1.
Sunglasses, really will “get old”
The base material of sunglasses lens itself can absorb a little ultraviolet ray, the coating of sunglasses lens can also reflect off part of the ultraviolet ray, and a lot of sunglasses lens will add ultraviolet absorbing raw materials. In this way, the majority of UV rays can be “shut out” and can no longer harm our eyes.
But this protection is not permanent.
2.
Because UV rays carry a high level of energy, the material of sunglasses will deteriorate, so that the ability of sunscreen ingredients to absorb UV rays decreases. And the shiny coating on the outside of the sunglasses is actually the result of metal vapor deposition, and these coatings can wear out, oxidize, and lose their reflective ability. All these will make the sunglasses' UV protection ability discounted.
In addition, if we do not cherish the use of sunglasses, it will often cause direct wear and tear of the lens, loose temples, frame and nosepiece deformation damage and other problems, which will affect the normal use of sunglasses and protective effect.
3.
Doing so can make your sunglasses more durable
A pair of qualified sunglasses are often not cheap, we can make it protect us longer if we take good care of it, specifically we just need:
When not in use, timely storage, so as to avoid wear and tear or by direct sunlight.
Driving friends, do not rest sunglasses on the center console to let the sun.
When storing sunglasses temporarily, remember to keep the lenses facing upwards to avoid wear and tear.
Use an eyeglass case or pouch as these specialized storage containers are soft on the inside and do not damage the lenses.
Do not carry your sunglasses in your pocket or throw them in your backpack to rub against other keys, wallets, cell phones, etc. This can easily damage the coating of your glasses. It is easy to damage the eyewear coating. It may also directly crush the frame.
Clean sunglasses, you can use detergent, hand sanitizer and other cleaners to make foam to clean the lens, rinse clean with a mirror cloth dipped in dry, or directly using a special wet mirror paper, than “dry wipe”, so less likely to produce scratches.
Wear sunglasses correctly, do not put the sunglasses high on the head, because on the one hand, it is easy to touch off the fall, on the other hand, may break the mirror legs.
4.
In fact, it is not difficult to choose qualified sunglasses, as long as you are in a regular store, recognize the “UV400” or “UV100%” logo sunglasses will be no problem, these two logos indicate that the sunglasses can reach nearly 100% protection against ultraviolet rays, enough to play a protective effect. These two logos indicate that the sunglasses provide nearly 100% protection against UV rays, which is enough to provide protection.
How to choose the color? Generally speaking, we can give priority to teal, gray lenses, because the color of the object has less impact on the daily use, especially driving is more convenient, will not affect the driver to observe the signal light. In addition, those who drive can also choose sunglasses with polarized lenses to reduce glare and drive comfortably.
When choosing sunglasses, there is a place that is easily overlooked, that is, “shape”. It's easy to think that sunglasses with a larger area and a curvature that fits your face have the best sun protection.
If the size of the sunglasses is not appropriate, the curvature does not fit our face, or the lens is too small, even if the lens UV protection ability is qualified, it is still very easy to leak light everywhere, so that the effect of sun protection greatly reduced.
5.
We also often see articles that say that the banknote inspection lamp + banknote, you can judge the sunglasses reliable or not. Because sunglasses can prevent ultraviolet rays, through the sunglasses, banknote inspection lamps can not be anti-counterfeiting signs bright.
This argument is actually debatable, because it has to do with the power and wavelength of the lamp. Many of the power of the detection lamp is very small, and the wavelength is fixed, some ordinary glasses can block the ultraviolet light emitted by the detection lamp, so that the anti-counterfeiting mark can not light up. Therefore, to judge the protective ability of sunglasses, or use professional instruments more insurance, and for us ordinary consumers, recognize the “UV400” and “UV100%” is the most important.
Resources：https://www.thepaper.cn/newsDetail_forward_27596494
