To evaluate the efficacy of unilateral lateral rectus muscle advancement surgery based on one-fourth of the angle of consecutive esotropia within 25 prism diopters (PD) which occurred after bilateral lateral rectus muscle recession for intermittent exotropia.

Medical records of 11 patients who underwent unilateral lateral rectus muscle advancement for consecutive esotropia from 2011 to 2014 and who were observed for at least 6 months after surgery were retrospectively reviewed. The change in the angle of deviation before and after consecutive esotropia surgery, success rate, and surgical effect were evaluated.

Preoperative esodeviation was -19.6 ± 4.7 PD at distance and -16.5 ± 7.4 PD at near. Unilateral lateral rectus muscle advancement surgeries were performed based on one-fourth of the angle of consecutive esotropia and the mean surgical amount was 4.8 ± 1.1 mm. Of the total 11 patients, 10 patients (91%) recovered to orthotropia or exodeviation within 8 PD. One patient had a recurrence of esotropia at postoperative 3 months, but the patient recovered to orthotropia at postoperative 12 months with alternative patch treatment and a prism glass prescription. The surgical effect of unilateral lateral rectus muscle advancement was 3.3 ± 0.7 PD/mm at postoperative 1 day, 3.7 ± 0.6 PD/mm at postoperative 1 week, and 3.8 ± 0.7 PD/mm at postoperative 6 months.

Unilateral lateral rectus muscle advancement surgery based on one-fourth of the angle of consecutive esotropia within 25 PD was successful in all 11 cases. The surgical effect was significantly greater in unilateral lateral rectus muscle advancement than in primary lateral rectus muscle recession. Thus, reduction in the amount of surgery should be considered carefully in unilateral lateral rectus muscle advancement for consecutive esotropia.