One-muscle surgery in small-angle residual esotropia

PURPOSE: To report the outcome of unilateral lateral rectus resection for treatment of small-angle residual esotropia following bilateral medial rectus muscle recession. METHODS: A retrospective medical record review was performed for all patients who had undergone bilateral medial rectus muscle recession for congenital esotropia prior to 6 years of age that required further surgical treatment of residual esotropia. We compared two different dosing strategies for resection of a single lateral rectus muscle in the nondominant eye. In group 1, the amount of resection was calculated by doubling the angle of strabismus and applying the recommended surgical dosage to one lateral rectus muscle. In group 2, the amount of unilateral resection was the same as the bilateral dosage for the measured angle, but augmented by 1.5 mm. Postoperative evaluation was performed 1 and 6 months after surgery. RESULTS: Data from 35 patients were analyzed, 17 in group 1 and 18 in group 2. No significant intergroup difference was noted in terms of age at first surgery (p = 0.266), initial surgical dosage (p = 0.693), residual angle of esotropia (p = 0.881), or age at reoperation (p = 0.679). Postoperative alignment was better in group 1 patients at 6 months than at 1 month (residual deviation 3.5(Delta) versus 6.7(Delta), p = 0.022). CONCLUSIONS: Resection of a single lateral rectus muscle with the surgical dosage calculated by doubling the angle of strabismus and applying the recommended surgical dosage to one lateral rectus muscle is a treatment option for patients with small-angle residual esotropia following bilateral medial rectus muscle recession