Anterior transposition of the inferior oblique in the treatment of unilateral superior oblique palsy.

Anterior transposition of the inferior oblique (ATIO), is an accepted surgical procedure for the treatment of primary inferior oblique overaction and dissociated vertical deviation. Our study was undertaken to see if ATIO could be useful in the treatment of preselected unilateral superior oblique palsy (SOP) patients. Three consecutive patients with unilateral SOP with preoperative primary-position hypertropia averaging 27 delta, Knapp class V, underwent ATIO. The results were excellent and none of these patients developed primary-position hypotropia. Complications of ATIO in our patients consisted of some elevation deficiency, elevation of the lower lid in upgaze, and reduced inferior "scleral show" in the surgically treated eye. We are proposing that ATIO be considered as a beneficial operation in unilateral SOP patients with at least 25 delta of preoperative primary-position hypertropia.