Vision

A monocle is a type of corrective lens used to correct or enhance the vision in only one eye.

Hemianopsia, or hemianopia, is a decreased vision or blindness (anopsia) in half the visual field, usually on one side of the vertical midline.

An eye examination is a series of tests performed by an ophthalmologist (medical doctor), optometrist, or orthoptist assessing vision and ability to focus on and discern objects, as well as other tests and examinations pertaining to the eyes.

Astigmatism is a type of refractive error in which the eye does not focus light evenly on the retina.

A cataract is a clouding of the lens in the eye leading to a decrease in vision.

Color blindness, also known as color vision deficiency, is the decreased ability to see color or differences in color.

Floaters are deposits of various size, shape, consistency, refractive index, and motility within the eye's vitreous humour, which is normally transparent.

Glasses, also known as eyeglasses or spectacles, are devices consisting of lenses mounted in a frame that holds them in front of a person's eyes.

Intraocular pressure (IOP) is the fluid pressure inside the eye.

Nyctalopia /ˌnɪktəlˈoʊpiə/ (from Greek νύκτ-, nykt- "night"; ἀλαός, alaos "blind, not seeing", and ὄψ, ops "eye"), also called night-blindness, is a condition making it difficult or impossible to see in relatively low light.

The Purkinje effect (sometimes called the Purkinje shift or dark adaptation) is the tendency for the peak luminance sensitivity of the human eye to shift toward the blue end of the color spectrum at low illumination levels.

Refractive error, also known as refraction error, is a problem with focusing of light on the retina due to the shape of the eye.

The Bates method is an alternative therapy aimed at improving eyesight.

Binasal hemianopsia (or Binasal hemianopia) is the medical description of a type of partial blindness where vision is missing in the inner half of both the right and left visual field.

Diplopia, commonly known as double vision, is the simultaneous perception of two images of a single object that may be displaced horizontally, vertically, diagonally (i.e., both vertically and horizontally), or rotationally in relation to each other.

Usher syndrome is an extremely rare genetic disorder caused by a mutation in any one of at least 11 genes resulting in a combination of hearing loss and visual impairment, and is a leading cause of deafblindness.

Monochromacy (mono meaning one and chromo color) is among organisms or machine the ability to distinguish only one single frequency of the electromagnetic light spectrum.

The field of view is the extent of the observable world that is seen at any given moment.

Prosopagnosia /ˌprɑːsəpæɡˈnoʊʒə/ (Greek: "prosopon" = "face", "agnosia" = "not knowing"), also called face blindness, is a cognitive disorder of face perception where 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.

Eye tracking is the process of measuring either the point of gaze (where one is looking) or the motion of an eye relative to the head.

Visual acuity (VA) commonly refers to the clarity of vision.

Dichromacy (di meaning "two" and chroma meaning "color") is the state of having two types of functioning color receptors, called cone cells, in the eyes.

Bitemporal hemianopsia (aka bitemporal heteronymous hemianopsia or bitemporal hemianopia) is the medical description of a type of partial blindness where vision is missing in the outer half of both the right and left visual field.

Mobility can be difficult for people with homonymous hemianopsia.

The ribbon synapse is a type of neuronal synapse characterized by the presence of an electron-dense structure, the synaptic ribbon, that holds vesicles close to the active zone.

The autokinetic effect (also referred to as autokinesis) is a phenomenon of visual perception in which a stationary, small point of light in an otherwise dark or featureless environment appears to move.

Night vision, or scotopic vision, is the ability to see under low light conditions.

Near-sightedness, also known as short-sightedness and myopia, is a condition of the eye where light focuses in front, instead of on the retina.

Retinal is also known as retinaldehyde.

Botulinum toxin therapy of strabismus is a medical technique used sometimes in the management of strabismus, in which botulinum toxin is injected into selected extraocular muscles in order to reduce the misalignment of the eyes.

Visual snow, visual static, or persistent visual snow is a transitory or persisting medical disorder in which sufferers see snow or television-like static in parts or the whole of their visual fields, constantly in all light conditions, even visible in daylight, darkness and with closed eyelids.

Eigengrau (German: "intrinsic gray", lit. "own gray"; pronounced [ˈʔaɪ̯gn̩ˌgʁaʊ̯]), also called Eigenlicht ("intrinsic light"), dark light, or brain gray, is the uniform dark gray background that many people report seeing in the absence of light.

Septo-optic dysplasia (SOD), (de Morsier syndrome) is a rare congenital malformation syndrome featuring underdevelopment of the optic nerve, pituitary gland dysfunction, and absence of the septum pellucidum (a midline part of the brain).

Light rays bend when they travel from one medium to another; the amount of bending is determined by the refractive indices of the two media.

The term congenital cataract refers to a lens opacity present at birth.

Visual memory describes the relationship between perceptual processing and the encoding, storage and retrieval of the resulting neural representations.

A myopic crescent is a moon-shaped feature that can develop at the temporal (lateral) border of disc (it rarely occurs at the nasal border) of myopic eyes.

Stereoscopic acuity, also stereoacuity, is the smallest detectable depth difference that can be seen in binocular vision.