The lenses of polarized sunglasses are coated with a thin chemical film. This film eliminates much of the harsh, brilliant light that’s reflected off water or highway surfaces on sunny days. They are designed to reduce glare and decrease the amount of reflections that your eyes see. Glare occurs when our eyes see a flat surface reflecting light at one angle. These reflections can make it more difficult to see clearly on sun-filled days.

Here is an example of how effective polarized sunglasses can be.