Flash photos typically produce a red reflection in people’s eyes, but sometimes that reflection can appear white or gray, ...

Larsen, MDThe pupil is the opening located in the center of the iris of the eye. It controls the amount of light that enters ...

"Miosis" is a medical term that describes the constriction of the pupils. Learn its causes, symptoms, and how to treat it.

It's caused by inflammation in the uvea, a layer of tissue just inside the outer white part of your eye. The uvea is made up of a layer of blood vessels, a muscular ring that surrounds your pupil ...

Dilated pupils are also caused by drug use, sexual attraction, brain injury, eye injury, certain medications, or benign episodic unilateral mydriasis (BEUM). The size of your pupils can say a lot ...

Nocturnal animals tend to have proportionally bigger eyes than humans do. They also tend to have pupils that open more widely in low light. So, at the outset, nocturnal eyes gather more light than ...

Pupillometry measures the size and reactivity of the pupil, the dark circle at the eye’s centre through which light enters. Typically, the pupil contracts and dilates depending on the amount of ...