Changes in binocular function in anisometropic nonstrabismic children with optical correction and occlusion therapy

PurposeTo identify factors that influence binocular function in anisometropic, nonstrabismic children before and after optical correction and amblyopia therapy.MethodsThis was a prospective observational study of consecutive patients with nonstrabismic anisometropia. Visual acuity and responses to the 4Δ base-out prism test, the Worth 4-dot test, and the TNO test were recorded after spectacle correction and every 3 months for 1 year. Factors affecting visual acuity and binocular function were analyzed using univariate and multiple stepwise regression analysis.ResultsA total of 118 subjects were enrolled. At the end of the first year, the mean improvement in visual acuity was 2.6 ± 2.3 lines. The percentage of patients showing a positive response to the 4Δ base-out prism test increased from 47% to 79%; fusion in the Worth 4-dot test, from 37% to 66%; and measurable stereopsis on TNO testing, from 59% to 80%. Better initial visual acuity and better final visual acuity were associated with better binocular function. Interocular refractive error difference was a predictor of poor binocular function in multiple regression analysis if the difference in spherical error exceeded 4 D. Patients with amblyopia showed significantly worse binocular function compared to those with no amblyopia.ConclusionsBinocular function of anisometropic children can be improved with refractive correction and amblyopia therapy.