What does stereopsis mean?
Stereopsis is the brain's ability to perceive depth and three-dimensional form by combining the slightly different images that each eye receives from the same scene. Because the eyes are separated, they view objects from marginally different angles; the visual system interprets these differences to create a unified sense of depth. This binocular depth perception helps people judge distances, distinguish overlapping objects, and navigate their surroundings. Stereopsis is especially important in activities such as reading, driving, sports, and delicate manual work. Although it is sometimes described simply as three-dimensional or stereoscopic vision, it specifically depends on the coordinated activity of both eyes. The term is formal and technical, appearing mainly in discussions of vision science, eye examinations, and the perception of spatial form. It should not be confused with stereoscopy, which refers to methods of presenting images so that viewers perceive three-dimensional depth.
nounThe perception of depth and three-dimensional form produced by combining the slightly different images received by the two eyes. Also called binocular depth perception or stereoscopic vision.
- The perception of depth and three-dimensional form from the combined visual input of both eyes.
"The surgeon tested the patient's stereopsis to determine whether both eyes were working together properly."
"Stereopsis allows people to judge the distance between objects and to distinguish overlapping shapes."
"The ophthalmologist used a stereotest to assess the patient's binocular vision and stereopsis."
The standard plural, though the word is uncommon outside specialist writing.
"Clinicians compared the stereopses of patients with different forms of visual impairment."
Your brain turns two slightly different pictures into one three-dimensional world.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does stereopsis come from?
The word combines the Greek stereos, meaning “solid” or “three-dimensional,” with opsis, meaning “appearance,” “sight,” or “vision.” Its development reflects the close relationship between stereo-, referring to solid or three-dimensional form, and -opsis, referring to visual perception. The resulting word names the visual process by which the brain derives depth from the images supplied by both eyes.
Related word forms
How stereopsis is actually used
A technical term used in optometry, ophthalmology, psychology, and vision science. It is uncommon in everyday conversation, where people more often speak of depth perception or seeing in three dimensions.
Easily confused with stereopsis
Stereopsis is the visual perception of depth, whereas stereoscopy is the technique or practice of viewing images that create an illusion of three dimensions.