Amblyopia Risk Factor Prevalence

PURPOSE: In 2003, the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) published a set of risk factors for amblyopia. The intent was to promote uniformity of reporting and development in screening. Because this prevalence is not yet known, this meta-analysis is an attempt to estimate it. METHODS: Major community preschool eye examination studies were reviewed and AAPOS cut-offs estimated. RESULTS: The approximate prevalence of anisometropia is 1.2%, hyperopia is 6%, astigmatism is 15%, myopia is 0.6%, strabismus is 2.5%, and visual acuity less than 20/40 is 6%. The mean combined prevalence is 21% ± 2% compared to a prevalence of amblyopia 20/40 and worse of 2.5%. CONCLUSIONS: Knowing risk factor prevalence simplifies validation efforts. Amblyopia screening with a risk factor sensitivity less than 100% is expected and desirable.