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Mydriasis : Causes, Symptoms, Treatment, Diagnosis, Prevention

What is Mydriasis?

Mydriasis is recognized as an eye condition when the pupil of the eye of a person finds difficulty in countering light and they become smaller than they normally ought to be. In Mydriasis, the pupils open and close when exposed to light and dimness. Dilation or broadening of the pupil is usual in situations of low light for permitting more light to reach the retina. In case of mydriasis, the muscles play an important role for opening as well as closing the colored portion of the eye, also called the iris. When this process is interrupted, the pupil takes more time to shrink.

What is Mydriasis?

Symptoms of Mydriasis

People who are affected by Mydriasis are very much sensitive to light. As in this condition, the pupil doesn’t narrow to block extra light and the exposure to light turns out to be much painful. Additionally, the patients suffering from Mydriasis suffer from blurred vision as the pupil is needed to shrivel in the light for illuminating the vision. In the majority of situations, affected people do not ever sense any symptom. The most noticeable symptom of Mydriasis is obviously pupil dilation.

Causes of Mydriasis

Mydriasis is habitually produced by stimulant use, like caffeine, amphetamines and different stimulating elements. It is also likely to happen through epileptic confiscations. The trauma of the head and neck too harm the cranial nerves, which hoard the eyes cause this problem. Mydriasis can turn out to be an indication of brain swelling, which is the result of ocular nerves’ pressure. There are few other usual conditions too like aneurysm, fungal and viral infections, botulism and conditions that are capable of damaging nerves and brain tumors cause Mydriasis.

Diagnosis of Mydriasis

The medical diagnosis of Mydriasis is done on the pharmacological examination of the enlarged pupil and different applications of pilocarpine eye drops turn out to be helpful in diagnosing the problem. However, the following procedures are always helpful:

  • Instill one drop of pilocarpine in both the eyes. Notice the result for 45 minutes. When the parasympathetic denervation is present, the eye affected with dilated pupil gets constricted.
  • If there is no constriction after the administration of dilute pilocarpine, then 1 drop of 1% pilocarpine is required to be instilled in both the eyes.
  • Even if after the administration of concentrated topical 1% pilocarpine drop, there doesn’t happen any constriction and further there isn’t any response to light, then the analysis of pharmacologic pupil can possibly be made.

Treatment of Mydriasis

Mydriasis is generally treated by discovering and curing the condition responsible for it. When Mydriasis is caused due to brain injury or head trauma then the swelling of the brain is treated first. When Mydriasis is the result of exposure to drugs or chemicals then the physicians stop the use of these compounds. When Mydriasis is produced by medicines for dilating the pupil for testing then the physician advises the patient to keep himself away from direct sunlight by wearing sunglass so that the interior portions of his eyes do not get affected. However, there are certain medicines, which can cure Mydriasis when none of the aforementioned conditions are responsible and they are: Scopolamine, phenylephrine drops, Atropine, Steroids, pilocarpine and sometimes a combination of scopolamine and Atropine.

Prevention of Mydriasis

Following are some preventive methods for Mydriasis:

  • Not rubbing the eyes forcefully when some irritating substance gets into their eyes.
  • Relaxing the stomach muscles as fear, excitement and strain in the stomach muscles can result in dilated pupils.
  • Not paying attention to distant items.
  • Moving to a well-lit place.
  • Wearing sunglasses when outside.


Mydriasis is generally a temporary condition and people who suffer from it do not come across any problem if they manage to keep their eyes well-protected. Additionally, the problem of Mydriasis does vanish once the element that is causing the problem is kept far away. Even when an eye doctor is examining the problem his process remains totally safe and the patient only experiences a slight discomfort without any pain. If someone has a problem of dilated pupils, then he must not forget to protect his eyes and consult an eye doctor immediately.


  1. American Academy of Ophthalmology. “Dilated Pupils: Causes and When to See a Doctor.” https://www.aao.org/eye-health/symptoms/dilated-pupils
  2. Healthline. “Dilated Pupils (Mydriasis): Causes, Diagnosis, and More.” https://www.healthline.com/health/mydriasis
  3. National Institutes of Health. “Pupil Disorders.” https://www.ncbi.nlm.nih.gov/books/NBK541122/
Pramod Kerkar, M.D., FFARCSI, DA
Pramod Kerkar, M.D., FFARCSI, DA
Written, Edited or Reviewed By: Pramod Kerkar, M.D., FFARCSI, DA Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:August 18, 2023

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