Head and eye movements in congenital nystagmus

Patients with congenital nystagmus exhibit a wide range of unusual nystagmus waveforms and strategies to obtain maximum visual acuity. We investigated target acquisition strategies, head-eye coordination, and the effects of alteration of head position relative to gravity on congenital nystagmus waveforms in five patients. No changes in the nystagmus were found when patients ' heads were placed in different positions relative to gravity. Two patients had distinctive abnormalities of head-eye coordination characterized both by failure of eye move-ment to precede head movement and by position of the eye In the orbit, after target acquisition, being In a direction opposite that of the head movement. We conclude that static changes in head position relative to gravity probably do not influence congenital nystagmus waveforms. In addition, some patients with congenital nystagmus may have abnormal head-eye coordination. (OTOLARYNGOL HEAD NECK SURG 92:656. 1984.) Congenital nystagmus is an oculomotor disorder characterized by involuntary eye movements that im-pair the ability to maintain visual targets on the fovea. 1 These involuntary eye movements are usually horizon-tal and increase in severity during attempted fixation. Yee et al. " studied vestibulo-ocular function in 41 pa-tients with congenital nystagmus. In 15 % the average eye position during sinusoidal rotation was abnormal, deviating tonically toward the side of the orbit in the direction of the slow component of the induced nys-tagmus. This abnormality was considered to be sec-ondary to a defect in fast-phase initiation. Such patient