Steroscopic acuity for moving retinal images.

Stereoscopic acuity in the human fovea remains unimpaired with retinal image motions of up to 2 deg/s. These findings apply to lateral motion of the test target alone, and to simultaneous lateral motion of both test and comparison targets. For good steroscopic acuity, depth motion can be tolerated only so long as the configuration does not move outside the disparity zone for optimal stereoscopic acuity, within 2-3 arc min of either side of the fixation plane. The presence during a short exposure of some stimulus components lying outside this zone leads to an overall reduction of stereoscopic acuity, either by dilution through summation, or by active inhibition of the best achievable depth resolution.