| We wear sunglasses at the present time all year round. Fashion sunglasses are not only a stylish accessory, they are vital to protect your eyes from ultra-violet rays. The penetration of UV-rays into the eyes may cause various ophthalmologic problems. Staying under the direct sunlight, in summer or in winter, is very harmful for your eyes. Our organisms were adapted to protect the eyes from bright light – iris-contraction and squinting reflexes reduce the penetration of UV rays into the eyes. But the UV-rays are still active on an overcast day, so these natural defensive mechanisms are not sufficient for absolute protection.
That's when sunglasses come to the rescue. Modern sunglasses with ultra-violet protection cover represent an effective device for individual protection against the sun radiation. For instance, wide-brimmed hats provide just 50 per cent ultra-violet shielding and aren't efficient in relation to reflected light. That's why your vision is misting and it is so difficult to drive a car when the sun shines brightly. Eyes irritation and headaches are instant symptoms when you stay under the sun rays for a long period of time. Furthermore, all this may lead to more serious diseases as time goes by. Sunglasses with good ultra-violet protection coat in their turn give high level of ultra-violet shield and better sight in the bright sun.
The diversity of lenses with ultra-violet protection cover is wide, so you will possibly need a brief guide to take a decision.
Firstly, take into consideration that color and level of darkening have nothing in common with the efficiency of UV-rays shielding. You should pay attention to these characteristics when choosing the type of lenses in dependence on your activity. In such a way, middle-dark lenses are perfect for wearing everyday when at the same time being under the bright sunlight for a long time requires dark lenses.
Polarized lenses are applied for driving or for water activities as this type of lenses diffuse the reflected light. For producing prescribed sunglasses manufacturers apply photochromic lenses as optical transmission in these lenses is about 25-80%.
There are also lenses of different colors used for various activities. This way, grey lenses are selected 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.
No matter what type of lenses you prefer, make certain that your sunglasses are with good anti-UV coat. |
