Relative Contribution of Disparity and Convergence to Stereoscopic Vision

Abstract

WRIGHT'S¹ apparatus for measuring stereoscopic acuity has been modified to enable the measurements to be extended to wider separation between the tested targets. When operated in the dark, it provided two illuminated circular apertures seen against a black background. The experiments were carried out under two conditions of observation. Under condition A, the observer looked binocularly at one of the targets (P) and then to the second (Q). Under condition B the observer looked at P only but saw Q extrafoveally. In each case he was asked to estimate their relative apparent distances, and judge whether Q was nearer or farther than P.