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All About Eyeglasses

Date Added: March 19, 2010 10:52:50 AM
Category: Education Training And Employment
We wear sunglasses at present time all year round. Fashion sunglasses are not only a stylish accessory, they are vitally important to protect your eyes from UV rays. The penetration of ultra-violet rays into the eyes may provoke various ophthalmologic illnesses. Staying under the sunlight, in summer or in winter, is unhealthy for your eyes. Our organisms were adapted to protect the eyes from bright light – iris-contraction and squinting reflexes minimize the penetration of ultra-violet rays into the eyes. But the ultra-violet rays are active on an overcast day, so these natural defensive mechanisms aren't sufficient for absolute protection. That is when sunglasses come to the rescue. Contemporary sunglasses with UV coat characteristics represent an efficient device for individual shielding against the ultra-violet radiation. For instance, wide-brimmed hats give only 50% UV protection and are not effective against light reflected from smooth surfaces like water, grass and snow. That is the reason why your sight is misting and it's so difficult to drive a car in a bright sunlight. Eyes irritation and headaches are momentary symptoms if you stay under the sun rays for a long time. Besides, all this may result in more severe diseases with time. Sunglasses with good ultra-violet protection coat in their turn give high level of ultra-violet protection and better eyesight in the bright sun. The diversity of lenses with UV cover characteristics is wide, so you'll possibly need a brief guide to make a decision. First of all, do not forget that color and degree of darkening have nothing to do with the efficiency of UV-rays protection. You should pay attention to these features when selecting the sunglasses depending on your activity. In such a way, middle-dark lenses are perfect for wearing everyday while staying under the bright sunlight for a long time demands darker lenses. Polarized lenses are applied for driving or for water sports since this type of lenses diffracts the reflected light. For manufacturing prescribed sunglasses producers use photochromic lenses because optical transmission in these lenses is about 25-80%. Lenses used for various activities are also of different colors. In such a way, grey lenses are preferred by painters and decorators. Brown and green lenses increase the contrast of colors. Multiple followers of the sportive style give their preference to yellow lenses. Whatever type of lenses you choose, make sure that your sunglasses are with good ultra-violet coat characteristics.
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