The invention of bifocals was one of the most important inventions of the 18th century. They have changed the lives of children and adults with vision problems. They rid people of eye strain and headaches. Additionally, bifocals eliminate the hassle of having to switch from one pair of glasses to another. Bifocals have also led to the development of more types of glasses. As Benjamin Franklin grew older, his vision deteriorated. He became both farsighted and nearsighted, and constantly changing his glasses frustrated him so much that he decided to fix the problem. He invented a pair of glasses integrating both lenses into a single frame called a bifocal. “Bifocals are a type of prescription eyeglasses designed for people who need near and distance vision correction. Benjamin Franklin developed the first pair of bifocals in August 1784” (“Beam “What Are Bifocals?”). With these two-lens bifocal glasses, one could look through the top half to see far and the bottom half to see closer. Many historians wonder who invented 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 bifocals (The Electric Franklin "The Inventions of Benjamin Franklin"). generally used by people over forty (Heiting "Bifocals and Trifocals for Vision Over 40"). Single vision glasses and bifocal glasses are very different types of glasses because they only help people who are nearsighted. This is why bifocals are very useful because they are two pairs of lenses in one frame. Bifocals are usually associated with adults, but there are many cases in which children also need bifocals...... middle of paper ...... and vision care , January 1, 2014. Web. May 23, 2014. .Heiting, Gary and Mark Mattison-Shupnick. “Bifocal and trifocal glasses for vision over 40 years old”. All about vision. All About Vision, January 1, 2014. Web. May 23, 2014. .The Electric Franklin. “The Inventions of Benjamin Franklin.” Ushistory.org. Independence Hall Association, July 4, 1995. Web. May 23, 2014. “Trifocal Eyeglass Lenses,” Trifocal Lenses,. Eyeglass Lens Direct, January 1, 2014. Web. May 23, 2014. .Twin Cities. “It’s the little things.” PBS. PBS, January 1, 2002. Web. May 23, 2014. “Welcome to forcaza.” welcome to forcaza. Np, and Web. May 23 2014. .