An individual or a device that is able to tell or to transmit information to others: "The communicator which the disabled person used to talk with his family was the invention of his neighbor who was himself a great verbal communicator."

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. Reflections from the cornea and retina are picked up by a television camera.

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 th area at which the person is looking. The computer then executes the command.