Dilated pupils can be caused by various factors, e.g. caused by staying in a dimly lit room or taking certain medications or psychoactive substances. It turns out, however, that emotions experienced by people also affect pupil width. Learn the most common causes of dilated pupils.

Dilated pupils- to explain their causes, it is worth paying attention to the pupils first.

The pupil is a natural opening within the iris of the eye and it determines how much light enters the retina. The pupil's width is caused by the activity of two opposing muscles, which are the pupil sphincter and the pupil dilator.

Both are innervated by fibers belonging to the sympathetic system - the part of the nervous system that functions without human will. When a large amount of light reaches the eye, the pupil becomes narrow, and when a person is in a poorly lit area, the pupil dilates.

These changes in pupil size are completely physiological and are designed to ensure that the correct amount of light enters the eyeball. But it's not just lighting that affects pupil width - a wide variety of completely different factors can lead to a constriction or widening of the pupils.

Dilated pupils: causes

Taking certain medications

Mydriasis can be caused by taking certain medications. Ophthalmologists quite often use this option - pupil dilation is necessary, for example, to assess the fundus. Thus, dilated pupils may be the expected effect of administering some pharmaceuticals to the patient, but it also happens that it is a side effect of taking certain medications. Among the preparations that may lead to dilatation of the pupils, the following can be mentioned:

  • atropine,
  • antihistamines (including promethazine)
  • agents from the group of cholinolytics (e.g. biperiden)
  • tricyclic antidepressants
  • some antipsychotic drugs (pupil dilation may occur after taking chlorpromazine and perazine)
  • pseudoephedrine (which can be found, among others, in agents used to open the nose)
  • drugsanticonvulsants (e.g., topiramate).

Drug use

Taking various drugs can lead to an exceptional degree of pupil dilation - many handbooks for parents mention that their attention should be drawn to the unusual size of their pupils. Significantly dilated pupils can be caused by alcohol intoxication, but also by taking drugs such as marijuana, LSD, cocaine and amphetamines.

Diseases

Dilation of one or both pupils may also be a symptom of some disease of the nervous system. In this case, the phenomenon may be caused, among others, by such problems as:

  • neuroinfections,
  • stroke,
  • aneurysms of the cerebral vessels,
  • brain tumors,
  • head injuries,
  • intracranial bleeding,
  • damage to cranial nerves (especially those involved in pupil width - we are talking here primarily about the third cranial nerve, i.e. the oculomotor nerve).

The pupil dilatation may also occur in the course of diseases strictly affecting the eyeball. The problem may arise in the case of anterior uveitis, as well as as a result of glaucoma or the experience of an eyeball injury. Another disease in which severe pupil dilation may occur is botulism.

Emotions

The width of human pupils is influenced not only by light, drugs and diseases reaching the eye, but also by emotions experienced by a person. It turns out that when people see some pleasant, interesting things or situations, their pupils can immediately dilate.

It is also mentioned that pupil dilation may occur when a person sees attractive people or during sexual intercourse. The dilatation of the pupils is related to the secretion of oxytocin in the body - this hormone may contribute to this phenomenon. The increased release of oxytocin occurs, inter alia, during sexual intercourse, which would explain why people's pupils dilate during sexual contact.

When the pupils widen in contact with a person you like, it does not necessarily mean you can get a better look at them. It turns out that people with dilated pupils generally seem … more attractive to us. This can be treated as a kind of nonsense, in practice, however, it was already considered in the Middle Ages, where women used to deliberately eat the fruit of the wolf's berry in order to widen their body.pupils.

Dilated pupils: when are they a cause for concern?

Human pupils are not the same all the time - as already mentioned, their size changes mainly depending on the amount of light reaching the eyeball. It is easy to check it - it is enough to direct a beam of light (e.g. from a flashlight in a phone) to the eye of a person and then, under correct conditions, both pupils should narrow.

Temporarily dilated pupils - especially in very poor lighting conditions - should therefore not be a cause for concern. However, anxiety may appear even when, for example, parents see that the child in a dark room has unnaturally dilated pupils (this may indicate that she has taken some drugs).

Fears may also appear when only one pupil dilates and when the pupils do not respond to light - it may indicate that the patient has some disease (even a very serious one, such as a stroke). Dilated pupils may be the result of some medical condition, especially when the patient has other abnormalities (e.g. sensory disturbances, severe headache or paresis).

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  • Photophobia is a symptom of the disease: which of them could it indicate?
  • What does eye pain show?
About the authorBow. Tomasz NęckiA graduate of medicine at the Medical University of Poznań. An admirer of the Polish sea (most willingly strolling along its shores with headphones in his ears), cats and books. In working with patients, he focuses on always listening to them and spending as much time as they need.

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