Definition

Nystagmus is a condition in which there is involuntary and rhythmic movement or oscillation of the eye. It is often caused by an underlying ocular or neurological disorder.

Description

The eye movements associated with nystagmus are varied. They can be either pendular, in which the oscillations are equal in all directions and or jerk, in which the movements may be faster in one direction than another. The frequency of the oscillation or movement and the amplitude of the oscillation also vary. The movements themselves may be vertical, horizontal, circular, or oblique in direction. Nystagmus can be sensory and develop as a result of poor vision, or it can be motor and develop as a result of a neurological problem.

Nystagmus may be congenital, or it may be acquired....