TENOTOMY OF THE SUPERIOR OBLIQUE MUSCLE FOR HYPERTROPIA

THE PURPOSE of this article is to describe a simple, effective and reliable surgical procedure for the cure of hypertropia associated with overaction of the superior oblique muscle. Hypertropia is due to weakness of one or more of the vertically acting extraocular muscles. This weakness may be acquired or congenital. It may be due to a structural weakness of the muscle itself, to an anomalous insertion of the muscle tendon or to abnormal innervation. Of 107 cases of congenital paralyses of the vertically acting extraocular muscles, Duane 1 found the superior rectus muscle affected in 58 (54 per cent), the inferior rectus muscle in 36 (33 per cent), the superior oblique muscle in 7 (7 per cent) and the inferior oblique muscle in 6 (6 per cent). In a critical analysis of 1,955 cases of anomalies of the extraocular muscles, White and Brown 2 found the vertically acting muscles affected