Moderate Amblyopia in Children Less than Seven Years of Age: Experience of the Amblyopia Treatment Study 1

A cohort of 419 children with moderate amblyopia participated in Amblyopia Treatment Study 1. These children were less than seven years of age with strabismic, anisometropic or combined amblyopia and visual acuity in the amblyopic eye from 6/12 to 6/30. The average age was 5.3 years. The cause was strabismus in 38%, anisometropia in 37%, and combined in 24%. The mean acuity of the amblyopic eyes was 0.53 logMAR. For patients randomized to patching, 43% were treated initially with 6 hours per day of occlusion, while 17% were treated with full-time occlusion. A similar level of visual impairment was found irrespective of the cause of the amblyopia. The visual acuity of the sound eyes of strabismic patients was significantly worse than that of patients with anisometropia (P <0.001). There was considerable variation in patching treatment practices.