They say that your eyes are the window to your soul — but they may also be a window to your health. Your eye color may predispose you to certain medical conditions, such as skin or eye cancer. And while actual changes in eye color are rare, they can also indicate an underlying health disorder that needs to be addressed. “Eyes can appear to change color due to an undiagnosed disease, a new medication or even trauma,” says David Silverstone, M.D., a professor of ophthalmology at the Yale School of Medicine. Sometimes, he adds, it’s due to an actual change in the iris, the colored part of your eye, and sometimes it’s due to something going on in another part of your eye that appears to change the eye color.
Here’s a look at what your eye color can mean for your health.
Can eye color predict your health?
Your eye color may offer some clues about how likely you are to develop certain cancers, or certain forms of eye disease, later on. Here’s what the research shows:
Those with lighter eyes have higher skin cancer risk.
A 2021 study published in the journal Cancer Causes and Control looked at over 35,000 men and found that, compared to people with dark eyes, people with hazel, green or blue eyes had up to a 24 percent greater risk of developing a type of skin cancer known as squamous cell carcinoma, and were up to 17 percent more likely to develop basal cell carcinoma. People who have less pigment in their eyes tend to have less pigment in their skin, which raises risk of skin cancer, explains Davinder Grover, M.D., a Dallas ophthalmologist and spokesperson for the American Academy of Ophthalmology (AAO). Not surprisingly, other research also suggests that folks with light-colored irises (blue or green) have a higher risk of developing eye melanoma than those with darker orbs.
People with brown eyes have a lower incidence of macular degeneration and diabetic retinopathy.
Age-related macular degeneration (AMD) is an age-related condition in which a part of your retina, the macula, is damaged. This causes you to lose your central vision, so that you cannot see fine details. It’s the leading cause of vision loss in people age 50 and older. Diabetic retinopathy is a diabetes-related condition that affects the blood vessels in your retina; over time, it can cause vision loss. It may be that pigment itself offers some protection, Grover explains. The AAO says those with brown eyes have a lower incidence of both of these conditions.
People with dark eyes may be more likely to develop cataracts.
You’re not off the hook if you have dark eyes: Research suggests you’re more likely to develop cataracts. A 2014 review of studies found that darker eye color is linked to an increased risk of cataracts. Researchers aren’t sure why this might be true. The authors of the review study speculated that the increased melanin in the irises of brown-eyed people could cause a buildup of heat in the eyes that is linked to cataracts. It’s also possible that the higher risk of cataracts in those with brown eyes may not be directly related to the color of your eyes, but due to where you live. “We know there is a connection between sun exposure and cataracts, and most people with darker eyes live closer to the equator,” Grover says. More research needs to be done to understand the link, but no matter the color of your eyes, you should wear sunglasses that provide 100 percent protection from all UV light, according to the AAO.
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What changes in eye color may mean for your health
If you notice any chances in your eye color, you should always get it checked out by your eye doctor, Grover stresses. It can indicate a wide range of conditions, some benign, some potentially serious. They include:
1. A hazy blue or white ring that forms around your cornea
This condition, called arcus senilisis, is caused by a build-up of lipids, or fat in your eye. Most older adults develop it, and it’s usually harmless, explains Grover. But it can make your eyes appear a different color. Grover recalls patients bring in older relatives concerned that their brown eyes had turned blue. If you do notice this ring, however, it’s always good to let both your eye doctor and primary care provider know, since it can be a sign of high cholesterol.
2. Pigment loss
There are certain eye conditions that can cause your orbs to lose pigment over time, says Grover. One is pigmentary glaucoma, a condition where pigment rubs off of the back of your iris, raising eye pressure. It can also happen after cataract surgery: “If a lens is placed in the wrong position, it can cause pigment to be released into the eye,” Grover explains. Both are treatable, so it’s very important to see your eye doctor if you notice any symptoms, such as halos or blurred vision.
3. Iris freckles
Just like you get freckles on your skin from sun exposure, you can also get them on your eye, Grover says. These are small brown spots on your iris that can make your eyes look like they’ve changed color. They’re harmless, but should be checked out by an eye doctor. You can also develop iris nevi, which are dark growths on your eye that look like a mole and are in fact caused by the same pigment cells, called melanocytes. While most aren’t dangerous, they can raise your risk of developing eye cancer.
4. Red in the clear covering over your eye
Uveitis is an inflammation of the middle layer of your eyeball. It can be caused by an infection such as shingles, or from an inflammatory disease such as rheumatoid arthritis or lupus. Most often, it just makes your conjunctiva — the clear covering over your eye — look red, Grover says. But it can also make your eye color look different if the inflammation causes your iris to stick to your lens. If you notice any redness or eye color changes, accompanied by light sensitivity, blurry vision, and/or seeing “floaters,” contact your eye doctor right away because uveitis can be serious; it can even lead to vision loss.
5. Black pupils
If you’ve had a blow to the eye, damage to the iris can cause tissue loss that makes the eye appear as if it’s a different color. “If the trauma is bad enough, the pupil might stay dilated, which can make the eye appear black,” says Silverstone. If this happens, it’s very important that you see your doctor for medical treatment, and also to rule out another serious condition that could cause dilated pupils such as a brain injury or stroke.
6. Different-colored eyes caused by different pupil sizes
This is a very rare condition that affects the eye and surrounding tissue on only one side of the face. It’s usually due to a stroke, tumor or spinal cord injury. One symptom is uneven pupil size, which can make it look like you have different-colored eyes, explains Grover.
7. Clouding of the lens
Cataracts can cause a clouding of the eye lens that can make your eye look milky white, says Silverstone. About a quarter of all people in their late 60s will have one, and more than a third of people in their 70s, according to the National Eye Institute. They can easily be removed with surgery.
8. Brown eyes becoming darker, hazel eyes turn brown
If you have glaucoma, the first-line treatment is often a class of medications called prostaglandins that can change eye color. “It can make brown or hazel eyes turn more brown, or a darker shade of brown,” says Grover, who notes that it doesn’t usually cause color changes in either blue or green eyes. If you use the lash growing prescription medication Latisse, you may notice these changes, too, Silverstone adds.
It’s important to remember that while your grandbaby’s eyes may have changed color from lighter to darker during the first year of life, as their body developed pigment, your eyes should stay constant. That’s why if you do notice any eye color changes, don’t panic, but do get them checked out.
Hallie Levine is a contributing writer and an award-winning medical and health reporter. Her work has appeared in The New York Times, Consumer Reports, Real Simple, Health and Time, among other publications.