A good sunglasses can effectively protect the eyes of the sunglasses for UK women can block 99% to 100% of the UVA and UVB, filter 75% ~ 90% of the visible light. In order to ensure that the sunglasses can filter enough visible light.
Plano sunglasses with best sales to ensure that it does not cause visual distortion.To ensure that the lens will not generate vision distortions if it can be hand-held sunglasses through the lens observe distant rectangular or linear, up, down, left and right slowly moving frame, if it is found that the distortion and deflection, bending, lens optical defects, unqualified.
Lens color should be uniform, a region will not suddenly become dark.If it is a gradient color lenses, lens colors should be gradually changed from the top down. Wearing cheap sunglasses when driving should choose gray so that it does not affect the color of the traffic lights