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Did you know that it is possible to have two different colored eyes? Just under 200,000 people in the United States have a rare condition known as heterochromia, which can cause color variations of the hair, skin, and eyes. In this article, I’ll review everything you need to know about heterochromia!
What is heterochromia?
The name of heterochromia is derived from the Greek words heteros, which means “different”, and chroma, which means “color.”
Usually, the term is used to describe the benign eye condition where a person has different colored eyes, resulting in a unique and interesting look. It may also be referred to as heterochromia iridum or heterochromia iridis.
Types of heterochromia
Heterochromia of the eye is subdivided into the following types:
The iris of one eye is a completely different color than the iris of the other eye. For example, one blue eye and one brown eye.
Sectoral (or partial) heterochromia
Part of the iris of one eye has a different color than the rest of the iris in the same eye. This can occur in one or both eyes. For example, one blue-brown eye.
The iris has a different color in the ring around the pupil (compared to the color of the rest of the iris) or with spikes of different colors radiating from the pupil toward the middle of the iris. The central (pupillary) zone of the iris is a different color than the mid-peripheral (ciliary) zone, with the true iris color being the outer color.
What determines eye color?
Eye color is determined by the production, delivery, and concentration of the pigment melanin in the iris. Blue eyes contain the least amount of melanin, whereas brown eyes are rich in melanin.
In cases of heterochromia, there is a difference in the coloration of the iris due to uneven distribution of melanin.
What causes heterochromia?
There are many types and causes of heterochromia. Most cases of heterochromia are benign and congenital.
Congenital heterochromia is when an infant is born with heterochromia, or it develops in early childhood as the iris attains its full amount of melanin. Usually, congenital heterochromia is a genetic trait that is inherited. It also can occur as a result of a genetic mutation during embryonic development.
In some cases, heterochromia is a symptom of another condition that is present at birth or develops shortly thereafter. Other causes of heterochromia in infants can include Horner’s syndrome, Sturge-Weber syndrome, and Waardenburg syndrome, to name a few.
Acquired heterochromia is when heterochromia develops later in life. Common causes of acquired heterochromia include eye injuries or surgeries, inflammation (iritis or uveitis), and certain glaucoma medications. Latisse, a repurposed glaucoma medication that is used as a cosmetic agent to grow and thicken eyelashes, can also cause a darkening of your iris color. Other less common causes of acquired heterochromia include Pigment dispersion syndrome, Fuchs’ heterochromic cyclitis, or iris tumors.
What if I notice my/my child’s eye color changing?
It is important to note that eye color is not fixed at birth. Many babies are initially born with a lighter eye color that darkens within the first two years of life. If you notice your child’s eye color darkening in those early years, there is no need for alarm; this is a normal process and not likely heterochromia or a cause for concern. If you notice any change in your child’s eye color past the age of three, or if you suddenly develop heterochromia later in life with no distinct cause, then a visit to an eye care professional is recommended to rule out a more serious condition.
As aforementioned, most cases of heterochromia are congenital and benign. It does not typically affect your vision or lead to any complications. However, if you suspect that you or your child has heterochromia, schedule an appointment with an eye doctor for a comprehensive eye exam.
If the eye is healthy and no other issues are present, treatment for heterochromia is not usually necessary. In other cases, the type of treatment needed will be determined by the underlying cause.
If a person with heterochromia wants to alter how their eyes look, colored contact lenses may be used for cosmetic reasons.
In the end, heterochromia refers to having two different color eyes and is most commonly a condition you’re born with. If you develop it later in life, see an eye doctor to determine the root cause.
What questions do you have about heterochromia? Comment below or schedule an appointment with a local eye care professional to learn more!