hmm, well I was going to say she can't fix things that intense, but remember when she got that special water from that dude (spirit of owasis water or something I dont know I can't spell) If it could bring a guy back to life, couldn't it have healed Toph's blindness. I mean she was ready to use it on Zuko, why not on Toph.

But to counter what I just said, I don't really believe Toph would decide to be healed. It has made her who she is. Toph is a very strong, tough chick and she knows that and in part it is because she's blind and has had to deal with different things. NOt that being blind defines her, but like Zuko said: 'not being born that way, having to struggle to be good has made him who he is. I don't know, just a thought.

Katara already used the spirit oasis water on Aang. The only way(if it worked) she could heal Toph from her blindness would be if she got some more

Wait, I gotta eat lunch. Don't chop anyone's balls off without me, Momo.

its pretty simple really. you can only heal and injury, and toph's blindness isn't the result of an injury, so there's really nothing to heal.

if toph was born blind i think we can assume it was a genetic disease that caused her blindness, so it raises horrible questions about the definition of 'injury' and 'defect', i'm not very good at explaining things but what i'm trying to say is, is toph's blindness really a thing that needs curing?if it's part of her DNA surely 'curing' her would mean changing who she is? and that's not curing at all.