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”.
The use of a convex lens to form an enlarged/magnified image is discussed in Alhazen’s Book of Optics (1021). Its translation into Latin from Arabic in the 12th century was instrumental to the invention of eyeglasses in 13th century Italy.
Englishman Robert Grosseteste’s treatise De iride (“On the Rainbow”), written between 1220 and 1235, mentions using optics to “read the smallest letters at incredible distances”. A few years later in 1262, Roger Bacon is also known to have written on the magnifying properties of lenses.
Sunglasses, in the form of flat panes of smoky quartz, were used in China during the 12th century. Similarly, the Inuit have used snow goggles for eye protection. While they did not offer any corrective benefits they did improve visual acuity via the pinhole effect. Read more