Device for detecting blinking of an eye under examination

摘要

An opthalmological instrument including a blinking detecting device for positively detecting when an eye is blinking to thereby eliminate errors in optical measurements due to variations in the signal light produced by the blinking. An optical system receives light beams reflected from a portion of an eye under examination to form an image of the front portion of the eye in an image plane. An image pickup element is disposed at the image plane and produces an output video signal in response thereto. A detecting circuit which receives the video signal determines whether or not the image pickup element exceeds a predetermined threshold value. If the threshold value is not exceeded, an indication is produced that blinking has occurred.