The condition "heterochromia iridium" has to do with the amount of color a person has, usually in the iris (the colored part) of the eyes, but can also affect the coloration of the hair and the skin. It is caused by the production of melanin, the pigment that causes coloration in all these areas. "Hyperiridium" means the irises have an abundance of melanin, whereas "hypoiridium" means a lower level of melanin is present. Heterochromia iridium may be caused as a result of inherited chromosomes from the affected individual's parent's genetic makeup, or it may also be caused by an injury to the eyes. It can result in two irises of contrasting colors; when I was a toddler, I had an injury where I fell on a stick, which entered my left orbital of my left eye. To this day, my right eye's iris is green, while my left iris is hazel (green with streaks of brown).