Where do pianists look while they're playing?
Function, a video series from Fractal NYC, outfitted two piano players with special glasses that track the movement of their eyes. Professor Daniel Beliavsky is a professional pianist and Charlotte Bennett is his student. Since Beliavsky is more experienced, he's more comfortable with the keyboard and looked at the sheet music more than his hands, whereas Bennett spent more time looking down at the keys. Impressively, Beliavsky is able to look ahead to where his hands will be in a few seconds.
Insight pianists gain from eye tracking can be an excellent tool to help them perfect their playing. That is, if they can watch without getting dizzy.