The point of observation translates with eye movement because it is not coincident with the center of rotation in the eye. 'Ocular occlusion' results. The amount of optical structure revealed by eye rotation depends on the distances of the occluding and ocduded surfaces. We review studies showing that ocular occlusion is detectable beyond near space and functionally effective in providing information about the separation of surfaces in depth. After discussing the typicality of ocular occlusion in visual experience, we explore the implications for analyses of optical flow, for our understanding of depth perception and the mission of the sensory apparatus, and for the notion of efference copy in vision.