Heterochromia

What is heterochromia?

Heterochromia is when you have eyes that are different colors, or you have color variations within the same eye. Eye colors range from light blue or gray to dark brown. Your iris is the part of your eye that’s colorful. Usually, both eyes match in color.

With heterochromia, the iris in one eye may be a completely different color than the iris in your other eye. For example, you may have one blue eye and one brown eye. Or, one iris may contain two or more different colors. For example, a brown eye might have one section that’s blue. Or, a brown eye might have spikes of blue that radiate out from the center (pupil).

Many people with heterochromia don’t have underlying health issues, and their differently colored eyes are a harmless and unique trait. However, some medical conditions can cause heterochromia.

So, it’s important to see an eye care specialist if you notice this sign in yourself or your child. They’ll diagnose and treat any underlying causes if needed. Or, they’ll simply reassure you that everything is fine and there’s nothing to worry about.

Heterochromia is rare, but healthcare providers don’t know the exact percentage of the population that has it.

What are the types of heterochromia?

Heterochromia can appear in three different visual patterns:

• Complete heterochromia (heterochromia iridum): One eye is a completely different color than the other.
• Sectoral, or partial, heterochromia (heterochromia iridis): One iris has a section that’s a different color from the rest. This is a continuous section, like a missing slice of pie (except that part of your iris is still there — it’s just a different color).
• Central heterochromia: One iris has an inner ring that’s a different color from the rest. This may look like spikes extending outward from the pupil.

What causes heterochromia?

Causes of heterochromia include:

• Genetic mutations that only affect eye color (and which are harmless).
• Congenital (present from birth) or acquired conditions.
• Eye injuries or complications from certain treatments.

Genetic mutations that only affect eye color

Harmless, isolated genetic mutations are a common cause of heterochromia. These mutations affect the genes that tell your body to make, transport and store melanin. Melanin is the pigment that gives color to your eyes.

Some people are born with mutations that affect eye color for no known reason, while others inherit the mutation as an autosomal dominant trait. Either way, such genetic variants cause no other symptoms. The mutation doesn’t harm your eye health and isn’t part of a medical condition.

Congenital or acquired conditions

Sometimes, congenital or acquired conditions can cause heterochromia. A congenital condition is something you’re born with. An acquired condition is one you develop later in life.

Many different conditions can affect melanocytes, which are specialized cells that produce melanin. One common example is Horner syndrome. Some babies are born with this condition, while some adults develop it later in life.

People with Horner syndrome have underlying nerve damage that affects one side of their face. This nerve damage affects eye color because the cells that produce melanin (melanocytes) rely on stimulation from your sympathetic nervous system to function.

Disruption of a nerve-signaling pathway in your face leads your melanocytes to produce less melanin. As a result, the iris on the affected side of your face has less melanin. Therefore, this iris appears lighter in color (the more melanin present, the darker your iris).

Besides Horner syndrome, there are many other conditions that can affect melanocytes or cause other changes that lead to heterochromia. Keep in mind, many of these conditions are rare.

Congenital causes of heterochromia

• Congenital Horner syndrome.
• Waardenburg syndrome.
• Parry-Romberg syndrome.
• Sturge-Weber syndrome.
• Neurofibromatosis Type 1.
• Ocular melanosis.
• Hypomelanosis of Ito.
• Bloch-Sulzberger syndrome.

Acquired causes of heterochromia

• Acquired Horner syndrome.
• Neuroblastoma.
• Fuchs heterochromic iridocyclitis.
• Intraocular melanoma.
• Central retinal vein occlusion.
• Posner-Schlossman syndrome.
• Swelling from uveitis.
• Glaucoma.

Eye injuries or complications from treatments

Additional causes of heterochromia include:

• Injury or trauma to your eye.
• Latanoprost eye drops, which treat glaucoma.
• LATISSE®, a cosmetic treatment that helps eyelashes grow.

How is heterochromia treated?

Healthcare providers don’t have a specific treatment for heterochromia. It’s often a harmless variation in eye color. However, providers treat underlying conditions that cause heterochromia when they’re present. Some causes, like neuroblastoma, require quick diagnosis and treatment.

For this reason, it’s important to see an eye care specialist for a proper diagnosis. They’ll give you a complete eye exam to check your eye health.

Color contact lenses

If your provider determines your heterochromia is harmless, there’s nothing you need to do for treatment. However, you may choose to get color contact lenses if you want both of your eyes to be the same color. This is a cosmetic choice that isn’t medically necessary. It’s completely up to you and your preferences.

Talk to an eye care specialist if you’re interested in color contacts. You need a prescription for color contacts, even if they don’t have any corrective power for your vision. Using contacts you buy without a prescription is unsafe and can result in serious eye injury.

When should I see a healthcare provider?

See an ophthalmologist or optometrist if you notice any changes in your eye color or appearance. They’ll figure out the cause and give you treatment if needed.

Heterochromia due to some congenital conditions, like Horner syndrome, may appear early in a baby’s life. If you notice your baby has different eye colors or other visual signs like small pupils or a drooping eyelid , tell their pediatrician. They’ll refer your child to specialists (including an ophthalmologist and neurologist) if needed to check for underlying conditions that may need treatment.

A note from Cleveland Clinic

If you notice your eyes are different colors, you might worry something is wrong. You may worry even more if you notice this sign in your child. The important thing to remember is not to panic. Heterochromia itself isn’t a disease, and it’s often harmless. But it can be a sign of some conditions that require treatment. So, schedule an appointment with an eye care specialist. They’ll find an explanation for the issue and, when needed, treat the underlying cause. Sometimes, the only treatment you need is hearing that everything is OK. And that’s just as important as any medicine.