Give Now

A Moment of Science

Heterochromia

Know anyone with two different colored eyes? The condition is called heterochromia. Learn more on this Moment of Science.

Sectoral Heterochromia

Photo: hessiebell (flickr)

Sometimes a person's eyes are different colors and other times just part of one eye is a different color, as in the picture

Know anyone with two different colored eyes?

The condition is called heterochromia. Eye color, like hair and skin color, is a result of melanin. Thus, when the eyes of an individual are different colors, the reason almost certainly has something to do with that person’s melanocytes, the cells that manufacture pigment.

Lots of pigment makes eyes brown, some pigment makes eyes green, and little to no pigment makes eyes blue. Most often, heterochromia is a result of some mishap in the life of one’s melanocytes, resulting in a blue eye not exhibiting the pigment of its darker-colored partner.

What can go wrong with melanocytes? They can get lost. Most of the melanocytes in our bodies are produced in one location in utero and have to journey to their individual destinations. To get to where they belong, other cells have to send them the proper signals.

A number of things can go wrong. One example is Waardenburg syndrome, where genetic mutation results in wayward melanocytes that never find their way to the iris for which they were intended. In some cases, only some of an eye’s melanocytes get lost, resulting in patches of different colors in the same eye.

Or nothing at all may be wrong with an eye’s melanocytes. Heterochromia can also be the result of an individual’s receiving different eye color genes. This can happen if two fertilized eggs become fused in utero.

Christopher Walken is one of a number of famous people who have heterochromia; one of his eyes is blue, the other is hazel.

  • Pingback: Evolving Toward Cancer | A Moment of Science - Indiana Public Media

  • vladimir zivanic

    my little daughter, 7yo :)

  • http://pulse.yahoo.com/_TDNRKNNJLJ43D5IVIELJ6AEH5Y Deborah

    my eyes…. this way since I was very young

  • http://profile.yahoo.com/QE75T2I3RMU7UK6W3GP4WNOE4M Fanny Zhao

    kate bosworth

  • http://twitter.com/LoriJB773 Lori Burgess

    I have one green eye and one brown eye with several green spots in it.

  • Billy Le

    i don’t see my eyes…….cuz i’m chinese small eyes. lolz:))

Stay Connected

What is RSS? RSS makes it possible to subscribe to a website's updates instead of visiting it by delivering new posts to your RSS reader automatically. Choose to receive some or all of the updates from A Moment of Science:

Support for Indiana Public Media Comes From

About A Moment of Science

Search A Moment of Science