To evaluate the effectiveness of refractive correction alone for the treatment of untreated anisometropic amblyopia in children 3 to <7 years old. Prospective, multicenter, noncomparative intervention. Eighty-four children 3 to <7 years old with untreated anisometropic amblyopia ranging from 20/40 to 20/250. Optimal refractive correction was provided, and visual acuity (VA) was measured with the new spectacle correction at baseline and at 5-week intervals until VA stabilized or amblyopia resolved. Maximum improvement in best-corrected VA in the amblyopic eye and proportion of children whose amblyopia resolved (interocular difference of < or =1 line) with refractive correction alone. Amblyopia improved with optical correction by > or =2 lines in 77% of the patients and resolved in 27%. Improvement took up to 30 weeks for stabilization criteria to be met. After stabilization, additional improvement occurred with spectacles alone in 21 of 34 patients observed in a control group of a subsequent randomized trial, with amblyopia resolving in 6. Treatment outcome was not related to age, but was related to better baseline VA and lesser amounts of anisometropia. Refractive correction alone improves VA in many cases and results in resolution of amblyopia in at least one third of 3- to <7-year-old children with untreated anisometropic amblyopia. Although most cases of resolution occur with moderate (20/40-20/100) amblyopia, the average 3-line improvement in VA resulting from treatment with spectacles may lessen the burden of subsequent amblyopia therapy for those with denser levels of amblyopia.
