Application of a Circular Polarizing Device to an Electronic Endoscope for the Purpose of Prevention of Catch-Light Phenomenon

Abstract: In recent years the electronic endoscope has been increasingly used by medical practitioners in Japan. However, it has been noted that the problem of too strong light refection, which, not only hampers the procedure but also causes eye exhaustion, at the same time making photographic or computerized image processing difficult, is more frequently experienced and is more serious in magnitude when compared with using a conventional fiberoptic endoscope (catch-light phenomenon). In order to ameliorate this problem the authors experimented with the use of circularly polarized light. The combined use of a circular polarizing device to the efferent light path and a filter which blocks certain types of Circularly polarized light to the afferent path has proved to be very effective in eliminating the incidence of catch-light troubles, thus making the endoscopic procedure smooth and efficient.