Polarized lenses are mainly employed for use in sunglasses, they provide protection from the sun and decrease glare levels thereby enabling better vision in certain conditions. The ability of polarized lenses to decrease glare from a reflective surface, such as the sun shining on to the hood of your car,or the surface of a body of water has made them invaluable to many who spend time outdoors for either business or leisure. Where as they were once something only those working on the water required, the ability to eliminate glare has now made polarized lenses widely used and commonplace.

So how exactly do they work?

Sunlight is absorbed by that which it shines upon, as it is not in and of itself polarized. In instances when it is not absorbed, it is reflected in one of the ways: vertically, horizontally or diagonally. This dictates how the light is reflected; when sunlight shines on a horizontal surface, the resultant light wave reflection will also be horizontal. The reflection will in turn hit your eyes in a similar manner and with the same type of angle, resulting in obscured vision. Polarized lenses are manufactured with a special filter that is specifically made to reduce glare by blocking reflected light as it hits your eyes. The filter is actually a series of small strips in a vertical pattern, similar to a set of venetian blinds. These strips in the filter serve to block horizontal light and allow only vertical polarized light to enter, thus eliminating glare.

A simple example of this (*and in turn a great way to verify that polarized lenses are indeed polarized as advertised) is to look at a reflective surface (example: the hood of your car) when wearing polarized lenses. If you slowly change your viewing angle by tilting your head either to the left or the right, you should observe a noticeable decrease in the glare being given off.

While polarized lenses may be of great assistance to some people in certain conditions and scenarios, it should be noted that the ability to reduce horizontal light may not be applicable in all situations where sunglasses or protective eye wear are worn.

Best uses?

The use of polarized lenses was introduced to the general public when fishermen discovered that glasses with polarized lenses enabled them to not only see just below the surface of the water, but also the lenses eliminated the glare produced when sunlight reflects off the surface of the water. Soon after, many other people in both professional and civilian situations began using polarized lenses. Eventually polarized lenses became a standardized item in the eyewear industry.

Essentially, polarized lenses can be put to use anytime there is a need to reduce or diminish exposure to reflected sunlight in order to maintain clarity. Typical uses would be when you are fishing, driving, running or jogging, boating and cycling.

If you've gone to the cinema to take in a 3D feature film in the last two years or so, then you've used polarized lenses. Where the effect of three dimensions was once achieved by using the familiar looking red and blue lenses as part of the stereoscopic process, new 3D technology utilizes polarized lenses. The biggest difference is that instead of one red lens and one blue lens, 3D glasses now use vertical polarization in one lens and horizontal polarization in the other lens, hence the reason the new 3D glasses use shaded gray lenses. The different polarization in each eye means your brain processes each type of polarization to create a realistic sense of depth in the image on screen. This is how the hyper-realism and three dimensional depth perception of films such as Tron: Legacy, Avatar and Up! is achieved.