I've read that there are blind people who can play Starcraft competently. This seems like it would be impossible to me.
Is it possible to play Starcraft if you are blind? How would this work?
Yes. Most famously, a player played against SlayerS BoxeR in a showmatch in Brood War at the Blizzard World Wide Invitational tourney in January of 2004. Boxer was blindfolded for the first three minutes, after which he played normally.
The player's name was Min Seok and he played Zerg. I'm not sure if there are other players. He utilized the game sounds and the keyboard instead of the mouse to move around. You can find a video here and some community commentary from TeamLiquid here.