Unilateral Anterior Transposition and Resection of the Inferior Oblique Muscle for the Treatment of Hypertropia

BACKGROUND: Anterior transposition of the inferior oblique muscle generally is restricted to bilateral cases because of reports of postoperative ipsilateral hypotropia or significant limitation of elevation when performed unilaterally. We performed unilateral anterior transposition of the inferior oblique muscle in patients with vertical and horizontal strabismus who were at risk of anterior segment ischemia. PATIENTS AND METHODS: Six patients underwent unilateral anterior transposition of the inferior oblique muscle in combination with a resection of the inferior oblique muscle. Two patients had lost an inferior rectus muscle in a previous procedure, and four patients had coexistent horizontal and vertical strabismus of various etiologies as well as poor unilateral vision. RESULTS: All six patients achieved vertical alignment within 10 prism diopters. CONCLUSIONS: Unilateral anterior transposition of the inferior oblique muscle appears to be a useful procedure in selected patients with vertical strabismus.