To evaluate factors predicting resolution of amblyopia and the time course of improvement in VA in children 3 to 7 years old with anisometropic amblyopia treated with spectacles alone.

Prospective, noncomparative intervention.

Measurement of corrected amblyopic logMAR visual acuity (VA) in newly diagnosed children at four-weekly intervals until VA stabilized or amblyopia resolved. The time course of improvement in VA and the factors related to amblyopia resolution were assessed.

Sixty children with a mean age of 5.3 years and mean anisometropia of 2.95 diopters (D) were included. Amblyopia improved by 2 or more logMAR lines in 56 patients (93%) and resolved in 27 patients (45%), with a mean improvement in VA of 0.38 logMAR. The improvement in VA in the amblyopic eye was considerable at four to 12 weeks then reached a plateau, after which it improved only slowly. Resolution of amblyopia was related to better initial VA (0.2 to 0.6 logMAR) and lesser amounts of anisometropia (<4 D). The time to resolution ranged from four to 40 weeks, but no patient with residual amblyopia showed an improvement in VA of more than 0.1 logMAR over four consecutive visits.

With spectacle correction alone, 3- to 7-year-old children with previously untreated anisometropic amblyopia achieved approximately four-line improvement and resolved nearly in half. The nearly two-month plateau periods during improvement of VA should be noticed. After four months with no improvement in VA, occlusion therapy or atropine penalization may be considered.