Skip to Content
Home > Wellness > Health Library > Cornea, Lens, and Iris
The iris is the colored part of the eye. A circular muscle in the
iris controls the amount of light entering the eye through the pupil, the black
area in the center of the iris.
The cornea is the outer clear, round structure that covers the iris and the pupil. The cornea directs light rays
into the eye and helps focus them on the light-sensitive retina at the back of
the eye, providing sharp, clear vision.
The lens is located behind the iris and is normally clear. Light passes through the pupil to the lens. Small muscles attached to the lens can make the lens change shape, allowing the eyes to focus on near or far objects.
ByHealthwise StaffPrimary Medical ReviewerAdam Husney, MD - Family MedicineSpecialist Medical ReviewerChristopher J. Rudnisky, MD, MPH, FRCSC - Ophthalmology
Current as ofAugust 21, 2015
Current as of:
August 21, 2015
Adam Husney, MD - Family Medicine & Christopher J. Rudnisky, MD, MPH, FRCSC - Ophthalmology
To learn more about Healthwise, visit Healthwise.org.
© 1995-2015 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
Our interactive Decision Points guide you through making key health decisions by combining medical information with your personal information.
You'll find Decision Points to help you answer questions about:
Get started learning more about your health!
Our Interactive Tools can help you make smart decisions for a healthier life. You'll find personal calculators and tools for health and fitness, lifestyle checkups, and pregnancy.
Feeling under the weather?
Use our interactive symptom checker to evaluate your symptoms and determine appropriate action or treatment.