Abstract
Purpose: To evaluate nystagmus and other ocular oscillation patterns of blind adults in relation to visual experience/chronic visual deprivation. Materials & Methods: Participants: blind (n=33, self-reported vision (=light perception, OU, with no light projection) and sighted (n=14) adults. Responses to requests to ‘look straight ahead’ were elicited in darkness and videotaped. Pupil tracking of videos yielded digitized eye position data from 25 participants whose self-reported age of blindness onset ranged from birth to 65 years and ten sighted participants. Results: Inspection of the graphs showed that no nystagmus occurred in sighted participants. Three of the ten participants with no visual experience had nystagmus. Of the 15 blind participants with 3-65 years of visual experience, six had jerk nystagmus in various directions, one had seesaw nystagmus, and six had stable gaze. Conclusions: Total lack of visual experience can give rise in adulthood to jerk nystagmus or a combination of oscillations, or (as stated by others) slow, random, eye movements alone. Adventitious blindness can leave straight-ahead gaze intact or may precipitate a jerk nystagmus with a decreasing velocity waveform.