Cryptogenic unilateral paralysis of the superior oblique muscle.

Fifteen patients spontaneously developed paralysis of one superior oblique muscle, which remained unexplained after an initial evaluation. Follow-up evaluation showed that all of the patients' conditions were improved. Twelve of the patients had enjoyed spontaneous, functional recoveries within four months. Three had residual diplopia that was relieved by prisms. No patient subsequently developed evidence of any local or systemic disease that could explain the ophthalmoplegia. One patient suffered a recurrence 3 1/2 years after his first episode that lasted three months and spontaneously cleared.