Webstandards, Accessibility and Usability at Penn State

The term "low vision" refers to the audience who have enough sight to use a visual browser but may need to enlarge text or use special high-contrast font and color settings in order to access online information. It is important that a Web page NOT inadvertently disable zooming or the ability to adjust color/font settings.

This Page

1. Tools Needed
2. Demo
3. Accomodations Needed
4. Hidden Audience
5. Testing and Demo Tools

Tools Needed

Low vision users need a mechanism to zoom content on a computer screen, sometimes to very large sizes. Zooming works well for vector-based text and PNG. graphics, but causes pixellation for bitmapped images such as GIF and JPEG.

Many users with special visual needs may implement custom stylesheets or plugins to override formatting specified on the page. The adjustments differ from person to person and can include zooming or light text on a dark background.

Demo

Top of Page

Accommodations Needed

This audience needs a technology which allow adjustments in visual formatting. CSS (Cascading Style Sheets) on HTML is one way to enable this since users can use their own styles. Flash, Word and PDF also enable zooming.

Depending on their visual needs, a user may need

• Always dark text on a light background (some prefer cream backgrounds over white) OR
• Always light text on a dark background (like a terminal) OR
• Always serif fonts OR
• Always sans-serif fonts OR
• Always zoomed to large sizes OR
• Or a unique combination of all of the above

Hidden Audiences for Low Vision Accommodation

1. Users of mobile Web devices such as an iPhone face the challenges of reduced screen size.
2. Users, particularly older users, may wish to zoom the text of a particular Web site because of small text size. In addition, some color combinations with bright colors and fonts are harder to read for all users to read.
3. People who may be photo sensitive (e.g. migraine sufferers) or work in poor lighting conditions may need to adjust their browser views and colors.
4. People accessing the Web in poorly lit conditions or on monitors with varying display capacities.

Top of Page

Low Vision Design Tips

• Lighthouse Org: Designing for People with Partial Sight
• Juicy Studios Color Contrast Ratio Analyser - This tool ensures that color schemes (text vs background) have sufficient contrast in lightness/darkness
• Font and Text Layout Recommendations - These recommendations are aimed for low vision users

Zooming Simulations

• Lighthouse: What the World Looks Like to People with Low Vision
• WebAim Low Vision Simulations

Top of Page