Nystagmus

Definition

Nystagmus is an involuntary, rhythmic oscillation of the eyes, usually in a horizontal, vertical, or rotatory direction. It may be congenital (usually benign) or acquired (indicates pathology).

Causes

• Congenital (often benign)
• Vestibular disorders (BPPV, Ménière's, labyrinthitis)
• Brainstem or cerebellar dysfunction
• Multiple sclerosis
• Medications (phenytoin, lithium, alcohol)
• Drug intoxication

Assessment

Assess during cranial nerve examination (CN III, IV, VI). Note direction, speed, and whether evoked by eye position. End-gaze nystagmus may be physiologic.

Nursing Interventions

Evaluate for vertigo, hearing changes, neurologic deficits. Identify and treat underlying cause. Safety: fall prevention if balance impaired. Check for medication toxicity in nystagmus with anticonvulsants.

NCLEX Relevance

Phenytoin toxicity often presents with nystagmus.