Abstract
Purpose: :
To assess the rate of normal blinking in men and women, through the use of a videonystagmography. To relate the results to age parameters and tear film break up time ( BUT).
Methods: :
The sample consisted of 89 volunteers. The study evaluated age, gender, and characteristics alongside blinking activity, which were: range, average length, and average frequency per minute, of each blink. The BUT ≥ 10 seconds ( s) was considered normal. Exclusion criteria: ocular pathology, severe systemic disease, rheumatic disease, ocular complaints, use of contact lenses or topical ocular medications, history of ophthalmic surgery, visual acuity worse than 0.3 logMAR. The blink was analyzed using the videonystagmography ( VNG Siberg DECLIE ®Laboratory, Antibes, France) coupled with the software version of SiBerg 2, which was connected to a laptop computer. The analysis of the blink was completely automatic and painless, and lasted 3 minutes for each volunteer. The data was then subjected to statistical analysis using SPSS, version 17.0.
Results: :
60 women and 29 men were analyzed, and differences between men and women were significant statistically. The average frequency of blinks per minute ( min) among the women was 23.81 blinks per min, and among the men was 31.67 blinks per min ( p= 0.002) . The average duration of each blink in women was 0.51 seconds ( s) and in men was 0.26s ( p= 0.009) . The average interval between blinks was 7.96 s in females and 5.49s in males ( p= 0.049) . Participants over 50 years old had a lower average according to duration ( 0.24s versus 0.49s) and a longer interval between blinks ( 10.50 s versus 6.06s) , p= 0.013 and p= 0.021, respectively. The BUT was normal in 33.7% of participants. Individuals with BUT < 10s had significantly lower time intervals between blinks ( 4.49s versus 12.41s) , p < 0.0001.
Conclusions: :
The evaluation through videonystamography efficiently concluded that: The profile of a normal blink in males and females differs significantly. Women have a lower frequency, higher average interval between blinks and a longer duration in the movement. Elderly Individuals ( > 50 years old) have shorter duration and longer intervals between blinks. People with BUT less than 10s have significantly shorter intervals between blinks.
Keywords: eyelid • clinical (human) or epidemiologic studies: systems/equipment/techniques • cornea: tears/tear film/dry eye