SAIF: Making Websites Accessible
Web accessibility issues for particular groups
People with a visual impairment
The access needs of visually impaired people are extremely variable. Flexibility, therefore, is the key to ensuring that your website is accessible to as many people as possible. People with some vision may need to be able to enlarge text (or make it very small), or change the contrast or colours on the web page. Others will access web pages using software which converts text into synthesised speech or makes it accessible via a braille display.
You must ensure that the design of your web pages does not make it difficult for a person with a visual impairment to be able to customise the page for his/her own needs.
Designing a website to be accessible to a person with a visual impairment - or indeed for anyone - can be a complex subject. The following general principles apply to designing for users with a visual impairment, but are just as relevant to all groups:
- Provide text equivalents for all non-text objects on the page - speech synthesisers can't read graphics, and graphic text can't be enlarged in the same way as ordinary text. All graphics should have text labels, i.e. alt-tags, alternative attributes in HTML (Hyper Text Mark-up Language).
- Don't design the page in a way that stops users from setting their own browser preferences, i.e. don't specify exact sizes for fonts or layouts - design everything in relative sizes.
- Use valid HTML and add structure to your pages by using the correct tags for headings, paragraphs, lists and so on. Many access software programs depend on the content of the pages being marked up correctly. Some software can give an overview of the page by extracting all the headers and links and presenting them on a single page. If you have no headers on your page and all your links say 'click here' then the accessibility of your website will be very low.
There is very useful, more detailed information about designing for users with visual impairment at the RNIB website.