Why do people have different eye color? (Heterochromia)

heterochromia I want to tell you about a very interesting phenomenon - it is heterochromia. Heterochromia - this is when a person has a different color eyes. The difference in eye color in humans is caused by an excess or deficiency of pigment - melanin. This rare phenomenon occurs not only in humans but also in animals, such as cats. Long - long people with different eye color considered children of the devil, witches, that is, people associated with witchcraft or black magic. They caused fear among ordinary people, but it is now known that the different eye color - this is not the tricks of supernatural power.

There are two types of heterochromia: first - a complete heterochromia, and the second type - a partial heterochromia. With the full color of one iris heterochromia is completely different from the color of the other iris. In partial heterochromia in one part of the human iris (eye) is different from the rest of the iris, that is, one eye has two colors. Is most common in people complete heterochromia, less partial, approximately, 4 persons from 1 million.
Why do people have different eye color?

Heterochromia - a mutation that occurs after fertilization. But do not be afraid of heterochromia. It has no effect on human health, which has different colored eyes. Man with heterochromia sees and perceives colors as well as the average person, but it has its own individual twist. By the way, heterochromia is more common in women than in the stronger sex. There are cases and so that heterochromia is acquired. Due to injury or disease (Hirschsprung's disease, Waardenburg syndrome), a person acquires a unique phenomenon.
Examples of famous people with heterochromia:

Kate Bosworth (sector getehromiya)

Mila Kunis

Tim Makilrot

Alice Eve

Simon Pegg

Christopher Walken

David Bowie (psevdogeterohromiya due to injury)

Henry Kevell

Jonathan Rhys Meyers

Strangely enough, but the owners of different eye colors are not always happy to have them heterochromia. So they can be advised, for example, to buy colored lenses (carnival lens) so that they can hide their identity from others. In the same way by the lens can artificially create a different eye color in humans.