Changes in the interpupillary distance following general anesthesia in children with intermittent exotropia: A predictor of surgical outcomes

Purpose: To determine whether changes in ocular alignment following general anesthesia, as measured by interpupillary distance, can be used as a predictor for surgical outcomes in children with intermittent exotropia. Methods: The authors obtained digital photographs of 40 children with exotropia and 20 children with epiblepharon (control group) before and immediately after induction of general anesthesia in the primary supine position. Differences in the anatomic interpupillary distance (aIPD) for each patient were measured and compared with the preoperative angles of deviation. They were also correlated with surgical outcomes on the first day and 1 year after surgery. Results: All 60 patients demonstrated an increase in aIPD following general anesthesia. The mean change in aIPD in patients with exotropia was similar to that in patients with epiblepharon (3.78% ± 2.53% and 3.15% ± 1.05%, respectively). In patients with exotropia, there was a significant positive linear correlation between the preoperative distance deviation (P) and the change in eye position (A): A = 0.362 P - 4.488, r² = 0.476 (P < .001). Five (71%) of seven patients whose changes were outside the 80% confidence interval for expected values had poor surgical outcomes on the first postoperative day and four had unsatisfactory results 1 year after surgery. Conclusions: Changes in aIPD following general anesthesia were strongly correlated with preoperative angle of deviation. Therefore, they may be a useful predictor of surgical outcomes in children with exotropia.