Low Vision, Colorblindness and Web Access

Remember that some visitors to your site will have to view your pages using special software to either enlarge the screen and/or change the colors.

Issues:

Some people who will visit your website will be using screen magnification software due to severe low vision. Although people with low vision may be legally blind, they can use adaptive technology to see computer screens under the right conditions.

Realize that you can help enable students with low vision to access your material by keeping a few points in mind when developing web pages.

A Simulation:

Imagine you have a low vision. Try looking at your computer monitor through a piece of onionskin paper. Or turn down the contrast and brightness until you can just barely see the screen. How would you like to have to get your work done under these conditions?

How would you better design Web pages if you had to view them through incorrect glasses?

Some Solutions:

• Keep people with low vision in mind when creating new Web pages.
• Avoid graphical text it possible. Realize that graphics/images become more and more pixelated as screen magnification increases.
• Provide a link to a longer description for complex essential charts, graphs, and images.
• Use standard fonts that can be easily read. Avoid cursive.
• Avoid relying upon horizontal scrolling by the user. People who use screen magnification software must pan around the screen and may miss information that is located near the far right edge.
• Test for accessibility of essential graphics by previewing your pages with screen magnification software.
• Avoid flashing or strobing objects on web pages.
• Color may be an issue. Provide enough contrast between your font colors and the background.
• Never rely upon color alone to convey information. 4% of Web users have some form of colorblindness. For example:

Unacceptable:

The following students listed in green have passed with honors. The students listed in red must repeat the class.

Joe Blow
Doug Smith
Marianne Summers

Better:

The following students listed in green and marked with asterisks (*) have passed with honors. The students listed in red and marked with # must repeat the class.

Joe Blow
Doug Smith #
Marianne Summers *

In the second example above, even someone with colorblindness who cannot distinguish red from green will be able to understand the content.

Some links for testing for colorblindness issues with online documents.