PRAIRIE DOC®
  • Home
  • About
  • People
  • TV
  • Perspective
  • Donate
  • Friends/Sponsors of the Prairie Doc
  • Radio and Podcasts
  • Contact
  • Foundation
  • Prairie Doc Publishing

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

7/30/2018

 
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?
​Watch On Call with the Prairie Doc® most Thursdays at 7 p.m. central on SDPTV and follow the Prairie Doc® on Facebook and YouTube for free and easy access to the entire Prairie Doc® library.

Comments are closed.

    Archives

    June 2025
    May 2025
    April 2025
    March 2025
    February 2025
    January 2025
    December 2024
    November 2024
    October 2024
    September 2024
    August 2024
    July 2024
    June 2024
    May 2024
    April 2024
    March 2024
    February 2024
    January 2024
    December 2023
    November 2023
    October 2023
    September 2023
    August 2023
    July 2023
    June 2023
    May 2023
    April 2023
    March 2023
    February 2023
    January 2023
    December 2022
    November 2022
    October 2022
    September 2022
    August 2022
    July 2022
    November 2021
    October 2021
    September 2021
    August 2021
    July 2021
    June 2021
    May 2021
    April 2021
    March 2021
    February 2021
    January 2021
    December 2020
    November 2020
    October 2020
    September 2020
    August 2020
    July 2020
    June 2020
    May 2020
    April 2020
    March 2020
    February 2020
    January 2020
    December 2019
    November 2019
    October 2019
    September 2019
    August 2019
    July 2019
    June 2019
    May 2019
    April 2019
    March 2019
    February 2019
    January 2019
    December 2018
    November 2018
    October 2018
    September 2018
    August 2018
    July 2018
    June 2018
    May 2018
    April 2018
    March 2018
    February 2018
    January 2018
    December 2017
    November 2017
    October 2017
    September 2017
    August 2017
    July 2017
    June 2017
    May 2017
    April 2017
    March 2017
    February 2017
    January 2017
    December 2016
    November 2016
    October 2016
    September 2016
    August 2016
    July 2016
    June 2016
    May 2016
    April 2016
    March 2016

    Categories

    All

    RSS Feed

Subscribe to Newsletter
Picture
PRAIRIE DOC® MEDIA IS A PART OF HEALING WORDS FOUNDATION.

Healing Words Foundation logo
  • Home
  • About
  • People
  • TV
  • Perspective
  • Donate
  • Friends/Sponsors of the Prairie Doc
  • Radio and Podcasts
  • Contact
  • Foundation
  • Prairie Doc Publishing