Mydriasis Dilated Pupils, Pupil Dilation Causes

A pupil is that opening or hole in the center of your eye’s iris. The function of your pupil is to adjust how much light enters your retina to protect it from intense light and improve vision.┬áNormally, the pupil dilates (opens) in limited light and constricts (closes) in bright light. Generally, the size of both pupils are the same and when they’re not it’s referred to as anisocoria.

Mydriasis is an eye condition marked by prolonged, abnormal dilated pupils, even in bright environmental conditions. Typically, it’s caused by some sort of health condition, trauma or drug. A couple of health and trauma related conditions that may cause pupil dilation are:

Side effects of certain drugs can potentially cause mydriasis, for instance hallucinogenics, cocaine, amphetamines, antidepressants, anticholinergics and antihistamines. Also, during the course of withdrawal from opiates, like morphine or heroin, your pupils may dilate. Mydriatic drugs are used by health care professionals to cause pupil dilation in order to examine the inside your eye or test for Horner’s syndrome.

Finally, the release of oxytocin, a hormone, can cause dilated pupils as well. And an abnormal constriction of your pupil is called miosis.