EYE-TRACKING LASER-DOPPLER VELOCIMETER STABILIZED IN 2 DIMENSIONS - PRINCIPLE, DESIGN, AND CONSTRUCTION

We developed an eye-tracking laser Doppler velocimeter to minimize eye -movement artifacts in the study of ocular hemodynamics in humans. The instrument compensates for both horizontal and vertical eye motions b y using galvanometer mirrors controlled by a dual-Purkinje eye tracker . The performance of the instrument is demonstrated in a preliminary s tudy of retinal arterial blood velocity in a normal subject. The subje ct's fixation point was adjusted manually to oscillate through a 2.3-d eg span at 0.3 Hz. In spite of this motion the pulsatile velocity wave form of the heart cycle could be continuously recorded. Without eye tr acking the velocity waveform was lost after the initiation of movement .