Isolated paresis of the inferior oblique.

Four cases of isolated superior oblique paresis are presented. The usual course of events was that of a gradually increasing diplopia and head tilt. All patients fulfilled the three-step test criteria, with a hypertropia that increased on side gaze to the ipsilateral side and on head tilt to the side opposite that of the paretic muscle. All patients were treated with a superior rectus recession. Three patients had their hypertropia reduced to between zero and 2 diopters. One patient needed, in addition to his superior rectus recession, an inferior rectus resection to eliminate the hypertropia. Vertical rectus surgery presents an alternative to superior oblique muscle tenotomy in treating inferior oblique paresis.