Heterochromia is the technical term used to describe the condition of one iris being a different color than another.
Sometimes, heterochromia is complete, meaning the entirety of the left iris is one color, while the entirety of the right iris is another. Other times, people have partial heterochromia, where only a portion of the iris is a different color. A third type of heterochromia is called central heterochromia, meaning the center of the irises is one color while the outer rings are another.
Usually, genetic heterochromia is harmless and poses no risk to someone who has it (other than continuous commentary and conversations with strangers when they take notice). However, there are times when heterochromia deserves attention from an optometrist or ophthalmologist.
Causes Of Heterochromia (Different Colored Irises)
There are multiple causes of heterochromia. Here are some of the most common.
Genetic links
Most of the time, heterochromia is genetic. Infants are either born with it, or their eyes change to be heterochromatic within the first few weeks after birth. This type is called congenital heterochromia, meaning it is passed on through genetics. Most of the time, congenital heterochromia poses no risk to the person, and there is no increased chance of developing any significant vision loss or other eye conditions.
However, there are other cases where heterochromia is a symptom of other conditions. If your baby is born with heterochromia, physicians will evaluate them to determine whether there are other health-related links. Regardless of the initial health assessment, we recommend scheduling an appointment with an ophthalmologist if your newborn has – or develops – heterochromia.
Links to other existing health conditions or diseases
Again, the majority of people born with heterochromia are just fine, and we call that “benign heterochromia.” More rare are cases of heterochromia caused by genetic defects, diseases, or trauma.
Examples of heterochromia linked to other conditions are:
- Horner’s syndrome is caused by a disrupted nerve pathway on one side of the face (often due to a tumor, stroke, or traumatic delivery at birth). Other symptoms on the affected side of the face include reduced pupil size, drooping eyelids, or the inability to sweat.
- Sturge-Weber syndrome is a rare neurological disorder present at birth and characterized by a port-wine stain birthmark on the forehead and upper eyelid on one side of the face. The mark is a sign of an overabundance of capillaries. Again, most patients with Sturge-Weber Syndrome are diagnosed at birth.
- Waardenburg syndrome refers to a group of genetic conditions. Some types also cause hearing loss that is present at birth. People with Waardenburg syndrome may also have wide-spaced eyes, very light blue eyes, patches of white or prematurely gray hair, or digestive ailments.
- Individuals with piebaldism have patches of skin void of pigment (melanin), so those areas (and the hair growing from them) may appear white. This can lead to different pigmentation in the irises or white patches of hair and the appearance of mottled skin elsewhere on the body.
- Hirschprung’s disease is a genetic condition that affects the colon and makes it difficult or impossible for babies to pass their stool. It is typically diagnosed within the first 48 hours and corrected via surgery.
- Bloch-Sulzberger disease also called incontinentia pigmenti, Bloch-Sulzberger disease affects skin pigmentation and may also affect nervous system function. It affects the ectodermal and mesodermal tissues, such as skin, eyes, teeth, and central nervous system.
Other genetic conditions that may cause heterochromia include:
- von Recklinghausen disease
- Bourneville disease
- Parry-Romberg syndrome
Injury or eye trauma may also cause heterochromia
Certain injuries, diseases, or eye trauma can also cause heterochromia to appear later in life. We refer to this as acquired heterochromia. Any change in your vision or the physical appearance or contours of the eye should trigger a call or visit to your optometrist.
Some of the causes of acquired heterochromia are:
- An acute eye injury.
- Glaucoma (or a side effect of some glaucoma medicines).
- Bleeding in the interior of the eye or just under the membrane.
- Swelling or inflammation due to uveitis or iritis.
- Using Latisse (Latisse is a repurposed glaucoma medication used to stimulate eyelash growth. It’s not worth the risks).
- Diabetes.
- Ocular melanosis.
- Iris ectropion syndrome.
- Pigment dispersion syndrome (this is a version of open-angle glaucoma that often goes diagnosed without routine, annual eye exams).
- Benign and malignant iris tumors.
- Central retinal vein occlusion.
- Chediak-Higashi syndrome.
- Eye surgery (this is very rare and should not discourage you from pursuing eye surgery).
Again, the majority of people with heterochromia are perfectly healthy and have no related side effects or related health conditions. A professional assessment and screening is the key to ensuring you or your loved one has benign heterochromia.
Notice Heterochromia In Yourself Or A Loved One?
Was your child born with heterochromia, or have you noticed your own irises changing color? Schedule a consultation at Atlantic Eye Institute.
While there is no way to “cure” heterochromia, underlying health conditions can be treated and supported. Once we’ve determined whether there is a genetic health or acquired health component, we can discuss how healthy lifestyle choices and disease management optimize your health, well-being, and vision.