Purpose: To evaluate the prognostic factors, particularly age at the time of surgery, for recurrence after unilateral medial rectus resection and lateral rectus recession (R&R) procedures in patients with intermittent exotropia, or X(T).
Methods: Medical records of 489 subjects who received unilateral R&R procedures with more than 12 months of follow-up were reviewed. The patients' surgical outcomes with a deviation of less than 10 prism diopters (PD) of exotropia and less than 5 PD of esotropia were defined as a success. Outcomes with more than 11 PD of exotropia were designated as recurrences, and those with esotropia of more than 5 PD after 3 months of operation were noted as overcorrection. The prognostic factors for recurrence were analyzed by the multivariate logistic regression test.
Results: Of the 489 subjects, 209 had successful surgical outcomes and 280 had recurrences, whereas overcorrection was not found. Mean age at operation was 8.9 ± 6.5 years, mean preoperative distant X(T) size was 32.9 ± 6.0 PD, and mean follow-up period was 27.5 ± 17.9 months. On the basis of the survival analysis in which survival represented time of recurrence, the mean duration was 31.2 ± 1.7 months. Age at onset, age at surgery, and immediate postoperative alignment proved to be significant factors influencing a favorable outcome by multivariate logistic regression analysis (P<0.05). However, gender, family history, and preoperative deviation size were not significantly predictive of success (P>0.05).
Conclusion: In unilateral R&R procedures, increasing patient age at the time of surgery was associated with lower recurrence rates. Recurrence rates also increased with the immediate postoperative angle and with the postoperative angle of deviation at 1, 3, 6, and 12 months.