How often do you change your sunglasses? Every year according to fashion? When are they damaged? Never ? Difficult to know when it is really necessary to change them (in any case, we had not frankly already posted the question). A Brazilian study rightly pointed out the fact that no recommendation exists as to the frequency of changing sunglasses, pointing out in passing that the tests which determine UV protection lack long-term vision.
Indeed, as the article on the Health.com site explains, in Brazil, the tests which determine the level of UV protection of sunglasses take place as follows:the lenses are subjected to 50 hours of exposure to 30 centimeters of 'a 450 Watt lamp that simulates sunlight (which corresponds on average to 2 days of sunshine in summer or 4 in winter, less for cities close to the equator like Sao Paulo). An older study had shown that Brazilians wear their sunglasses on average two hours a day… for two years. The researchers thus wish to alert the health authorities so that these tests are revised:there is no guarantee that the UV protection offered by the glasses remains the same over time (and the glasses break more easily too). Their recommendation, until we know more about it:change the sunglasses after two years of wearing them regularly.
While waiting to learn more on the subject, there are still some precautions to take. When it comes to sunglasses, size matters! Indeed, if you wear glasses for outdoor activities, whether skiing or boating, it is better to wear large sunglasses, which offer greater protection. At the time of purchase, we only take glasses with CE certification and 100% UV or UV400 protection (the color of the lens or the price of the glasses are not enough to know if the glasses are effective) and above all, we do not do not buy if they are exposed outside because the glasses will inevitably have started to deteriorate. Finally, we keep the reflex to wear them all year round, and not just in summer:in winter, the reflection of UV rays on the snow is very important and can cause long-term damage.
