Abstract: Devices, methods, and processor-readable media for eye tracking using statistically derived linear functions are described. Two simple linear functions may be identified, one for the horizontal and one for the vertical, with two parameters each, that fully correct for horizontal and vertical estimation bias error in a cross-ratio gaze estimation method. An implicit calibration step may be performed that finds the parameters of said linear functions statistically based on undirected user point of gaze measurements that indicate the extremities of the error between gaze vectors and glint vectors. Various hardware devices are described that may implement the novel eye tracking techniques.