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Glasses

Glasses, also called eyeglasses or spectacles are frames with worn lenses before the eyes normally for vision correction, goggles, or protection against UV rays.

Modern glasses are typically supported by sitting on the bridge of the nose and temples placed over the ears. Historical types include the pince-nez, monocle and impertinent.

<A href = " http://www.himfr.com/buy-magnetic_loop/ "> magnetic <Bucle / Glass A> frames are usually made of metal or plastic. The lenses were originally made from glass, but many are now several types of metals and plastic, including CR-39 and polycarbonate. These materials reduce the risk of breakage and weigh less than glass lenses. Some plastics also have more advantageous optical properties than glass like better transmission of visible light and greater absorption of light ultraviolet. [1] Some plastics have a higher rate of refraction than most types of glass, which is useful in the manufacture of corrective lenses shaped to correct vision abnormalities such as myopia different for thin lenses for a particular recipe. The new plastic lens, called Ijaw can also address higher order aberrations that naturally occur on the surface of our eyes. These lenses create sharper vision and help the halos, bursts, and the comet-tail often associated with night drivinlasikre. Guided LASIK also corrects aberrations front wave of higher order.

scratch-resistant coatings can be applied for most goals in their plastic providing scratch resistance similar to glass. Hydrophobic coatings designed to ease cleaning are also available as well as anti-reflective coatings to reduce glare, improve night vision and make the user's eyes more visible.

CR-39 lenses are most common objectives of plastic because of their low weight, high scratch resistance and low transparency of ultraviolet and infrared radiation. And Polycarbonate lenses are lighter and more Trivex unbreakable, which makes them better for impact protection [1], however, offer poor optical because of the dispersion of high and low Abbe number 31.

Not all glasses are designed solely for vision correction, but are used for protection, viewing visual information (such as stereoscopy) or simply for aesthetic or fashion values. Safety Glasses is a kind of eye protection against flying debris or against the visible and near-visible or radiation. Sunglasses allow better vision light the day, and may protect against damage caused by high levels of ultraviolet radiation.

The first historical reference to date of the expansion back to the ancient Egyptian hieroglyphs in the eighth century BC, representing "simple glass meniscal lenses". The first written records of enlargement since the first century AD, when Seneca, a tutor of Emperor Nero, wrote: "The letters, but small and indistinct, are expanded and more clearly through a glass globe filled with water [3]. Emperor Nero is also said have been the gladiatorial games with an emerald as a corrective lens.

The glasses are said to be used by Abbas Ibn Firnas, in the ninth century, who had devised a way to produce very clear glass. These vessels can be formed and polished round rocks used for viewing and reading were known as stones. The first evidence of a 'grow a convex lens forming a magnified image, the book goes of Optics published by Alhazen in 1021. Its translation into Latin of the 12th century played a role the invention of eyeglasses in 13th century Italy.

Sunglasses in the form of flat panels of smoky quartz, protected the eyes from glare and used in the China in the 12th century or earlier. However, offered no corrective powers.

Around 1284 in Italy, Salvino D'Armate attributed the invention the first eye wear glasses.The first pictorial evidence of the use of glasses, however, Tomaso da Modena in 1352 Portrait of the cardinal Hugh de Provence, reading a scriptorium. Another example would be an early representation of eyeglasses found north of the Alps in an altarpiece of the church of Bad Wildungen, Germany, in 1403.

Many theories abound to be paid by the invention of traditional glasses. In 1676, Francesco Redi, a professor of medicine University of Pisa, wrote that he possessed a manuscript whose author complains that 1289 would be unable to read or write it was not for the recent invention of glasses. He has also produced a recording of a sermon in 1305, where the speaker, a Dominican monk named Fra Giordano da Rivalto said the glasses had been invented less than twenty years ago, and had met the inventor. On the basis of this evidence, Redi credited another Dominican monk, Fra Alessandro da Spina of Pisa, with the re-invention of glasses after their original inventor kept secret a claim contained in da Spina's obituary.

Other stories, possibly legendary, credit Roger Bacon invention. Bacon is known for having one of the first recorded references to the properties of lenses in 1262 [9], although this was preceded by the book Optics 1021 Alhazen. [3 Bacon Treaty] De Iride ("On the Rainbow"), which was written as a student of Robert Grosseteste, no later than 1235, mentions using optics to "read the small print to an incredible distance." While exact date and inventor may be forever disputed, it is almost certainly clear that spectacles were invented between 1280 and 1300 in Italy.

These early shows have convex lens that can correct both hyperopia (vision) and presbyopia which often develops as a symptom of aging. Nicolas of Cusa is believed to have discovered the benefits of concave target in the treatment of myopia (nearsightedness). However, it was not until 1604 that Johannes Kepler published his treatise on optics and astronomy, the first correct explanation of why convex and concave lenses could correct presbyopia and myopia.

The American scientist Benjamin Franklin, who suffered from both myopia and presbyopia, invented bifocals in 1784 to avoid having to change on a regular basis between the two pairs of glasses. [10] The first lenses for correcting astigmatism were constructed by the British astronomer George Airy in 1825 [10].

Over time, the construction of spectacle frames also evolved. The first eye were designed to be held in place by hand or put pressure on the nose (nose). Girolamo Savonarola suggested that eyepieces could be held in place by a ribbon passed through the head the user, in turn, guaranteed by the weight of a hat. The modern glass, held by temples passing over the ears, was developed in 1727 by the British optician Edward Scarlett. These drawings were not immediately successful, without, however, and several styles of handles attached as goggles Scissors and impertinent maintains more than 18 years and the 19th century.

In the 20th century, Moritz von Rohr at Zeiss (with the help of H and A. Boegehold Sonnefeld [11]), developed the Zeiss lenses Punktal spherical point of approach, which has dominated the field ocular lens for many years.

Despite the growing popularity of contact lenses and corrective eye surgery, glasses remain commonplace as technology has improved. For example, it is now possible to purchase frames in special memory metal alloys that return to its proper shape was folded. Other executives have spring hinges. Any of these models offers the ability to dramatically increase resilience to stress daily use and occasional accidents. Modern frames are also often the strong, lightweight materials such as titanium alloys, which were not available in ancient times.

1 May 1992, United states Federal Trade Commission stated (art. 456.2) that optometrists must give the patient a complete recipe immediately after eye exam, effectively giving the patient the choice of where you buy your glasses. [12] The result has been greater competition between manufacturers of eyeglasses and therefore lower prices for consumers. This trend has been accelerated by the proliferation of Internet technology, offering consumers the opportunity to bypass traditional distribution channels and buy glasses directly from manufacturers.

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Himfr is a scholar, focusing his research on Chinese cultures. If you are interested in purchasing China goods, please visit www.himfr.com

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