Choosing sunglasses must can eye

The sunglasses on the market there are good and bad, the quality is uneven, now age everyone as long as the prevention of uv protection and healthy eyes, what's the correct selection of ultraviolet prevention wound eye glasses? Recommended reading: myopia how to choose sunglasses? 紫外- A and UV - B easy eye lesions caused by ultraviolet light wave length can be divided into the UV - 一个( Between 320 and 400 nm) ，UV- B（ Between 280 and 320 nm) And UV - C ( Between 100 and 280 nm) 。 In general, the shorter the wavelength the higher the energy, hurtful is, the greater the energy of the strongest UV - C in the atmosphere will be isolated; Of eye problems are mainly the ultraviolet UV - A and UV - B，UV- A is lead to cataracts, and macular lesion, can cause skin aging, black; 紫外- B the shorter wavelength, energy than UV - relatively A strong, easy to cause eye 'and light keratitis. Uv damage eyes, choose sunglasses have the steps! The choose and buy sunglasses to pick UV400 lenses if can through optical glasses, or buy bigger brand sunglasses, will be guaranteed, the most important is choose UV400 uv lens, isolated from below the wavelength of 400 nanometers. Another main function, the sun glasses is to reduce the intensity of visible light, let a person feel not too bright light, see contrast will be better, in order to avoid the retina is stimulated too long, cause eye fatigue and injury. To choose places where the sun glasses filter rating in general indoor environment, drive, or walk walk inside the city, can filter out 50% 60% of visible light sun glasses is enough, big brand can indicate the degree of optical filter the sun glasses, about to choose 2 or 3, if no data, the most simple judgment method, is put on the sunglasses, about in front of a mirror can see the eye contour. If you want to go to the beach, mountain climbing or skiing, ultraviolet ray is stronger, because these places suggested choice can filter out 80% 90% of visible light sun glasses, that is, filter degree level 3 to 4 this interval, the level of the sun glasses up after the eyes detail outline is not clear. Uv damage eyes, choose sunglasses have the steps! Inferior very injured eye lens to poor quality of the unqualified dyeing lenses, can filter out only visible light, and can't block uv rays, wear such inferior sunglasses, but more damage than not wearing eyes, because in normal light, the pupil will have protection mechanism, the pupil shrinks, let the lower proportion of the visible light and ultraviolet light into the eye, Inferior lens filter out only visible light, the pupil will think now the light is not so strong, at this time, dilated pupils, the ultraviolet rays to penetrate the retina and lens instead, hurt the eyes.