What is the UV index of sunglasses? _Sunglasses knowledge_

In summer, the sun is strong, and the damage to the skin and eyes is not small. So you can see a lot of people wearing sunglasses on the street in summer. And at different times, the intensity of ultraviolet rays is also different, and the damage to the human body is different. Let's take a look at what the UV index of sunglasses means. The UV index of sunglasses refers to the function of anti-ultraviolet rays, and also refers to the effect of filtered ultraviolet rays. This is also one of the criteria for judging the quality of a pair of sunglasses. For sunglasses, the UV index should be to eliminate the light in this band of 280-400nm. At present, the UV protection of most sunglasses can reach between 96% and 98%. It is generally indicated on the tag of the sunglasses. Such as effective anti-UV400, 100% UV blocking and other words. The UV index refers to when the sun's position in the sky is higher, the sun's light hits the surface of the earth. The extent to which these rays of light reaching the earth's surface damage human skin. The UV index variation range is represented by a number from 0-15. The higher the UV index, the greater the damage to the skin. UV-B ultraviolet rays with wavelengths between 280 and 320 microns can cause eye diseases, such as keratitis, skin cancer, and cataracts if the wavelength is between 320 and 380 microns. Today's sunglasses that can block UV400 have an excellent function of filtering ultraviolet rays, which can filter out harmful light with a wavelength of 400 microns and protect the eyes from damage. What blocks UV rays is the material of the lens. The raw material that absorbs ultraviolet rays is added to the liquid of the lens, so as to achieve the function of anti-ultraviolet. What blocks the light is the color of the lens. The darker the color, the more light is blocked. Not all sunglasses have the function of high-quality UV protection. If the sunglasses cannot effectively filter the UV rays, wearing sunglasses will cause the pupils to dilate because they block the light, and more harmful light will enter the eyes more easily and cause damage to the eyes. . Therefore, when buying sunglasses, be sure to choose a regular place to buy. Something like this is good, excellent quality and cheap. Can effectively protect against UV rays.