Heterochromia refers to a difference in coloration, usually of the iris but also of hair or skin. Heterochromia is a result of the relative excess or lack of melanin (a pigment). It may be inherited, or caused by genetic mosaicism, disease, or injury. A long - long time ago people with different eye colors were believed to be the children of devil, witches, or people associated with witchcraft or black magic. They caused fear among ordinary people, but now it is known that different colored eyes is not the tricks of supernatural power.