What Causes Different Colored Eyes?

What do Mila Kunis, Christopher Walken, and Alexander the Great have in common? Aside from being well-known figures to many people across the world, all three of them also have an eye condition known as Heterochromia, or two different colored eyes.

Heterochromia is fairly uncommon, occurring in less than 1 percent of the population. It can be caused by several factors and present itself in different ways.

What causes Heterochromia?
The color of our eyes comes from the appearance of the pigment that is present in the iris, the central part of the eye. Brown eyes are rich in melanin pigment deposits, making them darker, while blue eyes lackmelanin. Heterochromia happens when the concentration and distribution of melanin isn't uniform. While the condition is often genetic, it can also be caused by injury - such as a punch leading to bleeding with the eye - inflammation, or glaucoma.

What are the different types of Heterochromia?
Heterochromia can show up in several different ways:

• Complete Heterochromia - each eye is a distinctly different color, such as one blue eye and one brown eye
• Central Heterochromia - the eyes show multiple colors, such as a blue iris with a brown ring around the pupil
• Sectoral Heterochromia - one iris has a splash of color that's unique from its overall hue

Is Heterochromia Cause for Concern?
Abnormalities in eye color are not necessarily a sign of an underlying health problem, but it can be a component of a few inherited genetic disorders. One example is Waardenburg Syndrome, which causes children to experience hearing loss, premature graying hair and degrees of Heterochromia. Another example is neurofibromatosis, which affects the nervous system and causes tumors to form on nerve tissue. Tumor formation inside the eye can cause Heterochromia.

If Heterochromia occurs suddenly, it could be a sign of an underlying medical condition. A comprehensive eye exam with your eye doctorcan rule out any serious issues.