Heterochromia - this is when a person has a different eye color. The difference in eye color in humans is caused by an excess or deficiency of pigment - melanin. This rare phenomenon is found not only in humans but also in animals, such as cats. Long - long people with different eye colors considered children of the devil, witches, that is people associated with witchcraft or black magic. They caused fear among ordinary people, but now it is known that different eye color - it's not the tricks of supernatural power.
There are two types heterochromia: the first - a complete heterochromia, and the second type - a partial heterochromia. With full color one heterochromia of the iris is completely different from the other color of the iris. In partial heterochromia one human part of the iris (eye) is different from the remainder of the iris, i.e. one eye has two colors. The most common complete heterochromia people, at least partly, about, in 4 out of 1 million people.,
Heterochromia - a mutation that occurs after fertilization. But you should not be afraid of heterochromia. It has no effect on human health, which has different colored eyes. Man with heterochromia sees and perceives color as well as the common man, but he has his individual twist. By the way, heterochromia is more common among women than among men. There are cases, and so that becomes acquired heterochromia. Due to injury or disease (Hirschsprung's disease, Waardenburg syndrome) a person acquires a unique phenomenon.