Polarizing: A polarizing filter's primary function is to reduce glare from sunlight on snow or water. Some manufacturers, such as Smith and Bollé, insert a polarized film between 2 thin lenses. Oakley uses a method they call infused molding. This combines a liquid infusion process to combine the lens material and the polarizing filter.
Photochromic: These lenses automatically change their tint level according to conditions and UV intensity. The more sun and UV rays, the darker the lenses become. If it's snowing or overcast the lens stays lighter. Indoors, they always stay light no matter the light intensity.