This is a very difficult question to answer with any certainty. I do not "actually see" things in my "mind's eye" or "actually hear" musical sounds in my "mind's ear". Some people can, of course, but I am not one of them. Just exactly what I do form in my mind is rather problematical to describe. I can play all right in the dark, but this might be a haptic faculty and not a visual one.
Also, I find it very hard to say precisely where I look when I play. I do look vaguely at the keyboard, just habit I suppose, but is the sequence of places I look at the same over the course of the same piece each time ? I don't know but I suspect it varies. During improvisation ? I think I tend to look at the positions of greatest aural interest rather than those of technical difficulty, but I cannot be absolutely sure.
Very good question.