Correcting Vision with Polished Crystals, Venetian Glass, and Laser Beams

The oldest known lens was found in the ruins of the ancient Mesopotamian city of Nineveh and was made from polished rock crystal. The Greek playwright Aristophanes mentions the use of such a lens to burn holes in parchment in one of his plays. Allegedly, Pliny the physician used a similar lens to cauterize wounds. A thousand years later monks started using "reading stones" which were sliced off sections of polished quartz spheres. Sometime in the latter half of the 1200s the monks put these reading stones up on their noses in what today we would recognize as spectacles.
It was in Venice, Italy, where glassmaking was (and still is) an art, that convex reading and magnifying glasses were refined. About three hundred years later, concave lenses were used to help the near-sighted Pope Leo the 10th. He apparently wore his special spectacles to aid him while hunting. It took just about three hundred more years for bifocals to be invented by America's own Benjamin Franklin.
It was in the mid 1800s that a protective lens was made to fit directly over the eyeball of a man who had lost his eyelid from skin cancer. This first "contact lens" protected his eye from drying out, which would have resulted in blindness. Over the next 150 years, contact lenses came into commercial use and moved from blown, to ground, to molded glass lenses and then to a whole variety of hard, then soft, plastic lenses.
The knowledge of refracting light with lenses has, more recently, brought us to correct vision by surgically altering the shape of the cornea with laser beams. Where will we go next?
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