To meet the summer you need a pair of sunglasses

Spring is coming, summer be far behind? To face the dazzling sunshine in summer, many friends all choose the sun glasses, friend how to choose sunglass? Small make up this will tell you that a lot of friend ~ is wearing sunglasses to decorative effect, but in the summer the sun glasses to protect the glasses block uv rays, if you buy a pair of inferior sunglasses so counterproductive, not only can't block uv rays, still can make the pupil grow larger, let the lens of the eye to absorb more ultraviolet light. Uv damage to the eyes mainly depends on its wavelength, the radiation intensity and radiation time, radiation and the person's own body quality, eye health, etc. The human eye cornea, lens is vulnerable to uv rays, sunlight keratitis, corneal endothelial injury and sunlight cataract is a common eye disease. Whether a pair of sunglasses with uv protection function, we are difficult to distinguish authenticity with the naked eye, but we can according to some of the products parameter as a basis for judgment. Some vendors often use such rhetoric to describe his sunglasses 'good uv protection', 'about can block ultraviolet light', 'the product UV400. ' So what does all these values reflect the? UV ultraviolet represents the vacuum ultraviolet ray, is the wavelength of 200 nm to 380 nm of the sun's rays. It is divided into the wavelength of 315 nm to 380 nm UVA, wavelength of 280 nm to 315 nm UVB and UVC wavelength of 200 nm to 280 nm. Reach the earth people exposure to ultraviolet UVA is ninety-seven percent. So did not indicate how many sunglasses UV good don't choose. Different color lenses have its corresponding function, the grey lens can be very effective in reducing the intensity of light does not affect the color contrast. Brown glasses can enhance some blue light color contrast and blocked, so the more bright day, wearing a brown of good, such as the snow fell. Yellow is more yellow than brown color, can largely enhance the color contrast, almost block all of the blue light, separately when the traffic lights, don't choose the color. Red and orange suit to cloudy in winter. Purple is suitable for the people going hunting in the green grass. Copper can mediate the color of the sky and the grass at the same time, suitable for playing golf. Blue and green can strengthen the contrast of yellow, suitable for playing tennis.
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