Nystagmus

What is Nystagmus?

Nystagmus is a condition characterised by involuntary, repetitive, rhythmic movements of the eyes. These movements may be horizontal, vertical, rotary or mixed, and can occur in one or both eyes. Nystagmus is not a disease in itself but a sign of an underlying condition affecting the motor control of the eyes. In children, nystagmus is usually congenital and associated with albinism, optic nerve hypoplasia, or idiopathic causes. Acquired nystagmus in adults may indicate neurological or inner ear disease.

Symptoms

• Involuntary rhythmic eye movements (may be noticed by others or felt as oscillopsia — the world appearing to wobble)
• Reduced visual acuity
• A preferred head position (null point) where movements are minimised
• Sensitivity to bright light (photophobia), particularly in albinism

Causes

• Congenital idiopathic nystagmus (CIN) — the most common type in children
• Albinism — associated with characteristic pendular nystagmus
• Optic nerve or retinal disease affecting early visual development
• Neurological causes (cerebellar disease, brainstem lesions) — in acquired nystagmus
• Vestibular disorders (inner ear pathology) — positional or gaze-evoked

Diagnosis

Full ophthalmic assessment including visual acuity, refraction, and dilated fundus examination. Electrodiagnostic tests (ERG, VEP) in children. Neuroimaging (MRI) where acquired neurological nystagmus is suspected.

Treatment

Refractive correction to optimise visual acuity. Contact lenses may be better than spectacles in nystagmus. Surgery (Kestenbaum procedure) to move the null point to the primary gaze position. Prismatic correction may reduce head turn. Gabapentin or memantine for acquired nystagmus in selected cases.