We blink. We either do it consciously or unconsciously, and we do it around 10,000 times per day – about every four seconds. Our eyes blink for many reasons. It serves to keep our eyes moist with tears (even if we’re not crying). It also protects our eyes from dust, foreign objects and bright lights. Without eyelids, how could you sleep?
Blinking is made possible by a muscle in the face called the obicularis oculi. It’s the only muscle that can close the eyelid and keep it shut. Some people lose the ability to use this important muscle – thus losing the ability to completely close their eyes. This can be very uncomfortable; the eye is unprotected and tears drain onto the face.
On Twitter, I was asked an interesting question about blinking:
This is actually a common myth, @XylemT. Men and women usually blink at identical rates. However, one study showed that women on birth control pills blinked 32% more.
Researchers from Oregon studied this by observing the eyes of 59 males and 86 females. Fourty-four of the females were taking birth control pills. After observing their eyes for 5 minutes, they found that men and women (who weren’t on birth control), blinked at comparable rates of 14.5 times a minute and 14.9 times per minute, respectively.
However, the women who were taking birth control pills blinked 19.6 times per minute! We’re not sure why.It’s possible that the pills affect our brain’s control center for involuntary blinking, the caudate nucleus. In fact, animal studies have shown that blink rates are influenced by the amount of dopamine that travels to that section of the brain. Although we don’t know if or how birth control increases dopamine levels, this shows how the intricacies of the body are still sometimes very much a mystery to us physicians.