How to identify the sunglasses uv protection function

Hot, street more and more women wear a sunglasses, in add summer for their enchanting amorous feelings at the same time, the sunglasses can also have the effect of preventing violent sunlight stimulation to the eyes. Recommended reading: summer driving sunglasses myth! Many women simply choose the design of sunglasses, and ignore the color, lens degree, prevent the internal factors such as uv index, not only less than sunglasses due role, or will produce the incommensurate symptom such as dizziness, eye acid bilges, sometimes slow, color vision illusion, depending on the walk of inequality symptoms, even may cause traffic accidents, it seems, the choose and buy sunglasses also can't careless. 1, tags: UV index sunglasses can block ultraviolet light, because the lens and add a layer of special coating, at the same time of block, absorb ultraviolet light, also block the part of the visible light, the light transmittance of the lens have fallen. So high quality sunglasses block uv ability strong, light transmittance drop it few, and the coating has certain hardness is not easy to wear. To identify whether a pair of sunglasses with uv protection function, can be seen in some product labels or lenses such as 'ultraviolet prevention', 'UV400' obvious logo. 'UV index', that is, filter out the effect of ultraviolet light, this is buying a standard sunglasses is very important. In the 286 - nm wavelength - 400 nm UV light is called, is generally 100% of the UV index is impossible, the vast majority of sunglasses UV index at 96% 98%. Labeled 'UV400' sunglasses can reach more than 90% uv defense level, its lens through special processing, can stop less than 400 nm wavelength ultraviolet light. Wear contact lenses can choose contact lenses with uv radiation functions, can filter out 90% of the ultraviolet light, then put on sunglasses, be at a higher level of security. 2, color: medium depth is better that the color of the lens should make the distortion of the color of the surrounding environment. Before without wearing sunglasses, observing the color such as red, green, yellow, and then put on sunglasses, observing the same object, observe the color of the two can't partial color, otherwise it will reduce the recognition ability of traffic lights. According to expert introduction, different color lenses have different functions, usually at a moderate depth of well, with gray, brown, green is preferred. And, depending on the lens color choice should be in color distortion, clear edges, can effectively identify the different color lights for the principle. 3, the lens: check diopter people usually take in the sun by adjusting the pupil size to adjust the luminous flux, when the light intensity than the human eye to adjust ability, will cause harm to the human eye. Sunglasses can have the effect of keep out sunshine, to alleviate eye fatigue or the damage caused by the strong light stimulation. The eye wear bad glasses, as in a dark room, the pupils get bigger, the remnants of ultraviolet ray will be raking in eye, make the eye injury. In addition, the rules of the lens surface is not smooth, see the outside world produces distorted object, make the eye acid bilges, which in turn are nausea, loss of appetite, forgetfulness, insomnia and other visual fatigue. In addition, in the cloudy and indoor when there is no need to wear sunglasses indiscriminately, wear, can aggravate the burden of adjustment eye, eye muscle tension and fatigue, make the vision loss, serious can appear the symptom such as dizziness, not long. Regular sunglasses belong to light series, according to the regulations of the national standard, the flat lens dioptre tolerance is plus or minus 0. 08 d, and did not affect vision optical spot disease. Diopter once overweight, can make the eye fatigue, eye injuries, even is 'cultivating' into patients with nearsightedness or farsightedness. Identify the lens quality fit and unfit quality has a simple identification method: put sunglasses in rocking back and forth in front of him, to see if the object and the lens to move together. If move together, the lens dioptre, adverse to the eyes. And the lens surface should be smooth, without a ripple, no defects, no bubble, no grinding crack.
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