Bifocals
In the Benjamin Franklin's house and museum in Philadelphia it is possible to see bifocals, probably English from about 1790.
Benjamin Franklin invented bifocals by cutting the lenses of two pairs of spectacles, preserving "half of each kind associated in the same Circle". Thus he could "move my Eyes up or down, as I want to see distinctly far or near".
- Photos by Luca Borghi ti.supmacinu|ihgrob.l#| (June 2017), courtesy of Benjamin Franklin Museum and page layout by Jessica Casaccia ti.supmacinu|aiccasac.j#| (September 2021)
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