Depth Perception under Monocular and Binocular Viewing Conditions
For those of us fortunate to have two functional eyes, some of this information is obtained by binocular depth cues — stereopsis and convergence. However, there are many situations in which an individual has only the benefit of one eye, yet is required to judge depth and distances. Situations when this might occur include when one eye has not developed or has suffered injury or disease, when work tasks only permit viewing with one eye (e.g. using a monocular microscope) or when a three-dimensional image is rendered two-dimensional (e.g. viewing a task on a closed circuit television monitor). In these circumstances we rely on monocular cues for judging depth.