Spontaneous and evoked potentials disappear from the electroretinogram (ERG) within four minutes after enucleation of the eyes of experimental animals (Granit).13 An extinguished ERG is also encountered clinically in senile macular degeneration, occlusion of the central retinal vein or artery, and detachment of the retina.8,11,18-21,27,28,31 The common factor in these experimental and clinical observations is the dependence of retinal function on an adequate blood supply. Nevertheless, recent reports suggest that the hallucinogenic drugs, mescaline and lysergic acid diethylamide (LSD), potentiate retinal activity despite a reduced blood supply to the retina.
Zádor34 reported that mescaline restored perception of movement in the blind eye of one of his patients with vascular disease. Klüver22 presented evidence that mescaline prolongs the ability of the retina to respond to subliminal stimuli from vascular entoptic phenomena. A single clinical test made in my own laboratory demonstrated that the hallucinogen LSD could