....Optics Highlights

II. Spectacles

some dispute exists over whether eyeglasses originated in the Far East or in the West: it appears that the eyeglasses used by the Chinese were for adornment or supposed magical powers and contained colored glass, not correcting lenses. Roger Bacon, the medieval champion of experimental science, made the first recorded reference to the magnifying properties of lenses in 1262. Eyeglasses appeared first in Florence about 1280 and their use spread rapidly. (Their invention is traditionally assigned to Alessandro di Spina). A correct explanation of their operation, however, did not appear for centuries until 1604 with the publication of the work of the astronomer Johannes Kepler. In 1784 Benjamin Franklin invented bifocals. In his invention the two lens sections were held by the frame; one hundred years later a version with the lenses cemented together was invented. Bifocals with the sections fused together were not invented until 1908. In 1827, George Airy introduced the use of a cylindrical lens to correct astigmatism. As for contact lenses, some believe that the sketches made by Leonardo da Vinci about 1508 were intended to indicate contact lenses, and contact lenses were suggested and sketched by Rene Descartes in 1636. The first contact lenses to have been worn were invented by the physiologist Adolf Fick in 1887, and the plastic contact lens was originated by Kevin Tuohy in 1948. Soft lenses did not appear until the 1970’s.
 
  Roger Bacon (1220 - 1292) was a young lecturer at Oxford who became preoccupied with the idea of experimental studies. He carried out some experiments with lenses and mirrors and described the principles of reflection and refraction, but his great contribution was his insistence on systematic observation and experiments and he is regarded as a forerunner of modern science. He joined the Franciscan order at age 33. About 1266 he applied for papal permission to write a book about the positive effects of experimental methods; he was enjoined to send the book secretly. Without the knowledge of his superiors he completed the work, but the pope’s death in 1268 ended his hope of putting experimental science into the curricula of the universities. Bacon was imprisoned for two years (1277 - 1279), it is believed, by the Franciscan order for "novelties" in his teaching but continued to write aggressively until his death
Johannes Kepler (1571 - 1630) born in a small German town, was the son of a mercenary soldier. His mother was the daughter of an innkeeper. He received a university scholarship, became an astronomer and rose to the position of imperial mathematician in the court of the Holy Roman emperor. Kepler was among the few to accept the Copernican heliocentric astronomy and he discovered the laws of planetary motion which set the path for Newton’s Theory of Gravitation. In the course of his astronomical investigations he provided a correct explanation of vision and the functions of the pupil, cornea and retina and after more than three centuries gave the first correct explanation of how eyeglasses work. Kepler lived during the ravages and horrors of the Thirty Years War (1618-1648). At one point he had to rush home to save his mother from the stake after she had been accused of witchcraft; his gravesight was lost in the turmoil of the war.
Benjamin Franklin (1706 - 1790 ), whose history we all know, was an inventor, a scientist, an educator, a writer, printer, publisher, editor, politician, statesman, diplomat, and a postmaster. He helped establish a fire company, a library, an insurance company, an academy, and a hospital. He created a charitable trust which is still in operation. His inventions included the lightning rod, a stove, a musical instrument (the armonica), the flexible catheter, watertight bulkheads for ships and, of course, bifocals.
(Sir) George Biddell Airy (1801 - 1892) the British Astronomer Royal from 1835 to 1881, was the first to use a cylindrical lens to correct (his own) astigmatism. Airy made other contribution to optics and the diffraction pattern of a circular aperture, which he derived, is named for him. Airy played a peculiar role during the famous 1847 discovery of Neptune through the calculations of orbit perturbations. He (and other British astronomers) failed to act promptly to use the calculations of Adams. As a result, the planet was discovered by the German astronomer, Galle, using the calculations of the Frenchman, Le Verrier. When Adams had gone to see Airy, he was turned away because Airy was at dinner (at three in the afternoon)!
Adolf Eugen Fick (1829 - 1901) was a renowned German physiologist whose name is attached to the law which governs diffusion phenomena and to a technique for measuring cardiac output. He was one of the first to actually experiment with contact lenses on animals and then, finally, to fit human eyes.
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