On the biophysics of vision

A photochemical system is considered which is similar to that of S. Hecht but which includes an intermediate substance between visual purple and visual white. This intermediate is assumed to change the embrane voltage of the photoreceptors. A simple model is presented from which one may calculate the frequency of the impulses resulting from the application of light. It is found that this physicochemicai model enables one to account for a considerable number of physiological phenomena of vision. Among these are the light and dark adaptation phenomena. By introducing a simple assumption regarding spatial interaction one can account for some psychological phenomena such as the effect of intensity, light-dark ratio, shape, and area on the critical flicker frequency. A number of other phenomena are discussed in terms of the model. This research was supported by the United States Air Force through the Air Force Office of Scientific Research of the Air Research and Development Command under Contract No. AF 18(600)-1454. Reproduction in whole or in part is permitted for any purpose of the United States Government.