What is nystagmus characterized by?

Nystagmus is a condition characterized by rhythmic oscillation of the eyes. This involuntary movement can manifest as a variety of patterns, including horizontal, vertical, or rotational movements. The oscillation can be pendular, where the movements are smooth, or jerky, where there are quick phases followed by slow phases. This condition is often indicative of underlying neurological issues or vestibular system disturbances and can be observed during clinical examinations.

The other options do not accurately define nystagmus. Involuntary blinking of the eyes pertains to a different phenomenon known as blepharospasm. Severe eye pain is not a hallmark of nystagmus but may suggest other eye conditions. Double vision, or diplopia, usually involves a misalignment of the eyes or neurological issues affecting eye coordination, rather than rhythmic movements. Understanding these distinctions clarifies what nystagmus truly entails.