I've been told by a friend who works at a school for the blind that no sighted person has ever learned to read braille by touch at the level that is comparable to a literate blind person. Is this true? Many sighted people can read braille fluently but most of these people seem to read braille visually.
This page suggests that people have learned to read braille by touch into their old age but it does not mention if these people were visually impaired and does not provide citations. It suggests that if you are not visually impaired, you should consider reading braille visually.
This forum thread asks a similar question and gives some personal experiences but it's hard to get a specific trustworthy answer to the question. The thread points to this PBS video which I cannot find online but that apparently describes experiments of having sighted individuals wear blindfolds and read braille. Both links describe a vague concept of "brain rewiring" in order to read braille by touch but it's unclear if this requires absence of vision.