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Optometry Reference Libraries

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Bifocals
2010-09-23 19:15:37

Bifocals are eyeglasses, commonly prescribed for presbyopia, with two distinct optical powers. Although there are arguments against him, Benjamin Franklin is generally credited with the invention of bifocals. After a correspondence between George Whatley and John Fenno it was thought that Franklin possibly invented the bifocals fifty years earlier than previously thought. Many inventions...

Word of the Day
cacodemon
  • An evil spirit; a devil.
  • A nightmare.
  • In astrology, the twelfth house of a scheme or figure of the heavens: so called from its signifying dreadful things, such as secret enemies, great losses, imprisonment, etc.
'Cacodemon' comes from a Greek term meaning 'evil genius.'
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