An eye tracking system and method is provided giving persons with severe disabilities the ability to access a computer through eye movement. A system comprising a head tracking system, an eye tracking system, a display device, and a processor which calculates the gaze point of the user is provided. The eye tracking method comprises determining the location and orientation of the head, determining the location and orientation of the eye, calculating the location of the center of rotation of the eye, and calculating the gaze point of the eye. A method for inputting to an electronic device a character selected by a user through alternate means is provided, the method comprising placing a cursor near the character to be selected by said user, shifting the characters on a set of keys which are closest to the cursor, tracking the movement of the character to be selected with the cursor, and identifying the character to be selected by comparing the direction of movement of the cursor with the direction of movement of the characters of the set of keys which are closest to the cursor.