People usually worry about their skin when considering sun damage. However, UV rays from the sun can damage eyes.
The National Eye Institute, part of the National Institutes of Health, found that UV radiation damages lens proteins. With time, this damage might lead to cataracts, which impede vision.
“When you don’t wear protection, ultraviolet radiation you can’t see is penetrating the eye, and the eye structures are very sensitive to it,” explains Nashville-based ophthalmologist and American Academy of Ophthalmology clinical spokesman Dr. Rebecca Taylor. The retina’s macula is fragile. “If you put a target in the center of the retina right behind the pupil, the macula would be the bull’s-eye,” Taylor says. “And when light enters the eye, it hits the macula like a laser.”
UV radiation may increase the risk of macular degeneration, a leading cause of age-related blindness. Sun exposure is also connected to eye cancer and photokeratitis (commonly known as “welder’s burn”), which can cause temporary blindness or blotchy vision.
Sun-related eye injury is more likely at specific times and places. Dr. C. Stephen Foster, an ophthalmology professor at Harvard Medical School, says spending time on a boat, amid snow, or in a car on a sunny day “is like getting a double dose of ultraviolet light.” A second exposure from reflected light follows the direct sun exposure. Sunlight is brighter at higher elevations, increasing eye hazards.
Sunglasses protect eyes from these issues. Not all hues are alike. “It doesn’t matter how dark they are or the lens color,” Taylor explains. “The most important thing is that the sunglasses block 99–100% UVA and UVB rays.”
Just search for a UV protection sticker or tag on cheap sunglasses. “Also, polarization has nothing to do with UV protection,” Taylor argues.
Lens size also matters. “The bigger the better,” she says. “With little, round John Lennon glasses, scattered rays come in from all sides.” In a 2018 Swiss study, large sunglasses blocked more UV rays than smaller ones, and UV-blocking goggles provided the highest protection.
However, sunglasses may not be necessary during certain times of day. Studies demonstrate that light-sensing photoreceptors in the eye set the body’s circadian clocks, which regulate sleep, food, and more. Research shows that mornings with “high levels” of bright light improve sleep. Wearing sunglasses in the morning may disrupt these processes.
Foster suggests going without sunglasses until 9 or 10 a.m. In the morning, the sun’s rays aren’t powerful enough to cause any damage, yet exposing the eyes to natural light can establish the body’s “internal clocks,” he explains.
