100 Greatest Science Inventions of All Time

By Kendall Haven | Go to book overview

Eyeglasses
Year of Invention: 1280

What Is It? Ground, clear lenses used to correct defects in human vision.

Who Invented It? Alessandro della Spina (in Florence, Italy)


Why Is This Invention One of the 100 Greatest?

As a boy, future U.S. president Theodore Roosevelt looked through his first pair of glasses and was awed at “suddenly having the world come into focus.” He said it was one of the most profound and memorable moments of his life.

Glasses create a clear, focused, and essential view of our ordinary world. They have made it possible for billions of people to read, become educated, enjoy life, and safely navigate our environments. As the need for clear, detailed vision increases in our modern world, so also does the importance of glasses.


History of the Invention

What Did People Do Before?

No one mentioned eyeglasses until 1250, though there must have been plenty of people with vision problems before then. In 1249, English scientist and inventor Roger Bacon wrote about “lenses to improve vision.” That’s the first recorded mention of using lenses to correct human vision. But there is no evidence that Bacon either had or made any. As early as A.D. 1000, people in China and parts of the Arab world are thought to have used polished concave surfaces to enlarge images and possibly to have used clear quartz lenses to look through as we would a magnifying glass.

In the mid-1200s, Venetian craftsmen (in Venice, Italy) gained exquisite skill in grinding and polishing lenses (mostly of clear quartz). Suddenly, magnifying lenses that did not distort an image were available (but expensive) for scientists to use. All glass was still colored (tinted by impurities and by the chemicals used in the glass-making process), often had tiny bubbles or blemishes, and was difficult to make smooth and nondistorting.


How Were Eyeglasses Invented?

Beginning in 1275, Dominican friar Alessandro della Spina worked with physicist Salvino delgi Armati on a variety of scientific experiments—many of them concerning the nature of light—in their hometown of Florence, Italy.

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