Clinical evaluation of stereopsis

Principles of the design and administration of clinical stereopsis tests are outlined. Once the presence of the distinct sense of the third dimension by binocular vision alone and without help from monocular cues has been established in a patient, the examination can proceed to the measurement of stereoscopic acuity. Best results are obtained with high-contrast, sharp, well-articulated and uncrowded elements from easily-recognized target sets, displayed with no time constraints. Polarization is the preferred method of right/left eye separation; time-sharing at a minimum of 60 Hz on computer displays with counterphase occluding goggles is a feasible procedure. Random-dot stereograms are problematic because not all observers can disentangle the coherent global disparity on a first view.

► Stereopsis is an important factor in the clinical evaluation of a patient's vision. ► Fundamental issues in the design and administration of stereopsis testing are dealt with. ► Tests are described for determining both the presence of stereopsis qualitatively and the performance limit quantitatively. ► Optimal conditions are outlined for best stereoscopic acuity.