You look in the mirror and notice that the dark circles in the middle of your eyes are bigger than usual. What's going on? Those dark circles are your pupils, the openings that let light enter your ...

The pupil is the opening located in the center of the iris of the eye. It controls the amount of light that enters the eye so that you can see clearly. The pupil size is controlled by muscles of the ...

A person’s pupils may be of different sizes (anisocoria) for several reasons, including physical trauma, response to light, and infection. The condition may also be present from birth. Pupils, or the ...

Many factors can influence pupil size. Typically, the pupils open up in low light situations to let in more light. However, some research suggests that attraction and mood might also cause pupil ...

Dilated pupils mean that your pupils appear larger in size. The most common reason for dilated pupils is low light in a dark room since lower light causes your pupils to grow. Dilated pupils are also ...