What is mydriasis?
Pupils are the black circles in your eyes. They gather light and bring it to the retina to form images. Typically, the pupils dilate, or widen, in response to low light so they can collect more light. Sometimes pupils will dilate for a reason unrelated to the levels of light in the environment. They may stay enlarged even in bright environments. Doctors refer to this condition as mydriasis. The opposite of mydriasis is when pupils constrict and get smaller. This is called miosis.