Why do we blink?

In my first year of optometry school, as part of the practical portion of our studies, we used to do vision screenings on kids in elementary schools around Boston. So picture me, the tall optometric freshman, kneeling down to examine the eyes of this adorable little 6 year old girl when she steps back and asks out loud "Harbir, why do we blink?". The whole classroom stopped and looked up at me...

I paused for a second, gathered as much information as I could from my 3 months of eye-related education, and began to answer. Well, cute little blonde-haired girl whose name I don't remember, there are 3 main reasons for blinking:

Number 1 is protection. Our eyelids and eyelashes provide a protective barrier against foreign objects such as dust, rocks, bits of metal, fruit flies, etc...

The second reason is lubrication. Every time we blink, our eyelids squeeze out small amounts of oil, water, and mucus to line the surface of the eye. Studies have shown that when we are engaged in activities that require more attention, we tend to blink less. That is why spending a lot of time on the computer can lead to dry eyes. So as soon as you're done reading this blog, get off the computer! Then come back and share it with all your friends :)

And last, but not least, the third reason for blinking is irrigation or removal of tears and waste. Our eyelids act similar to squeegees, the wonderful onomatopoeically named tool that helps smoothly remove water from car windows and such. Each time we blink, the lids pull tight and sweep tears and debris off the surface of the eye and towards the drainage duct which is located at the inner corner of the eye.

And that's why we blink.