Amblyopia Outcomes Through Clinical Trials and Practice Measurement: Room for Improvement: The LXXVII Edward Jackson Memorial Lecture

Purpose: To describe amblyopia prevalence and outcomes using results from randomized studies and a clinical registry. Design: Review of published studies, analysis of data in Intelligent Research in Sight (IRIS) Registry from 2013 to 2019, personal perspective. Methods: Literature review, analysis of IRIS Registry data and IRIS-50, a visual acuity quality measure. Results: Clinical trials have reduced the treatment burden of amblyopia by reducing hours of patching and frequency of atropine eye drops with clinical success of about 83%. There is no appreciable age effect if treatment is started before 5 years of age, outcomes are stable to at least 15 years of age, and treatment can be somewhat effective until 12 years of age. The IRIS Registry identified 1,760,066 individuals with amblyopia for a prevalence of 2.47%. Refractive error alone accounted for 68.9% of childhood cases. Mean amblyopic eye visual acuity improved 1.8 lines for children 3-6 years of age and 0.8 lines for 7-12 years, but mean residual amblyopia was more than 2 lines. Among 18,841 children aged 3-7 years eligible for IRIS-50, 77.3% were successful. The odds ratios for success were significantly lower for African-American (0.67; 95% confidence interval [CI] = 0.58 to 0.78) and Hispanic or Latino (0.84; 95% CI = 0.75 to 0.94) children compared with white children. Conclusions: Clinical trials provided evidence of a beneficial effect from several treatments, with substantially reduced doses than previously recommended. Registry data from clinical practice found residual visual acuity impairment among all ages and races, especially among minorities.