Also, in the past some goggle manufacturers (Marker) have used Trivex (also known as NXT); it has similar impact-resistance to polycarbonate, but is 10% lighter and has somewhat better optical qualities. It also may be a bit more scratch-resistant than polycarbonate, but still requires an anti-scratch coating when used in eyeglasses. I'm not sure if any still use Trivex.
POC makes some of their high-end goggles with NXT lenses. Typically those lenses are also also photochromic and polarized (and expensive).