Gaze determines a subjects current line of sight or fixation point. The direction of the eye gaze can express the interests of the subject and is a potential porthole into the current cognitive processes. Existing techniques for eye gaze tracking can be divided into video-based techniques and non-video-based techniques. However, non-video-based techniques are intrusive and interfere with the subject, while video-based techniques have significant shortcomings such as lacking sufficient accuracy and imposing physical constraints on the subject.