Enter Passwords Using Only Eye Movements
 

EyePassword™ allows gaze-based password/pin entry. It prevents shoulder surfing and does not generate any keyboard and mouse events making it more difficult to use standard event loggers. EyeSaver™ turns on the screen saver when a user looks away from the screen and automatically turns off the screensaver when the user looks back at the screen.

http://hci.stanford.edu/research/GUI...lications.html