Bilateral Lateral Rectus Recession for Exotropia: A Survival Analysis

Exotropia may progress during the childhood years, and the ideal time for surgical intervention remains uncertain. We reviewed our results following bilateral lateral rectus recession in 57 consecutive patients. In order to identify possible predictive covariates, we performed survival analysis using survival time as the time from surgery to failure. The patients' age at the time of surgery ranged from 11 months to 50 years (mean, 68 months). Follow up after surgery ranged from 1 to 105 months (mean, 47 months). Outcomes were considered failures if there was (1) a distance exodeviation greater than 10 prism diopters at any time after surgery, (2) a distance esodeviation greater than 10 delta more than 6 months postoperatively, or (3) further surgery for exotropia or esotropia. By these criteria, surgery was successful in 58% of cases. Results of the survival analysis indicated an estimated mean time to failure of 68 months. Patients with intermittent exotropia were more likely to remain aligned postoperatively than were those with constant deviations. The age at onset of exotropia, age at surgery, angle of deviation at different fixation distances, early postoperative alignment, and presence of symptoms, amblyopia, anisometropia, or incomitance before surgery were not predictive of success. We conclude that exotropia surgery may be performed with the same likelihood of success at any age, but patients with intermittent deviations do better.