Setting: Early 1600s Europe. Magic works in this version of reality but has little to do with the question, aside from healing some of the damage.
I need to blind a character permanently. It doesn't have to be total blindness, though, as the main point is that he can't see well enough to fight properly. (At least at first.) I don't want to permanently scar him, however, so fire, vitriol and the like is out.
I'm planning at the moment to have someone throw a whole bunch of lime powder(Calcium oxide) into his face. The worst of it can be brushed off to prevent lime burns, but enough of it is going to get into his eyes that - by the time something can be done - the cornea will be badly damaged. They're on the run so they're not going to have time to spend dealing with the problem.
How quickly will lime begin to burn the skin? How much damage will it do initially? If they throw a bucket of water on him before brushing off the lime would that be a very bad thing or would it work in the rush of the moment to keep the damage from getting much worse?
How much damage will the lime powder do to the eyes? I know you reflexively close your eyes if something's coming at you, but I'm planning on this being a low enough light condition and fast enough that he doesn't have a chance to protect his face and eyes the way he would ordinarily.