At present time sunglasses are worn all year round. Fashion sunglasses are not only a stylish accessory, they are essential to protect your eyes from UV rays. The penetration of ultra-violet rays into the eyes may cause different ocular illnesses. Being under the sunlight, in summer or in winter, is unhealthy for your eyes. Human organism was adapted to protect the eyes from sunlight – squinting and iris-contraction reflexes reduce the penetration of UV radiation into the eyes. But the UV-rays are still active on an overcast day as well, so the above mentioned natural defensive mechanisms are not enough for full protection. That is when wearing sunglasses goes to the rescue. Modern sunglasses with ultra-violet cover characteristics represent an efficient appliance for individual shielding against the UV radiation. For instance, wide-brimmed hats provide only 50% UV protection and aren't effective against reflected light. That's the reason why your sight is misting and it is so hard to drive a car when the sun shines brightly. Eyes irritation and headaches are momentary symptoms if you are under the sun for a long time. Moreover, all this may bring to more serious problems with time. Sunglasses with good ultra-violet coat characteristics in their turn give high level of ultra-violet shield and better sight in the bright sun. The diversity of lenses with UV cover characteristics is great, so you will possibly need a brief guide to take a decision. Firstly, do not forget that degree of darkening and color have nothing in common with the effectiveness of ultra-violet radiation shielding. You should take these characteristics into consideration when selecting the sunglasses in dependence on your activity. In such a way, middle-dark lenses are ideal for wearing everyday when at the same time staying under bright sun for a long period of time requires darker lenses. Polarized lenses are used when driving or for water activities because this type of lenses diffuse the reflected light. For manufacturing prescribed sunglasses manufacturers take photochromic lenses as optical transmission in these lenses is about 25-80 per cent. There are also lenses of different colors used for various activities. This way, grey lenses are chosen by painters and decorators. Green and brown lenses improve the contrast of colors. Numerous followers of the sportive style show preference to yellow lenses. Doesn't matter what type of lenses you choose, make certain that your sunglasses are with good UV coat characteristics. |
