The iris is the colored part of the eye located between the cornea and lens. The iris' round, central opening (the pupil) shrinks and widens to control light coming into the eye. This allows you to see well under different lighting conditions.
Inflammation of the iris is called iritis.
Evans M. Uveitis and other intraocular inflammations. In: Yanoff M, Duker JS, eds. Ophthalmology. 3rd ed. St. Louis, Mo: Mosby Elsevier; 2008:chap 7.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.