Retinal Processes in Total Color Blindness

Retinal processes in two typical achromats were investigated. by the method of electrostimulation. From measurements of time courses of electrical excitability of the eye following a brief illumination, two kinds of process were distinguished. 1. The time courses of the two processes showed no dependence on wavelengths of lights, and their magnitudes varied like the scotopic visibility curve, as the wavelengths of spectral lights were varied. Therefore they were interpreted as subserving achromatic vision. 2. The spatial distribution of both processes was found very similar to that of the density of rods in the retina. 3. The two processes differed, however, with respect to intensity ranges of illumination which elicits them ; the working range of the one process was from 10-6 to 104 millilamberts, and that of the other from 10-6 to 102, when tested with a flash of white light lasting 40 msec. 4. Dark-adaptation curves were obtained from the achromats. They showed two parts like a normal dark-adaptation curve. These two parts were accounted for in terms of the two kinds of achromatic process studied above.