I knew for years blind people can use computers well, in fact, there is Max, the virtual guide dog here in SL. There is a big learning curve to use him, and one has to learn and remember a LONG list of commands, but I obtained a free copy months ago and tried him out, and while it was a challenge to learn for a sighted person even, Max did work quite well.
Doggie: I was referring to times my wife spent in Virtual Ability. She doesn't use Max, which is really obsolete technology anyhow. She uses Radegast, which doesn't rely on scripts that other people can turn off at whim. Too, Radegast works with OpenSim, and Max relies on scripts with limited permissions that can't be ported there.
So at least when the Non-Profits have to bail out of SL, they won't have to leave that segment of the population behind.