Observations on voluntary nystagmus.

Unitl recent times, reports concerning voluntary nystagmus have been dismissive, most observers regarding the phenomenon as a form of ocular acrobatics or an amusing party trick. The introduction of sophisticated recording apparatus coupled with renewed interest in ocular kinetics has resulted in a more analytical approach. Clinical and electro-oculographic study of the condition in 5 subjects was undertaken in an attempt to relate voluntary nystagmus to the known mechanisms of oscular movement control. The frequency of the movement varied from 15 to 23Hz and amplitude from 2 to 5 degrees. The wave form was similar to that seen in acquired pendular nystagmus. It was concluded that, depsite differences in frequency, the similarity in form of the movements of voluntary nystagmus and acquired pendular nystagmus suggested a possible identity in the mechanisms of the movements.