pendular nystagmus

[pĕnjə-lər, -də-]
n.
  1. A nystagmus that in most positions of gaze has oscillations of equal speed and amplitude, usually arising from a visual disturbance.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.