The polycarbonate material used in our lens protects against the intense shock of flying objects striking the lens. In the sporting world, unpredictable accidents can result in serious injury. But the polycarbonate used in SWANS lenses are used for the helmet shield on space helmets as it does not change with varying temperature as well as being 10 times stronger against impacts than glass. With this knowledge, you can be reassured that SWANS sunglasses will protect you from those unpredictable sporting accidents.