Nystagmus is an involuntary, shaking, “to and fro” movement of the eyes.

Nystagmus is typically classified as congenital or acquired, with multiple subcategories.

Congenital nystagmus onset is typically between 6 weeks and 3 months of age. Congenital motor nystagmus tends to be horizontal, bilateral, idiopathic (cause unknown) and is sometimes inherited. Sensory nystagmus also occurs early in life and is secondary to poor vision caused by a variety of eye conditions such as cataracts (cloudiness of the eye’s lens), strabismus (eye misalignment) and optic nerve hypoplasia.

Acquired nystagmus occurs later and has many etiologies. Acquired nystagmus can be associated with serious medical conditions.

• Cataract
• Strabismus
• Amblyopia
• Optic nerve hypoplasia
• Leber’s congenital amaurosis
• Aniridia
• Achromatopsia
• Severe refractive error
• Retina coloboma
• Other optic nerve and retina disorders
• Albinism
• Medication use
• Vitamin deficiency
• Fetal alcohol syndrome
• Trauma
• Inner ear (vestibular) problems
• Stroke (most common cause in older people with acquired nystagmus
• Brain tumor (rare cause of acquired nystagmus)

All children and adults with nystagmus should be evaluated by an ophthalmologist (and primary care physician) to determine if any association exists with other conditions.

Nystagmus can be inheritable, sometimes with a strong family history, dominant, recessive and x-linked patterns have been reported. The severity of nystagmus often varies amongst members of an involved family.