OverviewThe iris is the colored portion of the eye, amembrane located between the cornea and lens that regulates the entrance of light into the eye by contracting and dilating.
Update Date 8/11/2015
Updated by: Franklin W. Lusby, MD, Ophthalmologist, Lusby Vision Institute, La Jolla, CA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.