The Relationship of Age and Other Baseline Factors to Outcome of Initial Surgery for Intermittent Exotropia

Purpose: To determine whether age at surgery is associated with surgical outcome of intermittent exotropia (IXT) at 3 years. Design: Secondary analysis of pooled data from a randomized trial. Methods: A total of 197 children 3 to <11 years of age with basic-type IXT of 15-40 prism diopters (Δ) were randomly assigned to 1 of 2 surgical procedures for treatment of intermittent exotropia. Masked examinations were conducted every 6 months for 3 years. The primary outcome was suboptimal surgical outcome by 3 years, defined as constant or intermittent exotropia of ≥10 Δ at distance or near by simultaneous prism and cover test (SPCT); constant esotropia of ≥6 Δ at distance or near by SPCT; or decrease in near stereoacuity of ≥2 octaves, at any masked examination; or reoperation without meeting any of these criteria. Results: The cumulative probability of a suboptimal surgical outcome by 3 years was 28% (19 of 72) for children 3 to <5 years of age, compared with 50% (57 of 125) for children 5 to <11 years of age (adjusted hazard ratio = 2.05; 95% confidence interval = 1.16 to 3.60). No statistically significant associations were found between suboptimal outcome and other baseline factors (magnitude of deviation, control score, fixation preference, or near stereoacuity) (P values ≥ .20). Conclusions: This analysis suggests that in children with IXT, younger age at surgery (3 to <5 years) is associated with better surgical outcomes; however, further evidence from a randomized trial comparing immediate with delayed surgery is needed for confirmation.