Professor Arai Kohei of Saga University's Faculty of Science and Engineering has developed this system where the users can input texts by just simply looking an on-screen keyboard. This system is called Mitsumeru Dake in Japanese, which means "Just Look."
So how does this works?
"In Professor Arai's system, a miniature camera attached to the computer notes the positions of three points for each eye: the inner corner of the eye, the inner lining of the eyebrow, and the center of the pupil. On the basis of these six positions, the system determines the direction in which the face is turned, and by following the line of sight it recognizes the exact location on the screen that the user is looking at. According to Professor Arai, even people wearing glasses can use the system."