EFFECTS OF VISUAL FUNCTION UPON CALORIC NYSTAGMUS

Abstract

The mode of development of caloric nystagmus was investigated and the following results were obtained:When the eyes were open in a bright room, the amplitude of caloric nystagmus was remark- ably decreased, but in a few cases using Bartels glasses, the amplitude decreased when the eyes were closed.Even when the eyes were completely covered, the developement of the mystogmus was different in those with closed eyes and those with open eyes, and closed eyes, even when vision was perfectly obstructed, and no definite tendency being different individually.In the dark room, when the position of the eye ball waschanged during the nystagmus the amplitudeand speed of the nystagmus tended to be greater when the eye boll was at the center than when it was turned toward the quick phase-This was different in a bright room and the speed and amplitude of nystagmus also dufferent individuatty.From these facts, the author assumed that thedegree of development of nystagmus would be inversely proportional to the degree of contraction of the eye muscles which produce motion of slow phase of nystagmus, and that the reduction of the amplitude and speed of nystagmus would be due to automatic crntrol exerted by the visual function over the vestibular function.