and are with absolutely distortion-free surface treatment. Many sunglasses have a smooth transition glasses, the lower part is darker and the top is lighter. On of the glass materials is polycarbonate, which are the lightest and most comfortable lenses. These lenses are the most impact resistant lenses available and are the lenses of choice in sunglasses, sports glasses, and safety glasses for eye protection. Polycarbonate lenses always come with a built-in scratch resistant coating, it makes them extremely strong and scratchproof. Also are used acrylic and polarized lenses. In polarized lenses one or more layers are pressed together with a polarized filter in between. Polarized lenses are used in sunglasses to reduce glare from reflective surfaces such as the surface of a lake or the hood of a car. All this lenses absorb all harmful UV light. Exposure to UV radiation can harm your eyes and affect your vision as well. The UV-B radiations cause most of the damage to our eyes and skin. They cause our skin to tan and are a major cause of cataracts. Finally, UV-A radiations are the least harmful, though they should to be filtered whenever possible.