Vertical abnormal retinal correspondence in three patients with congenital absence of the superior oblique muscle.

Three patients with large vertical deviations diagnosed as palsy of the superior oblique muscle were found to have a congenital absence of the muscle during surgery. They also showed large, vertical abnormal retinal correspondence, which caused paradoxical vertical diplopia when the deviations were corrected with Fresnel membrane prisms or surgery. Each patient showed large, long-standing, vertical deviations for which head tilting could not have compensated.