Extraocular Muscle Imaging in Complex Strabismus

Abstract

Abnormalities of extraocular muscle are an unusual cause of complex strabismus. The traditional evaluation based on clinical examinations is insufficient for the interpretation of incomitant motility disorders resulting from extraocular muscle anomalies. Extraocular muscle imaging by computed x-ray tomography (CT) or magnetic resonance imaging (MRI) can provide useful information for diagnosis, pathophysiology, and treatment of complex strabismus. Five cases of complex strabismus resulting from congenital anomalies of the extraocular muscles and their successful evaluation using extraocular muscle imaging are described. Orbital CT or MRI scan was obtained in five patients who had unusual incomitant strabismus. It confirmed the diagnosis of the absence of the medial rectus muscle, accessory lateral rectus muscle, atrophy of the inferior or both superior and medial rectus muscles, and abnormal thickening of the levator palpebrae superioris and superior rectus muscle. Extraocular muscle imaging is a useful technique for evaluating anatomic abnormalities. It should be considered when evaluating patients with atypical strabismus.