The Kilohertz Eye Tracker is
designed for tracking eye movement in refractive laser surgery. The device is an optical positioning sensor, having a sampling rate up to 1 kHz. The Kilohertz Eye Tracker projects two IR beams onto subject's pupil and scans the beams x-y at kilohertz rate. Scattered light from the pupil is detected and enhanced due to cat-eye effect. Pupil center is detected along two orthogonal directions independently. The device can also be used to track other object with symmetric geometry