Stereoscopic depth perception by static stereo-deficient observers in dynamic displays with constant and changing disparity.

The performance of 11 static stereo-deficient subjects and 11 static stereo-normal subjects was compared on two types of dynamic stereo displays--one where disparities were constant during motion and one where disparities changed continuously. Computer-generated displays simulating horizontal motion of figures at different depths or rotation of figures about a vertical axis were viewed through a Brewster stereoscope. About one-half of the subjects in our static stereo-deficient sample were able to make depth judgments on the basis of disparity in both types of dynamic displays. The clinical feature which appeared to distinguish those static stereo-deficient subjects who could use disparity information in dynamic displays from those who could not was early onset constant strabismus. These results indicate that a complete evaluation of stereo ability should include tests with dynamic displays, possibly including both constant and changing disparities.