However! If you think outside the box, you might get a fairly accurate gaze tracker and a different GUI design to get this to work. That vision (no pun intended) is more of a long term one. An easy short term use for eye gaze use would be automatically setting GUI window focus based on eye gaze. That already might save you a keyboard-mouse switch. As long as you have no more than four windows on your screen, you can make it work with the current tech already.
And how about getting in the precision area like a finger has on a touchscreen?
You think, this is possible?
Because touch works pretty well, if the UI is good (big) enough ...