Sites accessible to people with low vision who like to enlarge text on their screens or who use Screen Magnification software will receive a Magnifiable Access Key. Users in this group include people who find standard font sizes on a computer screen too small, people with tired eyes after a long day at the office or with a more serious visual impairment caused by conditions such as glaucoma, retinal degeneration or diabetic retinopathy.
Those users who require screen magnification software may enlarge a web page so much that they can see only one or two characters on the screen at a time. As a result you should not use any fixed widths or fixed font sizes so every element of a page enlarges by the same ratio. You should also ensure you use a consistent page layout and navigational scheme so these users can find their way around pages of your website more easily.
Update static equivalents of dynamic content at the same time as the dynamic content.
Read about how Alt Page criterion scoring works.
Make certain foreground and background colours contrast enough so someone with low vision can read text on their screen. This includes images with text.
Read about how Colour Contrast criterion scoring works.
Use consistent style so users who have magnified their screens can find their way around a page more easily. They can get lost easily if they can only see a character or two at a time on their screens.
Read about how Consistent Style criterion scoring works.
Do not use fixed size fonts so users with low vision can enlarge fonts.
Read about how Font Size criterion scoring works.
Title each frame so users can keep track of their location on the page.
Read about how Frame Title criterion scoring works.
Provide a transcript and audio description of any multimedia content. Screen magnification users may have scripts turned off or may have trouble watching moving content especially if it cannot be enlarged.
Read about how Multimedia Sight criterion scoring works.
If you must have moving or flickering content provide a means to turn it off. It can cause problems for someone with a magnified screen.
Read about how No Flicker criterion scoring works.
For any necessary plug-ins provide a link to a free device-independent plug-in that meets UAAG guidelines so it will run with screen magnification software if at all possible. If you must - at the very least - provide a text alternative to the content.
Read about how Plug-ins criterion scoring works.
Users of screen magnification software will often define their own stylesheets or turn them off altogether to make screens easier to read.
Read about how Without Styles criterion scoring works.