Intensified charge-coupled-device-based eyetracker and image stabilizer

An electro-optical eyetracker measures eye movement to stabilize a laser beam on the fundus in one dimension. Motion is detected by laser illumination of a fundus feature. The illuminated area is imaged on an intensified linear CCD. Electronics determine the intensity centroid of this image. Centroid motion on the CCD corresponds to eye movement in one dimension. Galvanometer-controlled mirrors reposition (at a 1-kHz rate) the illuminating beam on the fundus. The same mirrors reposition the centroid at the CCD center. Additional beams are also stabilized on the fundus. For typical fixational eye movement amplitudes and frequencies the beams follow the fundus feature within +/-10 microm.