Explain why do eyes turn red when crying?

In short (click here for detailed version)

When we cry, our eyes turn red because tears cause the blood vessels around the eyes to dilate, increasing blood flow and giving this reddish coloration.

Explain why do eyes turn red when crying?
In detail, for those interested!

First cause: increase in blood flow.

When we cry, our eyes tend to become red. This redness is mainly due to the increase in blood flow around the eyes. Indeed, when tears flow, the blood vessels around the eyes dilate to allow for faster transportation of tears to the tear ducts. This vasodilation leads to an increase in blood flow in this area, which results in a reddish coloration of the delicate skin around the eyes.

Second cause: release of inflammatory molecules.

When we cry, the release of inflammatory molecules plays an important role in the process of eye reddening. Tears contain substances such as cytokines and prostaglandins, which are inflammatory molecules. When these molecules are released in large quantities during an intense emotional reaction, they can cause eye irritation and an increase in blood flow in the eye area. This can lead to redness of the eyes, accentuated by the dilation of blood vessels due to inflammation. The presence of these inflammatory molecules therefore contributes to the appearance of red eyes during crying.

Third cause: eye irritation

When eyes are irritated, they can become red. This irritation can be caused by various factors such as smoke, dust, irritating chemicals, or even contact with allergens. When the eyes come into contact with these substances, it can trigger an inflammatory reaction. Blood vessels on the surface of the eye can then dilate to increase blood flow to the affected area, which can give the eyes a red and irritated appearance.

Eye irritation can also trigger the release of inflammatory chemicals such as histamine. These molecules can cause vasodilation of blood vessels, contributing to the redness of the eyes. Additionally, irritation can cause itching and tearing, which can worsen eye redness by increasing friction and compromising the protective barrier of the ocular surface.

It is important to protect your eyes against potential irritants and to consult a healthcare professional in case of persistent or severe irritation. The use of soothing eye drops or other treatments recommended by an ophthalmologist can help relieve irritation and reduce redness in the eyes.

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Frequently Asked Questions (FAQ)


Why do eyes turn red when we cry?

The eyes turn red when we cry due to several complex physiological mechanisms.


Does everyone have red eyes when crying?

Everyone can have red eyes when crying, but the intensity of the redness can vary depending on different factors.


Are red eyes from crying harmful to eye health?

In general, eye redness caused by tears is temporary and does not lead to serious consequences for eye health.


How can we relieve the redness of the eyes caused by tears?

To relieve redness in the eyes caused by crying, it is recommended to rest, rinse the eyes with clean water, and use artificial tears if necessary.


Can red eyes while crying be a sign of a more serious health problem?

In rare cases, persistent redness of the eyes when crying can be a symptom of an underlying medical condition. It is advisable to consult a doctor in such cases.

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