Polarized sunglasses have been around since 1936, when Edwin H. Land began experimenting with making lenses with his patented Polaroid filter. An increasing number of sunglasses today have polarized lenses, made of Polaroid polarized plastic sheet, to reduce glare caused by light reflected from polarizing surfaces such as water as well as by polarized diffuse sky radiation, or skylight. This can be especially useful when fishing, as the ability to see beneath the surface of the water is crucial.
The polarized sunglasses used by fishermen have polarized filters with the transmission axis oriented vertically to block the light reflected by the water surface. These sunglasses have increased in popularity and is are now a must have for all other water sports. They are also becoming popular with truck drivers and for general outdoor activities. These have seen a jump in sales during the last five years and are now the fastest growing segment in eyewear.
To check if your sunglasses are polarized, you can look through the glasses at the reflection of any object on a window panel. Remember that you have to look at an angle to the glass. If the intensity of the reflection does not change with respect to what you see through the window, they are not polarized.
Polarized sunglasses are better than normal sunglasses decrease the intensity of everything by the same amount. Polarized sunglasses can selectively eliminate the reflection from light coming from above the water surface.
These type of sunglasses have been very popular in fishing and watersports. It is useful in fishing and watersports because they help a lot by reducing the suns glare and its blinding effect. Even without glare, sunglasses also selectively reduce other reflections from objects above water, including clouds and even the sky. Polarized sunglasses also make the water seem darker but more transparent if you look at it from an angle but not straight down.
Polarized sunglasses can also help you when driving because of bright reflections of the sun on the cars ahead. Polarized sunglasses will help more with the reflections from the glass than from the metal as the glasses are polarized to a higher degree. Polarized sunglasses also help with the brightness of the road itself. If the road is wet, you get the same anti-glare power than at sea.
These can also help in skiing and non-water sports. Polarized sunglasses can not help with snow glare although they often advertised for that purpose. However, polarized sunglasses can make features far away really stand out when the sun is high. On the other hand, when the sun is low, these sunglasses could be detrimental. There are a lot of other uses of polarized sunglasses other than in water sports and the reason is that the reflector always remains horizontal.