stereopsi
Stereopsi is the perception of depth and three-dimensional structure produced by the brain's interpretation of binocular disparity—the slight differences between the images projected onto the two retinas by the eyes' horizontal separation. When the brain fuses these two views, it computes relative disparities to infer distance, enabling a 3D representation of the world. Stereopsi relies on precise alignment of the eyes and intact binocular interaction, and can be influenced by luminance, contrast, and motion.
Developmentally, stereopsi emerges during infancy as binocular vision becomes coordinated; most people develop functional stereopsi in
Measurement and clinical relevance: Stereoacuity is the smallest detectable binocular disparity, often tested with random-dot stereograms
Disorders: Stereopsis can be reduced or absent in conditions such as strabismus (misaligned eyes) and amblyopia;
History and applications: The phenomenon was demonstrated in the 19th century by Charles Wheatstone using the