THE DELINEATION OF RETINAL ZONES WITH DARK TUBE VISION

Abstract

In this communication there is described the effect of increasing the stimulated area of the central or foveal part of the retina upon the critical frequency of flicker. In order to do this, the vision of one eye—the right—was directed through a long black tube at a screen of constant brightness, the different areas stimulated being obtained and measured by using holes of various diameters in black paper placed over the far end of the tube. Between this end of the tube and the screen was a rotating sectored disk with which the fusion frequency was obtained and measured.It was found that the graph obtained by plotting the measurements has three breaks in it which correspond to the five central retinal zones delineated by histologists It was also found that the fusion frequencies are proportional to the logarithms of the diameters (or areas) of the retinal zones; or primarily, to the number of cones stimulated.A similar set of measurements was made on the periphery of the retina which showed both similarities to and differences from the central or foveal effects.