Sunlight is absorbed or reflected in many directions. Sunlight reflected from a horizontal surface,
like land, water or vehicles around you is often reflected back horizontally, producing a very strong glare that affects your vision.
For us, it means that ground reflections cause a lot of interference with our vision on water or pavement.
Polarized sunglasses have a built-in, laminated filter that allows only vertical light rays to pass through,
and almost totally blocks horizontal rays to eliminate glares. This is most noticeable when boating or fishing, since you can suddenly see through the surface, which was previously clouded by the reflections from the sun and sky above.