The iris is a circular, pigmented membrane that provides the eye its color and the opening in the center is the pupil of the eye.
The iris is made up of muscular fibers that control the amount of light entering the pupil so that you can see clearly. The iris accomplishes this task by making the pupil smaller in bright light and larger in dim light.
For most people, breaking, losing, or misplacing their glasses is an annoying inconvenience. But for Christiaan Rollich, who was severely nearsighted, not wearing glasses or contacts meant not seeing at all.
"My vision was so bad the army wouldn't accept me," says Rollich, who grew up in the Netherlands and moved to the U.S. 15 years ago. "If I took out my contacts, I wouldn't be able identify anybody in the room, no matter how close they were."
Fortunately for Rollich, implanted contact lenses...