What do we know about eyeglasses?
Glasses, also known as eyeglasses (formal) or spectacles, are frames bearing lenses worn in front of the eyes. They are normally used for vision correction or eye protection. Safety glasses are a kind of eye protection against flying debris or against visible and near visible light or radiation. Sunglasses allow better vision in bright daylight, and may protect one's eyes against damage from high levels of ultraviolet light. Specialized glasses may be used for viewing specific visual information (such as stereoscopy). Sometimes glasses are worn simply for aesthetic or fashion purposes.
History
Precursors
The earliest written record of magnification dates back to the 1st century AD, when Seneca the Younger, a tutor of Emperor Nero of Rome, wrote: "Letters, however small and indistinct, are seen enlarged and more clearly through a globe or glass filled with water". Nero (reigned 54–68 AD) is also said to have watched the gladiatorial games using an emerald as a corrective lens.
The first eyeglasses
The first eyeglasses were made in Italy at about 1286 originally consisting of thin pieces of glass which were placed directly onto the eye ball. According to a sermon delivered on February 23, 1306, by the Dominican friar Giordano da Pisa (ca. 1255–1311): "It is not yet twenty years since there was found the art of making eyeglasses, which make for good vision...And it is so short a time that this new art, never before extant, was discovered...I saw the one who first discovered and practiced it, and I talked to him." Giordano's colleague Friar Alessandro della Spina of Pisa (d. 1313) was soon making eyeglasses. The Ancient Chronicle of the Dominican Monastery of St. Catherine in Pisa records: "Eyeglasses, having first been made by someone else, who was unwilling to share them, he [Spina] made them and shared them with everyone with a cheerful and willing heart." By 1301, there were guild regulations in Venice governing the sale of eyeglasses.
The 'Glasses Apostle' by Conrad von Soest (1403)
