Heterochromia
Heterochromia means "different (hetero-) colors (-chromia)." Usually the term is used to describe the condition where a person has different colored eyes — one blue eye and one green eye, for example. Other terms to describe different colored eyes are heterochromia iridis and heterochromia iridum. "Iridis" and "iridum" refer to the iris of the eye. The iris is the thin, circular structure that surrounds the pupil and contains the pigment melanin, which gives our eyes their distinctive color. The amount of melanin in the iris determines whether we have blue eyes, green eyes, hazel eyes or brown eyes. Blue eyes have the least amount of melanin in the iris; brown eyes have the most. Heterochromia usually is benign. In other words, it is not an eye disease, and it does not affect visual acuity. Heterochromia also occurs in animals.
I actually have slight heterochromia! one of my eyes is a darker grey while the other is very light.
