An electronic device that allows a person to control a computer by looking at words or commands on a video screen. A very low intensity light shines into one of the user’s eyes. A television camera picks up reflections from the cornea and retina. As the direction of the person’s gaze moves, the relative position of the two reflections changes, and the computer uses this information to determine the area at which the person is looking. The computer then executes the selected command.