As the summer comes, sunglasses have become a fashionable element for people to chase, from dozens of yuan, hundreds of dollars to thousands of dollars or even thousands of yuan of various types of sunglasses are dazzling. It is necessary to have a pair of sunglasses in the summer, but if you choose a pair of inferior and unqualified sunglasses, you can not only resist the ultraviolet rays, but also enlarge the pupils and make the lens of the eyes absorb more ultraviolet rays. Eye diseases such as cataracts, so sunglasses are not an optional accessory. So, what should the citizens pay attention to when buying sunglasses?
Many people know that strong ultraviolet rays can cause sunburn, but many people do not know that their eyes will be "sunburned." As the extremely delicate part of the human body, the eyes are easily sunburned by ultraviolet rays. The sun has a cumulative effect. Over time, it is bound to be harmful to the eyes. It is called "chronic light damage" in medicine.
The main function of sunglasses is to block the damage of ultraviolet rays to the eyes, not just to improve the visual effect. This requires that the transmittance of sunglasses to ultraviolet light in the sun is as low as possible, that is, the higher the reflectance and absorption rate, the better.