What is Central Heterochromia?
Heterochromia is an eye condition characterized by color differences in your iris, the colored part of your eye.(2) This can occur between the two eyes or within one eye.
Central heterochromia is when one eye contains multiple pigments. It is caused by an uneven distribution of melanin in your iris.
Central heterochromia causes a color abnormality that stems from the pupil at the center of the eyes, like cat eyes.
The outer ring will almost always be blue or green. And it is common for the inner ring to be gold or hazel. So the person may appear to have hazel eyes.
Most of the time, central heterochromia happens randomly, without any real cause for concern.(3)
In very rare cases, heterochromia is linked to a congenital syndrome, such as(2):
- Waardenburg syndrome
- Parry-Romberg syndrome
- Horner's syndrome
- Sturge-Weber syndrome
For the vast majority of cases, there is no need to treat heterochromia.
If there are underlying causes, or it is congenital heterochromia, you may need treatment.
Otherwise, heterochromia does not typically affect someone’s eye health or vision.
Other Types of Heterochromia
There are two other types of heterochromia. One affects the same eye, and the other affects both eyes:
Segmental (Sectoral) Heterochromia
Segmental heterochromia is also known as heterochromia iridum, sectoral heterochromia, or partial heterochromia.
It occurs when different areas of the same iris vary in pigment.(3) For example, someone might have blue eyes with bits of brown or brown eyes with a patch of green.
Someone with this type of heterochromia might appear to have speckled eyes. The speckle can be very interesting to see, though it is not always obvious. You may not notice segmental heterochromia unless you look up close.
Complete heterochromia, also known as heterochromia iridis, is when the iris in one eye is a different color than the iris in the other eye. Someone who has totally different colored eyes might have complete heterochromia.(3)
What Determines Eye Color?
Gene variations determine eye color. Most genes that are linked to eye color produce, transport, or store a pigment called melanin.(4)
A typical iris consists of five layers.(1)
- Iris pigment epithelium (IPE)
- Dilator muscles
- Stromal layer (SL)
- Anterior border layer (ABL)
The amount of melanin in the front layers of the iris determines eye color.(5)
Someone with a lot of melanin might have brown eyes. Someone else with less melanin may have a lighter eye color, like blue or green.
Wearing certain colors (especially bright colors that accentuate your eye color) can change the appearance of the color of your eyes. For example, while wearing a blue T-shirt does not make green eyes blue, the reflection can make them appear more bluish than greenish.
How Rare is Central Heterochromia?
Heterochromia is a rare eye condition, but it’s also rarely an eye health concern. Fewer than 200,000 Americans have the condition.(6)
If you have central heterochromia, you are not alone. Some famous people have heterochromia. Mila Kunis and Kate Bosworth are both believed to have it.
What Causes Central Heterochromia?
Central heterochromia is typically a benign condition that occurs because of the uneven distribution of melanin. It’s not usually caused by a medical condition or eye disease like glaucoma. And it does not usually affect vision.(3)
Central heterochromia can happen due to an eye injury or eye inflammation. See an ophthalmologist if you notice that the iris in one or both of your eyes has changed color.
How is Central Heterochromia Diagnosed?
To be diagnosed with central heterochromia, you must see an opthalmologist. This eye doctor will do a routine eye exam to look for uneven or totally different pigment dispersion in your eyes.
If you are diagnosed with central heterochromia, it's typically not a cause for concern. But your eye doctor may ask you questions to find out if an underlying health condition has caused your difference in eye color.
If you do have an underlying eye condition or have had an eye injury that has caused heterochromia, your eye doctor may recommend a specific course of action. You may need to see another type of doctor to treat that specific condition.
Treatment for Central Heterochromia
There are no treatments for central heterochromia.(3) Central heterochromia does not generally affect people’s eyesight, so treatment isn’t necessary.
Some people may choose to wear colored contact lenses in both eyes to change the color of their eyes. Or they may wear one colored contact lens to match the color of the other eye. Contacts are just for aesthetics and personal choice.
If you do choose to wear colored contacts, talk to your eye doctor about contacts that are right for you. You will need a proper eye exam to get a contact prescription. If you do not need corrective lenses, you can still buy colored contacts that are strictly cosmetic.
Central Heterochromia Prognosis
Most people who have central heterochromia are perfectly healthy. The eye condition is not typically known to affect their eye health, general health, or vision. Therefore, people who live with central heterochromia have an excellent prognosis.
That said, it’s important to talk to your eye doctor about changes in your eye color. You always want to be sure to rule out any underlying causes, even though they tend to be rare.
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