Polarized sunglasses are designed to reduce the glare caused by the reflection of sunrays, particularly from the horizontal planes like water, snow, flat road and car hood.In order to understand the working principle of polarized sunglasses, let's discuss in brief about the reflection of light from the plain, smooth surfaces. When light falls on a flat and smooth medium, the reflected light is directed in the horizontal planes (polarized), rather than dispersing or scattering in all directions. The horizontally oriented reflected light is experienced as annoying flashes of white, known as glare. A prolonged exposure to such light intensities may result in temporary blindness. Sources from http://www.buzzle.com/articles/how-do-polarized-sunglasses-work.html.
Light travels as waves through the air. These waves vibrate in all directions. When light hits a reflective surface, all the reflected light then vibrates parallel to the surface. For example, light reflecting off the surface of water, the road or the bonnet of your car will vibrate in a horizontal direction.The majority of reflective surfaces that cause us glare are horizontal.So polarized sunnies have polarizing filters set in a vertical direction. Only light vibrating vertically can get through the filter, everything else is blocked out. 100% of the reflected light is blocked.
"In polarized sunglasses, a special filter is used that helps in eliminating the reflected light of high intensity or glare. In other terms, this polarized filter allows passing only a portion of light having wavelengths that are not aligned with the particles of the filter. Speaking about the composition of polarized filters, they are made up of chemical compound coated on a transparent glass or plastic lens. The chemical film consisted of tiny molecules that align in a parallel fashion with respect to one another. If the chemical film is coated uniformly on the lens, the molecules absorb the entry of all light intensities that matches their alignment. Since glares are mostly caused by the horizontally oriented light waves, polarized sunglasses are designed in such a way that they allow passing of only vertical polarized light. With such polarized sunglasses, the texture and shape of objects become more clear, irrespective of the glare. This way, polarized lens reduces the glare effect. One of the drawbacks of polarized sunglasses is that liquid crystal displays (LCD's) may not be visible while viewing at specific angles.
It is really a difficult question.I only know that polarized sunglasses can eliminate most of the reflected light from water surface,ground etc.,so they can give you a better view than the ordinary ones.
Polarized sunglasses are more protective than common sunglasses. Polarized sunglasses are filled with polarized lenses. Compared common sunglasses lenses, the polarized lenses can filter glares and reflective light. Also, the lenses can prevent UV rays and reduce intensive sunlight so as to provide people good and comfortable vision to see somethings.