Voluntary nystagmus is a rapid to-and-fro synchronous movement of the eyes that is initiated and maintained by conscious effort. Voluntary nystagmus has a frequency of 10-25 Hz, with an amplitude of up to 6 degrees, and can be maintained for up to 35 seconds. It usually has its first appearance between ages 8 to 15 years. It can be produced in both light and darkness, without fixation, at all eye positions, and even with closed eyes. It is accompanied by oscillopsia with visual blurring (summary by Aschoff et al., 1976). [from
OMIM]