Poets romanticize eyes as the windows to the soul. Scientists, on the other hand, are more interested in whether they’re windows to our health. Eye doctors already know they can learn a lot about both physical and mental health by looking deep into the retina.
But what about a more superficial look at the eyes, namely at the colored part of the eye, or the iris?
While you can’t 100 percent predict health outcomes or quality of vision based on eye color alone, some studies suggest certain health risks may be related to eye color. For example, an analysis published in 2022 in the journal Cancer Causes and Control found that blue or light-colored eyes and hazel, green, or medium-colored eyes are associated with a higher risk of two common types of skin cancer, basal cell carcinoma and squamous cell carcinoma (but not melanoma), than dark brown eyes.
What else do we know about eye color and health risks?
Blue Eyes May Be More Sensitive to Light
People with blue eyes have a higher tendency toward intraocular straylight, a phenomenon in which light passing through the eye is scattered, resulting in an increased glare, hazy vision, and decreased contrast, a study of European car drivers found.
“People with blue eyes have decreased melanin pigment in the front layer of their iris, causing light to scatter and absorb some of the longer wavelengths of light that come in,” says Usiwoma Abugo, MD, a spokesperson for the American Academy of Ophthalmology and ophthalmologist at Virginia Eye Consultants, in the Norfolk, Virginia, area. “That’s how their eyes get the blue color, much like how the sky gets its blue color.
“The lack of pigment is also what can make those eyes potentially more sensitive to light. Several studies looked at the amount of straylight entering the eyes of people with different eye colors. They found that people with light blue eyes, when compared to other eye colors, had significantly more straylight inside the eye, leading to glare or sensitivity,” say Dr. Abugo.
Light-Colored Eyes Are Linked to a Higher Risk of Some Cancers
As mentioned earlier, lighter-colored eyes may mean an increased risk for skin cancer. Research has also found that those with hazel, green, or blue eyes have a higher risk of melanoma of the uvea — the middle layer of the eye, which includes the iris — than their darker-eyed peers.
Melanoma of the uvea is a rare cancer that occurs in about five to six of every one million adults in the United States each year, according to theKellogg Eye Institute. In addition to being fair-skinned and having light-colored eyes, other risk factors for this disease include having certain medical conditions, including congenital ocular melanocytosis or ocular melanocytoma, or having a family history of uveal melanoma, which is usually due to a mutation in a gene called BAP1.
Brown Eyes Are Associated With Few if Any Health Risks
Few if any specific health concerns are associated with having brown eyes.
A study published in 2000 found that people with brown eyes had a greater risk of developing cataracts and, therefore, should protect their eyes from direct exposure to sunlight. But this should be taken with a grain of salt as there are no recent studies to corroborate this, and more research is needed to establish a significant link.
“In general, everyone should make sure to wear 100 percent UV-blocking sunglasses when outdoors to minimize their chances of developing cataracts and other eye diseases,” Abugo advises. “Leading a healthy lifestyle — following a healthy diet, exercising, and not smoking — are also preventive measures people can take.”
Red, Yellow, and White in the Eyes
While the color of your irises may not tell you all that much about your health, certain changes in the appearance of your eyes may signal underlying conditions that need to be checked out by a doctor.
Red Whites
If the bright white part of your eyes (called the sclera) goes red, it could be a sign of anything from conjunctivitis (or pink eye) to a subconjunctival hemorrhage.
“Scleritis (when the white part of the eye appears red and swollen) could be a symptom of an autoimmune disease,” says Abugo. Though you can manage some of these issues with over-the-counter products like allergy medications or eye drops, you should see an eye doctor if the redness and irritation persist.
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Yellow Whites
Yellowing of the whites of the eyes (or skin) is what’s known as jaundice. While it’s common in babies, it can be a signal of a serious underlying condition in adults.
Jaundice tends to cause the entire sclera to look yellowish, but it’s also possible to develop a yellow spot or lump in the conjunctiva, which is the clear layer of tissue covering the sclera.
“Yellowing of the eye could be a pinguecula or pterygium growth,” says Abugo. According to theAmerican Academy of Ophthalmology, these growths on the conjunctiva are thought to be caused by exposure to sun, wind, and dust.
Hazy Pupils and Irises
When cataracts develop, they can create visible cloudiness over the pupil and iris of the eye. However, they may cause changes in vision long before they change the outward appearance of the eye.
White Corneal Ring
Developing a gray or white ring around your cornea — the clear layer of tissue covering your iris and pupil — is usually not a cause for concern, according to StatPearls, but it could be a sign of an underlying condition, such as atherosclerotic disease or advanced carotid vascular disease.
Called corneal arcus, it’s usually considered benign in people over age 50, but in those under 50, it warrants a blood test to look for lipid (fat and cholesterol) abnormalities.
Preventive Care for All Eye Colors
Annual eye exams will help you stay on top of any changes in your eyes that could reflect an underlying condition or deeper issue.
Abugo says that eye color can be representative of a condition someone already has, rather than a predictor of anything to come.
“Because eye color isn’t always predictive of developing disease, recommendations for eye health remain the same for everyone despite eye color,” she says. “Take care of your overall health with good healthy lifestyle habits, get your regular eye exams with an ophthalmologist to catch eye disease early, always wear 100 percent UV-blocking sunglasses when outdoors, and wear eye protection when needed.”
