In Avengers: Endgame after the time skip Professor Hulk explains to those that meet him in the cafe that he merged Banner and Hulk together to get the best of both, Banner's intellect and Hulk's strength and powers. One of these powers is super healing as we see in Thor: Ragnarok when Banner jumps onto the Rainbow Bridge and is all but killed in the process until Hulk comes out and they are both fine again.
However, in Avengers: Endgame we see that Professor Hulk is damaged by perfoming
the reverse snap
and is still seen to be damaged by it at the end of the movie.
Ignoring that this might have been because it was the
that damaged him so badly it could also have been down to his regenerative powers not being as strong as they once were. As such Banner's bad eyesight could have transferred into Professor Hulk and with his regenerative powers at a lower level than they once were he could no longer repair this. Therefore, he now needs to wear glasses.