The first eyeglasses that helped vision were invented in 1280 in Florence, Italy by the friar Alessandro della Spina and his friend, the physicist Salvino degli Armati. The glasses had convex lenses that aided far-sightedness. These are in contrast to conclave lenses used for the near-sighted that were invented in later years.
If you mean bifocles, the combination of the two types of lenses which used a top lens for distant viewing and a lower lens for reading, they were developed around 1760 by Benjamin Franklin. I'm not sure where.
Hope I could help!
2006-08-13 13:25:37
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answer #1
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answered by Elerth Morrow ™ 5
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EYEGLASSES
Eyeglasses with convex lenses for correcting farsighted vision were probably invented in Italy around the year 1268-1284, perhaps by Salvino D'Armate of Pisa or by Alessandro Spina of Florence. Early glasses were also made in China around the same time. The earliest glasses did not have arms; they perched on the bridge of the nose. Eyeglasses with concave lenses for nearsightedness (or myopia) were not invented until the 1400s.
Glasses with arms were invented in the 1600s. Bifocals (combining convex and concave lenses to correct both nearsightedness and farsightedness) were invented by Benjamin Franklin around 1775. Glasses with hinged arms were invented in 1752 by James Ayscough. Ayscough also made the first sunglasses (glasses with green- or blue-tinted lenses).
Polarizing filters (which are very effective at filtering out glare) were invented by Edwin H. Land (and patented in 1929). Katherine J. Blodgett (1898-1979) invented a micro-thin barium stearate lens coating that made glass completely nonreflective and "invisible" (patent #2,220,660, March 16, 1938).
2006-08-13 13:14:26
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answer #2
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answered by Carey 3
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The first recorded use of a corrective lens was by the emperor Nero, who was known to watch the gladiatorial games using an emerald[1]. Glasses first began to appear in common use in northern Italy late in the 13th century; most likely in the late 1280s. It is not clear when the technology was invented. It has been said that Marco Polo reported seeing many pairs of glasses in China as early as 1275[citation needed]. In 1676, Franciscus Redi, a professor of medicine at the University of Pisa, wrote that he possessed a 1289 manuscript whose author complains that he would be unable to read or write were it not for the recent invention of glasses, and a record of a sermon given in 1305, in which the speaker, a Dominican monk named Fra Giordano da Rivalto, remarked that glasses had been invented less than twenty years previously, and that he had met the inventor. Based on this evidence, Redi credited another Dominican monk, Fra Alessandro da Spina of Pisa, with the re-invention of glasses after their original inventor kept them a secret, a claim contained in da Spina's obituary record. In 1738, a Florentine historian named Domenico Manni reported that a tombstone in Florence credited one Salvino d'Armato (died 1317) with the invention of glasses. Other stories, possibly legendary, credit Roger Bacon with the invention. Bacon's published writings describe the magnifying glass (which he did not invent), but make no mention of glasses. His treatise De iride ("On the Rainbow"), which was written while he was a student of Robert Grosseteste, no later than 1235, mentions using optics to "read the smallest letters at incredible distances".
These early spectacles had convex lenses that could correct the presbyopia (farsightedness) that commonly develops as a symptom of aging. Nicholas of Cusa is believed to have discovered the benefits of concave lens in the treatment of myopia (nearsightedness). However, it was not until 1604 that Johannes Kepler published in his treatise on optics and astronomy, the first correct explanation as to 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 regularly switch between two pairs of glasses. The first lenses for correcting astigmatism were constructed by the British astronomer George Airy in 1827.
Over time, the construction of spectacle frames also evolved. Early eyepieces were designed to be either held in place by hand or by exerting pressure on the nose (pince-nez). Girolamo Savonarola suggested that eyepieces could be held in place by a ribbon passed over the wearer's head, this in turn secured by the weight of a hat. The modern style of glasses, held by temples passing over the ears, was developed in 1727 by the British optician Edward Scarlett. These designs were not immediately successful, however, and various styles with attached handles such as scissors glasses and lorgnettes remained fashionable throughout the 18th and into the early 19th century.
In the early 20th century, Moritz von Rohr at Zeiss (with the assistance of H. Boegehold and A. Sonnefeld[1]), developed the Zeiss Punktal® spherical point-focus lenses that dominated the eyeglass lens field for many years.
Despite the increasing popularity of contact lenses and laser corrective eye surgery, glasses remain very common and their technology has not stood still. For instance, it is now possible to purchase frames made of special memory metal alloys that return to their correct shape after being bent. Other frames have spring-loaded hinges. Either of these designs offers dramatically better ability to withstand the stresses of daily wear and the occasional accident. Modern frames are also often made from strong, light-weight materials such as titanium alloys, which were not available in earlier times.
2006-08-13 17:41:00
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answer #3
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answered by myllur 4
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