EFFECT OF DARK-ADAPTATION ON EYE-MOVEMENT RECORDINGS BY MEANS OF ELECTROOCULOGRAPHY

1. Saccadic movements with monocular fixation and the other eye covered either by a black patch or translucent occluder were recorded in five normal subjects with electrooculography (EOG) during dark adaptation for 30 min in a dimly lit environment (4 lx). 2. The EOG magnitude of the eye covered with the black patch decreased significantly during the first 20 min of adaptation, while the reduction was much smaller and lasted for a shorter period in the eye covered by a translucent occluder. 3. Dark adaptation measured with EOG magnitude was found to be independent in the two eyes when they are exposed to different illuminations. 4. No significant changes of saccadic peak velocity measured with EOG were observed in the different experimental conditions. 5. Dark adaptation of an eye has to be achieved at a given illumination before EOG calibration and recording are performed. This state is obtained much quicker with a translucent lens than a black patch as an occluder.