the miracles of modern science

There are many great reasons, wearing sunglasses, but there are two main reasons. The first reason is to protect you from your eyes, brilliant sunshine to the optical lens dark sunglasses help block the bright light. The second is, the sun's ultraviolet rays, in the long run, your eyesight caused irreversible damage, including blindness, and even cancer is extremely harmful. A good pair of sunglasses can provide the necessary protection, prevent ultraviolet radiation risk.
So, you might ask, how Sunglasses really work? The answer my friend is really very simple. Colored lenses are called let less light reaches your eyes have a darkening effect. This in turn, let you squinting in the bright sunlight, and ultimately help you avoid eye fatigue strong glare of the sun with headache. Less squinting, also mean better visual acuity.
Ultraviolet filtering effect, however, is a more complex. With special coating surface UV filter lens, allowing light to pass through, and the reflection at the same time does not need uv. In the optical spectra, ultraviolet radiation is considered to be the waves of high frequency. Therefore, special chemical optical surface coating must be able to reflect the higher frequencies of light, while the low frequency light easily through. This is really one of the miracles of modern science.
Sunglasses vision correction and you have complex prescription sunglasses. These glasses not only to protect the basic dazzling light and ultraviolet radiation, but also like ordinary glasses to give the necessary correction your vision. This increases the sunglasses creation process step third: coloring, UV glazing, now corrected visual acuity. Or for the interests of those who want no prescription Sunglasses, brown clip-on lens, fit in the normal prescription glasses.