Here are a few of the most well known blind country blues singers:

Blind Lemon Jefferson - born blind
Sonny Terry - farm injury at age 16
Willie McTell - born blind in one eye- lost his remaining vision by late childhood
Rev. Gary Davis - partially blind at birth- lost what little sight he had before he was an adult
Blind Boy Fuller - began to lose his eyesight in his mid-teens. According to researcher Bruce Bastin, "While he was living in Rockingham he began to have trouble with his eyes. He went to see a doctor in Charlotte who allegedly told him that he had ulcers behind his eyes, the original damage having been caused by some form of snow-blindness." However, there is an alternative story that he was blinded by an ex-girlfriend who threw chemicals in his face.
Blind Willie Johnson - blinded by an accident at age seven.
Blind Blake - No one seems to know much about Blake's blindness. The only photo is an "autographed" picture with "Cordially yours, Blind Blake" in the exact same handwriting as the "Cordially yours, Blind Lemon Jefferson" photo.
Blind Willie Dunn - was not blind, but thought it made him sound authentic. It was Eddie Lang's recording name when he recorded with Lonnie Johnson.

I could find no instance of blindness being caused by drinking home-made alcohol.