Long-term results of bifocal therapy for accommodative esotropia.

We studied the long-term course of 65 accommodative esotropes who required bifocals to maintain alignment at near. Average follow-up was 10.5 years. Forty patients (61.5%, group DC [bifocals discontinued]) were able to discontinue bifocal use after an average of 5.5 years wear. Twenty-five (38.5%) continued to wear bifocals (or a suitable alternative such as reading glasses), after an average 9.7 years of follow-up. Surgical correction of deteriorated accommodative esotropia was performed for 20 patients (50%) in group DC, and nine (36%) of those in group C[bifocals continued]. Surgery produced an average reduction in the accommodative convergence relationship (near esodeviation in prism diopters [pd] minus corrected distance measurement, AC/A) of approximately 10 pd in both groups. Surgical patients unable to discontinue bifocal wear began with a clinically higher AC/A than those in group DC. Non-surgical patients in group DC experienced spontaneous improvement of the AC/A over time (average, 6.2 pd). On average, this did not occur in those of group C. Average age of bifocal discontinuation was 9.7 years in surgical patients and 9.3 years in the non-surgical. Surgical patients had significantly lower hyperopia (+2.4 diopters [D]), than non-surgical (+3.5 D), and an earlier age of onset of bifocal wear (3.29 versus 4.64 years). Although bifocals may be successfully discontinued in a majority of patients at an average age of 9.5 years, a significant percentage require long-term wear, some, despite surgery. The only factor that predicted long-term bifocal wear was a relatively high AC/A.