Abstract
The present work was designed to elucidate a frequency of optokinetic nystagmus in normal subjects.
Five healthy adult men and five women with normal vestibular function were examined with regard to horizontal and vertical nystygmus by rotating the optic cylinder, which was rotated for 180 seconds with angular accereration 1°/sec2. In both of horizontal and vertical nystagmus, the frequencies of nystagmus reach at the maximum value between 40°/sec and 100°/sec, and then, maintain this level or decrease gradually.
By analysing the frequency obtained, the eqation of critical ellipse for the horizontal nystagmus or for the vertical (downwords or upwords) nystagmus in any subject was made.
According to the author's opinion, it seems to be useful for the examination of the eqilibrium function of patients to survey horizontal and vertical nystagmus by rotating the optic cylinder and to evaluate the result by putting the obtained data on the patient into the above-mentioned formula.
