| We wear sunglasses nowadays all year round. Designer sunglasses are not just a stylish accessory, they are indispensable to protect your eyes from ultra-violet rays. The penetration of ultra-violet rays into the eyes may bring different ocular problems. Staying under the direct sunlight, in summer or in winter, is unhealthy for your eyes. Our organisms were adapted to shield the eyes from bright light – iris-contraction and squinting reflexes minimize the absorption of ultra-violet radiation. But the UV-rays are still active on a cloud day as well, so the mentioned natural defensive mechanisms are not sufficient for absolute protection.
That is when sunglasses go to the rescue. Modern sunglasses with UV coat characteristics represent an effective device for individual shielding against the ultra-violet rays. For instance, wide-brimmed hats provide just 50% UV protection and aren't efficient in relation to reflected light. That's the reason why your eyesight is misting and it's so difficult to drive a car in a bright sunlight. Headaches and eyes irritation are instant symptoms when you stay under the sun for a long period of time. Moreover, this all may lead to more severe problems as time goes by. Sunglasses with good ultra-violet protection cover in their turn give high level of UV shield and better eyesight in bright sunlight.
The diversity of lenses with UV cover characteristics is wide, so you will probably need a guide to make a decision.
First of all, do not forget that level of darkening and color have nothing in common with the efficiency of ultra-violet shielding. You have to take these features into consideration when choosing the sunglasses depending on your activity. In such a way, middle-dark lenses are ideal for wearing everyday while being under the bright sunlight for a long time demands dark lenses.
Sunglasses with polarized lenses are used when driving or for water sports because the mentioned type of lenses diffracts the light reflected from horizontal surfaces. For manufacturing prescribed sunglasses producers use photochromic lenses since optical transmission in these lenses is around 25-80 per cent.
Lenses used for different activities are also of various colors. This way, grey lenses are preferred by decorators and painters. Brown and green lenses improve the contrast of colors. Numerous followers of the sportive style show preference to yellow lenses.
Whatever type of lenses you choose, make sure that your sunglasses are with good UV cover characteristics. |
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