Two polarized lenses stacked vertically, the lens will appear opaque phenomenon. The polarizer lens specially designed so that only the parallel light through the lens, when stacked vertically in the two lenses most of the light is blocked. At the time of purchase, as long as such a simple operation, we can immediately know the authenticity of products and good or bad. Usually identify the polarizer identification plate, the naked eye black stripes, but to wear the the polarizer look you can see the naked eye you do not see the black stripes, sunglasses will not. You can also experience specific to the sun, in the sunlight, the polarizer will be significantly comfortable than ordinary sunglasses a lot. Of course, the difference between the polarizer and sunglasses also clearly reflected in the price, general polarizer prices currently on the market in about a few hundred dollars, as little more than thousands of thousands of thousands of professional outdoor polarizer.
If the sunglasses do not provide UV protection, it will give you more exposure to UV light. The cheap sunglasses filter out a portion of the light, causing your iris to open to receive more light. This also would allow more ultraviolet light to enter, increasing the damage caused by the ultraviolet rays on the retina. Therefore, a variety of sunglasses is really different. For the specific use of the environment, the selection of suitable, high-quality sunglasses will provide you with maximum protection.