[Carotinoid retinopathy. II. Electrophysiologic findings in 23 carotenoid-treated patients]

Twenty-three patients on long-term therapy (up to 14 years) with carotenoids (up to 336 g) were tested electrophysiologically. The EOG revealed a small but not significant delay of the light peak. Arden's ratio, however, was normal. The ERG was depressed as far as photopic activity was concerned. At low dosages of carotenoids the scotopic ERG amplitudes were found to be hypernormal, whereas at higher dosages the increase in amplitude during dark-adaptation was markedly delayed. There was a dose-dependent prolongation of b-wave implicit time and a dose-dependent reduction in oscillatory potentials. The marked effect on the b-wave and on the oscillatory potentials and the site of the retinal crystals permit the assumption that a mechanism of carotenoid action is located in the middle layers of the retina.