How were eyeglasses invented?

Answer 1

SOURCE: http://www.didyouknow.cd/spectacles.htm

Roman tragedian Seneca (4 BC–AD 65) is said to have read "all the books in Rome" by peering through a glass globe of water. A thousand years later, presbyopic monks used segments of glass spheres that could be laid against reading material to magnify the letters, basically a magnifying glass, called a "reading stone." They based their invention on the theories of the Arabic mathematician Alhazen (roughly 1000 AD). Yet, Greek philosopher Aristophanes (c. 448 BC-380 BC) knew that glass could be used as a magnifying glass. Nevertheless it was not until roughly 150 AD that Ptolemy discovered the basic rules of light diffraction and wrote extensively on the subject. (The laws of diffraction was formulated much later by Snellius, between 1600 and 1620.)

Venetian glass blowers, who had learned how to produce glass for reading stones, later constructed lenses that could be held in a frame in front of the eye instead of directly on the reading material. It was intended for use by one eye; the idea to frame two ground glasses using wood or horn, making them into a single unit was born in the 13th century.

In 1268 Roger Bacon made the first known scientific commentary on lenses for vision correction. Salvino D’Armate of Pisa and Alessandro Spina of Florence are often credited with the invention of spectacles around 1284 but there is no evidence to conclude this. The first mention of actual glasses is found in a 1289 manuscript when a member of the Popozo family wrote: "I am so debilitated by age that without the glasses known as spectacles, I would no longer be able to read or write." In 1306, a monk of Pisa mentioned in a sermon: "It is not yet 20 years since the art of making spectacles, one of the most useful arts on earth, was discovered." But nobody mentioned the inventor.

In the Middle Ages wearing spectacles signified knowledge and learning. Painters of the time often included spectacles when portraying famous persons even when depicting people who lived before the known invention of spectacles. On numerous paintings the religious teacher Sofronius Eusebius Hieronymus (340 - 420 AD) is portrayed with a lion, a skull and a pair of reading glasses. He is the patron saint of spectacle makers.

It actually is true that eating carrots can help you see better. Carrots contain Vitamin A, which feeds the chemicals that the eye shafts and cones are made of. The shafts capture black and white vision. The cones capture colour images.

Answer 2

The truth is that nobody knows who invented eyeglasses. At some point in Italy between 1268 and 1289 someone came up with the idea, but the actual inventor remains anonymous. What we do know is that the earliest lenses were made from quartz and were usually set into bone, metal, or leather. As soon as early opticians figured out how to make glass without bubbles and other obstructions, they started making lenses out of glass.

Although glasses spread quickly throughout Europe and Asia, there was one major problem: keeping them on the wearer's face. Early glasses acted a bit like scissors, pinched onto the bridge of the nose. Ouch. It took nearly four hundred years before opticians figured out that rigid sidepieces resting on top of the ears might do the trick.

No history of spectacles would be complete without some mention of Benjamin Franklin, who invented bifocals in the 1780s. Annoyed at having to constantly switch glasses whenever he wanted to read or take in the sights while traveling, Franklin had his reading glasses cut in half and fused with his distance glasses. Now that's American ingenuity for you.

Answer 3

Bejamin Franklin invented bifocles, but I see the first answer was the best.