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Barriers to access for people with disabilities

The Internet has become an enriching part of many people's lives, none more so than people with disabilities who are often excluded from activities and information in the physical world. The Internet has the potential to provide communication, support communities, easier access to information and online shopping, an independence that some people with disabilities have not experienced before.

But there are a number of ways in which current technology and design practices can create barriers for users with disabilities. A website that cannot be navigated via the keyboard will be inaccessible for someone who can't use a mouse. A deaf person will be disappointed to find a webcast without captioning or subtitles. A blind person might like to know the content of a flash movie. A dyslexic person might be overwhelmed by long pages of text that are not easy to scan.

Some statistics :

According to the W3C, 10% to 20% of the population in most countries has disabilities.

Exact statistics are hard to come by. Definitions of disability vary and figures are more likely to be an understatement of the situation. Some disabilities are easily recognised while others aren't. Especially illiteracy, poor language skills and learning difficulties often go unrecognised. A person with slow reading skills, for example, might not advance in education because he is unaware that he could ask for extended time in examinations. Dyslexic people are often considered lazy and, unaware of their condition, might believe so themselves, preventing them from setting their goals higher.

According to the UK Higher Education Statistics Agency 74,000 disabled students were enrolled during the academic year 1999/2000. [source]

Some figures:

  • 34% medically disabled students with chronic conditions such as diabetes, asthma, chronic fatigue syndrome, etc.
  • 28% students with learning disabilities such as reading disability, dyslexia, attention deficit.
  • 6% hearing impaired students.
  • 5% students with mobility disabilities.
  • 3% visually impaired students.

[Links to statistical resources can be found in the resources section.]

Visual disabilities :

People with visual impairment encounter problems when websites:

  • are presented in complicated and confusing layout,
  • don't use colours sensibly,
  • don't provide text equivalents for images and multimedia,
  • don't support keyboard access or the use of screen readers
  • don't allow user control over colours, font sizes and moving content.


Blind people are likely to access web pages using assistive technology, such as braille displays or screen readers that read the content of a page out loud, but they cannot access any information contained in graphics unless a text alternative is offered.

Low vision

Just as government agencies and book publishers offer large print versions of books and document, web designers have to permit users to adjust font sizes according to their requirements. Some users with low vision use screen magnifiers, but being able to increase the font size of text on web pages could be sufficient or preferable to magnifications that show only part of the screen.

Someone with low vision will also find scrolling and moving text more difficult to follow.

Colour blindness

We can assume that 1 in 12 visitors to our websites [source] has some form of colourblindness, of which red-green colour blindness is most common. People with colour blindness might encounter problems when design doesn't provide enough contrast, they might not be able to read text on intensely coloured backgrounds or are unable to identify link colours correctly.

Perception of colour also changes with old age. Strong colour contrast and bright saturated colours, such as orange, are then easier to identify than pastels or dark green and blue combinations.

This does not mean that we should design dull websites. Colours have advantages, but it is important to use them sensibly and to provide contrast.

Check the resources section for some excellent articles on the issue and tools for testing the colour scheme your site.

Hearing disabilities :

Sound is often used to alert computer users to problems, such as hardware problems or user errors. In Windows Operating Systems these sounds can be turned into visual alerts by using the appropriate build-in accessibility options.

However, this does not work with audio content delivered over the Internet. Users with hearing disabilities will have problems with audio presentations, where no captioning or text alternative is provided.

In this context we should also consider the fact that sign language might be a deaf person's first language and that comprehension of written language might be slow.

Motor disabilities :

Computer trainers often comment on the fact that mice are hard to use for senior citizens, whose fingers might not be as steady or mobile anymore. People with motor function disabilities encounter the same problems. Limited muscular control can cause lack of coordination or involuntary movement or impede movement altogether. People with motor skills disabilities often use a specialized mouse or keyboard or use speech input.

Sufferers of Work-related Upper Limb Disorders (WRULD), such as RSI (Repetitive Strain Injury) and CTS (Carpal Tunnel Syndrome) also tend to avoid using the mouse because it causes them pain. They prefer specialist keyboards (and/or voice input).

For these users it is important that a web page can be accessed without the use of the mouse. Web designers can easily ensure that it is possible to tab through links or to certain parts of the page and that the main links can be triggered with certain key combinations.

These users will also experience difficulties with applications that require a time limited response and with user agents that don't support keyboard input.

Cognitive disabilities / Learning and reading difficulties :

When 'Accessibility' is mentioned, some people think of unappealing pages without graphics and large amounts of unformatted black text on white background. But to be truly inclusive we shouldn't forget about one user group that appreciates a touch of colour and prefers text in more digestible chunks. Individuals with cognitive difficulties, such as memory loss, Down syndrom, attention deficit disorder, dyslexia, or people with slow reading speed often find it difficult to process large amounts of text.

Colour and graphics can be used to break up text and also to make it easier to navigate the site structure. Consistent navigation icons can increase association and recognition.

Headers and subheaders, bullet lists, margins and indentation can be used to make text more interesting and scannable.

Moving content like animations or scrolling text should be avoided, however. Users with cognitive disabilities might find it difficult to focus when distracting movement cannot be turned off.

People with cognitive difficulties will benefit from:

  • Clear, simple and jargon-free language,
  • clear organisation of the website,
  • consistent design and navigation,
  • the use of graphics in a sensible manner,
  • making scrolling and animated content stoppable.

Learn more :

W3C: How People with Disabilities Use the Web. [Open link in new browser window.]

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