Low vision describes any number of situations where a person has lost a significant amount of their vision, but not enough to be considered blind. It can be caused by any of a number of factors, each of which presents as a slightly different set of visual challenges.
Examples of low vision
- brain injuries
- diabetic retinopathy
- eye injuries
- eye cancer
- macular degeneration
- retinal detachment
- retinitis pigmentosa
- various infections
People with low vision may rely on the browser’s zoom features, or they may use screen magnification software such as ZoomText or MAGic, which show a small portion of the screen at a time. Low vision users are also often screen reader users so keep those requirements in mind as well.
When designing for users with low vision, we need to:
- Use good contrasts and a readable font size. Ensure that your software passes WCAG 1.4.3 Contrast (Minimum) – Level AA.
- Publish all information on web pages (HTML), not PDFs or other inflexible formats.
- Use a combination of color, shapes, and text.
- Follow a linear, logical layout and ensure text flows and is visible when text is magnified to 200%.
- Put buttons and notifications in context.
- Provide a visible focus state. Ensure that your software passes WCAG 2.4.7 Focus Visible – Level AA.
- Provide a clear visual distinction between content (text, images), and controls (buttons, links, etc.) .
We need to avoid:
- Disabling pinch-to-zoom.
- Using low color contrasts and small font sizes.
- Burying information in downloads.
- Only using color to convey meaning.
- Spreading content all over a page and forcing a user to scroll horizontally when text is magnified to 200%.
- Separating actions from their context.
Sources for the list above:
- Dos and Don’ts on designing for accessibility and the accompanying poster on designing for users with low vision (PNG) by Karwai Pun at the UK Accessibility in Government Blog
- Deque University accessibility training
How to design mobile app experiences for the visually impaired by Ayesha Zafar on Invision discusses steps specific to mobile interactions.
- Macular Degeneration simulator and video
- Glaucoma simulator
- Simulator for Macular Degeneration, Diabetic Retinopathy, Cataracts, and Glaucoma
- WebAIM’s Color Contrast Checker – will tell you if two colors you enter pass accessibility guidelines
- Responding to Color by the Cooperative Extension Service of the University of Kentucky.
- Karwai Pun’s Dos and Don’ts on designing for accessibility and the accompanying poster on designing for users with low vision.