Surgical Dosing for Correction of Consecutive Exotropia

Because surgical tables have not previously been available for consecutive exotropia, this study aimed to determine the appropriate surgical dosing for medial rectus (MR) advancement in this condition.

Retrospective case series.

Data were reviewed for patients with consecutive exotropia who underwent MR advancement with or without lateral rectus (LR) recession.

A total of 44 patients were included averaging 35 ± 20 (stamdard deviation ) years of age. Mean preoperative exotropia was 29 ± 15∆ at distance and 33 ± 19∆ at near. Thirty-four patients underwent unilateral or bilateral MR advancement, and 10 patients underwent MR advancement combined with LR recession. For the MR advancement group, mean advancement was 4.9 ± 1.4 mm. At the last follow-up visit, exotropia at distance was reduced from 26 ± 12∆ to 7 ± 11∆. For the MR advancement + LR recession group, mean MR advancement was 6.2 ± 2.0 mm, and the mean total surgical dose, including LR recession, was 14.6 ± 4.7 mm. Overall, distance exotropia at last follow-up was surgically reduced from 39 ± 18∆ to 9 ± 14∆. Exodrift from initial to final follow-up was 6.6∆ for MR advancement alone and 7.5∆ for MR advancement + LR recession. Regression analysis of surgical dose-response suggests that each MR advancement should be augmented by 2 mm more than Parks' general surgical recommendation for treating exotropia by MR resection.

Augmentation of MR advancement may improve the correction of consecutive exotropia and is effective while affording opportunity to explore the MR muscle.