Comparing graded anterior transposition with myectomy in primary inferior oblique overaction – A clinical trial

PURPOSE: To compare the effects of graded anterior transposition with myectomy in primary inferior oblique overaction (IOOA). METHODS: In a randomized clinical trial study, patients entered into two groups: graded anterior transposition (Group 1) and myectomy (Group 2). In the myectomy method, 8 mm of the inferior oblique (lO) muscle was excised in the lower temporal side, and in the graded anterior transposition group, the IO muscle was recessed according to Wright's method. Patients were followed up for at least 1.5 months. IOOA was graded from 0 to +4. Surgical success was defined as reduced IOOA to a grade of +1 or less. RESULTS: In a randomized clinical trial study, a total of 30 patients (60 eyes) were included in the study (32 eyes in Group 1 and 28 eyes in Group 2). Pre-operation IOOA was 3.18 ± 0.78 and 3.25 ± 0.70 in Groups 1 and 2, respectively. Mean IOOA in Group 1 and 2 was 0.95 ± 0.24 and 0.40 ± 0.10 at 6 months after the surgery, which means the mean correction of the overaction was statistically significant in both methods (P < 0.001). The success rate in the myectomy procedure was higher than graded recession. The weakening effect was better in higher grades of overaction (P < 0.001). The overall success rate of Groups 1 and 2 was 75% and 96.4%, respectively (P = 0.029). CONCLUSIONS: In both groups, IOOA significantly decreased after the operation. The success rate of the myectomy procedure was found to be significantly higher than graded anterior transposition.