Why Do We Blink Our Eyes

Why Do We Blink Our Eyes?

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We all blink a lot! But what does blinking do for us? Why do we blink? 

If you have ever wondered why we blink our eyes, you’ll find this post helpful! We’ll also cover some other interesting facts about blinking, like; 

  • What happens if we don’t blink? 
  • How many times does the human eye blink in a day? What is the record for the longest time without blinking? 
  • How long does it take to open and close our eyes? 
  • Why do babies blink less?

So if some of these questions about blinking have ever crossed our minds, now is the time to settle this once and for all 🙂

Join us, and let’s uncover the mysteries of blinking our eyes.

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What Is Eye Blinking?

Blinking refers to the rapid action of closing and opening the eyelid.

On average, we blink about 15-20 times per minute, between 20,000 and 30,000 times a day, which translates to keeping our eyes closed for 10% of our waking hours.

Blinking can last between 40 and 200 milliseconds. Although this speed can be affected for different reasons, such as fatigue or certain medications.

When blinking, the eyelids completely cover the pupils, and the retina has no image in focus.

And even though our visual input is interrupted drastically for a moment, we usually do not perceive our blinking even though, in reality, the world momentarily disappeared from our visual input.

A Fun Fact:

During a military parade in Beijing, a Chinese Navy missile technician could go for 57 minutes and 24 seconds without blinking.

During the soldiers’ parade of the People’s Liberation Army, it is customary that soldiers have to last 40 seconds without blinking. Our protagonist could not participate in the parade because of an eye infection.

So he purposefully trained his eyes to be able to attend the next parade. He succeeded and was named ‘Staring King’ after achieving the World Record for ‘the longest time without blinking.’

What are the main functions of blinking?

The two main functions of blinking have always been considered to be:

  • Moisturizing our eyes, lubricating the eyeballs
  • Protecting them from dust and other foreign bodies.

Lubrication is done through our tears, which are composed of water, oil, and other components such as lysosomes, which function as natural antibiotics.

There are different types of glands in the eyelid. When blinking, a mechanism allows these glands to secrete the different components of our tears.

At the same time, a horizontal movement is made in the eyelid that causes the eye debris to move to the tip, towards the tear duct.

In turn, the protection provided by blinking is reinforced by the presence of our eyelashes.

By momentarily closing our eyes when we blink, we prevent potentially harmful stimuli from affecting us, such as too-bright light, a wind current, dusty air, and so on.

However, scientists have indicated that we blink even more frequently than strictly necessary to cover two additional functions. Discover with us why we blink so much!

Why do we blink so often?

In 2012, a group of Japanese scientists investigated that briefly closing our eyes while blinking may help us focus our attention and clarify our thoughts, according to an article published in the Proceedings of the National Academy of Sciences and based on previous studies.

According to these researchers, although blinking may seem involuntary and spontaneous, they indicate that people tend to blink at predictable times.

For example, we might blink:

  • At the end of each sentence, when we are reading
  • When we are in a conversation, we might blink when the speaker pauses,
  • When we watch a video with others, we tend to blink simultaneously when the action is delayed briefly. For example, without realizing it, we might take the opportunity to blink when the protagonist leaves the scene.

These are the moments when the brain suppresses attention since it knows these aren’t the most relevant moments of the situation.

The research involved scanning the brain activity of 10 people while they watched episodes of comedian ‘Mr. Bean. The same program was used in previous studies to measure the degree of activity in the cerebral cortex of each person as they blinked while watching the videos.

According to the results of this research, blinking could be used to briefly disconnect us from visual stimuli, allowing us a greater attention span when we reopen our eyes after a brief mental rest.

They were able to prove that blinking activated a network of connections that is normally activated when we are at rest. This means that the simple act of blinking is not just not seeing something for a brief moment.

When blinking, the activity of the attention network is inhibited. When opening the eyes again, the attention network is activated again.

In addition, the brain is able to ignore the darkness produced by a blink. It allows us to continue to have a continuous view of our surroundings. In the same way, it is able to ignore our nose.

When we blink, the brain shuts down momentarily in certain areas responsible for detecting environmental changes, so we do not notice the ‘blackout’ and experience the environment and the world as a continuum.

Although more research is needed, it turns out that blinking not only hydrates our eyes but also alters our mental state when we blink.

Why Do Babies Blink Less Often?

The average adult blinks about 15 times per minute. However, newborns and infants blink much less frequently. As little as once per minute.

Studies have shown the relationship between blinking and dopamine. They indicate that blinking is regulated by the brain’s dopamine, one of the neurotransmitters that enable brain cells to communicate.

Taking drugs to increase dopamine levels also increases the frequency of blinking. Some pathologies might also be the cause for our blinking to increase or decrease in frequency.

For example, schizophrenia causes more frequent blinking, and Parkinson’s disease causes less frequent blinking.

Dopamine also relates to other functions, such as movement control, hormone levels, learning, or motivation.

This relationship with the dopamine system could explain the frequency of blinking in infants.

However, several other causes could also be thought to be related to a lower blinking frequency in infants:

The first hypothesis indicates that babies, having smaller eyes and sleeping more than adults, need less lubrication in their eyes. However, a study by Leigh F. Bacher in 2011 did not find a relationship between eye surface area and spontaneous blinking, although he was able to relate blinking to gaze changes.

The second hypothesis suggests that babies, finding themselves for the first time in a completely new world to them, are so interested and curious, as well as focused on assimilating all the visual information they are receiving, that babies cannot ‘bother’ to blink as that would be a distraction for them.

This theory could make sense if we think about when an adult is focused on something. The frequency of adults’ blinking is lower when we are focused.

And the third hypothesis, as mentioned earlier, would relate the frequency of blinking in babies to the dopamine levels in their brains.

In babies’ brains, the dopamine system is still developing, and it is suspected that the low frequency of blinking in infants may be a natural part of brain development.

Bacher and his research team suggest that if it is possible that blinking could be used as a measure of dopamine activity, it could help predict individual differences in personality, cognitive abilities, and risk for dopamine-related conditions.

However, there is still no unanimous theory about why infants’ blinking frequency is lower than that of adults.

Blinking, Much More Than a Lubricant for Our Eyes...

As early as 1927, Scottish scientists Erik Ponder and W. P. Kennedy conducted a study to investigate the nature of the frequency of spontaneous blinking in adults.

The researchers found that the frequency of blinking was invariant in different environments. In dark or brightly lit rooms, blind people blinked with the same frequency as sighted people. Nor did anesthetizing the surface of the eye change the frequency of blinking.

However, Ponder and Kennedy could see how ‘blink frequency’ increased with mental stress. People blinked more frequently when they were excited or angry.

This led the scientists to propose that, in addition to providing hydration to our eyes, blinking could relieve tension in the same way as the fingers’ nervous movement.

In another study published in 2017 in the journal Current Biology, researcher Gerrit Maus suggests that blinking allows us to focus our gaze.

According to Maus, eye muscles are slow and imprecise, so the brain could command the eye muscles to make precise corrections after measuring the difference between what we see before and after a blink.

Therefore, although there was traditionally a widespread idea that the sole purpose of blinking was to keep the eye hydrated and protect it from the entry of foreign bodies or bright light, it has been demonstrated that blinking has a much deeper function related to our attention and focus.