There are many dilemmas about invention of glasses. According to some sources the invention of the first wearable pair of eyeglasses occurred in the 13th century in Italy.
Salvino D'Armate probably invented eyeglasses in around 1285, though various sources suggest an earlier origin. He shared the invention of his new device with Allesandro della Spina, an Italian monk, who made it public and is often credited with inventing eyeglasses. The first eyeglasses had frames made of metal or bone and had lenses made out of quartz because the ''opticians'' of that time didn't have the capabilities of producing flawless lenses in glass.
In the 14th century, Venetian craftsmen were making "disks for the eyes"'. Italians gave these glass disks that were finely ground the name lenses because they were similar in shape to lentil beans. The earliest lenses were convex, the bulged outward in the middle, and they were used to correct far-sightedness.
By the fifteenth century, spectacles had found their way to China.
In 1451 Nicholas of Cusa in Germany produced eyeglasses to aid people who were near-sighted using concave lenses that were thinner at the center and thicker at the ends.
Early eyeglasses had glass lenses set into heavy frames of wood, lead or copper. Natural materials of leather, bone and horn were later used for production of frames. In the early seventeenth century, lighter frames of steel were invented. The modern style of eyeglasses frame, which could be placed over the ears and nose, was invented in 1727 by British optician Edward Scarlett.
American scientist and philosopher Benjamin Franklin is credited with the invention of bifocals, dividing his lenses for distant and near vision. These two lenses were held together in a metal frame.
Sir George Biddle Airy, an English astronomer and mathematician, invented glasses to correct astigmatism in 1827 which were meant to be held by hand. Later glasses were designed to be held in place by ribbon or by exerting pressure on the bridge of the nose, such as with pince-nez.
Construction of frames also improved over the centuries, and today they are made in wide array of styles and designs. Frames are generally produced of metal or plastic, and lenses are produced of glass or plastic.
In 1955 the unbreakable lenses were invented and in 1971 a new lens were developed which combined the properties of plastic with glass.