Vision

thumb|upright=1.3|Colored pencils

thumb|The act of making a 2D image with a mobile phone camera. The display of the phone shows the [[photograph that will be made and stored.|right]]

ability to interpret the surrounding environment using light in the visible spectrum

A cataract is a cloudy area in the lens of the eye that impairs vision. Cataracts often develop slowly and can affect one or both eyes. Symptoms may include faded colours, blurry or double vision, halos around light, trouble with bright lights, and difficulty seeing at night. This may result in difficulty driving, reading and recognizing faces. Poor vision caused by cataracts may also result in an increased risk of falling and depression. In 2020 Cataracts caused 39.6% of all cases of blindness and 28.3% of visual impairment worldwide. Cataracts remain the single most common cause of global bl

inability or decreased ability to see colour, or perceive colour differences, under normal lighting conditions

portion of the electromagnetic spectrum that is visible to the human eye

thumb|upright=1.4|right|A simplified illustration of the parallax of an object against a distant background due to a perspective shift. When viewed from "Viewpoint A", the object appears to be in front of the blue square. When the viewpoint is changed to "Viewpoint B", the object appears to have moved in front of the red square. thumb|right|This animation is an example of parallax. As the viewpoint moves side to side, the objects in the distance appear to move more slowly than the objects close to the camera. In this case, the white cube in front appears to move faster than the green cube in t

Prosopagnosia, also known as face blindness, is a cognitive disorder of face perception in which the ability to recognize familiar faces, including one's own face (self-recognition), is impaired, while other aspects of visual processing (e.g., object discrimination) and intellectual functioning (e.g., decision-making) remain intact. The term originally referred to a condition following acute brain damage (acquired prosopagnosia), but a congenital or developmental form of the disorder also exists, with a prevalence of 2–2.5%.

blind point of human eye

focusing ability of eye

Diplopia is the simultaneous perception of two images of a single object that may be displaced in relation to each other. Also called double vision, it is a loss of visual focus under regular conditions, and is often voluntary. However, when occurring involuntarily, it results from impaired function of the extraocular muscles, where both eyes are still functional, but they cannot turn to target the desired object. Problems with these muscles may be due to mechanical problems, disorders of the neuromuscular junction, disorders of the cranial nerves (III, IV, and VI) that innervate the muscles,

difference in luminance and/or color that makes objects visually distinguishable

practice of engaging in visual perception unaided by a magnifying or light-collecting optical device, such as a telescope or microscope. Vision corrected to normal acuity using corrective lenses is considered "naked"

thumb|Decreasing brightness with depth (underwater photo as example)

cause of vision problems

type of vision in which an animal having two eyes is able to perceive a single three-dimensional image of its surroundings

fluid pressure inside the eye

The optical effect on the visibility of objects seen through air with distance

upright|thumb|Stereopsis caused by alternating stereo images. If the two images were viewed side by side in a stereoscope, the same 3D image would be perceived, but without motion. In the science of visual perception, stereopsis is the sensation that objects in space extend into depth, and that objects have different distances from each other. This sensation is much stronger than the suggestion of depth that is created by two-dimensional perspective.

total area or space visible in a person's peripheral vision with the eye looking straight forward

visual phenomenon where there is difficulty of seeing in presence of disturbance from a bright light

Retinal (also known as retinaldehyde) is a polyene chromophore. Retinal, bound to proteins called opsins, is the chemical basis of visual phototransduction, the light-detection stage of visual perception (vision).

measuring the point of gaze or motion of an eye relative to the head

extent of the observable world seen at any given moment

lens implanted in the eye to treat cataracts or myopia

international authority on light, illumination, color, and color spaces

thumb|150px|Three-dimensional structure of cattle rhodopsin. The seven transmembrane domains are shown in varying colors. The chromophore is shown in red. thumb|right|400px|The retinal molecule inside an opsin protein absorbs a photon of light. Absorption of the photon causes retinal to change from its 11-cis-retinal isomer into its all-trans-retinal isomer. This change in shape of retinal pushes against the outer opsin protein to begin a signal cascade, which may eventually result in chemical signaling being sent to the brain as visual perception. The retinal is re-loaded by the body so that

thumb|If a viewer stares at the white dot in the center of this image for 5–60 seconds and then looks at a plain white surface, a negative afterimage will appear, showing a person's face in a more natural color scheme. This can also be achieved by the viewer closing their eyes.

frame|right|Three hues in the Munsell color model. Each color differs in value from top to bottom in equal perception steps. The right column undergoes a dramatic change in perceived color.

visual perception under well-lit conditions

Blindsight is the ability of people who are cortically blind to respond to visual stimuli that they do not consciously see due to lesions in the primary visual cortex, also known as the striate cortex or Brodmann Area 17. The term was coined by Lawrence Weiskrantz and his colleagues in a paper published in a 1974 issue of Brain. A previous paper studying the discriminatory capacity of a cortically blind patient was published in Nature in 1973.

optical illusion technique

cognitive process of visually interpreting the human face

vision of the eye under low light conditions

visual ability to perceive the world in three dimensions (3D)

medical condition

thumb|Threshold increment versus background luminance for various target diameters (in arcmin). Data from tables 4 and 8 of Blackwell (1946), plotted in Crumey (2014). The flat curves at low light indicate Eigengrau. thumb|An example of noise observed in the dark thumb|Another example of noise observed in the dark Eigengrau (German for 'intrinsic gray'; ), also called Eigenlicht (Dutch and German for 'intrinsic light'), dark light, or brain gray, is the uniform dark gray background color that many people report seeing in the absence of visible light.

visual effect whose source is within the eye itself

response of the eye to light and dark

visible effect of polarised light

postulated existence of three photoreceptor types in the eye

part of vision that occurs on the edges of the field of vision

inability of a person to correctly determine their body position in space

ability to see in low light conditions

reflex where rotation of the head causes eye movement to stabilize vision

vision in which each eye is used separately

Chronostasis (from Greek , , 'time' and , , 'standing') is a type of temporal illusion in which the first impression following the introduction of a new event or task-demand to the brain can appear to be extended in time. For example, chronostasis temporarily occurs when fixating on a target stimulus, immediately following a saccade (i.e., quick eye movement). This elicits an overestimation in the temporal duration for which that target stimulus (i.e., postsaccadic stimulus) was perceived. This effect can extend apparent durations by up to half a second and is consistent with the idea that the

measuring tool

color that cannot be perceived under ordinary viewing conditions

perceptual effect of contrasting stimuli

tendency of the brain to prefer visual input from one eye over the other

common method of quality control, data acquisition, and data analysis

medical condition

tiny bright dots moving quickly in the visual field

optical phenomenon

process of inferring the speed and direction of elements in a scene based on visual, vestibular and proprioceptive inputs

ability to process visual and spatial information