Quantitative videographic analysis of blinking in normal subjects and patients with dry eye

Objective: To study patterns of eye blinking in normal subjects and patients with dry eye. Methods: We developed an automated, noninvasive blink monitor that permits quantitative analysis of 6 parameters of blinking. We used this method under normal conditions and then examined the effects on the patterns of blinking in patients with dry eye; several steps in this method were designed to exacerbate or ameliorate ocular surface desiccation. Results: The mean (±SD), maximum, and coefficient of variation of the interblinking time in normal subjects and patients with dry eye were 4.0±2.0 and 1.5±0.9 seconds, 8.9±4.0 and 4.2±2.4 seconds, and 55%±21% and 65%±24%, respectively. Those values for the blinking time were 0.20±0.04 and 0.27±0.16 seconds, 0.35±0.12 and 0.99±1.30 seconds, and 23%±9% and 46%±34%, respectively. The use of artificial tears or spectacles with moist panels and moist inserts tended to normalize the patterns of blinking in the patients with dry eye, whereas exposure to wind made them more abnormal. Conclusions: Our technique permitted a rigorous analysis of blinking that was previously unavailable. We have shown that local ocular surface conditions alone can significantly affect patterns of blinking. This method should be applicable to studying psychologic and any other factors that may influence blinking.