Andy,
They use it very well, indeed.
I would recommend that you check out "web accessibility" web sites.
There are software programs (and also embedded functions in operating systems like Windoz) that assist visually impaired (blind is not a good description, because I know many well-sighted individuals who are "blind as bats").
There are also hardware devices (basically enlarged screens) that help visually impaired individuals navigate computer applications.
And I know many visually impaired individuals who know more about computers than I do. I had the priveledge of meeting three professional web developers who are members of the American Federation for the "Blind" and are visually impaired.
You would be wise to pay closer attention to accessibility issues. It is important for all web developers and designers to create accessible web sites.
Look at the growing number of civil suits against companies, like AOL and local organizations by visually impaired individuals.
Also check out
http://www.section508.gov/.
========================================
Buh Bye!
Cheers,
Me