Anatomy The iris is the part of the eye that makes up your eye color. A circular muscle with a hole in the middle, the iris ...

Function Controls how much light enters the pupil. Structure Transparent, bi-convex, flexible disc behind the iris. It is attached to the ciliary muscles by the suspensory ligaments. Function ...

The amount of light entering the eye is controlled by a reflex action. The size of the pupil changes in response to bright or dim light. This is controlled by the muscles of the iris.