Surgical outcomes of inferior oblique muscle weakening procedures for eliminating inferior oblique muscle overaction: a prospective randomized study

Abstract

Purpose The aim of this study was to evaluate the outcomes of weakening surgical procedures for eliminating inferior oblique muscle overaction (IOOA). Patients and methods A prospective randomized interventional study was performed on 20 eyes of 12 patients with IOOA. The eyes were classified randomly into three groups. The first group included six eyes treated with inferior oblique (IO) myotomy. The second group included eight eyes treated with IO myectomy. The third group included six eyes treated with IO muscle recession. The ductions, versions, and degree of IOOA were analyzed in all patients before and after surgery. Patients were included in the study only if they achieved a minimal follow-up period of 3 months. Results Orthotropia was achieved in 13 (65%) eyes: three (15%) eyes in IO myotomy group, five (25%) eyes in IO myectomy group, and five (25%) eyes in IO recession group. One (5%) eye of IO myotomy group showed residual degree of IOOA. Underaction of IO occurred in one (5%) eye of IO myectomy and recurrence occurred in five (25%) eyes of all groups. Conclusion Recession is the most effective procedure to eliminate IOOA, whereas myectomy at insertion is the second most effective procedure and myotomy is the least effective procedure.