Check out this neat demonstration of how polarized lenses/sunglasses reduce glare.
Polarized lenses are made by applying a special chemical to the lenses in a vertical pattern which in turn helps block out horizontal light waves that typically produce glare. The American Academy of Ophthalmology explains it more eloquently:
Think of it like a miniblind hanging in front of a window. Only light that passes through the blind’s openings can be seen. On polarized sunglasses, the filter creates vertical openings for light. This means that only light rays that approach your eyes vertically can fit through those openings. The lenses will block out all the horizontal light waves bouncing off a smooth pond or a shiny car hood, for instance.
As a result, the image you see with polarized lenses is a bit darker than usual, but objects look crisper and clearer, and details are easier to see. People who use polarized sunglasses for long stretches of time often say they are less tired than usual after hours of battling sun glare.
