Cyclodeviation in acquired vertical strabismus.

The prevalence and pattern of cyclodeviation can differentiate among superior oblique palsy, dysthyroid ophthalmopathy, myasthenia gravis, and skew deviation. Excyclodeviation was detected in 30 of 33 patients with superior oblique palsy, eight of 15 patients with dysthyroid ophthalmopathy, three of six patients with nondysthyroid restrictive ophthalmopathy, and one of 13 patients with myasthenia. No cyclodeviation was found in cases of skew. Incyclodeviation was found in two patients with dysthyroid ophthalmopathy, two with nondysthyroid restrictive ophthalmopathy, and three with myasthenia. The amount of cyclodeviation did not vary between head-tilt positions, but did vary between primary and eccentric gaze positions, usually in the same direction as the amount of hyperdeviation. The patient's awareness of the presence of cyclodeviation varied with the degree of cyclodeviation, being 100% (4/4) for 15 degrees, 86% (12/14) for 10 degrees, and only 55% (11/21) for 5 degrees.