Bilateral medial rectus muscle recession for divergence insufficiency pattern esotropia

Purpose: We have identified a group of mostly elderly patients characterized by chronic, slowly progressive esotropia with diplopia at distance. This study was undertaken to analyze the outcomes after bilateral medial rectus muscle recessions in this group of patients with a divergence insufficiency pattern of esotropia. Materials and methods: This is a retrospective consecutive case series of eight patients treated for divergence insufficiency pattern esotropia with bilateral medial rectus muscle recessions. Results: Age at presentation was 44 to 77 years (mean age, 60) and symptoms of diplopia at distance had been present between 3 and 30 years (mean, 12.6). Six patients had been managed with progressively larger amounts of base-out (BO) prism in their distance correction over an average of 12.5 years. Each patient had a manifest esotropia at distance and smaller or no deviation at near. The mean preoperative esodeviation was 20.4 prism diopters (range, 12 to 35) at distance and 5.4 PD (range, 0 to 18) at near with a mean distance-near difference of 15.0 PD. Bilateral medial rectus muscle recession of 3.0 to 4.25 mm (mean 3.5) was performed on each patient. The mean postoperative esodeviation at distance was 3.4 PD (range 0 to 10) and the mean near deviation was 1.8 PD exophoria (range, 8 PD exophoria to 10 PD esotropia) with a mean distance-near difference of 5.1 PD. Three patients still required some prism in their spectacles for the relief of diplopia postoperatively (2 BO, 8 BO, 10 BO). The mean follow-up period was 8.5 months (range, 6 weeks to 46 months). Conclusions: Bilateral medial rectus muscle recession is an effective treatment for slowly progressive divergence insufficiency pattern esotropia in elderly patients. The reduction in the difference between the distance and near magnitudes of esodeviation afforded by this treatment suggests that a subtle loss of medial rectus muscle elasticity is the etiology.