Did you know that while most babies are born with brown eyes, their eye color could change to blue, green, brown, hazel, or gray by the end of their first year? This is determined by the protein called melanin, which is also what determines skin color, that is present in the iris (the colored ring around the pupil responsible for filtering light).
Nowadays it’s common to see people deliberately change their eye color through cosmetic surgery or temporarily with contacts, but a natural transformation in them can signal some underlying medical condition or health issue. This is why it’s important to consult a doctor, especially if you also experience symptoms like eye pain, redness, and blurred or limited vision.
Here are some of the most common reasons why your eye color might change:
1. Eye Color at Birth
A baby’s eye color changing isn’t necessarily a problem, but it is interesting to learn the reason behind it. As we mentioned, melanin, produced by special cells called melanocyte, is responsible for determining eye color. Only when they are exposed to light will they show their true colors (like skin that darkens under sunlight). Most babies, regardless of race, are born with brown eyes, although some Caucasian babies have blue or gray eyes at birth.
“The melanocytes in the eyes of newborns have never been exposed to light, so they haven’t become fully active,” writes Healthline, “As melanocytes are activated by light over an infant’s first year of life, eye color may change. Typically, this means turning from a blue/gray (low melanin) to hazel/green (medium melanin), or to brown (high melanin).”
A person with heterochromia would be hard to miss because this condition causes people to have two (or more) different colors in their eyes! Also known as heterochromia iridis and heterochromia iridium, it is a harmless condition that could be a congenital effect or even has resulted from injury or illness.
According to Healthline, “It’s also possible for small segments of the same iris to be different colors. For example, half of your left eye could be blue and a half could be brown.”
3. Fuchs Uveitis Syndrome
Fuchs heterochromic uveitis/Fuchs heterochromic iridocyclitis, or more commonly known as Fuchs uveitis syndrome, is another condition where a person has two different colored eyes. But unlike heterochromia, here only one eye is affected and it isn’t exactly harmless. In fact, it can cause the uvea, located in the middle of the eye, to become inflamed.
“This typically leads to the lightening of the iris of the affected eye, although in some cases the condition causes iris darkening. The end result is a difference in eye color between the eyes or heterochromia,” explains LiveStrong.
They also say that eye color change is one of the first symptoms of the disease, and that people with the condition are more likely to develop cataracts or glaucoma.
4. Pigmentary Glaucoma
A broad term describing a variety of eye conditions affecting the optic nerve is Glaucoma, and it can be quite serious. Occurring due to fluid moving in and out of the tiny chamber in front of the eyes, it could lead to vision loss and even blindness.
“Fluid moves in and out of this chamber, nourishing the tissue there. This fluid flows out of the eye through a spongy meshwork that acts as a drain,” says Healthline.
Another form of glaucoma, known as pigmentary glaucoma, occurs when a person develops pigment dispersion syndrome. While the symptoms for both these conditions are similar, the latter can also cause peripheral vision loss, meaning it would be difficult for the patient to see out of the side of their eyes.
“With pigmentary glaucoma, these pigment granules block normal fluid flow through the front chamber of the eye. This causes glaucoma, wherein increased pressure in the eye can lead to vision loss,” says LiveStrong. “The dispersion of pigment from the iris can cause eye color changes, and the two eyes may be different colors if they are affected unequally.”
5. Horner Syndrome
Caused by a disruption in the nerve pathways that travel from the brain to the face and eyes, Horner syndrome usually develops as a result of other health issues like stroke, tumors, or spinal cord injury. According to LiveStrong, it is “a triad of symptoms caused by impairment of specific fibers in the third cranial nerve that innervate the eye and face.”
Other symptoms that could develop as a result of Horner syndrome include a droopy eyelid, smaller pupil size, and less sweating on the affected side of the face. LiveStrong stresses that this condition is most likely to cause an eye color change in children less than a year old, but it may also occur in adults on rare occasions.
6. Tumors of the Iris
As unlikely as it may seem, the iris of the eye can also be affected by cancer, with tumors growing right underneath it. According to Healthline, “Most iris tumors are cysts or pigmented growths (like moles), but some are malignant melanomas (a form of aggressive, life-threatening cancer).”
Healthline also states that this is a condition that mostly doesn’t present with any other symptoms, although sometimes “changes in the eye’s appearance can be seen. Thick, pigmented spots called nevi can change, grow larger, or pull the pupil in a different direction.”
If you suspect that you have an eye tumor, it is imperative that you consult a specialist immediately. Your doctor will be able to determine the seriousness of the condition and provide necessary treatment options (which may involve radiation therapy or surgery).
7. Side Effect of Medicines
You might already be aware that certain medications prescribed to treat health conditions also come with a long list of side effects, but did you know that one of them could also include a change in eye color? Medications for eye conditions like glaucoma are one of them.
LiveStrong also mentions a couple of other medications that are known for causing temporary or permanent eye color change. These include latanoprost (Xalatan) and bimatoprost (Lumigan) drops, prescribed to glaucoma patients to reduce internal eye pressure, as well as bimatoprost (Latisse), a medicine applied to the upper eyelid to enhance eyelash growth for cosmetic reasons.
8. Age-Related Causes
Although quite rare, some people’s eye color can also change even after infancy. A study published in “JAMA Ophthalmology” in 1997 stated that “10 to 15-percent of white children experienced subtle changes in eye color after age 6 and into early adulthood.”
But according to the researchers, this is most likely to occur only in people of a certain genetic disposition, so it would have been a trait that was passed down through generations family history. They also say that those with lighter-colored eyes are more likely to notice a change, compared to those with darker-colored irises.
9. Other Possible Explainations
If you cannot point to any of the reasons on this list as the cause of your eye color transformation, it could also be due to things like a traumatic eye injury, allergies, liver problems, or even cancer.
A reddening of the whites in your eyes, accompanied by itchiness and dryness could signal undiagnosed allergies. Alternatively, if the whites of the eye are turning yellow, it could be an indication of a more serious problem like liver disease. Rachel Bishop, MD, chief of the consult service section of the National Eye Institute, also says that change in a single eye could be the result of melanoma of the iris.