Abstract: The human eye, with the assistance of an eye tracking apparatus, may serve as an input controller to a computer system. Much like point-select operations with a mouse, the eye can "look-select", and thereby activate items such as buttons, icons, links, or text. Applications for accessible computing are particularly enticing, since the manual ability of disabled users is often lacking or limited. Whether for the able-bodied or the disabled, computer control systems using the eye as an input "device" present numerous research challenges. These involve accommodating the innate characteristics of the eye, such as movement by saccades, jitter and drift in eye position, the absence of a simple and intuitive selection method, and the inability to determine a precise point of fixation through eye position alone.