Crystal glasses box is expensive, and after wearing let a person feel very cool and refreshing, someone will think it is a purpose. It is of no scientific basis. Crystal was first used in the glasses was because at that time, also can't manufacture optical glass, there is no better than the crystal optical materials. Scientific practice has proved that the light through the crystal occurs after the double refraction to produce foldover, and crystal block ultraviolet and infrared light effect is not good, most can go through. Geological hard brittle crystal glasses is expensive because crystal is strong, unfavorable annihilation and less pure crystal production, not because the eyes have a special maintenance effect, crystal glasses do people feel cool and refreshing, less because the crystalline lens of the ultraviolet and infrared absorption temperature is low, but does not raise. And raise glasses box.