polarized bifocal sunglasses
Polarized sunglasses were originally used to reduce reflected glare from the water in boating and fishing fields. With the development of polarized sunglasses, many others who participate in outdoor activities that require clear vision, such as skiers, bikers, golfers, joggers and so on are also interested in polarized sunglasses. Polarized sunglasses not only can reduce the glare from long, flat surfaces, but also are suitable for light-sensitive individuals working indoors, such as those continually exposed to light throw windows.
How does a polarized lens work in reducing glare? In fact, reflected light travels in a more horizontal direction instead of scattering in all directions. This way causes dangerous light which we view as glare. The polarized lens contains special materials which can filter out this type of light and thus reduce glare.
Thought polarized sunglasses provide a lot of advantages, such as comfort, glare reduction and so on, they are not perfect. For example, people may not want to filter the light reflected from icy patches during downhill skiing because low light can not send the message that they are approaching others. Furthermore, polarized lenses may also reduce the visibility of images appeared on the dashboards or other places because these images are created by liquid crystal displays (LCDs) and showed by digital screens. Another disadvantage of polarized lenses is the potential disability in seeing the cell phone or GPS device. This disadvantage may create fatal consequence in some special conditions. For example, boaters or pilots may make mistakes once the decision they have made is strictly based on the information showed by digital screens.
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