Nystagmus

Involuntary rhythmic eye oscillations

Overview

Nystagmus is an involuntary, rhythmic oscillation of the eyes, which may be horizontal, vertical, torsional, or mixed. Infantile nystagmus appears in the first months of life, either as a result of visual sensory disorders such as albinism, achromatopsia, aniridia, or congenital cataract, or without an identified cause as idiopathic motor nystagmus. People with infantile forms generally do not perceive the world as moving, and many adopt a head posture that places the eyes in a null zone where the oscillation is least. Acquired nystagmus develops later in life from conditions affecting the brainstem, cerebellum, or vestibular system, including multiple sclerosis, stroke, tumors, and the effects of drugs or alcohol, and it often causes oscillopsia, the illusion that the surroundings are moving. Certain patterns, such as downbeat nystagmus, point to particular locations of disease. Management depends on the type and can include optical correction, prisms, medications for some acquired forms, and eye muscle surgery to shift the null zone.