Glossary
Searchable terminology from accessibility, web standards, and related fields.
19 results found in vision.
- Astigmatism
- A common refractive error caused by an irregularly shaped cornea or lens, resulting in blurred or distorted vision at all distances. The cornea is shaped more like a rugby ball than a sphere, causing …
- Central Vision (Foveal Vision)
- Central vision is the area of sharpest sight in the visual field, corresponding to the fovea at the centre of the retina. It is responsible for detailed tasks such as reading, recognizing faces, and d…
- Cerebral Visual Impairment (CVI, Cortical Visual Impairment, Brain-Based Visual Impairment)
- A form of visual impairment caused by damage to or dysfunction in the brain's visual processing centres, rather than problems with the eyes themselves. CVI is the leading cause of childhood vision imp…
- Color Vision Deficiency (Color Blindness, CVD, Colour Blindness)
- A condition in which a person has difficulty distinguishing between certain colors, most commonly red and green (deuteranopia/protanopia), but also blue and yellow (tritanopia) or all colors (achromat…
- Convergence Insufficiency (CI)
- A binocular vision disorder in which the eyes have difficulty turning inward (converging) to focus on nearby objects, causing symptoms such as double vision, eye strain, headaches, difficulty reading,…
- Glare Sensitivity (Photophobia, Light Sensitivity)
- An increased sensitivity to light that causes discomfort, visual difficulty, or pain, commonly experienced by people with various eye conditions including cataracts, macular degeneration, and albinism…
- Hemi-Attention (Hemispatial Neglect, Unilateral Neglect, Visual Neglect, {'': ['Visuo-Spatial Neglect', 'Visuospatial Neglect', 'VSN']})
- A neurological condition in which a person has reduced attention or awareness to one side of space, typically the side opposite to a brain injury. Unlike hemianopsia (where visual input is lost), hemi…
- Hemianopsia (Hemianopia, Half-Field Vision Loss)
- Loss of vision in one half of the visual field in one or both eyes, typically caused by damage to the brain's visual pathways rather than the eyes themselves. The most common form is homonymous hemian…
- Optic Ataxia (Visuomotor Ataxia)
- A neurological condition characterised by impaired reaching for objects using visual guidance, despite having adequate vision and motor strength. People with optic ataxia can see an object and describ…
- Optic Flow (Visual Flow, Optical Flow)
- The pattern of apparent motion of objects, surfaces, and edges in a visual scene caused by relative movement between the observer and the scene. Optic flow provides critical information about self-mot…
- Optic Nerve Hypoplasia (ONH)
- A congenital condition in which the optic nerve is underdeveloped, resulting in varying degrees of vision loss from mild visual impairment to complete blindness. It is one of the most common causes of…
- Parallax (Visual Parallax, Binocular Parallax)
- Parallax is the apparent displacement or difference in position of an object when viewed from two different vantage points. In human vision, binocular parallax — the slight difference between the imag…
- Presbyopia (Age-Related Farsightedness, Loss of Accommodation)
- An age-related vision condition in which the eye gradually loses the ability to focus on nearby objects, typically becoming noticeable after age 40. Presbyopia affects the vast majority of older adult…
- Prosopagnosia (Face Blindness)
- A neurological condition characterised by the inability to recognise familiar faces, despite otherwise intact visual and cognitive abilities. People with prosopagnosia may fail to recognise family mem…
- Sensory Overload (Sensory Overwhelm, Overstimulation)
- A state in which the brain receives more sensory input than it can effectively process, leading to stress, anxiety, difficulty concentrating, and in severe cases, meltdowns or shutdowns. Sensory overl…
- Vision Therapy (Visual Training, Orthoptics, Eye Training)
- A program of visual activities and exercises prescribed to improve visual skills and processing, often used to treat conditions like amblyopia, strabismus, and convergence insufficiency. Vision therap…
- Visual Acuity
- A measure of the sharpness or clarity of vision, typically expressed as a fraction (e.g., 20/20) or percentage indicating the smallest detail a person can resolve at a standard distance. Visual acuity…
- Visual Clutter (Visual Noise, Visual Complexity)
- An excess of visual elements in an environment or interface that makes it difficult to locate, identify, or focus on relevant information. Visual clutter is a significant barrier for people with cereb…
- Visual Field Loss (Visual Field Deficit, VFL, Field Loss)
- A reduction in the area of vision that a person can see without moving their eyes or head. Visual field loss can affect any portion of the visual field — central, peripheral, or specific quadrants — a…