• Question: Why do some people have different colours for each eye?

    Asked by elsieexo to Carolyn, Peter, Richard, Sara, Siana on 18 Nov 2015.
    • Photo: Richard Unwin

      Richard Unwin answered on 18 Nov 2015:

      Hi elsiexo,

      That’s a great question.

      It’s called ‘heterochromia’ and affects about 1 in every 150 people. Its most often caused by the genes we inherit from our parents, although it’s not known why they would colour the different eyes a different colour. Luckily it doesn’t seem to be problematic from a health point of view, and there are several famous people with the condition, including the actors Mila Kunis, Christopher Walken and Jane Seymour.

    • Photo: Sara Falcone

      Sara Falcone answered on 18 Nov 2015:

      Hello 🙂

      I am one of those people xD although it is not obvious one of eyes is greener and the other is browner.
      In most cases it depends of a different activation of the genes responsible to produce the pigment that give the color (called melanin, eumelanin more specifically). It can also happen in animals, in fact it is the most common in cats. In most cases it depends on our genes, that can be carring a mutation in one eye but not in the other. But it could also be caused by a pathology, like an infection. Do you know Mila Kunis? Well one of her eyes has a lighter shade of green/brown because when she was younger she had a bad eye infection (called uveitis)

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