There is an old Russian proverb – “fear has big eyes”. It means that a person who is afraid of something, everything seems even more frightening than it actually is. That is, a frightened person tends to exaggerate the danger. But where did this proverb come from? Most likely, it is based on the fact that when a person is frightened, his eyes really do become “big”, or more precisely – wide open and with enlarged pupils. The reason is that fear triggers serious changes in the human body that affect the entire organism, including vision.
When a person is afraid, his eyes open wide and his pupils dilate. Photo source: kartinkof.club
What happens to the body during fear
Fear arises when we feel a threat to our life or the life of loved ones, health, well-being, etc. It is an unpleasant and very strong emotion, but extremely useful. Scientists even call fear a “gift of evolution,” since this feeling helps us survive in emergency situations.
Physiologically speaking, the fear response begins in a part of the brain known as the «amygdala» (amygdala). This brain structure sends signals throughout the body to prepare it for defense or flight, that is, the amygdala is responsible for the so-called “fight or flight” response.
This happens as follows – the brain sends an impulse to the adrenal glands, which release stress hormones such as adrenaline and cortisol. These hormones, when released into the blood, increase our heart rate and also cause blood to flow to those areas that should be active in emergency situations.
When a person is afraid, the physiological reaction “fight or flight” is activated. Photo source: dzen.ru
Stress hormones also affect the respiratory system – during a stressful situation, we begin to breathe faster so that oxygen-rich blood spreads throughout the body. At the same time, the blood vessels narrow and blood pressure increases, which allows the body to direct more oxygen to the muscles.
To ensure that a person has enough energy to act in an emergency, the liver ensures the release of additional glucose. The muscles become more tense, including those located near the hair follicles, resulting in the appearance of “goosebumps” on the skin, which we have already discussed earlier. This is the reason why animals have fur standing on end, making them appear larger than they actually are.
It should be said that in parallel with the activation of the sympathetic nervous system, which is responsible for all the above processes in the body, when a person experiences fear, the parasympathetic nervous system is suppressed. The latter is aimed at accumulating energy. For example, digestion slows down, since in an emergency it does not benefit the “fight or flight” reaction, but only takes away some of the energy.
Dilated pupils with fear — This is another protective function of the body that arose during evolution. Photo source: pinterest.com
Why do pupils enlarge with fear
The dilation of the pupils, as you might guess, is associated with the above processes in the body, namely the release of adrenaline. At the same time, the eye muscles tense up and the blood flow to them increases. Therefore, when a person is scared, not only can his pupils dilate, but the color of his eyes can also change.
Surely you have a question – what advantage does dilated pupils, or so-called “tunnel vision” give us? This is another protective mechanism developed by evolution. In times of danger, it is important for more light to fall on the retina, especially if the danger arose in poor lighting. This helps a person see better in poor lighting, and therefore better assess the situation, which increases the chances of salvation.
It should be understood that this feature developed in our ancestors long before artificial lighting appeared. Now, if a person gets into an unpleasant situation in good lighting, dilated pupils only interfere – leads to a blurry and fuzzy image, in addition, peripheral (side) vision disappears.
Frequent and prolonged stress, including fear, leads to deterioration of vision. Photo source: mediasat.info
Why regular fear worsens vision
Fear can save our lives, because at this moment the body seems to receive a dope and directs all its forces to the “fight or flight” reaction. However, if this situation is repeated frequently, that is, a person regularly experiences fear, his body begins to break down.
As a result of high blood pressure and high pulse, the cardiovascular system primarily suffers. But stress also negatively affects vision. Due to rapid breathing, as mentioned above, the level of oxygen in the blood increases and the level of carbon dioxide decreases. The result is a condition called hyperventilation. For this reason, such unpleasant sensations as “black spots” and “sand in the eyes” arise.
The consequence of severe fear is the sensation of “sand in the eyes”. Photo source: korrektsiya-zreniya.ru
If the body is often in a state of stress for a long time, dry mucous membranes, eye muscle strain, eye twitching, and increased eye pressure occur. All this ultimately leads to a decrease in visual acuity and the development of certain vision diseases.
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Finally, let us remind you that there are people who do not experience fear at all. The reason for this is a rare disease called Urbach-Wiethe syndrome. You can learn more about this disease by following the link.