A lot of objects can reflect light. Some of the light is horizontally polarised and some vertically polarised, depending on the angle the light is hitting the object. The light that reflects from an object which obstructs our view is known as glare. Usually it is an intense ray of reflected light, often horizontally polarised. Polarised lenses in designer sunglasses contain a special filter that reduces the horizontally polarised light. Objects that can reflect such light include water, snow and glass.
People who enjoy a lot of water related activities such as fishing will feel the fuller benefits of polarised sunglasses. As water reflects light, it makes it difficult for fishermen and fisherwomen to see under the water. Polarised sunglasses remove or at least reduce some of the glare making the water seem clearer.
Snow, similar to water can reflect light. This is very dangerous for people who are actively partaking in snow based activities such as skiing. Skiing is already a high risk activity. Skiers have enough to deal with when it comes to the ice, hidden dangers, slopes and more. Polarised lenses are highly recommended for skiers as by reducing glare, it removes one of the possible risks of injuring yourself. Removing the glare from the snow allows skiers to have better vision ahead allowing them more time to plan ahead as they enjoy themselves. Polarised snow goggles exist for skiing and other similar activities.
Roads reflect a lot of horizontally polarised light which is why polarised sunglasses are recommended for frequent drivers. Drivers don't want to be hindered by sunlight being reflected from the road surface. It's dangerous for drivers if they are unable to have good vision ahead of them. Removing the glare from the road allows better clarity of vision, more time for judgment and can save lives.
The advantages of polarised lenses are that they remove glare, allow the wearer clearer vision under certain conditions, are comfortable for the eyes and selectively decrease the amount of light. Polarised lenses do come with its disadvantages which should be made aware of. The lenses can reduce the visibility of LCD screens used in the dashboard of some cars, bank machines and other equipment and vehicles. Polarization is heavily affected by the angle you look at objects and also by the time of day (the location of the sun). Overall, polarised sunglasses are far more recommended for outdoor activities, especially for exercises, sports or driving.