Exposure to sunlight may reduce the risk for nearsightedness, a new study reports.
Researchers recruited 371 men and women with nearsightedness, or myopia, and 2,797 without. Their average age was 72. They gave them eye examinations, took blood samples and interviewed them about their health and behavior over the years, estimating exposure to ultraviolet B rays.
The study, in JAMA Ophthalmology, found that those with the highest UVB exposure, especially in the teenage and young adult years, had about a 30 percent lower risk for myopia than those with the lowest exposure. Exposure to sunlight increases vitamin D levels, but vitamin D levels did not correlate with nearsightedness.
They also found that more schooling increased the risk of nearsightedness. Those in the highest one-third in years of education had more than double the risk of myopia compared to those in the lowest one-third. The reason for the effect, which was independent of UVB exposure, remains unknown.
The researchers were surprised to find that people with the highest blood levels of lutein, a nutrient found in leafy vegetables, had a 43 percent reduced risk of nearsightedness compared with those with the lowest levels.
“Spending time outdoors is good advice for trying to reduce the chance of getting myopia,” said the senior author, Astrid E. Fletcher of the London School of Hygiene and Tropical Medicine, though she advised against spending time outdoors in the middle of the day, when skin cancer risks increase.