Glossary

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AI sycophancy(also: Sycophantic AI, AI agreeableness bias)

The tendency of AI systems, particularly large language models, to provide overly affirmative, agreeable, or encouraging responses that cater to the user rather than providing accurate information. In accessibility contexts, AI sycophancy poses serious safety risks — for…

Ability assumption in AI(also: Visual ability assumption, Sighted bias in AI)

The tendency of AI systems to assume users possess typical sensory, cognitive, or physical abilities, leading to inappropriate responses or instructions. In the context of visual AI assistants for blind users, ability assumptions manifest as the system asking users to "read the…

Accessible Photography(also: Blind Photography, Inclusive Photography)

The practice and technology of enabling people with visual impairments to take, manage, browse, and share photographs. People who are blind or have low vision face challenges at every stage of photography: aiming the camera at a target, composing the frame, reviewing the result,…

Adventitious blindness(also: Acquired blindness, Late blindness, Acquired visual impairment)

Vision loss that occurs after a period of sighted experience, as opposed to congenital blindness (present from birth). People with adventitious blindness retain visual memories, mental imagery, and familiarity with visual concepts like color and spatial layout, which…

Age-Related Vision Loss(also: Age-Related Visual Impairment)

Vision impairment that occurs as a consequence of aging, representing the most common cause of blindness and low vision worldwide. Conditions include age-related macular degeneration, glaucoma, diabetic retinopathy, and cataracts. The prevalence of significant visual impairment…

Albinism(also: Oculocutaneous Albinism, Ocular Albinism)

A group of inherited conditions characterized by reduced or absent melanin pigment production, affecting the skin, hair, and eyes. Ocular effects commonly include reduced visual acuity, nystagmus (involuntary eye movements), photophobia (light sensitivity), and reduced depth…

Amblyopia(also: Lazy eye)

A neurodevelopmental vision disorder in which one eye has reduced visual acuity that cannot be fully corrected with glasses or contact lenses, caused by abnormal visual development in early childhood. The brain favors one eye and partially suppresses input from the weaker eye,…

Assisted Photography(also: Accessible Photography, Camera Aiming Assistance)

Assisted photography refers to technologies and techniques that help people with visual impairments take photographs by providing non-visual feedback about camera aiming, composition, and image quality. These systems typically use computer vision to analyze the camera view and…

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 light to focus on multiple points rather than one. Astigmatism frequently…

Audio Enriched Links(also: AEL, Audio Link Preview)

A JAWS screen reader extension that provides spoken previews of linked web pages before a blind user follows a hyperlink. When activated on a focused link, the system fetches the destination page in the background and speaks a summary including the page title, its relationship…

Audio Game(also: Audiogame, Audio-Based Game, Accessible Game)

A video game designed primarily or entirely around audio output rather than visual graphics, making it accessible to players who are blind or have visual impairments. Audio games use techniques such as 3D spatial audio, sound effects, text-to-speech, and musical cues to convey…

Audio-Tactile Interface(also: Audio-Haptic Interface, Multimodal Tactile Interface)

A user interface that combines tactile (touch-based) interaction with auditory feedback to convey information that is otherwise visual. Audio-tactile interfaces are widely used in accessibility to make graphical content such as charts, maps, and diagrams accessible to blind and…

Be My Eyes

A mobile application that connects blind and low-vision users with sighted volunteers or AI-powered visual assistance for help with visual tasks. Originally launched in 2015 as a crowdsourced human-to-human video call service, Be My Eyes has since integrated AI features ("Be My…

Blind(also: Blindness)

A visual impairment severe enough that a person cannot use vision as their primary means of perceiving information, typically defined legally in the United States as best-corrected visual acuity of 20/200 or worse in the better eye, or a visual field of 20 degrees or less.…

Blind-Perspective Training(also: Non-Visual Training, Blindfold Training)

An educational and vocational training approach where all learners, regardless of their level of functional vision, are taught skills using non-visual techniques such as touch, hearing, and proprioception. In this model, sighted trainees may be encouraged to wear a blindfold to…

Blindness(also: Blind, Total Blindness, Complete Vision Loss)

A condition characterised by the complete or near-complete absence of functional vision, ranging from no light perception to minimal light awareness that cannot be used for practical tasks. Blind individuals typically rely on non-visual senses and assistive technologies such as…

Blindness and Low Vision(also: BLV, visual impairment, vision impairment)

Blindness and low vision (BLV) collectively describes the spectrum of significant visual impairment ranging from complete absence of sight to partial sight loss that cannot be fully corrected with standard glasses or contact lenses. The World Health Organization defines low…

Blocks-Based Programming(also: Block Programming, Visual Block Programming, BBPE)

A programming paradigm designed to introduce coding concepts to beginners — particularly children — by representing code as visual, interlocking blocks that are dragged and dropped to construct programs, rather than requiring typed syntax. Popular environments include Scratch,…

Braille Contractions(also: Braille Short Forms, Braille Abbreviations)

Abbreviated representations in Grade 2 braille where a single braille cell or short sequence of cells stands for a common word, letter combination, or word fragment. For example, a single cell can represent the word "the" or the letter group "ing." Contractions follow…

Braille Literacy(also: Braille Reading and Writing)

The ability to read and write using the braille system, a tactile code of raised dots representing letters, numbers, and symbols. Braille literacy is fundamental to educational achievement, employment, and independence for people who are blind or have low vision. It encompasses…

Braille Mathematics(also: Math Braille, Braille Math Notation)

The various systems of Braille codes designed specifically to represent mathematical expressions, formulas, and notation in a tactile format readable by blind individuals. Because standard literary Braille does not have enough symbols to represent the full range of mathematical…

Braille Translation Software(also: Braille Transcription Software, Braille Converter)

Software that converts print text into braille or braille into print, applying the appropriate contraction rules, formatting conventions, and code systems (such as UEB or Nemeth). Braille translation software is essential for producing accessible materials but can be…

Braille literacy(also: Braille fluency)

The ability to read and write using the Braille tactile writing system of raised dots. Braille literacy rates among blind people have declined significantly — from over 50% in the 1960s to under 10% in some countries — due to factors including mainstreaming in education, reduced…

Bus stop accessibility(also: Accessible bus stops, Bus stop landmarks)

The design, infrastructure, and information features that make bus stops findable, identifiable, and usable by people with disabilities. For blind and low-vision riders, bus stop accessibility depends heavily on the presence of detectable physical landmarks such as shelters,…

Central Vision(also: 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 distinguishing fine detail and colour. Loss of central vision, commonly caused…

Central Vision Loss(also: Central Field Loss, Central Scotoma)

Loss of vision in the central part of the visual field, typically caused by damage to the macula — the area of the retina responsible for sharp, detailed vision. People with central vision loss experience difficulty seeing fine details directly in front of them, often describing…

Cerebral Visual Impairment(also: CVI, Cortical Visual Impairment)

Cerebral visual impairment (CVI) is an umbrella term for visual deficits resulting from damage to the brain rather than the eyes. It affects visual perception, including visual acuity, cortical image processing, and pattern recognition. CVI is often associated with additional…

Cocktail party effect(also: Selective auditory attention)

The well-documented human ability to focus auditory attention on a single speech source among multiple simultaneous conversations, while still detecting relevant information (such as one's name) in unattended streams. The cocktail party effect is foundational to the design of…

Color Identifier(also: Color Detector, Color Recognition Device)

A color identifier is an assistive technology device or application that detects and announces the color of objects for people with vision impairments. Standalone hardware devices use a light sensor pressed against an object to identify its color and speak the result aloud.…

Color Perception(also: Color Vision, Chromatic Vision)

Color perception is the ability to detect, distinguish, and identify colors. Impairments in color perception range from complete color blindness (achromatopsia) to partial deficiencies in distinguishing specific color ranges, such as red-green or blue-yellow color vision…

Concurrent speech interface(also: Simultaneous speech, Parallel audio streams)

An interaction paradigm that presents multiple speech audio streams simultaneously, spatially separated using techniques like head-related transfer functions, to enable users to scan or monitor several information items in parallel rather than listening to them sequentially.…

Cone Dystrophy(also: Cone-Rod Dystrophy)

A group of inherited eye disorders that affect the cone cells in the retina, which are responsible for color vision, central vision, and visual acuity in well-lit conditions. People with cone dystrophy typically experience progressive loss of color vision, decreased visual…

Corrective feedback(also: Error correction feedback, Instructional feedback)

Specific information provided to a user after an action that identifies what was done incorrectly and how to improve on the next attempt. In accessible interaction design, corrective feedback for blind users is typically delivered through text-to-speech (e.g., "make it longer,"…

Currency Accessibility(also: Accessible Currency, Banknote Accessibility)

The design of physical money — coins and banknotes — so that people with visual impairments or other disabilities can independently identify and use different denominations. Many countries produce banknotes in different sizes, colours, or with tactile features (raised print,…

Data Sonification(also: Auditory Data Display, Sonified Data Visualization)

The systematic mapping of data values to non-speech audio parameters such as pitch, volume, rhythm, timbre, or spatial location to make datasets perceivable through hearing. Data sonification is a key accessibility technique for making charts, graphs, and other data…

Dichoptic presentation(also: Dichoptic display, Dichoptic filtering, Dichoptic stimulation)

A technique in which different visual information is presented separately to each eye, typically using color-filtered glasses (red-cyan or red-green anaglyph), polarized lenses, or head-mounted displays. In clinical settings, dichoptic presentation is used as a therapeutic…

EVITA(also: Enabling Visually Impaired Table Access)

A specialized table browser developed at the University of Manchester designed to enable visually impaired users to navigate, browse, and read HTML data tables non-visually in a manner analogous to how sighted readers interact with tables in print. EVITA provides keyboard-based…

Early Blind(also: Congenitally Blind, Early Onset Blindness)

A person who was born blind or lost their vision before approximately age 5-7, before visual memories and spatial concepts based on vision were fully established. Early blind individuals develop spatial understanding entirely through non-visual senses—touch, hearing,…

Eccentric viewing(also: Preferred retinal locus, PRL)

A viewing strategy used by people with central vision loss (such as from macular degeneration) in which they learn to look slightly off-center to use a healthier area of the retina instead of the damaged macula. The part of the retina they train themselves to use is called the…

Egocentric Spatial Reasoning(also: First-Person Spatial Understanding, User-Relative Spatial Reasoning)

The ability of a system to understand and describe the spatial positions of objects relative to the user's body and perspective, rather than from a bird's-eye or absolute reference frame. For AI systems assisting blind travelers, egocentric spatial reasoning is critical —…

Expanded Core Curriculum(also: ECC)

A specialized curriculum for blind or visually impaired (BVI) students that supplements traditional academics with skills that sighted students typically learn through observation. The ECC covers nine areas of instruction: compensatory skills, sensory efficiency, orientation and…

Eyes-free Interaction(also: Eyes-free Input, Nonvisual Interaction, Eyes-free Interface)

Interaction techniques that allow users to operate devices without looking at the screen or interface. Eyes-free interaction is essential for people who are blind, but also benefits sighted users in contexts where visual attention is unavailable or dangerous, such as while…

Eyes-free interaction(also: Eyes-free interface, Non-visual interaction)

An interaction paradigm in which users operate technology without relying on visual feedback, instead receiving information through auditory, haptic, or other non-visual channels. Eyes-free interfaces are essential for people who are blind or have low vision, but also benefit…

Frequency mapping(also: Pitch mapping, Frequency-position mapping)

A sonification technique that encodes spatial position or data values as changes in audio frequency (pitch), creating an intuitive correspondence between vertical position and pitch height — low positions produce low-frequency sounds and high positions produce high-frequency…

Gesture sonification(also: Touch sonification, Gesture-to-sound mapping)

The technique of converting touchscreen finger movements into real-time audio representations by mapping spatial position to sound parameters — typically pitch for vertical position and stereo panning for horizontal position. Gesture sonification enables blind and visually…

Glaucoma

A group of eye diseases that damage the optic nerve, usually caused by abnormally high intraocular pressure. It is one of the leading causes of irreversible blindness worldwide, affecting over 80 million people. Glaucoma typically causes gradual peripheral vision loss that may…

Glaucoma

A group of eye conditions that damage the optic nerve, typically associated with elevated intraocular pressure. Glaucoma is a leading cause of irreversible blindness worldwide. It usually causes gradual loss of peripheral vision first, which can progress to tunnel vision and…

Grade 1 Braille(also: Uncontracted Braille, Alphabetic Braille)

The basic level of braille in which each letter, number, and punctuation mark is represented by its own distinct braille cell, with no abbreviations or contractions. Grade 1 braille is typically used by beginning braille learners and for labeling purposes. While straightforward…

Grade 2 Braille(also: Contracted Braille)

The standard form of braille used in most published materials, which employs contractions — single braille characters or short groups of characters that represent common words, letter combinations, or word parts. Grade 2 braille is more concise than Grade 1, reducing reading and…

Graphic Accessibility(also: Image Accessibility, Visual Content Accessibility)

The practice of making graphical content — including charts, diagrams, maps, photographs, and illustrations — perceivable and understandable by people who cannot see them. Graphic accessibility encompasses a range of techniques from simple alternative text descriptions to…