One of the most influential and memorable men of his time, Benjamin Franklin was born in Boston, Massachusetts in 706. In British America, a time before the colonies declared independence, Franklin practiced his hands-on skills as a young printer on the road, eventually ending up in Philadelphia, Pennsylvania where he grew to exceed expectations in business and become famous for his Poor Richards Almanac (Bulliet et al, 203, p. 578). While Franklin played a critical role in creation of historical institutions, such as the Philadelphia Free Library and the University of Pennsylvania, he also contributed to the scientific field via publication of his 75 paper, Experiments and Observations on Electricity (Bulliet et al, 203, p. 578). One could speculate Franklins background as a young printer helped fuel his curiosity for tinkering with mechanics well into his adult life, as his inventions of the notorious lightning rod and wood-burning stove would easily demonstrate. However, of all his creations, Franklins engineering of bifocal glasses stood the test of time as most practical for use in the modern era.
As mentioned, the much-needed upgrade in spectacles during the late 8th century came from Benjamin Franklins ingenious invention of
dual lenses in a single frame. At this time in human history, it was impossible to correct ones vision with laser-based surgery, forcing individuals who suffered from near-sightedness (myopia) and far-sightedness (hyperopia) to carry two different pairs of glasses (Petroski, 203, p. 337). Each of those eyeglasses came with a different type of lens to adapt to one visual impairment over another when deemed necessary. As one can imagine, having to constantly switch between pairs of eyeglasses to function normally in everyday life would prove inconvenient as well as annoying. Franklin addressed and solved this troublesome issue in society by engineering a pair of glasses with dual lenses, split horizontally across the middle of the glass. Henry Petroski, author of Engineering: The Evolution of Eyeglasses, describes the design of the eyeglasses in context as the upper portion of Franklins new lens carried the least convex for distant objects to assist with far-sightedness, while the bottom portion held the most convex for reading and helped with near-sightedness (Petroski, 203, p. 337). This design, addressing both visual impairments in a single pair glasses, was truly the beginning of the bifocal lens, all thanks to Benjamin Franklin.