electrooculogram(redirected from Dark current)
Also found in: Dictionary, Encyclopedia, Wikipedia.
A record of electric currents in electro-oculography.
A record of electric currents in electrooculography.
Recording of eye movements and eye position provided by the difference in electrical potential between two electrodes placed on the skin on either side of the eye. The EOG consists of two potentials: the standing potential (resting potential, dark phase, dark current) which is evoked by moving the eyes in the dark and originates from the retinal pigment epithelium and the light potential (light rise) which is evoked by moving the eyes in a lighted environment and originates from the photoreceptors. Clinically, the ratio between the light and dark potentials (sometimes also called the Arden index or Arden ratio) is assessed. If that ratio is less than 1.8 it indicates a malfunction of the structures from which the potential originates. The EOG is also used to monitor eye movements (Fig. E3). See Best's disease; fundus flavimaculatus; resting potential of the eye.