High-speed video analysis of spontaneous and reflex to light blinking

The study of the blink can provide a lot of information regarding ocular surface health, cognitive status, psychological health, human neurological disorders, etc. Blinking can be classified as spontaneous, reflex and voluntary. Between the reflex blinks, direct and consensual reflex can be categorized, being direct that from the eye that is being stimulated and by consensual the other one. A system to evaluate of spontaneous and reflex to light blinking is proposed using a led flash and a high-speed camera that records the blinking of each eye. The LED flash only illuminated one eye and alternated arbitrarily. The light intensity diffused by the eye is almost constant when the eyelid is open but changes when the eyelid closes until reaching a maximum peak, and so does the intensity that was registered by the camera. This variation is directly related to the variation of the eyelid position. Several parameters characterizing the blinks have been defined from the fitting of the blink curve to an exponentially modified Gaussian function. Sequences of 60 seconds of 9 subjects blinking were recorded. Results show that there are no significant differences between reflex and spontaneous blinking, however, significant differences between direct and consensual reflex blinking have been found.