Abstract
Three rare cases are presented that showed a peculiar set of eye movement disorders in the course of Fisher's syndrome, that is, eye movements similar to internuclear ophthalmoplegia, but with restriction of abduction instead of adduction. Characteristics of the abnormal eye movements are summarized as 1) bilateral restriction of the abduction range, 2) bilateral slowing of adducting saccades, and 3) dissociated nystagmus and/or overshooting of the abducting eyes. The possible mechanisms causing these disorders are discussed, and two hypotheses are proposed: 1) possible impairment of inhibition to the medial rectus and 2) independent peripheral control of phasic and tonic eye movements. The latter explanation, primarily assuming peripheral disorders, was considered more suitable.
