Eye Movements During Sleep

Eye movements were recorded by DC oculogram in eight normal subjects during 31 nights of sleep. A consistent series of ocular positional changes and movements occurred in every subject. Initially, eyelid closure induced upward movement of the globes. The eyes then remained elevated during 55% to 85% of the time spent in stages 2, 3, and 4. With the onset of stage of rapid eye movement, the eyes moved down abruptly to or below the central position. Movements during this stage were quite unlike waking eye movements but showed a similar pattern in every subject. These movements were 5% to 15% horizontal, 25% to 35% vertical, and 55% to 65% oblique. The movement sequences and the time intervals between movements were not random. The results suggest that during sleep there is a pattern of activity of the oculomotor system which is similar in every subject.