What Is Heterochromia?
Most of us notice a person’s eye color almost immediately when we meet them.
A striking pair of eyes can make a deep impression, and what could be more striking than a pair of eyes that don’t match? In scientific terms, that’s heterochromia, a phenomenon fairly common in cats and dogs but much rarer in humans, affecting only three out of every five hundred people. It comes in a few different varieties and happens for different reasons.
The Forms of Heterochromia
Josh Henderson and Alice Eve are two famous examples of heterochromia, each having one blue eye and one green eye. Completely mismatched irises like theirs are formally called heterochromia iridium or complete heterochromia.
Some people merely have a patch of a different color in one iris. That’s segmental heterochromia or heterochromia iridis. A good example is Henry Cavill, who has a patch of brown in his left iris, but otherwise his eyes are blue. Anthony Stewart Head has this form of heterochromia as well.
The most common form of heterochromia is central heterochromia, where the irises match each other but have a ring of a different color around the pupils. Olivia Wilde, for instance, has rings of brown at the center of her blue eyes. Central heterochromia may not stand out quite as dramatically as the asymmetrical types, but it is still very striking.
What Causes Heterochromia?
Most cases of heterochromia come from a harmless mutation in one of the genes affecting the way pigment develops in a person’s irises, but it could also happen after an injury or disease later in life. After prolonged inflammation in one of her eyes, Mila Kunis was left with mild heterochromia.
The most famous example of heterochromia caused by an injury was David Bowie. At age 15, he took a punch to his left eye in a fight over a girl. The iris was left paralyzed, resulting in uneven pupils or anisocoria for the rest of his life. While his eyes appeared asymmetrical due to the left eye being permanently dilated, the irises weren’t actually different colors.
Folklore of Asymmetrical Eye Color
Throughout history, different cultures have had different traditions about mismatched eyes. Pagans in eastern Europe thought they were witch eyes. Many native American cultures believed they were ghost eyes that gave the person the ability to see into heaven and earth. In modern times, we simply think they’re fascinating!
Let Us Take a Look at Your Eyes!
If you weren’t born with heterochromia, it is very unlikely you will develop it, but any change to your eyesight is worth bringing to our attention. You might only need a simple prescription change, but we want to make sure there aren’t any early signs of an eye disease that could threaten your vision.