It is common to meet a brown-eyed boy, a hazel-eyed woman, a blue-eyed girl or a gray-eyed man. But if a person has one blue and one brown eye, how do you describe them, eye-wise? Yes, this condition is real and some people are actually born with two different-colored eyes – all-natural with no colored contact lenses. Medically, this is called heterochromia, which means the iris is multi-colored.
Heterochromia is a rare phenomenon that literally means “different (hetero-) colors (-chromia),” and this term is used to describe the condition in which a person has different colored eyes. It doesn’t necessarily mean that one eye has a light green color and the other is chocolatey brown. Vast differences in colors is possible, but heterochromia also means that the eye contains various colors that differ from the other. Heterochromia is not an eye disease and does not affect the visual acuity of a person; it’s only a color issue.
Where does eye color come from?
Eye color is determined by the amount of a pigment called melanin. People with a lot of melanin in the irises have brown eyes. Those with middling amounts of melanin in their irises have hazel or green eyes. People with little melanin amount in their irises have either gray or blue eyes. Eye color is genetically designated, and it is how the genes interact that provide the full range of color in people’s eyes.
Sometimes, the concentration and distribution of melanin in a person’s irises isn’t uniform, which leads to heterochromia. This phenomena can be caused by a lot of different factors.
What causes heterochromia?
The instance of having two differently colored eyes is very uncommon, and it happens to just 11 out of 1,000 Americans.
Heterochromia happens for different reasons. In the vast majority of cases, people are just born with it. If the trait is apparent since the person was a baby, chances are it came from the family gene pool. This means, it’s a congenital heterochromia. Since this is a dominant autosomal trait, chances are one of the person’s parents has this too. But there are also other causes other family DNA, such as:
- Genetic mutation – A mutation in one of the person’s genes that regulate eye color may happen during development of the embryo.
- Genetic disorder – Some inherited genetic disorders can cause heterochromia. One example is the Waardenburg syndrome that causes children to experience prematurely graying hair, hearing loss and varying degrees of heterochromia.
- Trauma during birth – Sometimes, facial trauma happens during birth, and this may prevent melanin from coloring the eye in the affected are of the face.
- Eye conditions – A case of heterochromia that happens later in life is often caused by eye injuries or uveitis. Eye injuries like a punch that leads to bleeding within the eye can cause heterochromia.
- Glaucoma – Changes in eye color happens to persons with glaucoma. Sometimes, the glaucoma itself can cause heterochromia, but sometimes it is caused by the medication. Lattice, a repurposed glaucoma medication that is now used as a cosmetic agent to thicken eyelashes, can cause the iris to change its color.
- Disease – Some diseases may cause heterochromia during a person’s life. One example is Horner’s syndrome, which is characterized by interruption of certain nerve impulses to the eye that causes a constricted pupil.
- Chimera – Under super rare circumstances, a person can be a chimera – a person containing two sets of DNA, one from an underdeveloped twin. Because of this condition, a person can have eyes with different colors as a result.
What are the different types of heterochromia?
There are three different types of heterochromia, and it is based on where the different colors are located in the eyes:
1. Complete heterochromia
This is where the iris of one eye has a completely different color than the iris of the other eye, let’s say, one is blue and the other is brown. This is where the heterochromia is very obvious.
2. Sectoral or partial heterochromia
This is where only a portion of the iris of one eye has a different color than the rest of the iris of that eye. This can occur in only one eye or both eyes. For instance, a person can have one green eye and one eye with both blue and hazel colors.
3. Central heterochromia
In this type of heterochromia, the iris has a different color with the portion near the border of the pupil, compared with the color of the rest of the iris. Usually, this has spikes of the central color radiating from the pupil to the middle of the iris. For instance, a person can have a blue iris and a golden-brown ring around the pupil. It’s kind of like an ombre effect for the iris.
Famous people with heterochromia
Heterochromia is rare, but there are some famous faces who have this fascinating eye condition.
1. Mila Kunis
Mila Kunis is known for her roles in comedies and her beautiful skin, but her differing eye colors are harder to spot. She has one green eye and a brown one. She underwent surgery because of chronic inflammation of her iris, making her go blind in one eye for many years. Her heterochromia was a side effect of the condition.
2. Kate Bosworth
One of the most well-known examples of heterochromia in Hollywood lies in Kate Bosworth’s eyes. Hers have a noticeably different color, with one being blue and one with a dark hazel color. She is almost as well known for her different colored eyes as her roles in movies such as 21 and Blue Crush.
3. Kiefer Sutherland
Kiefer Sutherland played a killer in the 1996 film, Eye for an Eye. Some fans say he has killer eyes, but in reality his eyes have different colors. The difference in Sutherland’s eyes may be subtle, but this trait of his was alluded by actor’s then-fiance Julia Roberts. In her Golden Globe acceptance speech in 1990, Roberts specifically thanked her “beautiful blue-eyed, green-eyed friend.”
4. Jane Seymour
Known for being a Bond girl and the lead in Dr. Quinn, Medicine Woman, Jane Seymour also has heterochromia. She has one greenish eye and one brownish eye. You may have missed it because of her beautiful brown hair and her excellent acting.
5. Mark Scherzer
Perhaps one of the most extreme cases of heterochromia among famous people is in the eyes of this pro baseball pitcher, Max Scherzer. Nicknamed as “Mad Max” and playing for the Washington Nationals, this famous athlete has one light blue eye and one dark brown eye.
6. Elizabeth Berkley
Known for her roles at Saved by the Bell, Showgirls and The First Wives Club, Elizabeth Berkeley is more than just epic one-liners and amazing hair. She also has a unique, beautiful eyes, with one being green, and one being half-brown and half-green.
7. Josh Henderson
You might recognize him from Desperate Housewives, but there’s something uniquely interesting from Josh Henderson. One of his eyes is medium blue, while the other is rich green. You may not notice it immediately, but if you have stared at him a lot, perhaps you have seen the difference.
8. Alice Eve
A British actress from She’s Out of My League and Star Trek, Alice Eve’s eyes are pretty striking. Her right eye is green, while her left eye is blue. She has been vocal with her condition, and she even told a pretty interesting story concerning it – in an interview with Conan O’Brien, she revealed that she actually dated a guy who didn’t notice her mismatched eye color for nine months.
9. Christopher Walken
The quintessential character actor with a nervy charm, Christopher Walken has one blue eye and one hazel eye. The intensity of his stares is partly why he can excel at portraying villains and weirdos, and it’s even more fascinating to think that maybe his different-colored eyes have something to do with it.
10. Henry Cavill
Yes, Superman himself has heterochromia. Henry Cavill’s eyes are mostly blue, but if you look at it closely (and fans know this by heart), his eyes has a tinge of brown in the top of his left eye. It’s a sectoral heterochromia.