaken to determine both the maximum age at which treatment of amblyopia can still be effective and the importance of near activities during occlusion. This review highlights the expansion of current knowledge regarding amblyopia and its treatment to help clinicians provide the best level of care for their amblyopic patients that current knowledge allows.

Impaired visual acuity caused by uncorrected refractive errors and amblyopia in a German paediatric cohort

PURPOSE

This study describes the prevalence of visual impairment caused by uncorrected distance refractive error and the spectacle coverage in a large cohort of German children and adolescents. Furthermore, we determined the prevalence of amblyopia and amblyopia treatment.

METHODS

Optometrists carried out visual acuity (VA) testing, non-cycloplegic autorefraction, VA retesting with the refractive correction obtained by autorefraction, and if necessary subjective refraction and cover-test in 1,874 subjects (901 girls/973 boys), aged 3 to 16 years. Additionally, a questionnaire on the history of previous eye care was completed.

RESULTS

Distance visual impairment (VI) with VA worse than 6/18 Snellen in the better eye was present in 0.5% (95% confidence interval [95% CI]: 0.2% to 0.9%) of children. Logistic regression showed a significant positive association between VI and older age (OR = 1.21, P = 0.03). Gender differences were not found (P = 0.77). The spectacle coverage of all participants was 74.8% (95% CI: 65.2% to 82.8%). Amblyopia was found in 29 participants (1.5%; 95% CI: 1.0% to 2.2%) with no age or sex differences. The causes of unilateral amblyopia (27 cases, 93.1%) were anisometropia in 55.6% of children, strabismus in 25.9% and the combination of these factors in 18.5%. All children with bilateral amblyopia (2 cases, 6.9%) showed bilateral high ametropia. We observed 15 children with current amblyopia, who had been treated with occlusion therapy in the past (62.2%; 95% CI: 42.7% to 83.6%).

CONCLUSIONS

The prevalence of impaired VA caused by uncorrected refractive error and amblyopia is comparable with previous studies conducted in urban areas worldwide. Adding the measurement of refractive error to existing medical check-ups, possibly using autorefraction, would be desirable.

Choosing appropriate tools and referral criteria for vision screening of children aged 4-5 years in Canada: a quantitative analysis

OBJECTIVES

To assess the diagnostic accuracy of five vision screening tools used in a school setting using sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV).

DESIGN

We compared the results of the five best evidence-based screening tools available in 2014 to the results of a comprehensive eye exam with cycloplegic refraction by a licenced optometrist. Screening included Cambridge Crowded Acuity Cards, Plusoptix S12 and Spot photoscreeners, Preschool Randot Stereoacuity Test and the Pediatric Vision Scanner (PVS). Referral criteria followed AAPOS (2013) guidelines and published norms.

SETTING

A large school in Toronto, Canada, with 25 split classrooms of junior kindergarten (JK: 4 year olds) and senior kindergarten (SK: 5 year olds) children.

PARTICIPANTS

Over 2 years, 1132 eligible children were enrolled at the school. After obtaining parental consent, 832 children were screened. Subsequently, 709 children had complete screening and optometry exam data.

MAIN OUTCOME MEASURES

The presence/absence of a visual problem based on optometrist's assessment: amblyopia, amblyopia risk factors (reduced stereoacuity, strabismus and clinically significant refractive errors) and any other ocular problem (eg, nystagmus).

RESULTS

Overall, 26.5% of the screened children had a visual problem, including 5.9% with amblyopia. Using all five tools, screening sensitivity=84% (95% CI 78 to 89), specificity=49% (95% CI 44 to 53), PPV=37% (95% CI 33 to 42), and NPV=90% (95% CI 86 to 93). The odds of having a correct screening result in SK (mean age=68.2 months) was 1.5 times those in JK (mean age=55.6 months; 95% CI 1.1 to 2.1), with sensitivity improved to 89% (95% CI 80 to 96) and specificity improved to 57% (95% CI 50 to 64) among SK children.

CONCLUSIONS

A school-based screening programme correctly identified 84% of those kindergarten children who were found to have a visual problem by a cyclopleged optometry exam. Additional analyses revealed how accuracy varies with different combinations of screening tools and referral criteria.

Conventional occlusion versus pharmacologic penalization for amblyopia

BACKGROUND

Amblyopia is defined as impaired visual acuity in one or both eyes without demonstrable abnormality of the visual pathway, and is not immediately resolved by wearing glasses.

OBJECTIVES

In performing this systematic review, we aimed to synthesize the best available evidence regarding the effectiveness and safety of conventional occlusion therapy compared to atropine penalization in treating amblyopia.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2018, Issue 8); Ovid MEDLINE; Ovid Embase; LILACS BIREME; ClinicalTrials.gov; ISRCTN; and the WHO ICTRP on 7 September 2018.

SELECTION CRITERIA

We included randomized/quasi-randomized controlled trials comparing conventional occlusion to atropine penalization for amblyopia.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened abstracts and full-text articles, abstracted data, and assessed risk of bias.

MAIN RESULTS

We included seven trials (five randomized controlled trials and two quasi-randomized controlled trials) conducted in six countries (China, India, Iran, Ireland, Spain, and the United States) with a total of 1177 amblyopic eyes. Three of these seven trials were from the original 2009 version of the review. We assessed two trials as having a low risk of bias across all domains, and the remaining five trials as having unclear or high risk of bias for some domains.As different occlusion modalities, atropine penalization regimens, and populations were used across the included trials, we did not conduct any meta-analysis due to clinical and statistical heterogeneity. Evidence from six trials (two at low risk of bias) suggests that atropine penalization is as effective as conventional occlusion in improving visual acuity. Similar improvement in visual acuity was reported at all time points at which it was assessed, ranging from five weeks (improvement of 1 line) to 10 years (improvement of greater than 3 lines). At six months, although most participants (363/522) come from a trial rated as at low risk of bias with a precise estimate (mean difference (MD) 0.03, 95% confidence interval (CI) 0.00 to 0.06), two other trials rated as at high risk of bias produced inconsistent estimates and wide confidence intervals (MD -0.02, 95% CI -0.11 to 0.07 and MD -0.14, 95% CI -0.23 to -0.05; moderate-certainty evidence). At 24 months, additional improvement was found in both groups, but there continued to be no meaningful difference between those receiving occlusion and those receiving atropine therapies (moderate-certainty evidence).We did not find any difference in ocular alignment, stereo acuity, or sound eye visual acuity between occlusion and atropine penalization groups (moderate-certainty evidence). Both treatments were well tolerated. Atropine was associated with better adherence (moderate-certainty evidence) and quality of life (moderate-certainty evidence), but also a higher reported risk of adverse events in terms of mild reduction in the visual acuity of the sound eye not requiring treatment and light sensitivity (high-certainty evidence). Skin, lid, or conjunctival irritation were more common among participants receiving patching than those receiving atropine (high-certainty evidence). Atropine penalization costs less than conventional occlusion.

AUTHORS' CONCLUSIONS

Both conventional occlusion and atropine penalization produce visual acuity improvement in the amblyopic eye. Atropine penalization appears to be as effective as conventional occlusion, although the magnitude of improvement differed among the trials we analyzed.

Comparison of amblyopia in schoolchildren in Ireland and Northern Ireland: a population-based observational cross-sectional analysis of a treatable childhood visual deficit

OBJECTIVES

This study reports the prevalence of persistent amblyopia (post-traditional treatment age) in schoolchildren in the Republic of Ireland (henceforth Ireland) and Northern Ireland (NI), UK; populations with broadly similar refractive and genetic profiles but different eye-care systems.

DESIGN

This is a population-based observational study of amblyopia and refractive error.

SETTING

Recruitment and testing in primary and post-primary schools in Ireland and NI.

PARTICIPANTS

Two groups identified through random cluster sampling to represent the underlying population; Ireland 898 participants (12-13 years old) and NI 723 participants (295 aged 9-10 years old, 428 aged 15-16 years old).

MAIN OUTCOME MEASURES

Monocular logMAR visual acuity (presenting and pinhole), refractive error (cycloplegic autorefraction), ocular alignment (cover test) and history of previous eye care. These metrics were used to determine prevalence and type of amblyopia and treatment histories.

RESULTS

Children examined in NI between 2009 and 2011 had a significantly lower amblyopia prevalence than children examined in Ireland between 2016 and 2018 (two-sample test of proportions, p<0.001). Using a criteria of pinhole acuity 0.2logMAR (6/9.5 Snellen) plus an amblyogenic factor, 4 of 295 participants aged 9-10 years old (1.3%, 95% CIs 0.4 to 3.6) and 3 of 428 participants aged 15-16 years old (0.7%, 95%CIs 0.2 to 2.2) were identified in NI. The corresponding numbers in Ireland were 40 of 898 participants aged 12-13 years old (4.5%, 95% CI 3.2 to 6.1). In NI strabismic amblyopia was the most prevalent type of persistent amblyopia, whereas anisometropic was predominant in Ireland. In Ireland, amblyopia was associated with socioeconomic disadvantage (OR=2.2, 95%CIs 1.4 to 3.6, p=0.002) and poor spectacle compliance (OR 2.5, 95% CIs 2.0 to 3.2, p<0.001).

CONCLUSIONS

Amblyopia prevalence persisting beyond traditional treatment ages was significantly lower among NI children compared with Ireland. Uncorrected anisometropia, compliance with spectacle wear and socioeconomic disadvantage were contributing factors in Ireland. Children without obvious visible eye defects were less likely to access eye care in Ireland, resulting in missed opportunities for intervention where necessary.

Amblyopia therapy in Asian children: factors affecting visual outcome and parents' perception of children's attitudes towards amblyopia treatment

INTRODUCTION

Amblyopia treatment in the form of glasses and/or patching in children poses a great challenge to parents. This study aimed to assess the factors that influence visual outcome in amblyopia and children's perception towards treatment.

METHODS

180 children (aged 3.0-7.0 years) with newly diagnosed amblyopia were recruited. The effects of age, gender, type of amblyopia, treatment and compliance on visual outcome at one year were assessed. Parents completed a questionnaire on children's attitudes towards amblyopia treatment.

RESULTS

150 (83%) children with a mean age of 5.2 ± 0.8 years returned for follow-up at one year. 130 (87%) had refractive amblyopia and 20 (13%) had strabismic and refractive-strabismic amblyopia. Visual acuity (VA) of 6/9 or better in the amblyopic eye was achieved in 121 (81%) children. On multivariable analysis, poor responders were more likely to have initial VA of worse than 6/15 (relative risk [RR] 4.17, 95% confidence interval [CI] 1.58-11.00, p = 0.004), prescribed combined (glasses and patching) treatment (RR 2.83, 95% CI 1.02-7.83, p = 0.045) and poor compliance (RR 6.10, 95% CI 1.90-19.57, p = 0.002) after adjustment for age, gender and type of amblyopia. While 7% of children initially reacted poorly to treatment, 5% remained uncooperative at the first follow-up visit. Children had difficulty with schoolwork (5%), mood changes (6%) and social problems (2%) associated with treatment.

CONCLUSION

Most children with amblyopia respond well to treatment, but more care (i.e. more parental education and closer follow-up) may be needed in children who are non-compliant and have poorer initial VA.

Preschool Vision Screening: Where We Have Been and Where We Are Going

PURPOSE

To discuss the evolution of instrument-based screening to detect amblyopia and its risk factors, and to summarize the importance of preschool vision screening.

DESIGN

Expert commentary.

METHODS

Author experiences were supplemented by a review and interpretation of pertinent medical literature.

RESULTS

Amblyopia remains a public health problem, as it is a common cause of monocular visual impairment. As a disease, amblyopia detection is best obtained by appropriate vision screening rather than by yearly mandated comprehensive eye examinations for all children; the US Preventative Services Task Force (USPSTF) recently reaffirmed their recommendations for vision screening in preschool children. Vision screening devices have evolved over the past 4 decades ranging from photoscreeners that use instantaneously developing film, to autorefractors that detect amblyopia risk factors, to nerve fiber layer scanners that detect the microtropia that nearly always accompanies amblyopia. When it is detected early, effective treatment for amblyopia can be initiated.

CONCLUSIONS

Amblyopia is a reversible cause of vision loss in children. Vision screening devices and screening programs have been extensively studied-experts and literature agree: vision screening devices and programs are cost-effective, are efficient, and are effective methods for amblyopia detection. The authors support the regular use of instrument-based vision screening in the medical home for all children until they reach a developmental stage where they can participate reliably in optotype-based vision screening.

The functional impact of amblyopia

Amblyopia is the most common disorder managed in paediatric ophthalmic practice in industrialised countries. Reports on the impact of amblyopia on tasks relevant to the activities of children, or on skills pertinent to their education and quality of life, is leading to greater understanding of the functional disabilities associated with the condition. This review considers the extent to which amblyopia affects the ability to carry out everyday tasks, with particular attention to studies of motor skills and reading proficiency in children. Collectively, these studies show that amblyopia results in poorer outcomes on tests of skills required for proficiency in everyday tasks and which relate to childhood academic performance. However, the relative contributions that the documented vision anomalies inherent in amblyopia contribute to various functional disabilities is not fully determined. Recent reports have demonstrated improvement following treatment in standardised measures of fine motor skills involved in practical, everyday tasks. Including measurement of functional performance skills in amblyopia treatment trials is desirable to show treatment effect on crucial, real-world activities.

Cost and quality of life of overlooked eye care needs of children

Background

The objective of this research was to conduct a systematic review and cost analysis to summarize, from the Ministry of Health perspective, the costs families might incur because of their child’s prescription for refractive errors and amblyopia correction.

Methods

Databases including MEDLINE, Embase, BIOSIS, CINAHL, HEED, ISI Web of Science, and the Cochrane Library as well as the gray literature were searched. Systematic review was conducted using EPPI-Reviewer 4. Percentage difference in cost of glasses and patches per patient per various diagnoses were computed. The cost of glasses and patches was projected over a 5-year time horizon. Cost-utility analysis was performed.

Results

In total, 302 records were retrieved from multiple databases and an additional 48 records were identified through gray literature search. From these, a total of 14 studies (10,388 subjects) were eligible for quantitative analysis. The cost of glasses increased significantly for congenital cataract patients to US$1,820, esotropia patients to US$840, myopes to US$411, amblyopes (mixed) to US$916, anisometropes to US$521, and patients with strabismus to US$728 over a 5-year period making them unaffordable for low-income families. Incremental cost of glasses of congenital cataract patients with delayed treatment was computed to be US$1,690 per health utility gained. Incremental cost of glasses for high refractive error was US$93 per health utility gained in non-compliant children. For amblyopia patients, incremental cost of glasses per quality-adjusted life years gained was US$3,638.

Conclusion

Cost of corrective lenses is associated with significant financial burden and thus other means of mitigating costs should be considered. Eyesight problems in children are perceived as low-priority health needs. Thus, educational interventions on substantial visual deficits of not wearing glasses should be offered to families and governmental health agencies.

A Randomized Trial of a Binocular iPad Game Versus Part-Time Patching in Children Aged 13 to 16 Years With Amblyopia

PURPOSE

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

METHODS

One hundred participants aged 13 to <17 years (mean 14.3 years) with amblyopia (20/40 to 20/200, mean ∼20/63) resulting from strabismus, anisometropia, or both were enrolled into a randomized clinical trial. Participants were randomly assigned to treatment for 16 weeks of either a binocular iPad game prescribed for 1 hour per day (n = 40) or patching of the fellow eye prescribed for 2 hours per day (n = 60). The main outcome measure was change in amblyopic eye VA from baseline to 16 weeks.

RESULTS

Mean amblyopic eye VA improved from baseline by 3.5 letters (2-sided 95% confidence interval [CI]: 1.3-5.7 letters) in the binocular group and by 6.5 letters (2-sided 95% CI: 4.4-8.5 letters) in the patching group. After adjusting for baseline VA, the difference between the binocular and patching groups was -2.7 letters (95% CI: -5.7 to 0.3 letters, P = .082) or 0.5 lines, favoring patching. In the binocular group, treatment adherence data from the iPad device indicated that only 13% of participants completed >75% of prescribed treatment.

CONCLUSIONS

In teenagers aged 13 to <17 years, improvement in amblyopic eye VA with the binocular iPad game used in this study was not found to be better than patching, and was possibly worse. Nevertheless, it remains unclear whether the minimal treatment response to binocular treatment was owing to poor treatment adherence or lack of treatment effect.

A Randomized Trial of a Binocular iPad Game Versus Part-Time Patching in Children Aged 13 to 16 Years With Amblyopia

PURPOSE

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

METHODS

One hundred participants aged 13 to <17 years (mean 14.3 years) with amblyopia (20/40 to 20/200, mean ∼20/63) resulting from strabismus, anisometropia, or both were enrolled into a randomized clinical trial. Participants were randomly assigned to treatment for 16 weeks of either a binocular iPad game prescribed for 1 hour per day (n = 40) or patching of the fellow eye prescribed for 2 hours per day (n = 60). The main outcome measure was change in amblyopic eye VA from baseline to 16 weeks.

RESULTS

Mean amblyopic eye VA improved from baseline by 3.5 letters (2-sided 95% confidence interval [CI]: 1.3-5.7 letters) in the binocular group and by 6.5 letters (2-sided 95% CI: 4.4-8.5 letters) in the patching group. After adjusting for baseline VA, the difference between the binocular and patching groups was -2.7 letters (95% CI: -5.7 to 0.3 letters, P = .082) or 0.5 lines, favoring patching. In the binocular group, treatment adherence data from the iPad device indicated that only 13% of participants completed >75% of prescribed treatment.

CONCLUSIONS

In teenagers aged 13 to <17 years, improvement in amblyopic eye VA with the binocular iPad game used in this study was not found to be better than patching, and was possibly worse. Nevertheless, it remains unclear whether the minimal treatment response to binocular treatment was owing to poor treatment adherence or lack of treatment effect.

Instrument-based pediatric vision screening

PURPOSE OF REVIEW

The purpose is to review currently available instruments for vision screening in young children.

RECENT FINDINGS

Instrumentation continues to evolve. Although the current generation of photoscreeners and autorefractors strive to identify amblyopia risk factors, newer technology aims to directly identify amblyopia in young children. Acceptance of instrument-based vision screening for this population has led to increased reimbursement for the procedure in primary care practices.

SUMMARY

Instrument-based vision screening in the young child is an accepted method of screening for amblyopia. Innovations in instrumentation will continue to improve its implementation.

Crowded letter and crowded picture logMAR acuity in children with amblyopia: a quantitative comparison

Aims

Clinically, picture acuity tests are thought to overestimate visual acuity (VA) compared with letter tests, but this has not been systematically investigated in children with amblyopia. This study compared VA measurements with the LogMAR Crowded Kay Picture test to the LogMAR Crowded Keeler Letter acuity test in a group of young children with amblyopia.

Methods

58 children (34 male) with amblyopia (22 anisometropic, 18 strabismic and 18 with both strabismic/anisometropic amblyopia) aged 4–6 years (mean=68.7, range=48–83 months) underwent VA measurements. VA chart testing order was randomised, but the amblyopic eye was tested before the fellow eye. All participants wore up-to-date refractive correction.

Results

The Kay Picture test significantly overestimated VA by 0.098 logMAR (95% limits of agreement (LOA), 0.13) in the amblyopic eye and 0.088 logMAR (95% LOA, 0.13) in the fellow eye, respectively (p<0.001). No interactions were found from occlusion therapy, refractive correction or type of amblyopia on VA results (p>0.23). For both the amblyopic and fellow eyes, Bland-Altman plots demonstrated a systematic and predictable difference between Kay Picture and Keeler Letter charts across the range of acuities tested (Keeler acuity: amblyopic eye 0.75 to −0.05 logMAR; fellow eye 0.45 to −0.15 logMAR). Linear regression analysis (p<0.00001) and also slope values close to one (amblyopic 0.98, fellow 0.86) demonstrate that there is no proportional bias.

Conclusions

The Kay Picture test consistently overestimated VA by approximately 0.10 logMAR when compared with the Keeler Letter test in young children with amblyopia. Due to the predictable difference found between both crowded logMAR acuity tests, it is reasonable to adjust Kay Picture acuity thresholds by +0.10 logMAR to compute expected Keeler Letter acuity scores.

Prevalence of Amblyopia and Refractive Errors Among Primary School Children

Purpose:

To determine the prevalence of amblyopia and refractive errors among 7 to 12-year-old primary school children in Tehran, Iran.

Methods:

This population-based cross-sectional study included 2,410 randomly selected students. Visual acuity was tested using an E-chart on Yang vision tester. Refractive errors were measured by photorefractometry and cycloautorefraction. Strabismus was checked using cover test. Direct ophthalmoscopy was used to assess the anterior segment, lens opacities, red reflex and fundus. Functional amblyopia was defined as best corrected visual acuity ≤20/40 in one or both eyes with no anatomical problems.

Results:

Amblyopia was present in 2.3% (95% CI: 1.8% to 2.9%) of participants with no difference between the genders. Amblyopic subjects were significantly younger than non-amblyopic children (P=0.004). Overall, 15.9% of hyperopic and 5.9% of myopic cases had amblyopia. The prevalence of hyperopia ≥+2.00D, myopia ≤-0.50D, astigmatism ≥0.75D, and anisometropia (≥1.00D) was 3.5%, 4.9%, 22.6%, and 3.9%, respectively. With increasing age, the prevalence of myopia increased (P<0.001), that of hyperopia decreased (P=0.007), but astigmatism showed no change. Strabismus was found in 2.3% of cases. Strabismus (OR=17.9) and refractive errors, especially anisometropia (OR=12.87) and hyperopia (OR=11.87), were important amblyogenic risk factors.

Conclusion:

The high prevalence of amblyopia in our subjects in comparison to developed countries reveals the necessity of timely and sensitive screening methods. Due to the high prevalence of amblyopia among children with refractive errors, particularly high hyperopia and anisometropia, provision of glasses should be specifically attended by parents and supported by the Ministry of Health and insurance organizations.

Effectiveness of the addition of citicoline to patching in the treatment of amblyopia around visual maturity: a randomized controlled trial

Aim:

To study the effectiveness of the addition of citicoline to patching in the treatment of amblyopia in the age group of 4-13 years.

Materials and Methods:

A randomized controlled trial, which included patients who were randomly divided into two groups. Both the groups received patching therapy till plateau was achieved in phase 1 of the study. Then in phase 2, group I received citicoline plus patching and group II continued to receive only patching.

Outcome Measures:

Outcome was measured by the visual acuity in logMAR every month in phase 1 till plateau was achieved and then for 12 months in phase 2.

Results:

No significant difference was found in the mean visual acuities in these two groups in phase 1 till plateau was reached. In phase 2, for the initial four months, there was no significant difference in the visual acuities in these two groups, at the respective intervals. However, five months onward, up to 12 months, there was a significant difference in the visual acuities in these groups. The result was the same in younger patients (< seven years of age) as well as in older patients (> seven years of age). In phase 2, the mean proportional improvement in group I was significantly more than that in group II, at two months and onward, at the respective intervals.

Conclusion:

The improvement in visual acuity with citicoline plus patching was significantly more than that with patching alone, in one year of treatment.

Whole-population vision screening in children aged 4-5 years to detect amblyopia

Amblyopia is a neurodevelopmental disorder that affects at least 2% of most populations and can lead to permanently reduced vision if not detected and treated within a specific period in childhood. Whole-population screening of children younger than 5 years is applied in many countries. The substantial diversity in existing programmes reflects their heterogeneous implementation in the absence of the complete evidence base that is now a pre-requisite for instituting screening. The functional importance of amblyopia at an individual level is unclear as data are scarce, but in view of the high prevalence the population-level effect might be notable. Screening of all children aged 4-5 years (eg, at school entry) confers most benefit and addresses inequity in access to timely treatment. Screening at younger ages is associated with increased risk of false-positive results, and at older ages with poor outcomes for children with moderate to severe amblyopia. We suggest that the real-life adverse effects of amblyopia should be characterised and screening and diagnosis should be standardised.

Use of Eyeglasses among Children in Elementary School: Perceptions, Behaviors, and Interventions Discussed by Parents, School Nurses, and Teachers during Focus Groups

Purpose.

To investigate the perceptions, behaviors, and recommendations that parents, school nurses, and teachers have regarding children's use of eyeglasses.

Approach.

Focus groups with parents, school nurses, and teachers were conducted.

Setting.

The study took place in one Southern California school district.

Participants.

There were 39 participants, including 24 parents, seven school nurses, and eight teachers.

Method.

An experienced moderator guided the focus group discussions. Transcripts were analyzed using grounded theory techniques.

Results.

Participants perceive visual impairment as a serious problem in the development of children. The lack of eyeglasses may lead to problems such as tiredness, headaches, inability to focus on school work, and decreased reading speed. Participants experienced disappointment, unhappiness, worry, and concern when they realized they needed eyeglasses at a young age. Negative societal perceptions toward eyeglasses, lack of eye doctors in minority communities, parental perceptions that children do not need eyeglasses, and peer bullying of children wearing eyeglasses are key obstacles to children's use of eyeglasses. Participants suggest school and national campaigns featuring respected public figures who wear eyeglasses to promote positive attitudes toward eyeglasses.

Conclusion.

Parents and teachers who closely follow the academic development of children have observed that visual impairment has negative consequences for the scholastic achievement of children. They recommend interventions to promote the attractiveness of eyeglasses in society. The participants discuss the need for a national preventative message for eye care similar to the message for dental care. The public health message should emphasize the importance of embracing and respecting differences among individuals.

Anisometropia magnitude and visual deficits in previously untreated anisometropic amblyopia

AIM

To assess the quantitative association between anisometropia magnitude and the losses of resolution and contrast sensitivity; and to exemplify how the function of fusion and stereopsis vary with anisometropia magnitude (AM) in previously untreated anisometropic amblyopes.

METHODS

A total of 57 patients with previously untreated anisometropic amblyopia without strabismus (range: 8-35 years), were measured refractive error, best corrected visual acuity (BCVA), fusion and stereopsis, and 48 patients have completed contrast sensitivity function test. AM was determined by dioptric vector addition model, and the amblyopia depth was determined by the difference of BCVA in logMAR units between the amblyopic and fellow eyes.

RESULTS

AM was significantly correlated with both amblyopia depth (Pearson R=0.728, P<0.001) and the inter-ocular difference of the area under the log contrast sensitivity function (AULCSF) (R=0.505, P<0.001). Depth of amblyopia and the inter-ocular difference of AULCSF was also significantly correlated (R=0.761, P<0.001). The more severity of amblyopia, the poorer levels of contrast sensitivity. Most pure anisometropes with AM was less than 3.0D retain fusion and some stereopsis, but when AM were more than 3.0D, especially for the anisometropes whose AM was more than 6.0D, fusion and stereopsis function were seriously impaired.

CONCLUSION

In the patients with previously untreated anisometropia amblyopia, higher degree of anisometropia is significantly associated with deeper amblyopia, worse contrast sensitivity, fusion and stereopsis functions.

Light transmission and preference of eye patches for occlusion treatment

PURPOSE

To investigate light transmission and preference for six eye patches for occlusion therapy.

METHODS

Six patches were examined, including; Ortopad Fun Pack, Ortopad Flesh, Kawamoto A-1, Kawamoto A-2, 3M Opticlude, and Everade Eye Guard. The size and the presence of a light blocking pad of patches were investigated. The amount of light transmitted through the patches was evaluated, using a digital light meter and a model eye, in three different environments; indoors with fluorescent light, outdoors on a sunny day, and strong light from illuminator. After patching the normal eye, the flash visual evoked potential (VEP) was measured. Thirty patients with amblyopia or horizontal strabismus, who received occlusion therapy as initial treatment, were included. After using all six patches, patients completed a 7-item questionnaire regarding the patch preference for size, color and shape, adhesive power, pain with removal, skin irritation after removing patch, parent's preference and overall opinion.

RESULTS

All patches had a light-blocking pad, except the 3M Nexcare. Ortopad had the strongest light blocking power in the three environments, and the 3M Nexcare had the weakest power. In flash VEP, Ortopad and Kawamoto patches showed flat, but 3M Nexcare and Everade Eye Guard showed normal response. There were significant preferential differences among the patches in all the items of the questionnaire (P<0.05). In comparison between the patches respectively, 3M Nexcare received the lowest satisfaction in pain when removing a patch and skin irritation after removing a patch. Kawamoto A-2 received the lowest score in the overall satisfaction.

CONCLUSIONS

We found differences in the light-blocking power and in the preference of the various patches for the occlusion treatment. This is a pilot study regarding only characteristics and preferences of patches. Further clinical studies regarding the relationship between characteristics or preferences of patches and outcomes of occlusion treatment are needed.

The relationship between anisometropia and amblyopia

This review aims to disentangle cause and effect in the relationship between anisometropia and amblyopia. Specifically, we examine the literature for evidence to support different possible developmental sequences that could ultimately lead to the presentation of both conditions. The prevalence of anisometropia is around 20% for an inter-ocular difference of 0.5D or greater in spherical equivalent refraction, falling to 2-3%, for an inter-ocular difference of 3D or above. Anisometropia prevalence is relatively high in the weeks following birth, in the teenage years coinciding with the onset of myopia and, most notably, in older adults starting after the onset of presbyopia. It has about one-third the prevalence of bilateral refractive errors of the same magnitude. Importantly, the prevalence of anisometropia is higher in highly ametropic groups, suggesting that emmetropization failures underlying ametropia and anisometropia may be similar. Amblyopia is present in 1-3% of humans and around one-half to two-thirds of amblyopes have anisometropia either alone or in combination with strabismus. The frequent co-existence of amblyopia and anisometropia at a child's first clinical examination promotes the belief that the anisometropia has caused the amblyopia, as has been demonstrated in animal models of the condition. In reviewing the human and monkey literature however it is clear that there are additional paths beyond this classic hypothesis to the co-occurrence of anisometropia and amblyopia. For example, after the emergence of amblyopia secondary to either deprivation or strabismus, anisometropia often follows. In cases of anisometropia with no apparent deprivation or strabismus, questions remain about the failure of the emmetropization mechanism that routinely eliminates infantile anisometropia. Also, the chronology of amblyopia development is poorly documented in cases of 'pure' anisometropic amblyopia. Although indirect, the therapeutic impact of refractive correction on anisometropic amblyopia provides strong support for the hypothesis that the anisometropia caused the amblyopia. Direct evidence for the aetiology of anisometropic amblyopia will require longitudinal tracking of at-risk infants, which poses numerous methodological and ethical challenges. However, if we are to prevent this condition, we must understand the factors that cause it to develop.

Preschool vision screening in primary care pediatric practice

OBJECTIVES

We determined the efficacy of pediatric-based preschool vision screening, as knowledge of vision screening effectiveness in primary care pediatrics is incomplete.

METHODS

Pediatricians and staff at nine primary care pediatric practices were trained in vision screening, and practices screened children aged 3-5 years from May 2007 through July 2008. Children failing or considered untestable were referred for pediatric ophthalmology examinations. We determined rates of testability, failure, referral, and ophthalmologic examination completion, as well as positive predictive values (PPVs) of screening failure and untestability. We also surveyed practices to assess the ease and accuracy of preschool vision screening.

RESULTS

Of 2,933 children screened, 93 (3.2%) failed the vision screening and 349 (11.9%) were untestable. Untestability was highest (27.1%) among 3-year-olds. The PPV for failing any aspect of the vision screening was 66.7%; for children aged 3, 4, and 5 years, the PPVs for failing were 30.0%, 77.8%, and 87.5%, respectively. However, only 38.7% of children who failed the vision screening received ophthalmologic examinations, despite multiple follow-up attempts. Pediatricians rated the ease and accuracy of screening 3-year-old children lower than for screening older children.

CONCLUSIONS

Visual acuity-based screening had good PPV for vision loss for 4- and 5-year-old children but was less successful for 3-year-olds. Rates of referral and ophthalmologic examination completion were low, especially among children from low-income families.

Two-year follow-up of a randomized trial of spectacles alone or combined with Bangerter filters for treating anisometropic amblyopia

PURPOSE

To compare spectacle correction alone to spectacle correction with Bangerter filters as treatments for anisometropic amblyopia in children 1 year after completion of a 1-year randomized trial.

METHODS

In a randomized clinical trial, 80 children (mean age, 4.4 years) with anisometropic amblyopia and a best median visual acuity (VA) in the amblyopic eye of 0.4 logarithm of the minimum angle of resolution (logMAR) were assigned to treatment with either spectacles or spectacles in combination with a Bangerter filter for 1 year. After 1 year, treatment with spectacles continued. If the VA differed by ≥ 2 lines, treatment with Bangerter filters was continued if originally prescribed. The main outcome measure was the median change in VA of the amblyopic eye after 2 years.

RESULTS

The median change in VA of the amblyopic eye did not differ significantly between the groups (0.4 log unit for both groups) at the 2-year visit. At that time, the VA in the amblyopic eyes and the fellow eyes was 0.0 median logMAR in both groups. Between years 1 and 2, the median VA improved in the amblyopic eyes; in the spectacles group (p = 0.0181) and in the Bangerter filter group (p = 0.0342). The median anisometropia decreased in both groups (p < 0.0001 for both comparisons).

CONCLUSION

We found stability in the VA improvement in both groups. The magnitude of the VA change 2 years after treatment with spectacles alone did not differ significantly from that after treatment with spectacles and a Bangerter filter for anisometropic amblyopia.

Randomised comparison of three tools for improving compliance with occlusion therapy: an educational cartoon story, a reward calendar, and an information leaflet for parents

BACKGROUND

We previously demonstrated that compliance with occlusion therapy for amblyopia was improved by the use of an educational programme, especially in children of parents of foreign origin and who spoke Dutch poorly. The programme consisted of: (i) a cartoon story for amblyopic children that explained without words why they should patch, (ii) a calendar with reward stickers, and (iii) an information leaflet for parents. In the current study, we assessed the individual effect of each component on compliance.

METHODS

We recruited 120 3- to 6-year-old children who lived in a low socio-economic status (SES) area in The Hague and were starting occlusion therapy for the first time. They were randomised to receive one of the components (three intervention groups), or a picture to colour (control group). The randomisation was blinded for treating orthoptist and researcher. Compliance was measured electronically using the Occlusion Dose Monitor (ODM). Primary outcome was percentage of compliance (actual/prescribed occlusion time). Secondary outcome was absolute occlusion hours per day. Parental fluency in Dutch was rated on a five-point scale.

RESULTS

Compliance could be measured electronically in 88 of the 120 children; in 32 others, it failed for various reasons. Parental fluency in Dutch was moderate or worse in 36.4 % (p = 0.327). Average compliance was 55 % standard deviation (SD) 40 (n = 18) in the control group, 89 % SD 25 in the group receiving the educational cartoon (n = 25, P = 0.002 compared with control group), 67 % SD 33 (n = 24, P = 0.301) in the reward-calendar group and 73 % SD 40 (n = 21, P = 0.119) in the parent-information-leaflet group. On average, children in the control group occluded 1:46 SD1:19 hours/day, 2:33 SD 1:18 hours/day in the group receiving the educational cartoon, 1:59 SD 1:13 hours/day in the reward-calendar group and 2:18 SD 1:13 hours/day in the parent-information-leaflet group. No child who received the cartoon story occluded less than 1 hour per day, against seven in the reward-calendar group, five in the parent-information-leaflet group and five in the control group.

CONCLUSIONS

Although all three components of the programme improved compliance with occlusion therapy in children in low-SES areas, the educational cartoon had the strongest effect, as it explained without words to a 4- to 5-year-old child why it should wear the eye patch.

Interventions for unilateral and bilateral refractive amblyopia

BACKGROUND

Refractive amblyopia is a common cause of reduced visual acuity in childhood, but optimal treatment is not well defined. This review examined the treatment effect from spectacles and conventional occlusion.

OBJECTIVES

Evaluation of the evidence of the effectiveness of spectacles, occlusion or both in the treatment of unilateral and bilateral refractive amblyopia.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 1), MEDLINE (January 1950 to January 2012), EMBASE (January 1980 to January 2012), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to January 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). There were no date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 24 January 2012. We manually searched relevant conference proceedings.

SELECTION CRITERIA

Randomised controlled trials of treatment for unilateral and bilateral refractive amblyopia by spectacles, with or without occlusion, were eligible. We included studies with participants of any age.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed abstracts identified by the searches. We obtained full-text copies and contacted study authors where necessary. Eleven trials were eligible for inclusion. We extracted data from eight. Insufficient data were present for the remaining three trials so data extraction was not possible. We identified no trials as containing participants with bilateral amblyopia. We performed no meta-analysis as there were insufficient trials for each outcome.

MAIN RESULTS

For all studies mean acuity (standard deviation (SD)) in the amblyopic eye post-treatment was reported. All included trials reported treatment for unilateral refractive amblyopia.One study randomised participants to spectacles only compared to no treatment, spectacles plus occlusion compared to no treatment and spectacles plus occlusion versus spectacles only. For spectacles only versus no treatment, mean (SD) visual acuity was: spectacles group 0.31 (0.17); no treatment group 0.42 (0.19) and mean difference (MD) between groups was -0.11 (borderline statistical significance: 95% confidence interval (CI) -0.22 to 0.00). For spectacles plus occlusion versus no treatment, mean (SD) visual acuity was: full treatment 0.22 (0.13); no treatment 0.42 (0.19). Mean difference (MD) between the groups -0.20 (statistically significant: 95% CI -0.30 to -0.10). For spectacles plus occlusion versus spectacles only, MD was -0.09 (borderline statistical significance 95% CI -0.18 to 0.00). For two other trials that also looked at this comparison MD was -0.15 (not statistically significant 95% CI -0.32 to 0.02) for one trial and MD 0.01 (not statistically significant 95% CI -0.08 to 0.10) for the second trial.Three trials reviewed occlusion regimes.One trial looked at two hours versus six hours for moderate amblyopia: MD 0.01 (not statistically significant: 95% CI -0.06 to 0.08); a second trial 2003b reviewed six hours versus full-time for severe amblyopia: MD 0.03 (not statistically significant: 95% CI -0.08 to 0.14) and a third trial looked at six hours versus full-time occlusion: MD -0.12 (not statistically significant: 95% CI -0.27 to 0.03). One trial looked at occlusion supplemented with near or distance activities: MD-0.03 (not statistically significant 95% CI -0.09 to 0.03). One trial looked at partial occlusion and glasses versus glasses only: MD -0.01 (not statistically significant: 95% CI -0.05 to 0.03).

AUTHORS' CONCLUSIONS

In some cases of unilateral refractive amblyopia it appears that there is a treatment benefit from refractive correction alone. Where amblyopia persists there is evidence that adding occlusion further improves vision. Despite advances in the understanding of the treatment of amblyopia it is currently still not possible to tailor individual treatment plans for amblyopia. The nature of any dose/response effect from occlusion still needs to be clarified. Partial occlusion appears to have the same treatment effect as glasses alone when started simultaneously for the treatment of unilateral refractive amblyopia. Treatment regimes for bilateral and unilateral refractive amblyopia need to be investigated further.

Compliance of amblyopic patients with occlusion therapy: A pilot study

BACKGROUND

Increasing evidence shows that good compliance with occlusion therapy is paramount for successful amblyopia therapy.

PURPOSE

To study the degree of compliance and explore factors affecting compliance in patients undergoing occlusion therapy for amblyopia in our practice.

DESIGN

Nonrandomized clinical intervention study.

MATERIALS AND METHODS

A total of 31 families with a child (aged 2-12 years), undergoing unilateral amblyopia treatment at the pediatric ophthalmology clinic of Sultan Qaboos University Hospital, Oman, were recruited for this one month study. Parents were interviewed and completed a closed-ended questionnaire. Clinical data including, visual acuity, refraction, diagnosis and treatment, for each patient was collected from the hospital chart and was entered in a data collection sheet. Compliance with occlusion therapy was assessed by self-report accounts of parents and was graded into good, partial, or poor. Association between various factors and degree of compliance was studied using logistic regression modeling.

RESULTS

Only 14 (45%) patients showed good compliance to occlusion therapy. 17 (55%) patients were noncompliant. Improvement in visual acuity strongly correlated with compliance to patching (P = 0.008). Other variables that were studied included, age at onset of therapy; gender; degree of amblyopia; type of amblyopia; use of glasses; and compliance with glasses. These did not emerge as significant predictors of compliance. All but one family with poor compliance stated that the main challenge in following the recommendation to patch for requisite hours was in getting their child to cooperate. Only in one instance, the family cited nonavailability of patches as the main hindrance to compliance. 10/31 (32%) families expressed a desire for more information and 18/31 (58%) parents did not understand that amblyopia meant decreased vision.

CONCLUSION

Poor compliance is a barrier to successful amblyopia therapy in our practice. Improvement in visual acuity is associated with better compliance with patching. Parents find it difficult to comprehend and retain verbal explanations of various components regarding occlusion therapy for amblyopia. Future study with a larger sample of patients is recommended to investigate the factors affecting compliance with amblyopia therapy and determine predictors for poor compliance.

Screening for visual impairment in children ages 1-5 years: update for the USPSTF

CONTEXT

Screening could identify preschool-aged children with vision problems at a critical period of visual development and lead to treatments that could improve vision.

OBJECTIVE

To determine the effectiveness of screening preschool-aged children for impaired visual acuity on health outcomes.

METHODS

We searched Medline from 1950 to July 2009 and the Cochrane Library through the third quarter of 2009, reviewed reference lists, and consulted experts. We selected randomized trials and controlled observational studies on preschool vision screening and treatments, and studies of diagnostic accuracy of screening tests. One investigator abstracted relevant data, and a second investigator checked data abstraction and quality assessments.

RESULTS

Direct evidence on the effectiveness of preschool vision screening for improving visual acuity or other clinical outcomes remains limited and does not adequately address whether screening is more effective than no screening. Regarding indirect evidence, a number of screening tests have utility for identification of preschool-aged children with vision problems. Diagnostic accuracy did not clearly differ for children stratified according to age, although testability rates were generally lower in children 1 to 3 years of age. Treatments for amblyopia or unilateral refractive error were associated with mild improvements in visual acuity compared with no treatment. No study has evaluated school performance or other functional outcomes.

CONCLUSIONS

Although treatments for amblyopia or unilateral refractive error can improve vision in preschool-aged children and screening tests have utility for identifying vision problems, additional studies are needed to better understand the effects of screening compared with no screening.

Randomized evaluation of spectacles plus alternate-day occlusion to treat amblyopia

PURPOSE

To compare spectacles plus patching >or=8 hours daily 6 days a week with spectacles plus patching >or=8 hours on alternate days to treat amblyopia in children 4 to 5 years of age.

DESIGN

Prospective, randomized clinical trial.

PARTICIPANTS

Forty children (median age, 4.3 years) with untreated amblyopia and a median best-corrected visual acuity (BCVA) in the amblyopic eye of 0.9 (range, 0.3-1.5) logarithm of the minimum angle of resolution.

METHODS

Refractive correction was provided, and the children were randomized to patching >or=8 hours daily 6 days a week or patching >or=8 hours on alternate days. The BCVA, binocular function, and refractive errors were measured repeatedly during the study.

MAIN OUTCOME MEASURE

Median change in BCVA of the amblyopic eye after 1 year.

RESULTS

The median change in BCVA of the amblyopic eye did not differ significantly between the 2 groups (0.6 log units for daily occlusion; 0.8 log unit for alternate-day occlusion). The final median BCVA in the amblyopic eyes was 0.1 logarithm of the minimum angle of resolution in both groups. Binocular function improved in both groups with no significant differences between the groups at 1 year. The median spherical equivalent refractive error did not change significantly during the study period in the amblyopic eyes in either group; however, a significant increase was found in the fellow eyes in both groups (daily occlusion, P<0.05; alternate-day occlusion, P<0.001).

CONCLUSIONS

The magnitude of change in the BCVA 1 year after spectacles plus prescribed alternate-day patching was not significantly different than that after spectacles plus prescribed daily patching to treat amblyopia in children 4 to 5 years old. The effect of patching was not separate from that of optical correction with a period of refractive adaptation. Thus, the improvement in visual acuity is a combined effect of spectacle wear and occlusion therapy.

Conventional occlusion versus pharmacologic penalization for amblyopia

BACKGROUND

Amblyopia is defined as defective visual acuity in one or both eyes without demonstrable abnormality of the visual pathway, and is not immediately resolved by wearing glasses.

OBJECTIVES

To assess the effectiveness and safety of conventional occlusion versus atropine penalization for amblyopia.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, EMBASE, LILACS, the WHO International Clinical Trials Registry Platform, preference lists, science citation index and ongoing trials up to June 2009.

SELECTION CRITERIA

We included randomized/quasi-randomized controlled trials comparing conventional occlusion to atropine penalization for amblyopia.

DATA COLLECTION AND ANALYSIS

Two authors independently screened abstracts and full text articles, abstracted data, and assessed the risk of bias.

MAIN RESULTS

Three trials with a total of 525 amblyopic eyes were included. One trial was assessed as having a low risk of bias among these three trials, and one was assessed as having a high risk of bias.Evidence from three trials suggests atropine penalization is as effective as conventional occlusion. One trial found similar improvement in vision at six and 24 months. At six months, visual acuity in the amblyopic eye improved from baseline 3.16 lines in the occlusion and 2.84 lines in the atropine group (mean difference 0.034 logMAR; 95% confidence interval (CI) 0.005 to 0.064 logMAR). At 24 months, additional improvement was seen in both groups; but there continued to be no meaningful difference (mean difference 0.01 logMAR; 95% CI -0.02 to 0.04 logMAR). The second trial reported atropine to be more effective than occlusion. At six months, visual acuity improved 1.8 lines in the patching group and 3.4 lines in the atropine penalization group, and was in favor of atropine (mean difference -0.16 logMAR; 95% CI -0.23 to -0.09 logMAR). Different occlusion modalities were used in these two trials. The third trial had inherent methodological flaws and limited inference could be drawn.No difference in ocular alignment, stereo acuity and sound eye visual acuity between occlusion and atropine penalization was found. Although both treatments were well tolerated, compliance was better in atropine. Atropine penalization costs less than conventional occlusion. The results indicate that atropine penalization is as effective as conventional occlusion.

AUTHORS' CONCLUSIONS

Both conventional occlusion and atropine penalization produce visual acuity improvement in the amblyopic eye. Atropine penalization appears to be as effective as conventional occlusion, although the magnitude of improvement differed among the three trials. Atropine penalization can be used as first line treatment for amblyopia.

Efficacy of Occlusion Treatment in Amblyopia and Clinical Risk Factors Affecting the Results of Treatment

PURPOSE

To evaluate the factors influencing visual outcome in strabismic, strabismic-anisometropic and anisometropic amblyopia following occlusion treatment.

METHODS

Records of 128 pediatric patients who had been treated for amblyopia by occlusion of the fellow eye between March 1992 and March 2003 were reviewed retrospectively. Age and level of visual acuity at initiation of treatment, occlusion time (full-time, part-time or minimal) and type of amblyopia were analyzed for the effect on visual outcome.

RESULTS

The mean age of the patients was 5.69 +/- 2.01 years (3 to 12 years). Mean follow-up time was 3 years 2 months (6 months to 10 years). Mean visual acuity improvements were similar for the subtypes of amblyopia (strabismic amblyopia 0.38 +/- 0.29 logMAR units, strabismic-anisometropic amblyopia 0.46 +/- 0.40 logMAR units, anisometropic amblyopia 0.35 +/- 0.24 logMAR units). Level of initial visual acuity, age at initiation of treatment and type of occlusion correlated with the final visual acuity (p = 0.000, p = 0.035, p = 0.012, respectively). When the analysis was performed according to the subtypes of amblyopia, initial visual acuity was the only factor associated with the final visual acuity in all types of amblyopia (p < 0.05).

CONCLUSION

The level of initial visual acuity is the most significant factor determining the success of treatment in amblyopia.

Interventions for unilateral refractive amblyopia

BACKGROUND

Unilateral refractive amblyopia is a common cause of reduced visual acuity in childhood, but optimal treatment is not well defined. This review examined the treatment effect from spectacles and conventional occlusion.

OBJECTIVES

Evaluation of the evidence of the effectiveness of spectacles and or occlusion in the treatment of unilateral refractive amblyopia.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and LILACS. Relevant conference proceedings were manually searched. There were no date or language restrictions. The searches were last run on 7 July 2008.

SELECTION CRITERIA

Randomised controlled trials of treatment for unilateral refractive amblyopia by spectacles, with or without occlusion were eligible. We included studies with participants of any age.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed abstracts identified by the searches. We obtained full text copies and contacted study authors where necessary. Eight trials were eligible for inclusion. Data were extracted from seven. No meta-analysis was performed.

MAIN RESULTS

For all studies mean acuity (standard deviation (SD)) in the amblyopic eye post treatment is reported.Comparison: Spectacles only versus no treatment (Clarke 2003). Mean (SD) visual acuity: spectacles group 0.31 (0.17); no treatment group 0.42 (0.19). Mean difference (MD) between groups -0.11 (borderline statistical significance: 95% confidence interval (CI) -0.22 to 0.00).Comparison: Spectacles plus occlusion versus no treatment (Clarke 2003). Mean (SD) visual acuity: full treatment 0.22 (0.13); no treatment 0.42 (0.19). Mean difference between the groups -0.20 (statistically significant: 95% CI -0.30 to -0.10).Comparison: Spectacles plus occlusion versus spectacles only: Clarke 2003 MD -0.09 (borderline statistical significance 95% CI, -0.18 to 0.00); PEDIG 2005b; MD -0.15 (not statistically significant 95% CI -0.32 to 0.02); PEDIG 2006a; MD 0.01 (not statistically significant 95% CI -0.08 to 0.10).Comparison: Occlusion regimes. PEDIG 2003a: 2 hours versus 6 hours for moderate amblyopia: MD 0.01 (not statistically significant: 95% CI -0.06 to 0.08); PEDIG 2003b: 6 hours versus full-time for severe amblyopia: MD 0.03 (not statistically significant: 95% CI -0.08 to 0.14). Stewart 2007a: 6 hours versus full-time occlusion: MD -0.12 (not statistically significant: 95% CI -0.27 to 0.03)

AUTHORS' CONCLUSIONS

In some cases of unilateral refractive amblyopia it appears that there is a treatment benefit from refractive correction alone. Where amblyopia persists there is some evidence that adding occlusion further improves vision. It remains unclear which treatment regimes are optimal for individual patients. The nature of any dose/response effect from occlusion still needs to be clarified.

The age-dependent effect of anisometropia magnitude on anisometropic amblyopia severity

INTRODUCTION

Anisometropia is an important cause of amblyopia. The relationship between anisometropia depth and amblyopia magnitude is not well characterized, as previous studies have been limited to patients identified because of their amblyopia. We analyzed results from anisometropic patients identified with photoscreening to eliminate this selection bias.

METHODS

We performed a retrospective observational study of preschool children with anisometropia >1.0 D identified during a statewide photoscreening program. Nine hundred seventy-four children with anisometropia were detected over a 9-year period. Visual acuity, cycloplegic refraction data, and patient age from a formal follow-up examination were analyzed. Effect of anisometropia magnitude on amblyopia was measured by ordinal logistic regression, taking age into account.

RESULTS

Six hundred forty (65.7%) children had amblyopia > or =2 lines. Three hundred sixty-four (37.4%) had > or =4 lines amblyopia. There was a statistically significant increase in risk of amblyopia with increasing magnitude of anisometropia. Calculated odds ratios for amblyopia with maximal meridional anisometropia of > or =2 to <4 D compared with >1 to <2 D was 2.13 (95% CI [1.63, 2.78], p < 1 x 10(-7)), and 2.34 (95% CI [1.67, 3.28], p < 1 x 10(-6)) when comparing > or =4 D to > or =2 to <4 D. Odds ratios for spherical equivalent anisometropia were also highly statistically significant.

CONCLUSIONS

Children with higher magnitudes of anisometropia had higher prevalence and greater depth of amblyopia. Older children had an increased risk of amblyopia compared with younger children for moderate levels of anisometropia. Low magnitude anisometropia in young children may not predispose to amblyopia; these findings have implications for vision screening criteria at various ages.

Vision First, a program to detect and treat eye diseases in young children: the first four years

PURPOSE

The Vision First program began in the fall of 2002 as a community outreach initiative by the Cleveland Clinic Cole Eye Institute in partnership with the Cleveland Metropolitan School District. It was designed to provide free eye examinations to all prekindergarten, kindergarten, and first grade students enrolled in Cleveland City public schools in order to diagnose refractive errors, amblyopia, and strabismus, so that treatment is instituted and the best possible visual outcome attained.

METHODS

Examinations are performed in 2 lanes of a specially outfitted recreational vehicle. All children undergo monocular visual acuity testing at distance and near, stereopsis testing, cover testing at distance and near, testing of versions, and external ocular inspection. If a child fails any part of this examination according to the guidelines set by the American Academy of Pediatrics, cycloplegic drops are instilled and an optometrist refracts the child on location and performs indirect ophthalmoscopy. Glasses are prescribed and follow-up with a pediatric ophthamologist is arranged.

RESULTS

During the first 4 years of the program, 22,988 examinations were performed. Seven percent of children had errors of refraction that necessitated optical correction, about 2.1% had strabismus, and 1.7% had amblyopia. The cost per student per year was around $23 excluding glasses.

CONCLUSIONS

About 10% of 5- and 6-year-old schoolchildren have eye problems that require either glasses or treatment for strabismus or amblyopia. The Vision First model brings eye care professionals to the schools and provides effective comprehensive screening of all children, as well as detailed examination and referral of those with significant eye problems.

Current concepts in the management of amblyopia

Traditional treatment of amblyopia, although still in use and of great value, has recently been challenged by data from studies relative to efficacy of different modalities and regimens of therapy. LogMAR-based acuity charts should be used, whenever possible, for diagnosis and monitoring. Refractive errors of certain magnitude should be prescribed, and correction worn for at least 4 months before occlusion or penalization are used. Occlusion has a linear dose-response effect (1 logMAR line gain per 120 hours of patching), and outcomes of 2 hour/day dosage are similar to more extended therapy, at least in moderate amblyopia, but increasing dosage beyond hastens the response. Pharmacologic, optical, or combined penalization is useful as an alternative or maintaining therapy, and is presumably of particular efficacy in anisometropic amblyopia. At least in moderate amblyopia, atropine penalization is as effective as patching in terms of visual acuity improvement and stereoacuity outcome.

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.

Legislative issues facing pediatric ophthalmology in 2006

PURPOSE OF REVIEW

There has been a surge in legislative activity concerning children's vision in recent years. This review will summarize and compare newly enacted state statutes and review legislation that has been introduced at both the state and federal level. Detailed reference sites are provided and may be a useful resource for those involved in legislative advocacy.

RECENT FINDINGS

The legislative arena has often mirrored the disparate views of ophthalmology and optometry regarding the most appropriate methods for identifying vision problems in young children. While state legislation mandating comprehensive eye examinations for all asymptomatic and risk free children was passed in Kentucky in 2000, no other state since has successfully enacted and implemented similar legislation. In contrast, numerous states, have enacted mandatory preschool vision screening legislation. Federal legislation, introduced separately by ophthalmology and optometry, would provide funds for uninsured children's eye exams, but the two bills have important differences in eligibility requirements. Issues such as eye safety and retinoblastoma detection have also been addressed through the legislative process.

SUMMARY

There has been a myriad of state and federal legislative activity in the area of children's vision. The momentum is likely to continue as additional states file new legislation.

Relationship between anisometropia, patient age, and the development of amblyopia

PURPOSE

Previous studies evaluating the effect of anisometropia on amblyopia development have been biased because subject selection occurred as a result of decreased acuity. Photoscreening identifies anisometropic children in a manner that is not biased by acuity, and allows an opportunity to evaluate how patient age influences the prevalence and depth of amblyopia.

DESIGN

Retrospective observational study of preschool children with anisometropia.

METHODS

A statewide preschool photoscreening program screened 119,311 children and identified 792 with anisometropia >1.0 diopters. We correlated age with visual acuity and amblyopia depth. Results were compared with 562 strabismic children similarly identified.

RESULTS

Only 14% (six of 44) of anisometropic children aged 1 year or younger had amblyopia. Amblyopia was detected in 40% (32 of 80) of 2-year-olds, 65% (119 of 182) of 3-year-olds, and 76% of 5-year-olds. Amblyopia depth also increased with age. Moderate amblyopia prevalence was 2% (ages 0 to 1), 17% (age 2), and rose steadily to 45% (ages 6 to 7). Severe amblyopia was rare for children aged 0 to 3, 9% at age 4, and 14% at age 5. Children with strabismus had a relatively stable prevalence (30% ages 0 to 2; 42% ages 3 to 4; and 44% ages 5 to 7) and depth of amblyopia.

CONCLUSIONS

Younger children with anisometropia have a lower prevalence and depth of amblyopia than older children. By age 3, when most children undergo traditional screening, amblyopia has usually already developed. New vision screening technologies that allow early detection of anisometropia provide ophthalmologists an opportunity to intervene early, perhaps retarding or even preventing the development of amblyopia.