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Santa Clara, CA
A 56-year-old female asked:

One of my pupils is dilated to almost twice the size of the other. what can cause this?

2 doctor answers3 doctors weighed in
Dr. David Dunn
Phlebology 42 years experience
Anisocoria: Anisocoria refers to unequal pupils. Physiologic anisocoria is very common and normal in up to 20% of people. The variation should be no more than 1mm and both eyes should react normally to light. It can be dangerous if it is a form of horner's syndrome (e.g. Carotid dissection) or from damage to the third nerve (e.g. Aneurysmal expansion) so you should get it checked out!
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Dr. Robert Uyeda
General Surgery 46 years experience
Unless you went to: Eye doctor and he administered eye drops to dilate your pupils, this is a dangerous sign of brain damage. Get to emergency dept of your nearest hospital right away.
Created for people with ongoing healthcare needs but benefits everyone.
Last updated May 7, 2018

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