Pupil size is controlled by the brain, which receives signals from each retina and sends a message for your eyes to adjust to the light. Muscles in the colored part of your eye, your iris ...

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 uvea is made up of a layer of blood vessels, a muscular ring that surrounds your pupil, and the iris, the colored part of your eye. Together, they help your eyes focus so you can clearly see ...