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All You Need To Know About Eyewear |
| Date Added: March 16, 2010 06:23:52 PM |
| Author: cokntact59 |
| Category: Shopping And Services: Health |
| Today we wear sunglasses all year round. Designer sunglasses are not only a stylish accessory, they are essential to protect your eyes from ultra-violet rays. The penetration of ultra-violet rays into the eyes may bring various ophthalmologic problems. Staying under the direct sunlight, both in summer and in winter, is very harmful for your eyes. Human organism was adapted to protect the eyes from sunlight – iris-contraction and squinting reflexes reduce the absorption of ultra-violet rays. But the ultra-violet rays are active on an overcast day, so these natural defensive mechanisms are not sufficient for absolute protection. That's when sunglasses go to the rescue. Modern sunglasses with anti-UV cover represent an efficient appliance for individual shielding from the UV rays. For example, wide-brimmed hats provide just 50 per cent UV protection and aren't efficient against light reflected from smooth surfaces like grass, water and snow. That is why your vision is misting and it is so difficult to drive a car in a bright sunlight. Headaches and eyes irritation are instant symptoms if you stay under the direct sun rays for a long period of time. What's more, this all may bring to more severe problems as time goes by. Sunglasses with good ultra-violet protection coat in their turn give high level of sun shield and better eyesight in bright sunlight. The variety of lenses with ultra-violet protection cover is great, so you'll possibly need a guide to make your choice. Firstly, note that color and degree of darkening have nothing to do with the efficiency of ultra-violet rays shielding. You should pay attention to these characteristics when selecting the type of lenses depending on your activity. This way, middle-dark lenses are perfect for wearing everyday while being under bright sun for a long period of time demands dark lenses. Sunglasses with polarized lenses are used when driving or for water sports because the mentioned type of lenses diffracts the reflected light. For producing prescribed sunglasses manufacturers apply photochromic lenses as optical transmission in these lenses is around 25-80%. Lenses used for various activities are also of different colors. This way, grey lenses are preferred by painters and decorators. Brown and green lenses improve the range of contrast. Multiple followers of the sportive style show preference to yellow lenses. Doesn't matter what type of lenses you prefer, ascertain that your sunglasses are with good anti-UV cover. |
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