Abstract

It has been known since the time of Wheatstone1 that, when a pair of two-dimensional (2D) images in which some regions possess appropriate disparity is presented so that each eye sees only one image, the viewer perceives a corresponding three-dimensional (3D) figure: numerous methods have since been devised to present appropriate stereopairs2. It is reasonable to ask if fixation by a young observer on those parts of the fused 3D figure which appear to lie in a different plane to that of the 2D stereopair will cause an appropriate change in accommodation. If this does occur, the retinal images of the 2D stimuli will blur, since the eye will no longer be focused on the plane of the 2D stimulus. This mismatch between the desirable levels of accommodation and convergence may lead perhaps to fatigue or to a weakening of the 3D percept3-5. For larger disparity stereo pairs there is already evidence that "appropriate " accommodation responses do occur to perceived depth6,7. The aim of the present study was to explore whether similar effects can be detected when clinical stereo tests in which images presenting lower levels of disparity are viewed and to evaluate the possible significance of any accommodation effects observed.

© 1998 Optical Society of America