3 colors Double Bridge UV400 Sunglasses Polarized Lens Wholesale Sun Glasses

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Metal Women Sunglasses Cat Eye Stainless Polarized Sun Shades Sun glasses

Sunglasses

Modern developments

In 1913, Crookes lenses were introduced,made from glass containing cerium, which block ultraviolet light. In the early 1920s, the use of sunglasses started to become more widespread, especially among movie stars. Inexpensive mass-produced sunglasses made from celluloid were first produced by Sam Foster in 1929. Foster found a ready market on the beaches of Atlantic City, New Jersey, where he began selling sunglasses under the name Foster Grant from a Woolworth on the Boardwalk. By 1938, Life magazine wrote of how sunglasses were a "new fad for wear on city streets ... a favorite affectation of thousands of women all over the U.S." It stated that 20 million sunglasses were sold in the United States in 1937, but estimated that only about 25% of American wearers needed them to protect their eyes. Polarized sunglasses first became available in 1936, when Edwin H. Land began experimenting with making lenses with his patented Polaroid filter. In 1947, the Armorlite Company began producing lenses with CR-39 resin.

At present, Xiamen, China, is the world's largest producer of sunglasses, with its port exporting 120 million pairs each year.

Sunglasses offer protection against excessive exposure to light, including its visible and invisible components.

The most widespread protection is against ultraviolet radiation, which can cause short-term and long-term ocular problems such as photokeratitis, snow blindness, cataracts, pterygium, and various forms of eye cancer.Medical experts advise the public on the importance of wearing sunglasses to protect the eyes from UV;for adequate protection, experts recommend sunglasses that reflect or filter out 99% or more of UVA and UVB light, with wavelengths up to 400 nm. Sunglasses that meet this requirement are often labeled as "UV400". This is slightly more protection than the widely used standard of the European Union (see below), which requires that 95% of the radiation up to only 380 nm must be reflected or filtered out. Sunglasses are not sufficient to protect the eyes against permanent harm from looking directly at the Sun, even during a solar eclipse. Special eyewear known as solar viewers are required for direct viewing of the sun. This type of eyewear can filter out UV radiation harmful to the eyes.