Sunlight can become partially polarized by the scattering of air molecules or by reflecting off something like a lake. This means that after scattering or reflecting the sun's waves oscillation angles, they are no longer random in all directions but have a preferred direction on average. In the case of a horizontal surface—like a lake or a road—the preferred direction is horizontal. This horizontally vibrating reflected sunlight is the nuisance we see as glare, and this is why polarized lenses are so useful to beach goers and motorists: they block glare. The polarized filters on these lenses preferentially block the horizontal component of light oscillation while transmitting the vertical component. The result is a darker image but with better contrast