Pendular Nystagmus
Involuntary eye movements characterized by equal velocity oscillations in both directions, resembling a pendulum.
Full Definition
Pendular nystagmus consists of sinusoidal eye movements with equal velocity phases in both directions, lacking the distinct fast and slow phases seen in jerk nystagmus. This type of nystagmus is often associated with reduced visual acuity from early infancy and may be seen in conditions such as albinism, aniridia, or congenital cataracts. The movements can be horizontal, vertical, circular, or elliptical, and may vary with gaze direction or convergence. Unlike jerk nystagmus, pendular nystagmus typically indicates a sensory rather than motor pathway abnormality and often suggests early visual deprivation during critical developmental periods.
Usage
Usage note: Distinguish clearly from jerk nystagmus in documentation; describe waveform characteristics when possible.
In Context
- "The infant exhibited pendular nystagmus with no null point, suggesting congenital sensory visual loss." — Pediatric neuro-ophthalmology consultation
- "Pendular nystagmus intensity decreased with convergence, indicating potential benefit from base-out prisms." — Motility assessment report