Aspects are generally directed to a high speed pupil detection system and method. In one example, the method includes receiving optical radiation reflected from an eye at one or more pixels of an optical sensor, reading-out a value of each of the pixels in a plurality of lines to progressively generate an image frame of a video image stream, the value of each of the pixels being based on a flux of the received optical radiation, identifying a first chord within a first line of the plurality of lines, identifying a second chord within a second line of the plurality of lines, the first chord and second chord being separated by a subset of the plurality of lines, and determining a location of a center of a pupil of the eye based on a two chord crossing of the pupil with the first chord and the second chord.
