What is Mydriasis?

What is Mydriasis? It's a condition where the pupil if the eye remains dilated, for abnormally prolonged duration. The reasons could be attributed to diseases, trauma or even drugs. Everybody would know that pupils dilate with darkness and constricts when it is bright. When this does not happen automatically and the pupil remains dilated, it's either called Mydriasis or referred as “Blown Pupil” colloquially.

The size of the iris is governed by circular and radial muscles. These muscles, are in turn controlled by parasympathetic and sympathetic nervous systems respectively. The former is responsible for the constriction of the pupil and the latter it's dilation. When this does not happen, it is either the malfunctioning of the parasympathetic nerve or hyperactivity of the sympathetic nervous system.

Normally the pupils dilate during strong emotional movements like an intercourse and constricts within few minutes. Abnormal dilation of pupils is often attributed to trauma due to head or eye injury, that damages the nerves or deactivates the sensitivity to light. There are few drugs that impair the iris movement causing temporary or permanent Mydriasis.

The other causes can be attributed to health conditions like Botulism, Traumatic iridoplegia, Adie's syndrome, Aortic arch syndrome, Brain Death, Weber Syndrome, use of cocaine, or plant due to potato or Angel’s trumpet, etc. However, proper medical attention should be sought to deal with this condition.  Only a qualified health professional might be able to analyze the cause of the problem and suggest the right medication that will suit the individual.


  1. What are the signs and symptoms of mydriasis?

  2. I like keeping mine around 7mm at least