An eye for computers

Humans suffer from an inherent disadvantage in using a computer: both hands are occupied with the keyboards and a person is unable to operate a mouse at the same time. So Sun Microsystems of California, USA, has filed several lengthy patents on a system in which the user's eye controls the text on a computer screen -- leaving the hands free to work on the keyboard. An infrared light on the monitor shines into the eye. The retina reflects it back to a sensor, which then determines the position of a person's gaze to within a centimetre. As the viewer's eye moves, the text on the screen scrolls to keep pace.