In the optical examination we may, if we prefer it, polarize the primary light; but it is usually more convenient to analyse the scattered light.
All polarized lenses have some color, as it is possible to polarize light only when the film is colored.
In other cases, while too small to be directly visible, they are large enough to scatter and polarize a beam of light.
Sheer Vision glasses have lenses with an anti-reflective coating for night driving.More options for night driving glasses can be found at Polarize 4 U.
The larger ones polarize light, have angular outlines like those of crystals, and may even show twinning and definite optical properties by which they can be identified as belonging to felspar, augite or some other rock-forming mineral.