In our daily lives we are constantly looking. We see and analyze what we observe through our eyes and, in fact, a large part of our cerebral cortex is dedicated to processing visual data. However, every few seconds something happens that we often do not even realize: we close our eyes to open them again immediately.

In other words, we blinked. This action can be forced and even controlled by us if we pay attention to it, but it is usually something we do unconsciously and unintentionally. But why do we do this? Why do we blink automatically?

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The blink

We call blinking the process by which we open and close our eyelids at a relatively high speed . This action is semi-voluntary, so it is possible to restrict it or provoke it voluntarily if we wish and pay attention or even temporarily cancel it, but as a rule its realization escapes our conscience.

The average human blinks around fifteen to twenty times per minute , although this does not follow a fixed time pattern but depends on the circumstances.

Causes of blinking

The blinking is produced mainly by the action of the striation, part of the basal ganglia (located deep in the brain), and is especially linked to the structure called the globus pallidus. Involvement of the cerebellum has also been found.

Likewise, the autonomic nervous system is also linked to the blink reflex, inhibiting or facilitating it when the body needs to be activated and to pay attention to the environment or to relax it.

The main reason why we blink is to keep the eye protected and lubricated : as the eyes are the most external perception organ we possess (along with the skin), it is necessary to be able to defend it from harmful chemicals that can be harmful. It also needs lubrication to function constantly and to allow clear and clean vision, which allows for blinking.

In addition, the eyes are constantly functioning and receiving information continuously, so it is necessary to be able to give them rest.

Blink functions

Blinking is an action that has multiple uses and can be altered for different reasons. Some of the main functions of blinking are as follows.

Defense of the eye

Blinking allows us to avoid damage to the eye from harmful external agents, such as chemical substances, physical aggressions (we tend to blink when we see something coming too close to our eye) or even from an excessive level of light that may damage the inside of our eye.

Lubricate and clean the eye

The surface of the eye is a lens on which images from the outside will be reflected. One of the functions of blinking is to keep the cornea clean and to allow it to function properly and be in good health, as blinking spreads the tears across the entire surface of the eye.

Relaxing the eye and brain

In addition to the eye, blinking brings relief to specific parts of the brain. It has been proven that the brain decreases the activation of the visual nuclei during the moments when we blink, which helps us to organize visual information .

Aspects that alter the blinking rhythm

There are multiple circumstances that can alter the blink frequency in humans. They usually have to do with mood or arousal level. Some of the things that alter the blink rate or rhythm are the following

1. Attention, surprise and interest

When something surprises us or catches our attention, we tend to greatly decrease the frequency with which we blink and even stop blinking for a few moments. This allows us not to lose information about the new situation or about what captures our interest.

2. Boredom and disinterest

Most people tend to blink less and slower when they are tired and/or bored.

3. Anxiety and nervousness

When we are nervous, stressed or anxious, most people tend to blink continuously and much more often than usual .

4. Consumption of psychoactive substances

The consumption of different substances with psychoactive effects can also alter the blinking, reducing it or increasing it.

5. Medical illness or mental or neurological disorders

It has been shown that different medical diseases or even mental disorders lead to either the alteration or elimination of blinking. In fact, the absence of blinking can be understood as a symptom of a disorder .

People who suffer from tic disorders, strokes or dementia or other disorders with a progressive degeneration of mental functions often have an altered or even absent blink.

Alterations have also been seen in subjects with mood disorders (people with depression tend to blink less and more slowly while people in manic phases tend to blink more). ) Similarly, people with schizophrenia and other psychotic disorders may have these types of disturbances.