Stereoscopic Vision I. Effect of Binocular Temporal Summation

1926 it was believed that stereoscopic vision required the simultaneous function of both eyes. Two simultaneous disparate retinal images Were thought necessary to produce a synchronous discharge in the optic nerves before a sense of depth could be achieved. With a sufficiently high rate of alternation of the "viewings" by the left and the right eyes a sense of depth could still be realized. Langlands did not study the time relationships between these alternate viewings in any detail as he was more interested in a quantitative analysis of the limits of stereoscopic visual acuity. The phenomenon of stereoscopy with alternate " viewings" has been studied by Pi Suiner (1947).