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Binocular vision is vision in which both eyes are used together. The word binocular comes from two Latin roots, bin for two, and oculus for eye. Having two eyes confers at least four advantages over having one. First, it gives a creature a spare eye in case one is damaged. Second, it gives a wider field of view. For example, a human has a horizontal field of view with one eye of about 150 degrees and with two eyes of about 180 degrees. Third, it gives binocular summation in which the ability to detect faint objects is enhanced. Fourth it can give stereopsis in which parallax provided by the two eye's different positions on the head give precise depth perception. Such binocular vision is usually accompanied by singleness of vision or binocular fusion, in which a single image is seen despite each eye's having its own image of any object. Vision can refer to: Visual perception is one of the senses. ...
Jump to: navigation, search This article needs to be cleaned up to conform to a higher standard of quality. ...
Jump to: navigation, search Latin is an Indo-European language originally spoken in the region around Rome called Latium. ...
Your field of view is that part of the observable world that you are able to see at any given moment. ...
Stereopsis is the process in visual perception leading to perception of the depth or distance of objects. ...
Parallax (Greek: παÏαλλαγή (parallagé) = alteration) is the change of angular position of two stationary points relative to each other as seen by an observer, due to the motion of said observer. ...
Depth perception is the visual ability to perceive the world in three dimensions. ...
Other phenomena of binocular vision include utrocular discrimination, eye dominance, allelotropia, and binocular rivalry. Jump to: navigation, search When dissimilar images are presented to each eye independently, then conscious perception alternates spontaneously and intermittently between each monocular view. ...
Some animals, usually prey animals, have their two eyes positioned on opposite sides of their heads to give the widest possible field of view. In such animals, the eyes often move independently to increase the field of view. Even without moving their eyes, some birds have a 360-degree field of view. Your field of view is that part of the observable world that you are able to see at any given moment. ...
An eye is an organ that detects light. ...
Prey can refer to: Look up Prey in Wiktionary, the free dictionary A prey animal eaten by a predator in an act called predation. ...
Other animals, usually predator animals, have their two eyes positioned on the front of their heads, thereby reducing field of view in favour of stereopsis. In such animals, the eyes usually move together. When the eyes move laterally, in the same direction, this is called a version. When the eyes move in opposite directions, to an object closer than where the eyes are pointing or farther than where the eyes are pointing, this is called a vergence. When the eyes move in, it is a convergence eye movement; when the eyes move out, it is a divergence eye movement. Jump to: navigation, search This snapping turtle is trying to make a meal of a Canada goose, but the goose is too wary. ...
Stereopsis is the process in visual perception leading to perception of the depth or distance of objects. ...
Generally, a version is a checkpoint at which a particular thing or idea varies from its previous state or condition. ...
Convergence means approaching a definite value, as time goes on; or approaching a definite point, or a common view or opinion, or a fixed state of affairs. ...
In vector calculus, the divergence is an operator that measures a vector fields tendency to originate from or converge upon a given point. ...
Some animals (including some humans, notably exotropes) use both of the above strategies. A starling, for example, has laterally placed eyes to cover a wide field of view, but can also move them together to point to the front so their fields overlap giving stereopsis. A remarkable example is the chameleon, whose eyes appear to be mounted on turrets, each moving independently of the other, up or down, left or right. Nevertheless, the chameleon can bring both of its eyes to bear on a single object when it is hunting, showing vergence and stereopsis. Genera Aplonis Poeoptera Grafisia Onychognathus Lamprotornis Cinnyricinclus Speculipastor Neochicla Spreo Cosmoparus Sarroglossa Creatophora Fregilupus (extinct) Necropsar (extinct) Sturnus Leucopsar Basilornis Streptocitta Sarcops Scissirostrum See also Myna, Oxpecker Starlings are small to medium-sized passerine birds in the family Sturnidae. ...
Jump to: navigation, search Genera Bradypodion Calumma Chamaeleo Furcifer Brookesia Rhampholeon For alternative meanings of the word, see chameleon (disambiguation) Chameleons (family Chamaeleonidae) are small to mid-size reptiles that belong to one of the best known lizard families. ...
Turret (highlighted) attached to a tower on a baronial building in Scotland In architecture, a turret (from Italian: torretta, little tower; Latin: turris, tower) is a small tower that projects from the wall of a building, such as a medieval castle or baronial house. ...
Binocular summation Binocular summation means that the detection threshold for a stimulus is lower with two eyes than with one. There are two forms. First, when trying to detect a faint signal, there is a statistical advantage of using two detectors over using one. Mathematically, the advantage is equal to the square root of 2, about 1.41. Second, when some cells in the visual cortex receive input from both eyes simultaneously, they show binocular facilitation, a greater level of activity than the sum of the two activities evoked separately from each eye. Any advantage in using two eyes in detection task over 1.41 is credited to this sort of mechanism, dubbed neural summation. Look up Threshold on Wiktionary, the free dictionary In general, a threshold is a fixed location or value where an abrupt change is observed. ...
Jump to: navigation, search The term stimulus (plural: stimuli) has several related meanings: In physiology, a stimulus is something external that elicits or influences a physiological or psychological activity or response. ...
Jump to: navigation, search The visual cortex is the general term applied to both the primary visual cortex (also known as V1) and the visual association area (V2, V3, V4, V5). ...
Binocular interaction Apart from binocular summation, the two eyes can influence each other in at least three ways. - Pupillary diameter. Light falling in one eye affects the diameter of the pupils in both eyes. One can easily see this by looking at a friend's eye while he or she closes the other: when the other eye is open, the pupil of the first eye is small; when the other eye is closed, the pupil of the first eye is large.
- Accommodation and vergence. Accommodation is the state of focus of the eye. If one eye is open and the other closed, and one focusses on something close, the accommodation of the closed eye will become the same as that of the open eye. Moreover, the closed eye will tend to converge to point at the object. Accommodation and convergence are linked by a reflex, so that one evokes the other.
- Interocular transfer. The state of adaptation of one eye can have a small effect on the state of light adaptation of the other. Aftereffects induced through one eye can be measured through the other.
The human eye The pupil is the central transparent area (showing as black). ...
The human eye The pupil is the central transparent area (showing as black). ...
Jump to: navigation, search The eye is an adaptation. ...
Utrocular discrimination Utrocular discrimination is the ability to tell, when both eyes are open, to which eye a monocular stimulus was shown.
Singleness of vision Once the fields of view overlap, there is a potential for confusion between the left and right eye's image of the same object. This can be dealt with in two ways: one image can be suppressed, so that only the other is seen, or the two images can be fused. If two images of a single object are seen, this is known as double vision or diplopia. Fusion of the images from the two eyes is considered to be separate from stereopsis for at least two reasons. First, some disorders of binocular vision, such as strabismus can spare fusion but abolish stereopsis. Second, the depth of an object either much nearer to or farther from where the eyes are fixating can be accurately judged despite the images of the object appearing double. Double Vision can refer to: Double Vision (album) - a 1978 album by Foreigner. ...
Diplopia is the medical term for double vision. ...
Stereopsis is the process in visual perception leading to perception of the depth or distance of objects. ...
Strabismus prevents bringing the gaze of both eyes to the same point in space Strabismus, also known as squint, crossed eye, wandering eye, or wall eyed, is a disorder in which the eyes do not point in the same direction. ...
Fusion of images occurs only in a small volume of visual space around where the eyes are fixating. Running through the fixation point in the horizontal plane is a curved line for which objects there fall on identical retinal points in the two eyes. This line is called the horizontal horopter. There is also a vertical horopter, which is effectively tilted away from the eyes above the fixation point and towards the eyes below the fixation point. The horizontal and vertical horopters mark the centre of the volume of singleness of vision. Within this thin, curved volume, objects nearer and farther than the horopters are seen as single. The volume is known as Panum's fusional area (it's presumably called an area because it was measured by Panum only in the horizontal plane). Outside of Panum's fusional area (volume), double vision occurs. Jump to: navigation, search The horopter is a 3D curve that can be defined as the set of points for which the light falls on corresponding areas in the two retinas, that is, anatomically identical points. ...
When each eye has its own image of objects, it becomes impossible to align images outside of Panum's fusional area with an image inside the area. This happens when one has to point to a distant object with one's finger. When one looks at one's fingertip, it is single but there are two images of the distant object. When one looks at the distant object it is single but there are two images of one's fingertip. To point successfully, one of the double images has to take precedence and one be ignored or suppressed. The eye of the image that takes precedence is called the dominant eye. Eye dominance (sometimes called eyedness) refers to the tendency to use one eye more than the other in certain tasks involving precise hand-eye coordination and a reasonably distant target. ...
Stereopsis is an ability to make fine depth discriminations from parallax provided by the two eye's different positions on the head. There are two sorts: quantitative stereopsis, in which the depth seen is very similar to the actual depth of the object being judged, and qualitative stereopsis, in which the depth is correctly nearer or father than the fixation point but the amount of depth does not grow with distance of the object from the fixation point. Quantitative stereopsis holds for small distances from the fixation plane (approximately within Panum's fusional area); qualitative stereopsis holds for larger distances from the fixation plane (outside of Panum's fusional area). Eventually an object can be moved so far from the fixation plane that there is no sense of depth of the double images--instead they appear to be on the fixation plane. Stereopsis is the process in visual perception leading to perception of the depth or distance of objects. ...
Parallax (Greek: παÏαλλαγή (parallagé) = alteration) is the change of angular position of two stationary points relative to each other as seen by an observer, due to the motion of said observer. ...
Allelotropia Because the eyes are in different positions on the head, any object away from fixation and off the plane of the horopter has a different visual direction in each eye. Yet when the two monocular images of the object are fused, the object has a new visual direction, essentially the average of the two monocular visual directions. This is called allelotropia. The origin of the new visual direction is a point approximately between the two eyes, the so-called cyclopean eye. The position of the cyclopean eye is not usually exactly centred between the eyes, but tends to be closer to the dominant eye.
When very different images are shown to the same retinal regions of the two eyes, perception settles on one for a few moments, then the other, then the first, and so on, for as long as one cares to look. This alternation of perception between the images of the two eyes is called binocular rivalry. Jump to: navigation, search When dissimilar images are presented to each eye independently, then conscious perception alternates spontaneously and intermittently between each monocular view. ...
Jump to: navigation, search When dissimilar images are presented to each eye independently, then conscious perception alternates spontaneously and intermittently between each monocular view. ...
Disorders of binocular vision To maintain stereopsis and singleness of vision, the eyes need to be pointed accurately. The position of each eye in its orbit is controlled by six extraocular muscles. Slight differences in the length or insertion position or strength of the same muscles in the two eyes can lead to a tendency for one eye to drift to a different position in its orbit from the other, especially when one is tired. This is known as phoria. One way to reveal it is with the cover-uncover test. To do this test, look at a cooperative person's eyes. Cover one eye of that person with a card. Have the person look at your finger tip. Move the finger around; this is to break the reflex that normally holds a covered eye in the correct vergence position. Hold your finger steady and then uncover the person's eye. Look at the uncovered eye. You may see it flick quickly from being wall-eyed or cross-eyed to its correct position. If the uncovered eye moved from out to in, the person has exophoria. If it moved from in to out, the person has esophoria. If the eye did not move at all, the person has orthophoria. Most people have some amount of exophoria or esophoria; it is quite normal. If the uncovered eye also moved vertically, the person has hyperphoria (if the eye moved from up to down) or hypophoria (if the eye moved from down to up). Such vertical phorias are quite rare. It is also possible for the covered eye to rotate in its orbit. Such cyclophorias cannot be seen with the cover-uncover test; they are rarer than vertical phorias. In physics, an orbit is the path that an object makes, around another object, whilst under the influence of a source of centripetal force, such as gravity. ...
During the cover-uncover test, a person with some phoria will notice a brief episode of double vision or diplopia after uncovering the eye. This is a normal consequence of the eye's being breifly misaligned. If the diplopia is enduring, that is considered a disorder. Diplopia is the medical term for double vision. ...
The cover-uncover test can also be used for more permanent disorders of binocular vision, the tropias. In the cover part of the test, the examiner looks at the first eye as he or she covers the second. If the eye moves from out to in, the person has exotropia. If it moved from in to out, the person has esotropia. People with exotropia or esotropia are wall-eyed or cross-eyed respectively. These are forms of strabismus with amblyopia. When the covered eye is the non-amblyopic eye, the amblyopic eye suddenly becomes the person's only means of seeing. The strabismus is revealed by the movement of that eye to fixate on the examiner's finger. There are also vertical tropias ([hypertropia]] and hypotropia) and cyclotropias. Person exhibiting esotropia of the right eye Esotropia is a form of strabismus where one or both of the eyes turn inward (often called lazy eye). The most common type of esotropia occurs in approximately one to two percent of the population. ...
Strabismus prevents bringing the gaze of both eyes to the same point in space Strabismus, also known as squint, crossed eye, wandering eye, or wall eyed, is a disorder in which the eyes do not point in the same direction. ...
Amblyopia, or lazy eye, is a disorder of the eyes. ...
Rembrandt as a person without binocular vision People whose eyes failed to align correctly could have no binocular vision. However, to an artist, this disability could have been a gift.
In an article published on September 16, 2004 in The New England Journal of Medicine, Margaret S. Livingstone, professor of neurobiology of Harvard Medical School, suggested that Rembrandt, generally considered one of the greatest painters in European art history, suffered from this disability. She made this conclusion after having studied 36 of Rembrandt's self-portraits. Jump to: navigation, search September 16 is the 259th day of the year (260th in leap years). ...
Jump to: navigation, search 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ...
Jump to: navigation, search The New England Journal of Medicine (NEJM) is a peer-reviewed medical journal published by the Massachusetts Medical Society with the highest impact factor for a general medical journal. ...
Neuroscience is a field of study which deals with the structure, function, development, genetics, biochemistry, physiology, pharmacology and pathology of the nervous system. ...
Harvard Medical School Harvard Medical School (HMS) is one of the graduate schools of Harvard University. ...
Rembrandt Harmenszoon van Rijn (July 15, 1606 – October 4, 1669) is generally considered one of the greatest painters in European art history and the most important United Provinces (Netherlands) painter of the seventeenth century. ...
A painter is a person who paints woodwork, walls, etc. ...
Medieval Art Main article: Medieval art Art during Medieval times was almost exclusively concerned with Christianity. ...
Because Rembrandt did not have normal binocular vision, even when he had both eyes open he used only one for many visual tasks. This could have helped him to flatten images as he saw them, and then put them onto the two-dimensional canvas. In the author's words: Dimension (from Latin measured out) is, in essence, the number of degrees of freedom available for movement in a space. ...
Canvas is an extremely heavy-duty fabric used for making sails, tents, marquees, and other functions where sturdiness is required. ...
- Art teachers often instruct students to close one eye in order to flatten what they see. Therefore, stereoblindness might not be a handicap -- and might even be an asset -- for some artists.
See also: Handicap (competition) Handicapped is an adjective used to refer to a person or animal who is partially disabled or unable to use a limb or limbs. ...
See also Amblyopia, or lazy eye, is a disorder of the eyes. ...
Jump to: navigation, search When dissimilar images are presented to each eye independently, then conscious perception alternates spontaneously and intermittently between each monocular view. ...
Diplopia is the medical term for double vision. ...
Eye dominance (sometimes called eyedness) refers to the tendency to use one eye more than the other in certain tasks involving precise hand-eye coordination and a reasonably distant target. ...
An eye is an organ that detects light. ...
Your field of view is that part of the observable world that you are able to see at any given moment. ...
Orthoptics, which literally means straightening of the eyes, dates back to the 1850s. ...
Stereopsis is the process in visual perception leading to perception of the depth or distance of objects. ...
Jump to: navigation, search Stereoscopy, stereoscopic imaging or 3-D (three-dimensional) imaging is any technique capable of recording three-dimensional visual information or creating the illusion of depth in an image. ...
Jump to: navigation, search Stereoscopy, stereoscopic imaging or 3-D (three-dimensional) imaging is any technique capable of recording three-dimensional visual information or creating the illusion of depth in an image. ...
Strabismus prevents bringing the gaze of both eyes to the same point in space Strabismus, also known as squint, crossed eye, wandering eye, or wall eyed, is a disorder in which the eyes do not point in the same direction. ...
Vision can refer to: Visual perception is one of the senses. ...
Vision therapy (or visual therapy) is a broadly-defined set of optometric programs related to the improvement of visual health and comfort. ...
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