Geordi had the option to fix his eyes completely but chose to keep the visor because it was better (like he could view different wavelengths and filter stuff and such). I can't remember if he had that conversion with Q or a starfleet doctor (or both?), but I'm certain it did come up at some point.

Edit: seems everyone who replied is right, plus other instances of advanced alien cultures offering the same thing. He could have just had a recording of his response ready.