Glossary
Searchable terminology from accessibility, web standards, and related fields.
78 results found in Visual Accessibility.
- Shoulder Surfing
- A form of visual eavesdropping where an attacker observes a person entering sensitive information such as passwords, PINs, or personal data by looking over their shoulder or from a nearby vantage poin…
- Simulation Glasses (Cataract Glasses, Vision Simulation Glasses, Low-Vision Simulation Goggles)
- Simulation glasses are wearable lenses or goggles that reproduce the functional visual experience of specific eye conditions — cataracts, macular degeneration, glaucoma, hemianopia, and others — by bl…
- Situational Visual Impairment (SVI, Situational Visual Impairments)
- A temporary reduction in a person's effective vision or reading performance caused by the environment or context rather than by a medical condition. Common examples include trying to read a phone scre…
- Tactile Diagram (Raised Diagram, Embossed Diagram)
- A diagram rendered in a tactile format that can be explored through touch, typically using raised lines, textures, and Braille labels on special paper or thermoform plastic. Tactile diagrams are essen…
- Tactile Exhibit (Touch Exhibit, Hands-On Exhibit, Tactile Display)
- A museum or gallery exhibit designed to be explored through touch rather than sight, allowing visitors to physically interact with objects, models, or replicas. Tactile exhibits are particularly impor…
- Tactile Learning Material (Tactile Teaching Aid, Hands-On Learning Material)
- Physical educational materials designed to be explored through touch, enabling students with vision impairments to understand concepts that are typically presented visually. Tactile learning materials…
- Teacher with Vision Impairment (TVI, Visually Impaired Teacher, Blind Teacher)
- An educator who is blind or has low vision and teaches in educational settings, often in schools for the blind where they share the lived experience of their students. TVIs are particularly prominent …
- Text Modification (Text Formatting, Text Presentation Modification)
- Changes to the visual presentation or formatting of text to improve readability without altering the actual content. Text modifications include adjustments to font type, size, color, spacing, line hei…
- Text Reflow (Content Reflow, Responsive Text)
- The ability of text content to rearrange and wrap within its container when the viewport is resized or text is zoomed, so that users can read without horizontal scrolling. Text reflow is essential for…
- Text Scaling Assistive Service (TSAS, Font Size Scaling)
- An Android platform service that allows users to increase or decrease the size of text displayed across applications. Text Scaling Assistive Service is critical for users with low vision who need larg…
- Tritanomaly (Tritan Anomalous Trichromacy)
- A rare type of colour vision deficiency where the short-wavelength (blue) cone cells have a shifted sensitivity range. Tritanomaly results in reduced ability to distinguish blue from yellow. It is the…
- Tritanopia (Tritan Dichromacy, Blue-Blind)
- A rare type of colour vision deficiency caused by the complete absence of short-wavelength (blue) cone cells in the retina. People with tritanopia have difficulty distinguishing blue from yellow and b…
- Typography (Typographic Design)
- The art and technique of arranging type to make written language legible, readable, and visually appealing. In accessibility contexts, typography encompasses font selection, size, weight, spacing (let…
- Visual Affordance (Visual Affordances)
- A visually conveyed cue that signals how an object can be used or what it represents - for example, a handle suggesting 'grasp', a button suggesting 'press', or color and labeling suggesting product i…
- Visual Presentation (Text Presentation)
- The way text and content are visually rendered on screen or in print, encompassing typography, layout, color, spacing, and formatting choices. Visual presentation significantly affects readability and…
- Visual Processing (Visual Processing Disorder, Visual Perception)
- The brain's ability to interpret and make sense of visual information received through the eyes. Visual processing difficulties can affect reading, spatial awareness, figure-ground discrimination, and…
- Zernike Polynomials (Zernike Coefficients, Zernike Modes)
- A set of mathematical functions used to describe the shape of optical wavefronts, commonly employed in ophthalmology and optometry to characterise the optical aberrations of the human eye. Each Zernik…
- ZoomText
- A commercial screen magnification and screen reading software for Windows, developed by Freedom Scientific (formerly Ai Squared). ZoomText provides up to 60x magnification along with features like smo…