DefinitionThe iris is the colored part of the eye. It is located between the cornea and lens. The round, central opening of the iris is called the pupil. Very small muscles in the iris cause the pupil to get smaller and bigger to control how much light comes into the eye. This allows you to see well in lighter and darker settings. The number of color granules in the iris determines the iris color (pigment). The amount of pigment is often related to a person's genes, skin type, and hair color. Inflammation of the iris is called iritis. Rarely, tumors can form in the iris. When tumors do form, most often they are melanoma. ReferencesEvans M. Anatomy of the uvea. In: Yanoff M, Duker JS, eds. Ophthalmology. 6th ed. Philadelphia, PA: Elsevier; 2023:chap 7.1. Taber's Cyclopedic Medical Dictionary. 24th ed. Philadelphia, PA: F.A. Davis Company; 2021. www.tabers.com/tabersonline/view/Tabers-Dictionary/752593/all/iris. Accessed October 20, 2023. | |
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Review Date: 10/13/2023 Reviewed By: Linda J. Vorvick, MD, Clinical Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited. | |
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Iris
