Background: Early childhood nystagmus may herald blindness, brain tumors, benign idiopathic motor nystagmus or spasmus nutans. Nystagmus unique to low vision was sought.
Methods: Videotapes and head/ eye movements of 18 congenitally visually impaired subjects were analyzed.
Results: Nystagmus of congenitally visually impaired subjects was characterized as small horizontal or vertical movements superimposed on larger oscillations. Small and large nystagmus movements were of pendular or jerk type. Slow-phase jerk nystagmus had increasing, constant and decreasing velocities. Fast-phase nystagmus changed direction periodically. Pendular nystagmus was out of phase and evolved to jerk nystagmus in two subjects. All subjects displayed head nodding, and one stabilized gaze with head movements.
Conclusion: Eye movement recordings allow characterization and differentiation of subjects with nystagmus and low vision from other nystagmus forms.