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

1. Saccadic movements with monocular fixation and the other eye covere d either by a black patch or translucent occluder were recorded in fiv e 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 t he first 20 min of adaptation, while the reduction was much smaller an d lasted for a shorter period in the eye covered by a translucent occl uder. 3. Dark adaptation measured with EOG magnitude was found to be i ndependent in the two eyes when they are exposed to different illumina tions. 4. No significant changes of saccadic peak velocity measured wi th EOG were observed in the different experimental conditions. 5. Dark adaptation of an eye has to be achieved at a given illumination befor e EOG calibration and recording are performed. This state is obtained much quicker with a translucent lens than a black patch as an occluder .