1. A method comprising: performing calibration to determine bias correction of a subject; capturing an image that includes a left eye of the subject and a right eye of the subject; identifying, from the image, a plurality of glints from the left eye and a plurality of glints from the right eye as left glint data and right glint data, respectively; determining, from the image, pupil center information of the left eye and pupil center information of the right eye as left pupil data and right pupil data, respectively; determining a left eye gaze location from the left glint data and the left pupil data; determining a right eye gaze location from the right glint data and the right pupil data; and determining a gaze location of the subject based at least in part on the bias correction of the subject and relating the right eye gaze location and the left eye gaze location.