In the hot summer, watermelon, sunscreen, and sunglasses all show up. Watermelon buy once every two days, sunscreen for one year, how long will you change your sunglasses? The frequency with which you change sunglasses depends on whether there is a new style that is more suitable for you. But you know? Sunglasses also have a "shelf life". If it works overtime, it will not only protect it, but will cause eye damage.
Exposure will affect the UV protection of sunglasses
Researchers at the University of Sao Paulo in Brazil conducted simulations in Europe, Australia, New Zealand and South America. The sunglasses were placed under a daylight simulator at a distance of 30 cm from the luminous point and continued to “exposure” for 50 hours to see how well the lens was degraded.
The British "Daily Mail" quoted researchers as saying that sunglasses for two years is still safe. Sunlight varies in different regions of the world, with the highest levels of UV in tropical countries and regions, even in winter, which means that UV protection in sunglasses degrades more quickly in these areas. In addition, the southern hemisphere residents change their sunglasses more than the northern hemisphere. The researchers also said that long sun exposure not only affects the UV protection of sunglasses, but also makes lenses more susceptible to breakage.
Researchers at the University of Sao Paulo in Brazil suggested that sunglasses need to be replaced every two years.