Normal saccadic structure of voluntary nystagmus.

Infrared oculographic recordings in three cases showed that voluntary nystagmus is composed of rapidly alternating small-amplitude saccades with normal velocity-amplitude characteristics. These bursts of reciprocating saccades are routinely associated with oscillopsia. This means in terms of oculomotor control theory that the brain stem mechanism mediating voluntary nystagmus must bypass the level in the oculomotor path where the saccadic corollary discharge (efferent copy) is initiated.