Long-term outcomes after same amount of bilateral rectus muscle recession for intermittent exotropia with the same angle of deviation

Purpose: To evaluate long-term outcomes of homogenous bilateral rectus recession in patients with the same preoperative angle of deviation in intermittent exotropia and investigate factors associated with surgical outcomes. Methods: In this retrospective review, patients with the same preoperative angle of deviation who underwent bilateral 6-mm lateral rectus recession between January 2008 and January 2014 were observed for 2 or more years. Patients were classified into two groups based on deviation angle: success (orthophoria or exodeviation < 10 prism diopters [PD]) or recurrence (exodeviation ≥ 10 PD). Preoperative and postoperative ophthalmologic factors were compared between groups. Results: The success and recurrence groups contained 50 and 49 patients, respectively. Preoperative maximum angle of deviation was 29.0 ± 1.8 PD at distance in the success group and 28.9 ± 1.8 PD in the recurrence group. Deviation at the 2-year follow-up was 3.7 ± 3.7 and 18.3 ± 5.3 PD in the success and recurrence groups, respectively (P < .001). Preoperative factors were not significantly different between groups except for presence of lateral incomitance; success group patients presented more lateral incomitance (P = .035). The success group also presented more esodeviation just after the operation and showed a more stable course during follow-up. Surgical outcomes of patients with 10 PD or more of esodeviation 1 week postoperatively were significantly more favorable than patients with less than 10 PD of esodeviation (P = .027, log-rank test). Conclusions: Presence of lateral incomitance and early postoperative overcorrection were significantly associated with favorable surgical outcome and should be considered when planning intermittent exotropia surgery.