I had never thought of this before. I know that some states do not allow people with intellectual disability to vote. Interestingly, it was not until 1964 that deaf women were allowed to vote it appears in elections within their own organization for the National Association of the Deaf. https://en.wikipedia.org/wiki/Deaf_history. I can find no indication that deaf adult males were ever prevented in voting in US elections but that may be false. As far as blind people, I wonder if literacy exams were used against them even if they could read braille.