This is one of those things that I wish Apple had developed but it doesn't matter since someone else is now working on it: a case for the iPad that adds a Braille so that blind users can use the tablet as well.
It's still in the concept stage but if I had money, I would provide funds to help with its development.
Known as the Omnifer case, gas pockets would raise braille points depending on what's displayed on the screen of the iPad. An special app would read what pixels are being lit on the screen. At least that the gist I'm getting. I wonder though, if there is an easier way. Simply (perhaps, not so), an app would "read" what's being displayed and the braille would layout the points accordingly.
Regardless of how this is implemented, I do wish that Apple would put some effort into this. I know that the next iOS should have better voice control. Maybe even the ability to read out what is being displayed. Personally, I would love that feature myself.