Retinal Induction in the Light-Adapted Human

Abstract

Retinal induction of the light-adapted human retina was investigated. 1. When red, green and blue lights are used for preillumination in the light-adapted state of the retina, the peak of the curve of electrical excitability lies at 1, 2 and 3 seconds respectively just as in the dark-adapted retina. As the intensity of the adapting light increases from 0.004 lux to 30 lux, the magnitude of the curve decreases steadily. 2. The curves of retinal induction are not qualitatively different from those obtained from the dark-adapted eye. The retinal induction decays with time in about 5-6 seconds in the retina adapted to a weak general illumination. This is in contrast with the fact that the retinal induction of the dark-adapted retina remains unchanged for about 20 seconds. 3. The magnitude of retinal induction or contrast effect is smaller as the adaptation level of the retina is higher. 4. In the retina light-adapted to a general illumination of 0.004 lux, the white light of 32 lux interposed between the inducing light and the white test light does not affect the direct induction.