You probably remember a time in childhood when you were shooed outside to play. Maybe an adult just wanted you out from underfoot or thought you needed more physical activity. It’s likely that neither of you knew that getting outside might also have been good for your eyes.
Nearsightedness, clinically called myopia, appears to be becoming more prevalent in the United States and around the world, but several studies have found that exposure to outdoor light may help prevent nearsightedness, the inability to see far off objects clearly.
Exposure to high-ambient light seems to make a difference in the prevention of myopia. In a study of about 1,000 6-year-old children in China, it was found that the addition of 40 minutes of daily outdoor activity reduced the rate of myopia over the next three years. A previous study in the United States found that, in children with two myopic parents, spending about two hours a day outside could reduce chances of needing glasses to about 20 percent, the same chance as a child with no nearsighted parents.
“Research is beginning to suggest that increased time spent outdoors may be a protective factor against the development of nearsightedness,” said Dr. Linda Chous, UnitedHealthcare’s chief eye care officer. “However, the benefits of outdoor time must be balanced with precautions to protect against some harmful wavelengths of light.”
While the links between outdoor time or sunlight exposure and myopia are still being debated, the negative effects of sunlight through exposure to UV rays and blue light are well-documented.
“We think of digital devices as creating huge risk for overexposure to blue light, but people forget that the sun emits a large amount of blue light, as well as harmful UV rays,” Dr. Chous said. “Overexposure to UV increases the risk of cataracts and other eye diseases, and overexposure to blue light may contribute to changes in the retina that happen as we age, called age-related maculopathy. Protection from UV and blue light is like ‘sunscreen for the eyes’.”
She recommends that children and adults always wear sunglasses when outdoors, even for short amounts of time.
Dr. Chous also has advice about shopping for sunglasses: “Just because lenses are tinted, doesn’t mean they will block UV light and blue light, so check the labels and make sure they block both before buying.”