To understand to what extent visual-pattern deprivation during infancy results in strabismus and nystagmus, the authors examined the long-term consequences of this type of deprivation in monkeys during the first 50 days of life. Three cynomolgus and three rhesus monkeys had the eyelids sutured closed within 24 hr of birth. At 25 days of age, the eyelids… (More)
Fig. 4. Spontaneous nystagmus in a reverse-eyelid sutured rhesus monkeys (Rh3) at 150 weeks of age. HR, right eye horizontal eye position; VR, right eye vertical eye position; HL, left eye horizontal eye position; VL, left eye vertical eye position. One-second tick marks are shown above the trace. In the dark there is a conjugate down-beating nystagmus. There is also a right-beating nystagmus that is more prominent in the eye deprived first (left). When the monkey views the inside of a full-field patterned OKN drum, there is a low-velocity left-beating nystagmus in primary gaze, a low-amplitude conjugate pendular nystagmus present in the horizontal and vertical planes, and a jerk nystagmus with velocity-increasing slow phases in eccentric vertical gaze. The velocity-increasing slow phases are best seen at high paper speeds (right portion of figure).