Efficacy and stability of amblyopia therapy.

To determine the efficacy and stability of therapy, we reviewed the charts of 64 amblyopes with strabismus and/or anisometropia who had been treated by direct occlusion. For patients aged 7 years or less (N = 39), 90% (35/39) showed some acuity gain, with 69% (27/39) achieving at least a doubling of acuity (0.3 log units). Fifty-four percent obtained 20/40 (6/12) or better after an average treatment period of 3.8 months. Some reduction in visual acuity (VA) subsequently occurred for 75% (24/32) of those patients followed. For patients aged 8 years or more (N = 26), 77% (20/26) showed some acuity gain with 31% (8/26) improving at least 0.3 log units. Twenty-seven percent (7/26) obtained 20/40 (6/12) or better after an average treatment period of 4.2 months, although no patients older than 10 years (N = 13) achieved 20/40 (6/12). Loss of some of the acuity gain subsequently occurred for 67% (12/18) of those followed. These findings indicate that VA can be improved by patching therapy in most patients older than 7 years, but the acuity improvement is somewhat less than in younger patients. At least 67% of all amblyopes followed for 1 year lost some of the acuity gain after cessation of therapy, regardless of the age when treated. As a reduction of the acuity gain is likely to occur within the first year after cessation of therapy, it is recommended that amblyopic patients of all ages be followed at regular intervals.