7 reasons why your pupils may be dilated, from low light to sexual attraction – Business Insider India

The size of your pupils can say a lot about your health and your state of mind.

In most cases, pupils change size based on the light and dilate, meaning that appear larger, when you're in a darker room. But your pupils may also change size based on injuries, drug use, or even sexual arousal.

Pupil size is controlled by the brain, which receives signals from each retina and sends a message for your eyes to adjust to the light. Muscles in the colored part of your eye, your iris, then work to constrict or dilate your pupils, letting in more or less light as needed.

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There are many different types of medications that can interfere with the nerves that make your pupils dilate, including:

The nerve fibers that control the size of your pupil are within a larger nerve that originates in your brainstem called the oculomotor nerve. When this nerve is injured, it can cause many different problems in your eyes.

"Severe head trauma can stretch the nerve and damage its fibers, which can result in a dilated pupil," Mackay says. Damage to the oculomotor nerve can also make your eyelid droop or limit your eye movement on the side of the injury Mackay says.

When you feel sexually attracted to someone, your nervous system is stimulated and your body releases several hormones including dopamine, norepinephrine, and serotonin.

When these chemicals are released, your pupils dilate, even if you're just looking at a photo of an attractive person.

If the injury bruises your iris muscles, your pupils will likely be dilated temporarily, but if your iris muscles are torn or otherwise damaged, the change may be permanent.

"There is likely not a single underlying cause," Mackay says, "But it can happen from underaction of the constricting muscle or overaction of the dilating muscle of the affected pupil."

But because there are some causes that are harmful, "a suddenly dilated pupil should be evaluated urgently, preferably by a qualified eye care provider," Mackay says.

In particular, if one or both of your pupils are dilated and you have other symptoms like a drooping eyelid or double vision, you should get medical attention as soon as possible, Mackay advises.

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7 reasons why your pupils may be dilated, from low light to sexual attraction - Business Insider India