My Samsung Android tablet supposedly had some sort of eye tracking, and it creeped me out. It was not intended as an input device, but some sort of supplement to the screen saver. As long as it detected that your eyes were looking at the screen, the screen saver would not activate. But if it could not, then it might fire up the screen saver at a very inopportune moment.
I could never really prove that it worked; if it worked at all then it worked badly. It was supposed to have an icon in the notification area when it was working. It did not take long for me to just disable it entirely, mostly because I really did not need this device constantly staring back at me for no good reason.
I have no idea whether any of the camera footage was sent off-device, but I would hardly be surprised if it were.