Sensory results after lateral rectus muscle recession for intermittent exotopia operated before two years of age

Abstract

Introduction: Early surgical treatment of early-onset intermittent exotropia is controversial. The condition does not always progress and postoperative esotropia can produce adverse consequences, such as suppression, amblyopia, and loss of binocular vision, particularly stereopsis. It is not known whether surgery prior to age 2 years improves or worsens the prospects for normal sensory outcome. Methods: We reviewed medical records of 23 patients with intermittent exotropia with onset before age 1 year and also received bilateral lateral rectus muscle recessions prior to age 2 years. Ten were identified who received follow-up examinations at age = 4 years, when testing with Worth 4-Dot and Titmus stereo circles would likely be reliable. Results: Mean age at follow-up examination was 82 months. Stereoacuity was measured at 40 arcsec in three patients, 100 arcsec in two patients, 140 to 400 arcsec in two patients, and none in three patients. Among the three patients without demonstrated stereoacuity, one had a history and clinical course consistent with congenital exotropia, and two were developmentally delayed. Overall, seven patients (70%) had favorable motor alignment, defined as a phoria or intermittent tropia <10Δ at distance or near with no deviation >15Δ. No patient required treatment for amblyopia. Conclusions: Early-onset intermittent exotropia appears to respond well to surgical treatment. Sensory outcomes demonstrate that high-grade stereopsis can be achieved in some cases. More than one clinical entity presenting as intermittent exotropia in infancy probably exists. It is not clear whether early surgical intervention improves sensory outcomes over nonsurgical management.