As Benjamin Franklin grew older, his vision worsened. He became both far-sighted and near-sighted and the constant switching of his glasses frustrated him so much that he decided to solve this problem. He invented a pair of glasses that incorporated both lenses into one frame called bifocals. “Bifocals are a type of prescription eyeglasses designed for people who need both near and farsighted vision correction. Benjamin Franklin developed the first pair of bifocals in August 1784” (Beam "What Are Bifocals?"). With these two-lense bifocals one could look through the upper half to see far away and the lower half for seeing closer things. Many historians question who invented the bifocals although, due to letters written by Benjamin Franklin to his friend George Whatley, it is a known fact that Franklin was indeed the true inventor of the bifocals (The Electric Franklin "Benjamin Franklin's Inventions").
They are generally used by people over forty years old (Heiting "Bifocals and Trifocals for Vision Over 40"). Single vision glasses and bifocals are very different types of glasses because they only help people with nearsightedness. This is why bifocals are very useful because they are two pairs of lenses within one frame. Bifocals are generally associated with adults, but there are many cases in which children too require bifo...
... middle of paper ...
...and vision care, 1 Jan. 2014. Web. 23 May 2014.
Heiting, Gary, and Mark Mattison-Shupnick. "Bifocals and Trifocals for Vision Over 40." All About Vision. All About Vision, 1 Jan. 2014. Web. 23 May 2014.
The Electric Franklin. "Benjamin Franklin's Inventions." Ushistory.org. Independence Hall Association, 4 July 1995. Web. 23 May 2014.
"Trifocal Glasses Lenses,."Trifocal Lenses,. Eyeglass Lens Direct, 1 Jan. 2014. Web. 23 May 2014.
Twin Cities. "It's The Little Things." PBS. PBS, 1 Jan. 2002. Web. 23 May 2014.
"welcome to forcaza." welcome to forcaza. N.p., n.d. Web. 23 May 2014.
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