There are many different degrees of blindness. I work for the National Council for the Blind of Ireland and most of our services are for visually impaired users and not users who are completely blind.

For example, a friend of mine can see perfectly well, but has a very rare and extreme form of dyslexia and is legally registered blind. He cannot read, or remember, or understand symbols, as he has a very short term memory, but he can 'see'. However, he is still considered blind for all intents and purposes. So, if a person is considered blind, it does not mean that he or she cannot see anything at all.

Some blind users may be able to make out some degrees of light and dark, shapes, and other forms, others may not be able to see anything at all. People who are new to assistive technology (AT) and accessibility are usually quite shocked and surprised when they discover that there are many successful blind people working in the IT industry. I know some truly great nerds who are completely...