Eyeglasses - Cognitive Information

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by: cokntact59
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Now sunglasses are worn all year round. Fashion sunglasses represent not only a stylish accessory, they are vital to protect your eyes against UV radiation. The penetration of UV-rays into the eyes may cause various ocular problems. Being under the sun, both in summer and in winter, is very harmful for your eyes. Human body was adapted to protect the eyes from bright light – squinting and iris-contraction reflexes reduce the absorption of ultra-violet radiation. But the UV-rays are still active on a cloud day as well, so the mentioned natural mechanisms aren't enough for absolute protection.
That's when wearing sunglasses comes to the rescue. Contemporary sunglasses with UV protection coat represent an efficient device for individual protection from the sun radiation. For instance, wide-brimmed hats provide only 50 per cent UV shielding and aren't effective in relation to light reflected from horizontal surfaces like water, grass and snow. That's why your eyesight is misting and it's so difficult to drive a car when the sun shines brightly. Eyes irritation and headaches are instant symptoms when you're under the sun rays for a long time. Moreover, all this may lead to more severe problems as time goes by. Sunglasses with good anti-UV coat in their turn provide high level of UV protection and better vision in the bright sun.
The diversity of lenses with ultra-violet coat characteristics is great, so you'll probably need a brief guide to take a decision.
Firstly, don't forget that color and level of darkening have nothing to do with the effectiveness of ultra-violet shielding. You have to pay attention to these characteristics when selecting the sunglasses in dependence on your activity. In such a way, middle-dark lenses are perfect for wearing everyday when at the same time staying under the bright sunlight for a long time requires darker lenses.
Sunglasses with polarized lenses are applied for driving or for water sports since this type of lenses diffracts the reflected light. For manufacturing prescribed sunglasses manufacturers use photochromic lenses since optical transmission in these lenses is around 25-80 per cent.
There are also lenses of various colors used for different activities. This way, grey lenses are selected by decorators and painters. Brown and green lenses improve the range of contrast. Multiple adherents of the sportive style give their preference to yellow lenses.
No matter what type of lenses you choose, make sure that your sunglasses are with good ultra-violet protection coat.

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