syvyysnäkemää

Syvyysnäkemää, commonly translated as depth perception, is the visual system's ability to perceive the distance to objects and the three-dimensional structure of the surrounding environment. It enables judging how far away objects are and how their positions relate to one another in space.

Depth perception arises from a combination of cues. Binocular disparity, the slight difference between the two eyes' images, underpins stereopsis, a major source of depth. Convergence and accommodation provide supplementary cues when focusing. Monocular cues also contribute: relative size, linear perspective, texture gradient, shading and lighting, occlusion, and motion parallax, where objects at different distances move at different speeds as the observer moves.

Developmentally, basic depth perception appears in infancy and continues to refine through early childhood. Abnormalities in vision, such as strabismus or amblyopia, can impair depth perception. Aging and ocular diseases can reduce depth sensitivity, particularly at low contrast.

Assessment of syvyysnäkemää uses clinical tests designed to measure stereopsis and depth judgments, such as dichoptic tests and dot-pattern stereograms. Clinically, impaired depth perception can affect daily activities and safety, while rehabilitation may involve correcting refractive errors, treating binocular disorders, or vision therapy.