Under the Disability Discrimination Act 1995 (DDA), a disability is a physical or mental impairment that has a long-term or substantial effect on a person's ability to carry out day to day tasks.
This ranges from people with physical and sensory impairments to people with diabetes, disfigurements, heart disease and epilepsy. Not all of these affect how an individual may access the internet however.
This includes people with no vision, or some functional vision. For example, screen readers are used by the blind to read web pages, and someone with poor vision may use screen magnification or adjust their browser settings to make reading more comfortable. This group also includes people with colour blindness and those with eyesight problems related to ageing.
This includes people who are completely deaf or have partial hearing in one or both ears and require the use of a hearing aid.
This refers to a wide range of people with varying types of physical disabilities. With regards to the web is refers largely to people with upper limb mobility, manual dexterity and co-ordination problems. This can be caused though a disability that an individual is born with or one that develops due to illness such as Multiple Sclerosis (MS), Parkinson's or a stroke. People with a broken bone would also temporarily fall into the category.
Cognitive impairment refers to people with dyslexia and learning difficulties. Dyslexia is a condition where people have difficulties with reading, writing or spelling. Learning problems can range from someone who has a serious mental impairment, or may be due to more common factors as poor literacy, a low level of skill using a computer, having to use the web in a second language, or problems understanding information.