Glossary
Searchable terminology from accessibility, web standards, and related fields.
27 results found in Low Vision.
- Aniridia
- A rare congenital eye condition involving the partial or complete absence of the iris, often accompanied by reduced visual acuity, light sensitivity (photophobia), nystagmus, and sometimes glaucoma or…
- Blue Cone Monochromatism (BCM, S-cone Monochromacy)
- A rare inherited vision condition in which only the blue (short-wavelength) cones function, resulting in severely reduced color vision, reduced visual acuity, photophobia, and nystagmus. Affected indi…
- Blurred Vision Simulation (Vision Simulation, Low Vision Simulation)
- A technique used in accessibility evaluation where evaluators simulate the visual experience of people with reduced visual acuity by artificially blurring their view of a website or application. Metho…
- CCTV (Closed Circuit Television, Video Magnifier, Desktop Video Magnifier, Electronic Magnifier)
- A camera-based magnification system used by people with low vision to enlarge text and images on a monitor. Traditional CCTVs consist of a camera mounted over a reading platform that captures material…
- CCTV Magnifier (Closed-Circuit Television Magnifier, Video Magnifier, Desktop Video Magnifier)
- An assistive device that uses a camera to capture an image of text or objects and displays it magnified on a screen, typically a television or computer monitor. CCTV magnifiers are one of the most wid…
- Color Filter (Color Filters, Display Color Filter)
- An operating-system or browser-level feature that alters how colors are rendered on screen, including grayscale, inverted colors, and filters for protanopia, deuteranopia, and tritanopia color vision …
- Cursor Locator (Pointer Locator, Cursor Finder, Find My Cursor)
- A software utility that helps users find the position of their mouse pointer on screen when it has been lost from view. Cursor locators typically activate through a keyboard shortcut or by detecting p…
- Deconvolution
- A computational process that reverses the blurring effects of convolution in an optical or imaging system. In the context of visual accessibility, deconvolution is used to pre-process images displayed…
- Dynamic Type (Dynamic Text Size, Text Scaling, Font Scaling)
- An iOS accessibility feature that allows users to adjust the system-wide text size to meet their reading needs, from very small to very large. Apps that support Dynamic Type automatically reflow and r…
- Fisheye View (Fisheye Lens, Graphical Fisheye)
- A focus+context visualization technique, introduced by Furnas, that magnifies a region of interest while progressively compressing surrounding context — analogous to a fisheye camera lens. Used in tre…
- Focus+Context (Focus plus Context, Focus and Context)
- A visualization interaction paradigm that integrates a detailed focus region and its surrounding context into a single unified view, rather than separating them. Techniques include fisheye views, sema…
- Goldmann Perimetry (Goldmann Visual Field Test, Kinetic Perimetry)
- Goldmann perimetry is a clinical technique for mapping the visual field — the total area a person can see while fixating on a central point. The test uses a moving stimulus of controlled size and brig…
- Icon Size (Target Size, Touch Target Size)
- The physical or rendered dimensions of graphical interface elements such as icons, buttons, and interactive controls. Research consistently shows that larger icon sizes improve interaction performance…
- Overview+Detail (Overview and Detail)
- A visualization interaction paradigm that presents a smaller overview view alongside a larger detail view, letting users navigate the whole while inspecting a part. Common in maps, document readers, a…
- Page Magnification (Page Zoom, Web Page Magnification)
- An accessibility feature that enlarges the entire visual presentation of a web page, including text, images, and layout elements, to make content easier to see for people with low vision or visual fat…
- Pelli-Robson Chart (Pelli-Robson Contrast Sensitivity Chart)
- The Pelli-Robson chart is a clinical tool used to measure contrast sensitivity — the ability to detect objects at low-to-moderate contrast levels. The chart consists of a series of letter-charts compo…
- Point Spread Function (PSF)
- A mathematical description of how a single point of light is spread or blurred by an optical system such as the human eye. The point spread function characterizes the degree and pattern of distortion …
- Pre-compensation (Display Pre-compensation, Image Pre-compensation)
- A technique in which images displayed on a computer screen are mathematically modified in advance to counteract the visual aberrations of the viewer's eye. Rather than relying on corrective lenses or …
- Precompensation (Display Precompensation, Image Precompensation)
- A technique in visual accessibility that pre-modifies displayed images in a way that is opposite to the optical distortion introduced by a user's eye, so that the image arriving at the retina more clo…
- 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…