Real Time Binocular Detection of Horizontal Vertical and Torsional Eye Movements by an Infra Red Video-eye Tracker

So far it has only been possible to detect horizontal and vertical eye movements during real time; torsional eye movements have to be calculated from video-tape that have been processed several times, and each investigation takes considerable time. We developed a real time binocular infra red video eye tracker for routine clinical examination which allows real time graphical visualization of horizontal, vertical and torsional eye movements with a bandwidth of 12 Hz (25 Hz refresh frequency). Eye movements in three dimensions can now be obtained as easy as has been done before with electronystagmography for the horizontal component. In contrast to previous systems described, we analyze only those parts of the video-frame that are essential for detection of all three eye movements. This results in a huge data-reduction accompanied by a speed-up of analysis. The black pupil centre is detected by an iterative process of analyzing several horizontal and vertical lines of the even video field. The algorithm sea...