Why do pupils dilate

By Max. D Gray. Updated: January 16, 2017
Why do pupils dilate

The small black spot in the center of our eyes is called a pupil. Its main function is to regulate the amount of light that enters the eye. Depending on the amount of light in our environment, the pupil either dilates or constricts. Interestingly, for reasons that are not as obvious, your pupil dilates during an emotional response or mental strain. If you want to know more about this interesting eye reaction, on we explain why pupils dilate.

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Whenever we are exposed to a change in lighting, our pupil either dilates or contracts to make up for the change in light. If we are entering a darker room, our pupil will dilate, so that more light enters the eye and we could see. Similarly, if we enter a bright room, our pupils will contract, to let in less light.


When we are in very dark places, and it is difficult to see clearly, the pupils dilate to let in as much light as possible.


With certain medicinal products, the pupils may dilate. In fact, the ophthalmologist often carries out this procedure when trying to discover the origin of eye problems.


Mood alters the size of the pupils: nerves, excitement, and emotion can cause the pupils to dilate. Pupil dilation is one of the consequences of a fight or flight response. Whenever you encounter a stressful or dangerous situation, a series of changes take place in your body: your heart rate increases, you begin to sweat, your muscles get tense, and your pupils dilate.

Studies have shown that when you see a photo of a disturbing image or of something that exites you, your pupils will dilate. Also, when you look at someone that you love or are attracted to, you will have the same response.


Recent studies have shown that your pupils react to the amount of mental effort exerted. For example, if you are asked to calculate 8 x 14, your pupils will dilate slightly. If asked to calculate 13 x 14, your pupils will dilate even more. Thus, the dilation of your pupils seems to be directly related to the amount of mental effort.


Consuming drugs or alcohol can also cause dilated pupils, because of the excitement that they cause.

This article is merely informative, oneHOWTO does not have the authority to prescribe any medical treatments or create a diagnosis. We invite you to visit your doctor if you have any type of condition or pain.

If you want to read similar articles to Why do pupils dilate, we recommend you visit our Family health category.

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Why do pupils dilate
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