Heterochromia

What Is Heterochromia?

Heterochromia is when a person has differently colored eyes or eyes that have more than one color.

Most of the time, it doesn't cause any problems. It's often just a quirk caused by genes passed down from your parents or by something that happened when your eyes were forming. In rare cases, it can be a symptom of a medical condition.

Heterochromia is common in some animals but rare in humans. It affects fewer than 200,000 people in the United States.

Symptoms and Types of Heterochromia

Your iris gets its color from a pigment called melanin. It's what makes them blue, green, brown, or hazel. Less melanin leads to lighter eye color. More melanin makes darker eyes.

There are three types of heterochromia:

• Complete heterochromia (heterochromia iridis) means one iris is a different color than the other. For example, you may have one blue eye and one brown eye.
• Segmental heterochromia (heterochromia iridium) means different parts of one iris are different colors.
• Central heterochromia is when the outer ring of your iris is a different color from the rest.

Causes and Risk Factors of Heterochromia

When you’re born with different-colored eyes, it’s called congenital heterochromia. Conditions that can cause this include:

• Benign heterochromia
• Piebaldism
• Hirschsprung disease
• Bloch-Sulzberger syndrome
• Von Recklinghausen disease
• Bourneville disease
• Waardenburg syndrome
• Sturge-Weber syndrome
• Parry-Romberg syndrome
• Horner’s syndrome

If your eye color changes after you're an infant, it's called acquired heterochromia. It may be caused by:

• Eye injury. More than 80% of eye injuries happen during projects around the house, sports, or other recreation.
• Glaucoma. This eye disease affects more than 3 million Americans. Fluid buildup raises pressure in your eye. It may cause vision loss, but early detection and treatment can help prevent that.
• Certain medicines, including glaucoma drugs like bimatoprost (Latisse, Lumigan) and latanoprost (Xalatan).
• Neuroblastoma. This is a cancer of the nerve cells that usually affects children under 10. When tumors press on nerves in the chest or neck, kids may have a drooping eyelid and a small pupil. They can also get heterochromia. See a doctor right away if your child's eye color changes.
• Eye cancer.Melanoma can affect your eye in rare cases. It happens in melanin, the pigment that gives your eyes, hair, and skin their color. One sign of eye melanoma is a dark spot on the iris. Blurry vision or sudden vision loss are also common.