Polarized sunglasses are a particular variety of sunglasses that where once commonly used only by fishermen and sailors to reduce glare from the water. Recently however, many other people have come appreciate the benefits of polarized sunglasses, such as outdoor sports enthusiasts, drivers and just general day-to-day users. Polarized sunglasses offer a reduction, or even elimination, of glare that can come off long flat surfaces such as a road, ski slope or the hood of car. As such, golfers, joggers, skiers and bikers can also benefit greatly from polarized sunglasses. They are also handy for people who are sensitive to bright lights and for eye operation patients.

Polarizing filters as used in polarized sunglasses can reduce or eliminate reflected light by removing light polarized at 90° to the filters polarization axis. If two polarizers are placed on top of each other at 90° angles to each other, no light passes through. Light that is reflected from flat surfaces or calm waters is generally horizontally polarized. The horizontally polarized light is blocked out by the vertically aligned polarizers in the lenses.

There is some controversy surrounding the effectiveness of polarized sunglasses when used in snow conditions. Although they can reduce the glare given off by the sunlight reflecting off the slope surfaces, some experts believe that polarized sunglasses do not provide enough contrast to enable people like downhill skiers to spot ice patches and other hard to distinguish dangers.

There can also be problems viewing LCD displays through polarized sunglasses, such as though commonly found in ATM machines or on dashboards. When view through a polarized lens from a certain angle, the display can appear invisible.

Taking the above into account, polarized sunglasses are not for everyone, however for most sports and activities, polarized sunglasses can offer substantial benefits and there is wide range of products on offer to suit every need.

Recent developments in polarized sunglasses include polarized photo chromic lenses which will change from dark to light depending on light conditions. In bright sunshine, the lenses turn dark to protect the eyes and in relatively darkness they lighten up to allow full vision. These are ideal for people who are very sensitive to light and need to travel around a lot or generally for people who value the convenience of only having to carry one pair of glasses around with them.