Did you know that we tend to blink 15-20 times each minute? In fact, if we add up the time we blink our eyes in an average day, our eyes are actually closed for about 10 percent of the time we are awake. Why do we blink so frequently and what is the actual purpose of blinking?
Blinking holds a couple of important purposes. The main purpose of blinking is to provide lubrication and maintain the eye’s moist environment. When we blink, our eyelids act to clean and replenish our tear film, which is the outermost layer of the eye on top of the cornea. The tear film is composed of compounds like water, mucus, and oil or other lipid based molecules. In addition to providing the eye with proper lubrication, the tear film forms a smooth surface for light to focus, prevents infection by housing antibacterial enzymes and lysosomes, and aids in the transfer of oxygen from the external environment to the cornea. This last point is extremely important since the cornea itself has no blood vessels and relies completely on the tear film for the nourishment from oxygen.
Another perhaps less evident purpose of blinking is to provide our brains with mental resting points as well as breaks from attention to what we are focusing on. For instance, when reading an article or book we tend to blink at the end or towards the end of sentences. Additionally, when talking with a friend, we tend to blink most frequently when our friends pause between sentences or statements. These ideas tend to support the point that blinking may provide our brains with a short period of time to process what we have paid attention to and prepare ourselves for new information.
Sounds good generally. The only thing I was confused about was when you say "When we blink, our eyelids act to wipe off our tear film". To me this reads as if the eyelids are taking away the tear film. Do you mean replenish here? or something else?