Glasses

History

Glasses were possibly invented in northern Italy, most likely in the late 1280s. The identity of the original inventor is unknown, although a possible source is the Arabs, who may have had magnifying lenses in the 10th century. Early glasses were also made in China around the same time. 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.

Related Topics:
Italy - 1280s - Arab - Franciscus Redi - University of Pisa - Dominican - Giordano da Rivalto - Alessandro da Spina of Pisa - Florentine - Domenico Manni - Salvino d'Armato - Roger Bacon - Magnifying glass

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These early spectacles had convex lenses that could correct the farsightedness (presbyopia) 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.

Related Topics:
Convex lenses - Presbyopia - Aging - Nicholas of Cusa - Concave lens - Myopia - 1604 - Johannes Kepler - Optics - Astronomy - American - Benjamin Franklin - Bifocals - 1784 - Astigmatism - British - George Airy - 1827

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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.

Related Topics:
Girolamo Savonarola - Hat - 1727 - Edward Scarlett

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Despite the increasing popularity of contact lenses and laser corrective

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eye surgery, glasses remain very common and their technology has not

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stood still. For instance, it is now possible to purchase frames made

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of special memory metal alloys that return to their correct

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shape after being bent. Other frames have spring-loaded hinges.

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Either of these designs offers dramatically better ability to

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withstand the stresses of daily wear and the occasional accident.

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