Matthew J. Thurtell, R. John Leigh

Patients with congenital and acquired forms of nystagmus are commonly encountered in clinical practice. Many report visual symptoms, such as oscillopsia and blurred vision, which can be alleviated if the nystagmus can be suppressed. Pharmacologic, optical, and surgical treatments are available, with the choice of treatment depending on the characteristics of the nystagmus and the severity of the associated visual symptoms. Downbeat nystagmus can be treated with 4-aminopyridine, 3,4-diaminopyridine, or clonazepam. Upbeat nystagmus can be reduced with memantine, 4-aminopyridine, or baclofen. Torsional nystagmus may respond to gabapentin. Acquired pendular nystagmus in patients with multiple sclerosis is often partially suppressed by gabapentin or memantine. Acquired pendular nystagmus in patients with oculopalatal tremor can respond to gabapentin, memantine, or trihexyphenidyl. Although acquired periodic alternating nystagmus is often completely suppressed by baclofen, memantine can be effective in refractory cases. Seesaw nystagmus can be reduced with alcohol, clonazepam, or memantine. Infantile nystagmus may not cause significant visual symptoms if "foveation periods" are well developed, but the nystagmus can be treated in symptomatic patients with gabapentin, memantine, acetazolamide, topical brinzolamide, contact lenses, or base-out prisms to induce convergence. Several surgical therapies have also been reported to improve infantile nystagmus syndrome (INS), but selection of the appropriate therapy requires preoperative evaluation of visual acuity and nystagmus intensity in different gaze positions. Other treatment options for nystagmus include botulinum toxin injections into the extraocular muscles or retrobulbar space. Electro-optical devices are currently being developed, in order to noninvasively negate the visual consequences of nystagmus.