What Is Iris Hypoplasia?

The iris, the colored part of the eye, is made up of muscles that can widen or narrow the size of the pupil, the hole at the center of the iris. When fully developed and working properly, the iris can open and close to adjust the amount of light getting to the retina (the light sensitive tissue at the back of the eye). Iris hypoplasia is the term for any condition that causes an intact iris to erode or prevents an iris from developing properly. This can occur due to inflammation (swelling) within the eye, inherited conditions preventing the iris from developing fully, and rarely, cases where the entire iris can be a stump or can be missing entirely (called aniridia). Hypoplasia may affect the iris's ability to block light. If this becomes a functional problem, an implantable artificial iris is now available to replace a hypoplastic or otherwise damaged iris.