The guarantee period of the 'sunglasses' have you noticed?

Sorching summer is not the past, the sunshine 'brazen', a lot of people in order to prevent bask in, go out like wearing sunglasses. However, you have noticed the sunglasses 'shelf life'? , according to a new study says a pair of sunglasses sell-by date in two years or so, 'expired', sunglasses are likely to lose its functions to protect the eyes. Recommended reading: sunglasses factory science: why do the children more than adults need to wear sunglasses in the British media quoted researchers at the university of Sao Paulo, Brazil, reported that the lens for a long time will reduce exposure to sunlight uv protection ability, will not be changed for a long time, easy to damage the cornea, causing vision problems. , according to research of exposure to the sun may give you a sunglasses degradation, the lens may be lighter, will also reduce the lens resistance ability, also is the shatterproof lenses index. The world health organization (who) published the ultraviolet radiation to human health, the article points out that the 18 million people worldwide each year because of cataract blindness, 5% were caused by ultraviolet radiation. Ultraviolet ray also can other serious diseases - — Keratitis, retinal damage, cataracts and macular degeneration, snow blindness, etc. Can filter ultraviolet sunglasses to become us, therefore, the important equipment of protecting our eyes in the sun. Researchers in Europe, Australia, New Zealand and South America to do simulation experiment, put the sunglasses in daylight simulators, 30 cm distance markers, 'sun' 50 hours continuously, at the same time observe the lens degradation degree of uv protection ability. Experimental results show that, as a result of sunshine is different in different areas of the world, the sunglasses in the tropical countries and regions of the highest uv, uv protection function will be degraded more quickly. The study says, sunglass degradation situation changes with the change of latitude and tropical summer especially high uv index, winter also won't reduce. The researchers suggest, buying sunglasses to wear more than two years had better change a new pair. Finally, sunglasses factory remind everybody, must choose a pair of suitable sunglasses, and replaced periodically, don't let a sunglasses eye invisible killer.
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