In his lore he set himself on fire, or that is what they say at least... but what if it was a champion?
who made 
blind?
i think it could be one of the following:
they are just that ugly
AAAHHH POISON
well, that is what they do
Post what you think :)
He light himself on fire leading to him being blind.
He talked back to this guy... Twice..
http://upload.wikimedia.org/wikipedia/it/thumb/8/8a/Kill_Bill_027.JPG/620px-Kill_Bill_027.JPG
Uhm... he set himself on fire? The lore explain why he is blind lol
Noob. he set himself on fire in protest of the Noxian occupation of Ionia.
He took Lux's laser to the face.
He did. It's in his lore
Except he was never blind, it's only Riot who has been claiming that.
when ionia was being invaded by noxus and ionia were fighting in their borders lee sin lit himself on fire for 7-10 days straight until a league match was held between ionia and noxus after the match was over he was put out but lost his vision. lee sin also used to be a summoner until he summoned a kid frim the kumungu jungles... well half of the kid, the resulting magic backlash destroyed the kids village.
He got bored and set himself on fire
he isnt blind otherwise he couldnt use any of his abilities especialy his Q
So no one wants to have fun, everyone likes the "truth" or something? was it 
then?
He did it because he killed his dad and married his mom.
There.
You get a Greek tragedy.
You asked for it.
