Sequential stereopsis: a simple demonstration

Vision Res. 1996 Jan;36(2):307-12. doi: 10.1016/0042-6989(95)00099-l.

Abstract

Most people strongly prefer to use back-and-forth eye movements in order to discriminate 3-dimensional distances among targets that are widely separated from each other in direction. This viewing strategy permits sequential stereopsis: a comparison between the foveally-seen pre-saccadic disparity of one target with post-saccadic disparity of the other. This note describes a simple and qualitatively compelling demonstration of the usefulness of sequential stereopsis, in a situations in which classical stereopsis, with steady fixation, is greatly degraded. Targets of high-spatial-frequency texture are used, with details that can be resolved foveally before and after saccades, but that are unresolvable in peripheral vision. Back-and-forth eye movements between such textured targets, separated by 8-10 deg from each other, led to estimates of threshold that average less than 45 sec arc disparity (corresponding to about 0.18% of viewing distance): some of the best performances ever reported for targets so widely separated.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Depth Perception / physiology*
  • Discrimination, Psychological / physiology
  • Distance Perception / physiology
  • Eye Movements*
  • Fixation, Ocular
  • Humans
  • Middle Aged
  • Pattern Recognition, Visual / physiology
  • Sensory Thresholds / physiology
  • Vision, Binocular / physiology