Summer how to choose and buy sunglasses

First of all, we have to clear the primary aim of purchasing sunglasses, is to try to cut ultraviolet harm to eyes, second is beautiful, so we must pay attention to the sun glasses UV index, namely filter ultraviolet effect. Ray-ban RB4221 - F men sunglasses 6170/55 blue eye to light the perception of the range is 380 ~ 780 nm wavelength of visible light, is refers to under 380 nm wavelength ultraviolet light, belongs to the invisible light. For example: UV380 significance to effectively prevent under 380 nm wavelength light. A qualified sunglasses not only can protect the eyes and tender skin around eyes, also have must prevent effect to tan. Because our eyes have self-protection instincts, eye pupil is on the basis of the strength of the light within the initiative to adjust the size, when eyes meet with strong light stimulus, the pupil will be natural, has cut into the eyes of the ultraviolet ray; When compare the dark light, the pupil will be natural to expand, increase the amount of light into the eye, and then have a better visual quality. Ray-ban sunglasses RB3449 men silver/lens dazzle colour blue 004/55 if we covet is cheap, or beautiful, choose inferior sunglasses, due to the inferior sunglasses not only can't prevent ultraviolet ray, also can make the light transmittance of the lens a serious decline, then through the lens of dim light, make the eye pupil dilation, ultraviolet (uv) will be a lot of shoots, after a long time may cause lens turbidity, retinal damage, cataracts, macular degeneration and other eye diseases. The sunglasses not only can't help, and can cause eye damage. So let's argue that want to buy good sunglasses, should choose to normal optician normal manufacturer production sunglasses with uv protection functions. Choose the colour of the sun glasses has exquisite ray-ban RB3532 men sunglasses 001/68 second gold is a choice of the colour of the sun glasses, common to the lens color has red, grey, green, blue wait for color. We think the colour of the lens with gray, green is good, because these color lenses of infrared, ultraviolet absorption is good, can improve visual contrast and clarity. Besides not glasses color is deeper, block the effect of ultraviolet radiation, the better, even if the lens color is deep, also not necessarily can effectively prevent ultraviolet ray, so must choose uv protection function of the lens are marked. In general the most appropriate color for depth, after wearing glasses, others only see your eyes is beautiful, if you wear sunglasses, others can very clearly see your eyes, then your lens color is too shallow. Of course when the choose and buy sunglasses, we also note that the lens is smooth, level off, the mirror with and without scratches and other lens surface. In the end, hope we can buy a pair of conducive to healthy eyes, was suitable to the sun glasses.
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