Thyroid-associated orbitopathy with superior oblique muscle involvement: a case report.

A 29-year-old male with a 5-year-history of hyperthyroidism complained of diplopia and proptosis. After subtotal thyroidectomy, he still had diplopia in a certain gaze. Computerized tomography showed inferior rectus muscle enlargement in the right eye and inferior rectus, medial rectus, and superior oblique muscle enlargement in the left eye. Ocular examination with the cover and uncover test revealed hyperphoria and exophoria in the left eye. The upward gaze of the right eye was more limited than that of the left eye. Since superior oblique muscle involvement in patients with thyroid orbitopathy is quite rare, we discuss its effect on ocular motility in patients with thyroid-associated orbitopathy.