A cute young couple wears sunglasses and lies head-to-head. A cute young couple wears sunglasses and lies head-to-head. Making a habit of wearing sunglasses will protect the future health of your eyes. (Photo: Ann Haritonenko /Shutterstock)

​It’s winter, but don’t put your sunglasses away

Your long-term eye health is affected by your everyday choices, new research shows.

Most people wear (and buy) their sunglasses in the summer. It's an undisputed must for the quintessential warm-weather wardrobe. But new eye-health research says it's vital to wear your shades all year round, not just in the warmer months.

That's more than just generic good advice: There are two main factors that can increase your chances of getting glaucoma when you are older, and one has to do with how much solar radiation your eyes get, which can be effectively controlled using sunglasses. 

A group of scientists from Brigham and Women's Hospital, Harvard Medical School and Tel Aviv University headed by Dr. Louis Pasquale, the lead researcher on a recent paper published in JAMA Opthalmology, looked at solar exposure and the history of where people lived, and compared that data to people who have exfoliation syndrome (XFS), the precursor to glaucoma. People with XFS have a six-times-higher chance of the progressive and non-reversible eye disease. The study, which was conducted both in the United States and Israel, found that "every hour per week spent outdoors during the summer, averaged over a lifetime, was associated with 4 percent increased odds of XFS." This is an important finding, since previous studies hadn't looked at lifetime solar exposure, only shorter-duration exposures. 

Even during the winters months it's important to protect your eyes from the sun.Even during the winters months it's important to protect your eyes from the sun. (Photo: Blazej Lyjak/Shutterstock)

In addition, people who live at higher latitudes experience higher rates of XFS (so if you think that living away from the tropics helps your eyes, the opposite is actually true). Why would this be the case? Pasquale told From The Grapevine that he believes "light reflected from the horizon into the eye is what contributes to this disease, as we generally are not gazing directly into the sun, particularly during midday when solar rays are strongest. At higher latitudes, light rays from the sun are more angulated and have more opportunity to reflect off the horizon into the eye." 

The study also looked at sunglasses-wearers vs. hat-wearers and found an advantage in preventing XFS in those who wore sunglasses: "Hats can’t block rays reflected from the horizon into the eye. Sunglasses can," said Pasquale. 

Similarly to skin cancer prevention guidelines, keeping out of the sun during prime-time hours (between 10 a.m. and 4 p.m.) will protect eyes, too. But your environment matters: "Be particularly cognizant of environments where there are lots of chances for reflection such as sand, water and snow. Take up golf (green grass does not reflect sun very well) and stay out of the sand traps!" Pasquale said. 

Speaking of sports, it's especially important to wear eye protection during winter sports like skiing and snowboarding. You may have heard of snow blindness (the medical term is photokeratitis), which is actually a sunburn on the eye's cornea. If it sounds painful, that's because it is – though it's usually temporary. “In photokeratitis, tiny blisters form on the surface of the cornea,” Dr. Gail Royal, an ophthalmologist in Myrtle Beach, S.C., told WebMD. “It’s a condition that will generally resolve on its own with proper medical treatment, but it’s uncomfortable enough to spoil your vacation.”

While scientists have long suspected blue-eyed people to be more susceptible to glaucoma, Pasquale's data doesn't really bear that out. Also, while women were at higher risk in this data set, researchers aren't sure why. Pasquale said he doesn't think there is a gender effect, but that it all boils down to time spent outdoors: "In some populations, men spend more time outdoors, but in others, the opposite is true."

No matter your eye color, location or the season, it's best to start wearing sunglasses at a young age, since the damage caused by UV rays is cumulative over a lifetime. When you're looking for new sunglasses, look for complete UVA/UVB protection and polarized lenses, which will specifically help with the glare issue. You'll not only be able to see better in situations when there's horizontal sunlight and reflected light, but your eyes will be more effectively protected. Last of all, find a pair that's comfortable on your face, and flattering, so you get into the habit of wearing them – if you aren't already. 


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​It’s winter, but don’t put your sunglasses away
Your long-term eye health is affected by your everyday choices, new research shows.