[Measurement of age-related changes in human blinks using a high-speed blink analysis system].

PURPOSE: To measure the spontaneous and voluntary blinks of both younger and older people using a new device that simplifies the detailed recording of eye blinking. METHODS: Fifty healthy volunteers (10 women and 15 men under 40 years of age, range: 22-38 years, and 20 women and 5 men above 60 years of age, range: 63-85 years) were examined after obtaining informed consent from each subject. Eyelid movements of all subjects were recorded using a high-speed blink analysis system. The spontaneous eye-blinks of the subjects were recorded during sessions consisting of a 40 seconds' period following which the subjects were instructed to blink as rapidly as possible for 5 seconds in which the blinks were again recorded. The upper lid position and movement data were plotted every millisecond by processing the recorded images. RESULTS: The frequency of the spontaneous blinks did not differ between the younger and older subjects. The women tended to blink more frequently in both age groups. The average amplitude and duration time of the spontaneous blinks in the younger subjects were greater than those in the older subjects. Voluntary blinks in the younger subjects were more frequent than in the older subjects. Women tended to make deeper and faster voluntary blinks. CONCLUSION: Whereas the frequency of the voluntary blinks differed between the younger and older subjects, that of the spontaneous blinks did not differ. The findings of this study also revealed the gender-related differences in spontaneous and voluntary blinks.