Optics of stereoscopic vision. 18th-century diagrams on optics, illustrating stereoscopic vision (stereopsis, also called stereo vision). This refers to the perception of depth and 3D structure as obtained by the use of two eyes (binocular vision) as in humans. These diagrams were published in 'A Compleat System of Opticks' (1738) by English mathematician Robert Smith (1689-1768).