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Sun glasses are protective devices that prevent eyes damaging and discomfort by reducing bright light and ultraviolet rays (Partridge, Eric The New Partridge Dictionary of Slang and Unconventional English). In the early 20th century, they were also known as sun cheaters (American slang). From 10 a.m. until 2 p.m. the sun is high and UV light is the strongest UV rays are also stronger at high altitudes and against the reflective surfaces of snow and water. Even if the sky is cloudy, Ultraviolet may be dangerous for your eyes and you should use protective sunglasses. Even though shaded areas reduce UV exposure, your eyes can still be exposed to rays that bounce from buildings, roads and other surfaces. When choosing sunglasses, better to wraparound frames, they limit sunlight effectively; protection of UVA and UVB rays should be 99 to 100%; gray or brown are the best for color recognition. The darkness of your lenses has no effect on UV Sunglasses are especially necessary for people with macular cataracts, etc. invest in more protection. degeneration, One of important features of your glasses is protecting your eyes from ultraviolet light from the sun. If UV light passes through the shades, it causes more damage then eyes without glasses at all. This is because the glasses lead the eye to dilate, letting in more potentially harmful UV than usual. So when buying sunglasses, look for the darkened
percentage marking of ultraviolet blocking. Most shades will have a sticker or a tag as well showing that they filter out 99% or 100% of UV. Polarized glasses are coated with a special film that helps reduce glare. Polarization reduces glare coming off reflective surfaces like water or pavement, this does not offer more protection from the sun, but can make activities like driving or being on the water safer or more enjoyable. Besides boaters, skiers, bikers, golfers and joggers benefit the most from polarized sunglasses. See also thug life glasses
