Make Your Website Accessible to Visually Impaired People
By Julie Howell, RNIB
The growth of the World Wide Web has meant that many people with serious sight problems are now able to enjoy a wealth of information that was previously unavailable to them. With the help of synthesised speech and braille display technology, even completely blind people can use the internet. But for these technologies to work properly, Web pages must be written in correct HTML (hypertext mark-up language).
Most people with sight problems have some useful vision, and read online text in exactly the same way as fully sighted people: with their eyes.
However, the needs of people with poor sight vary, depending on how their eye condition affects their vision. Some people require large text, while others can only read smaller letters. Many pople with sight problems need a highly contrasting colour scheme, while some can only read yellow text on a black background.
To cater for everyone, Web sites should be flexible in design, enabling the individual to adjust the text and colour settings to suit their needs and circumstances.In contrast, people with very little or no vision read Web pages with the help of access technology installed on their computer. Synthesised speech software reads the content of Web pages aloud through a speaker, while Braille software outputs to a retractable display, so that the Web site can be read by touch.
Careful design is paramount for people accessing the Web in these ways, as inappropriate use of HTML can render a site unreadable.
An accessible Web site is one that can be visited by anybody. It is perfectly possible to produce an attractive, dynamic design that remains fully accessible. Web sites that are designed intelligently benefit everyone not only people with disabilities.
1. Is the text legible?
Contrast is the most important factor to consider when designing sites that everyone can use. Go for text and background colour combinations that offer maximum contrast.
2. Is the design flexible?
Is it easy to change the colours and the size of the text by adjusting browser settings?
3. Does every image have 'alt-text'?
The alternative text attribute of the image tag exists to provide a description of the image for people accessing the site via speech synthesis software.
4. Is there a site map?
A site map will help visitors to get an impression of the layout of the site quickly, and will make it easier to navigate.
5. Do links make sense out of context?
Sighted people scan screens of information to locate the parts that interest them. If you cannot see, and rely on synthesised speech technology to 'hear' Web sites, you need another way to get a quick impression of the content of a page. Commonly, the access software blind people use will provide a list of all the links on a page as a means of getting the 'flavour' of the content. If a link contains only the words 'click here', its function will not be obvious if it is presented out of context.
6. Are image maps accompanied by text links?
Some of the software packages that blind people use cannot read image maps, so it is important to make text links available as well.
7. Do frames have titles, or is 'noframes' used?
Some blind people may be using software that cannot read frames. It is vital that the NOFRAMES tag is used to offer these people alternative frames-free versions of your pages.
If you are writing pages in anything other than HTML, you may be excluding some people from your site.
9. Is Access Adobe available for PDF files?
Adobe Acrobat Reader is not compatible with the access software many blind people use. Access Adobe transforms PDF files into HTML.
10. Do all pages pass the "Bobby Test"?
There are various online and downloadable semi-automated accessibility checking tools. Including the free online accessibility checker WebXact (formerly Bobby). There is no longer free downloadable version of Bobby. However the online tool allows you to check a page at a time. Bobby 5 can be purchased from Watchfire and installed on a computer and used to check complete websites for accessibility problems. The Bobby Test will test for HTML 4.0 compatibility, that all graphic elements have text equivalents, and that written summaries have been provided for graphs and statistical material.
Fore more detailed information see AbilityNet's informative publication for the ICT Hub How to Commission and Design Accessible Websites (1.69 Mb PDF document. Requires Adobe Reader if you don't already have already have this, download it from Adobe).
- Using zoom layouts - alternative style sheets for improving your site’s accessibility
- Web 2.0 & Accessibility for Disabled Users
- Web Accessibility and the Law
- Web Accessibility Resources
Published: 6th April 2000 Reviewed: 5th April 2006
Copyright © 2000 Julie Howell, RNIB
All rights reserved