Has UV exposure been linked to eye cancer?
The most common type of eye cancer is ocular melanoma, but it is very rare. While skin melanomas are strongly linked to sun exposure, there is no known link for most ocular melanomas, especially those starting at the back of the eye. More research is still needed to determine the connection between UV exposure and various types of eye cancer.
Only some rare ocular melanomas, such as those in the conjunctiva, may have a potential link to UV exposure. While the sun's UV rays may not cause most eye cancer, they can cause cancers on the eyelids and other sensitive skin around the eyes. Eyelid skin cancers account for 5% to 10% of all skin cancers.
Can you get eye cancer if you look at the sun?
You’re unlikely to get eye cancer from looking at the sun, but that doesn’t mean it’s a safe thing to do. It’s never a good idea to look directly at the sun, even if you’re wearing sunglasses — they don't block enough of the sun’s harmful UV rays.
Looking right at the sun can result in damage to your retinas, the light-sensitive tissue at the back of your eyes. Sun-related retinal damage is called solar retinopathy, or a burned retina.
Just a few minutes of staring at the sun can cause permanent damage. How quickly damage occurs depends on how strong the sunlight is and how wide your pupils are. Factors like cloudy skies and medications can affect your risk.
Symptoms of solar retinopathy include:
- Watery eyes
- Blurred vision
- Blind spots
- Eye pain
- Headaches
- Light sensitivity
In the most severe cases, solar retinopathy may result in blindness.
Eye conditions linked to UV exposure
You don’t have to stare directly at the sun to experience UV-related eye issues. Invisible UV radiation penetrates the Earth’s atmosphere and reaches your skin and eyes in the form of UVA and UVB rays. Sun exposure can contribute to a range of eye conditions, including:
- Photokeratitis (sunburned eyes)
- Pinguecula
- Pterygium (surfer’s eye)
- Cataracts
- Age-related macular degeneration (AMD)
- Eyelid cancers
Photokeratitis is perhaps the most immediate manifestation of a sun-related eye problem. The equivalent of a sunburn, it can occur within hours of the eyes’ exposure to the sun.
Excess time spent outdoors without sunglasses can lead to the development of pingueculae and pterygia. These are growths that form on the surface of the eye after months to years of chronic UV exposure.
Spending a lifetime in the sun can increase your risk of developing age-related eye conditions like cataracts and macular degeneration. Cataract development is very common as you get older, and age is the leading cause. However, roughly 10% of cataract cases can be attributed to too much exposure to UV rays.
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Types of eyelid and eye cancer linked to UV exposure
Research has established a relationship between sun exposure and skin cancer of the eyelids, including:
- Basal cell carcinoma – Cancer that forms in the basal cells, which are located on the outer layer of the skin. Around 90% of eyelid cancers are basal cell carcinoma.
- Squamous cell carcinoma – Cancer affecting the squamous cells that line the surface of the skin and body cavities (lungs, throat, etc). Around 5% of eyelid cancers are squamous cell carcinoma.
- Melanoma – Cancer that develops in melanocytes, which are the cells responsible for producing melanin (pigment) in the hair, skin and eyes.
The association between ultraviolet radiation and other eye cancers, particularly ocular malignancies like conjunctival melanoma and uveal melanoma, is still being studied. However, recent research suggests these types of cancer may be linked to UV exposure.
Research findings on UV-induced eye cancer
Cases of UV-induced skin melanoma happen more often following mutations in two genes: BRAF and RAS. When either of these genes mutates, it can turn healthy cells into cancer cells and cause them to grow uncontrollably.
Certain studies have examined the genetic makeup of conjunctival melanoma, which is a cancer that occurs on the conjunctiva (the eye’s clear, outer membrane). Researchers found similar mutations in the BRAF and RAS genes. This suggests a link between UV radiation and conjunctival melanoma.
A separate study analyzed the genetics of uveal melanoma. This cancer occurs in the uvea, the middle layer of the eye. The uvea is made up of the iris (the colored part of the eye), the ciliary body and the choroid.
The study found that all its iris melanoma samples showed evidence of genomic UV damage. In other words, the prolonged, consistent UV exposure damaged the DNA in the iris cells. In all, the most common type of uveal melanoma — choroidal melanoma — is not known to be associated with UV exposure. However, the rarer iris and conjunctival melanomas do show UV links in recent studies.
Link between the UV Index and cancer risk
Research suggests that geographic factors and the UV Index may help determine a person’s risk for eyelid cancer. The UV Index reflects the intensity of the sun’s UV rays. It’s measured on a scale of 0 to 11+.
A person’s risk of damage from UV radiation depends on the day’s UV Index reading for their location:
- 0-2 is a low risk of UV-related harm
- 3-5 is a moderate risk of damage from sun exposure
- 6-7 is a high risk of harm without sun protection
- 8-10 is a very high risk of sunburn or skin damage that can occur quickly without protection
- 11+ is an extreme risk of damage to the skin and eyes that can occur within minutes of unprotected exposure
One study interviewed a random sample of people to record skin cancer diagnoses across the United States. Results showed a significantly higher prevalence of skin cancer in states with a high average UV Index reading of 8 or above.
These findings make it even more critical to protect your skin and eyes from the sun when you go outdoors. Wearing sunglasses, a wide-brimmed hat and broad-spectrum sunscreen are some of the best ways to prevent UV damage to your skin and eyes.
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Prevent and protect against UV-linked eye cancers and conditions
Unprotected sun exposure can raise your risk of UV-related eye conditions, including certain types of eye and eyelid cancers. To help prevent sun damage to your eyes, you should:
Protect your eyes outdoors
Regardless of the time of year, wearing sunglasses outdoors can help safeguard your eyes against UV exposure. Make sure your sunglasses offer 100% protection against UVA and UVB rays. Shades labeled UV400 sunglasses should offer this maximum level of UV protection.
Certain cosmetic and skincare brands offer eye makeup and eye creams with SPF to provide UV protection while hydrating the skin around your eyes.
Avoid indoor tanning
Indoor tanning methods, such as tanning booths and sunbeds, may be more harmful than natural sun exposure. Tanning beds project 10 to 15 times more UVA rays than the sun. UVA rays are responsible for skin aging.
If you want a sun-kissed look without the radiation risk, consider spray tanning. Many tanning salons offer spray tans as a safer alternative to sunbeds. There are also many at-home tanning lotions, foams, sprays and oils that provide a safe and natural glow to your skin.
Be mindful of the UV Index
Most weather apps provide the UV Index reading as part of the forecast. You can use this to prepare for the day.
For example, if the UV Index (UVI) is particularly high, try to stay indoors or in a shaded area. On days when the UVI reading is not as high, sunglasses, sunscreen and a wide-brimmed hat should do the trick.
Know if you’re at higher risk
The data linking UV exposure to eye cancer is limited. But other factors can increase your risk of developing eye cancer, including:
- Advanced age
- Having light skin and/or eye color
- Being a biological male
- Having brown spots on the uvea (called ocular melanosis)
- Having a diagnosis of dysplastic nevus syndrome (which causes many abnormal moles)
- Being in an occupation that exposes you to high levels of UV radiation, such as a welder
If you’re at higher risk for eye cancer or any other eye condition, UV protection is especially important.
Get regular eye exams
Having an eye exam every year is a great way to keep your vision clear and ensure your eyes are healthy. Your eye doctor will check for signs of ocular cancer and other eye conditions.
If you notice any changes in the appearance of your eyes or the surrounding area, contact your eye doctor right away. Don’t wait for your next scheduled checkup. Having new symptoms checked immediately allows for early detection and treatment, and it can improve your outcome.
Stay informed and protected
Sun damage can occur at any time of year, whether it’s bright and sunny or gloomy and overcast. For this reason, it’s important to wear sunglasses anytime you’re outdoors during the day.
Incorporating sun-safety habits into your daily routine will help keep your eyes healthy and your vision clear through all four seasons.
READ MORE: How to test if sunglasses are UV-protected
