Benefits from polarized sunglasses

The history of sunglasses has witnessed some technological and aesthetical improvements in sunwear lenses. One of them is the creation and application of polarized sunglasses. Before the invention of polarized sunglass lenses, sunglasses were barely used to block out bright sunlight. Their styles were also quite simple. Those early sunglasses were equipped with crude frames and came in usually hand-held styles, which were quite different from sunglasses that can be seen today. Compared with regular sunglasses, polarized sunshades have definitely brought additional benefits to modern users.

The breakthrough made by polarized sunglass lenses

The invention of polarized lenses was a great breakthrough that it enabled sunglasses to block out harmful UV rays in sunlight and unwanted glare. In the 1930s, the Army Air Corp formed a well known company named Bausch & Lomb. The original purpose was to develop an anti-glare style of sunglasses for pilots. The company gained a huge success that the lenses created could eliminate 99% of reflective glare. This type of lenses was incorporated with a frame design that was slightly droopy. Researchers also applied a dark green tint in order to absorb the yellow band of the light spectrum.

The theory of polarization

A polarized lens is integrated with a vertically oriented polarizer, which is used to effectively block the horizontally polarized light from a flat surface. Those surfaces include still water, flat pavement, or even glass and shiny metals. Light reflection from these surfaces often makes people hard to focus properly and get a clear vision. Polarized sunglasses can remove the unwanted glare from these surfaces. Note that vertically reflected light is allowed to pass through the lenses but it is not the major source of glare that affects human vision. Wearing polarized sunglasses can help avoid some dangers. For instance, walking on a flat pavement with a pair of polarized sunglasses helps see other pedestrians clearly.

How to verify polarized lenses

Some methods are available to test a lens that whether it is truly polarized. A tester can go to a surface that highly reflects a large amount of light, such as a calm lake. Then put on the sunglasses and look at the most reflective area of the lake. During this process, the tester should turn to the right and left to find differences. In each movement, a true polarized lens will first get light and then darkens. This process proves the effectiveness of polarized lenses in blocking glare. Another way to verify polarized sunglasses is to put two pairs together and rotate one of them to 90 degrees. If both pairs are authentic, light will be blocked.

Polarized sunglasses may be problematic

Polarized sunglasses are widely used by the public now. They are becoming more and more popular during outdoor activities. These sunglasses are competent in most outdoor environments. However, reports show that polarized sunglasses are not perfect in certain circumstances. For example, they do not work well near reflective snow surfaces. In addition, when it comes to LCD surfaces, polarized sunglasses often have a poor performance. Currently, LCDs are commonly equipped in car dashboards, bank machine displays and so on. In certain angles, sunglasses make those LCDs invisible.