What is the iris of the eye?

 

Green, blue, hazel, brown, grey. What color are your eyes? When you notice the eye color of a friend or family member, you are looking at the part of the eye known as the iris. The muscles of your iris have the important job of expanding and contracting, controlling how much light reaches the back of your eye. 

Have you ever noticed the small black circle in the middle of your eye? This circle is actually a hole in the center of your eye called the pupil, and its size may change depending on the amount of light in the room. Did you know that your iris controls the size of your pupil?! In bright light, the iris closes your pupil, restricting the amount of light that enters the eye. In lower light, the iris opens the pupil back up, allowing more light in!