Heterochromia iridum refers to a physical characteristic that consists of having different colored eyes, or two distinct colors apparent in the same iris. Heterochromia iridum can be associated with a genetically-transmitted anomaly, a wound, or a tumor
. It is caused by a change in the iris' melanin levels, which is the pigment that gives the eyes their color. Heterochromia iridum does not necessarily cause problems with vision, and generally has no consequences.