Anterior transposition vs anterior and nasal transposition of inferior oblique muscle in treatment of dissociated vertical deviation associated with inferior oblique overaction

Purpose To compare results of two surgical techniques; anteriorization (ATIO) vs anterior nasalization (ANT) of IO muscle in management of DVD associated with IOOA. Methods Twenty-one patients with DVD associated with IOOA were included in this study. Group A consists of 11 patients who underwent ATIO and group B with 10 patients who underwent anterior transposition of IO to the nasal border of inferior rectus ANT. All patients were followed for at least 6 months postoperatively. The primary outcome variables were changes in DVD in primary position and side gazes, IO action and V pattern. Results The average of correction of DVD in primary position, in adduction and in abduction was 10.63 PD, 24.6 PD ( P 0.05) in ATIO group and 14.6 PD, 25.2 PD and 1.7 PD ( P