Microsoft is working on Eye-tracking feature for windows 10. Microsoft announced that eye tracking feature will initially be available for windows 10 for testing purpose. This new feature might be available in next update of windows 10.
Inspired from an idea in hackathon 2014, a wheelchair for people suffering from ALS was using eye for movement. Microsoft worked on the same tech and with modification introduced same tech for windows 10 where user can navigate by staring at screen.
Microsoft is using Tobii Eye Tracker 4C which can track where a person is looking. With the help of this tracker OS will detect where a person is looking on screen and user can navigate OS just by looking at screen.