The iris is a structure behind the transparent cornea of the eye. It has a circular opening called the pupil that changes size in response to the light level. Your pupils are usually the same size as ...

Normally, a person's pupils naturally widen (or dilate) in low-light environments to allow more light into the eye. However, in a new study, researchers reported that a person's pupils also dilate ...

Please provide your email address to receive an email when new articles are posted on . We tend to think of the pupil as a simple structure but, in fact, it is constantly in flux. The pupil is ...

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 ...