Risk factors associated with poor outcome after medial rectus resection for recurrent intermittent exotropia.

Purpose: To describe characteristics of recurrent intermittent exotropia after bilateral lateral rectus (BLR) recession, and identify factors associated with poor outcome after unilateral medial rectus (MR) resection for recurrent intermittent exotropia.

Methods: We retrospectively reviewed 124 patients who have undergone unilateral MR resection for recurrent intermittent exotropia after BLR recession. Patients were followed for at least 2 years after MR resection. Clinical characteristics and risk factors associated with poor outcome after unilateral MR resection were evaluated. Successful outcome was defined as distant deviation within the range of 4 prism diopters (PD) esotropia and 10 PD exotropia at last visit after MR resection.

Results: Among 124 patients, 50 patients (41.1%) were male, and the mean age at the time of MR resection was 9.5 ± 3.1 years. The average follow-up period after MR resection was 43.8 ± 23.7 months. Forty-seven patients (37.9%) were classified to have poor outcome at last visit, and 29 patients (23.4%) underwent third operation. None of the patients was overcorrected after MR resection. Multiple logistic regression analyses showed that distant deviation at post-operative 3 months and male gender were associated with poor outcome (OR 1.49; 95% CI 1.27-1.73; P < 0.001, and OR 5.19; 95% CI 1.42-18.98; P = 0.013, respectively).

Conclusion: Ocular deviation at 3 months after unilateral MR resection for recurrent intermittent exotropia may play a valuable role in anticipating poor outcome. Patients whose exotropia exceeded 9 PD at distance at 3 months' follow-up tended to recur while those whose exotropia remained below 9 PD at distance showed a stable disease course.