Sunglasses

In prehistoric and historic time, Inuit peoples wore flattened walrus ivory "glasses", looking through narrow slits to block harmful reflected rays of the sun. It is said that the Roman emperor Nero liked to watch gladiator fights with emeralds. These, however, appear to have worked rather like mirrors. Sunglasses made from flat panes of smoky quartz, which offered no corrective powers but did protect the eyes from glare, were used in China in the 12th century or possibly earlier. Ancient documents describe the use of such crystal sunglasses by judges in ancient Chinese courts to conceal their facial expressions while questioning witnesses. James Ayscough began experimenting with tinted lenses in spectacles in the mid-18th century, around 1752. These were not "sunglasses" as that term is now used; Ayscough believed that blue- or green-tinted glass could correct for specific vision impairments. Protection from the Sun's rays was not a concern for him. One of the earliest surviving depictions of a person wearing sunglasses is of the scientist Antoine Lavoisier in 1772.