Depth Perception: Meaning And Significance

Perception is the process by which individuals become aware of objects, events, and relationships utilizing the senses, which involves activities like observation, recognition, and discrimination. There are five perception types: visual perception, auditory perception, olfactory perception, haptic perception, and gustatory perception. Among these five types of perception, depth perception falls under visual perception, and depth perception comes from various depth cues.

What is Depth Perception?

The ability to recognize the world in three dimensions (3D) and to determine the distance of objects is known as Depth perception. The brain of the human being accomplishes it by processing distinct pictures from each eye and merging them to form a single 3D image. Depth perception makes it possible for the eyes of individuals to understand the distance between objects and to tell if something is near or far away from him/her.

Visual Cues and Depth Perception

Depth perception depends on visual cues. These cues are the physical signals and the brain's explanation, which are amenable to the individual's vision as the brain and the body work together. In order to have depth perception, an individual must have monocular vision, binocular vision, and oculomotor vision.

Monocular Cues − For an individual who does not have both eyes working together properly, even then, monocular cues permit them some sense of depth perception. They are still needed even when they are, offering cues that include:

  • Motion parallax − This cue contributes to the self-motion of an individual. It takes place when the head of the individual moves back and forth. At slightly different speeds, the objects at distinct distances move. Objects move in the opposite direction of the head motion, and faraway objects move according to the head of the individual.

  • Interposition − When objects overlay one another, then gives an individual monocular cue regarding which one is closer.

  • Aerial perspective − Color and contrast cues suggest how after away an object might be. As light travels, it spreads and causes unfocused outlines, which the brain elucidates far away.

Binocular Cues − In binocular vision, the most vital factor has two eyes. People with visions from only one ye have to depend on other visual cues to measure depth, and their perception of depth is generally less precise. There will be a huge impact on an individual's life from early childhood learning to job life if the depth perception is not precise. This is because the binocular cues are at work to make the depth perception necessary for countless tasks. Some of the cues provided through binocular vision involve 

  • Disparity Changing − These cues are features of stereopsis that permit the eyes to create depth perception based on the distance between them. This disparity sensitivity and how the brain processes the slight difference contribute to an exact 3D image.

  • Differences in velocity − Binocular vision is behind the distinct processing in speed and velocity that contributes to depth perception of the interaction with the universe in motion.

Oculomotor Cues − The eye muscles work based on oculomotor cues, which involve two vital factors known as convergence and accommodation.

Convergence − The way the angle of the eye inward when people look close to an object is elaborated by this factor. This motion works when the individual concentrates on something only a short distance away.

Accommodation − This cue works only at short distances. Eye muscles change the concentration of the eye's lens, helping an individual to see distinct objects at district distances with exact depth and perception.

Causes of diminished Depth Perception

There are several causes for the lack of depth perceptions. Those are:

  • Amblyopia − This is also known as lazy eye. This is a condition where one is weaker than the other one. This occurs as abnormal development in childhood and functions as a lower vision in one or both eyes.

  • Optic nerve hypoplasia happens when the optic nerve, which sends visual signals from the eyes to the brain, has incomplete development before birth. It can impact the partial or total loss of vision in children.

  • Strabismus − This happens when the eye point in different directions, like pointing straight ahead and another pointing inward or downward.

  • Blurry Vision − Several conditions blur the vision in one or both eyes, like trauma to an eye.

  • Injury to one eye − Trauma can temporarily or permanently alter the vision.

Test for Depth Perception

The first step for assessing depth perception is a thorough eye checkup. An ophthalmologist will test the individual's vision by gauging the visual acuity or quality. If one eye is blurry and the other is not, then the depth perception is limited. To check strabismus like esotropia, a cover test is used for checking it. This is a problem related to eye muscles where the eyes do not work well together. Double vision occurs if the eyes are not in accurate alignment with each other. Moreover, this leads to not having a good depth perception. Some tests are used for measuring the fine levels of depth perception. Those are:

  • Random dot stereograms − This measures 3D vision using images made up of dots.

  • Contour stereo tests − This measures 3D vision with shapes and mages designed to create contours.

Improvement in Depth Perception

The improvement of depth perception is possible, but the treatment will be based on the reason for their depth perception issues. The lowest levels of interference involve simple strategies like:

  • Eye Exercise − It is made to improve depth perception.

  • Screen time limitation − Made to avoid overuse damage from the type of concentration involved.

  • Improved lighting − Used to maximize depth perception ability in older adults.

Treatment for a specific condition like strabismus will concentrate on making the weaker eye stronger. Sometimes, it can be done with the help of eyeglasses, eye patches worn for half of the day, or eye drops. Nevertheless, these do not work in some cases and need surgery to improve depth perception. Researchers are studying virtual reality to use it for treating depth perception problems.


From the above discussion, it can be concluded that depth perception is the ability to view the world from e dimensions that are binocular cues, monocular cues, and oculomotor cues. Several causes exist for the diminishing nature of depth perception, and several tests can identify these causes. These problems related to depth perception can be improved by several strategies as well. More study is needed for depth perception. Furthermore, the use of virtual reality proved to be useful for the treatment of amblyopia, strabismus, and other problems related to depth perceptions.