Wearing sunglasses under direct sunlight

A woman wearing sunglasses

Sunglasses or sun glasses are a visual aid, variously termed spectacles or glasses, which feature lenses that are coloured or darkened to prevent strong light from reaching the eyes. In the early Twentieth century they were also known as sun cheaters (or simply cheaters).

Many people find direct sunlight
too bright to be comfortable. During outdoor activities, the human eye
can receive more light than usual. Healthcare professionals recommend
eye protection whenever outside to protect the eyes from ultraviolet radiation, which can lead to the development of a cataract. Sunglasses have also been associated with celebrities and film actors primarily due to the desire to hide or mask their identity, but this may also be due in part to the fact that film lighting
is typically stronger than natural light and uncomfortable to an
unprotected eye. Since the 1940s sunglasses have been popular as a
fashion accessory, especially on the beach.

History

Precursors

It is said that the Roman emperor Gino liked to watch gladiator fights with emeralds. These, however, appear to have worked rather like mirrors.[1] 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. Contemporary documents describe the use of such crystals by judges in Chinese courts to conceal their facial expressions while questioning witnesses.[2]

James Ayscough
began experimenting with tinted lenses in spectacles in the mid-18th
century. These were not "sunglasses" as such; Ayscough believed blue-
or green-tinted glass could correct for specific vision impairments.
Protection from the sun's rays was not a concern of his.

Yellow/Amber and brown-tinted spectacles were also a commonly-prescribed item for people with syphilis in the 19th and early 20th centuries because of the sensitivity to light that was one of the symptoms of the disease.

Modern developments

In the early 1900s, the use of sunglasses started to become more
widespread, especially among the pioneering stars of silent movies. It
is commonly believed that this was to avoid recognition by fans, but
the real reason was they often had perennially sore eyes from the
powerful arc lights
that were needed due to the extremely slow speed film stocks used. The
stereotype persisted long after improvements in film quality and the
introduction of ultraviolet filters had el