Sunglasses
Sunglasses or sun glasses (informally called shades or sunnies; more names below) are a form of protective eyewear designed primarily to prevent bright sunlight and high-energy visible light from damaging or discomforting the eyes.
They can sometimes also function as a visual aid, as variously termed spectacles or glasses exist, featuring lenses that are colored, polarized or darkened.
Their usage is mandatory immediately after some surgical procedures, such as LASIK, and recommended for a certain time period in dusty areas, when leaving the house and in front of a TV screen or computer monitor after LASEK.
Since the 13th century and until the spread of contemporary UV-shielding spectacles against snowblindness, Inuit made and wore snow goggles of flattened walrus or caribou ivory with narrow slits to look through to block almost all of the harmful reflected rays of the sun.
[4][5] In many different forms and with many different materials, the indigenous peoples of North America and northern Asia crafted highly efficient equipment to protect their eyes against the damaging effects of strong sunlight in icy circumstances.
[6] Pliny the Elder claimed that the Roman emperor Nero liked to watch gladiator fights using cut emeralds.
[7] The first sunglasses, made from flat panes of smoky quartz called Ai Tai, meaning "dark clouds,"[8] which offered no corrective powers but did protect the eyes from glare, were used in China in the 12th century or possibly earlier.
Documents describe the use of such crystal sunglasses by judges in ancient Chinese courts to conceal their facial expressions while questioning witnesses.
[11] King Louis XIV's court watched the 1706 solar eclipse through a telescope with a smoky glass filter attached.
One of the earliest surviving depictions of a person wearing sunglasses is one from 1772 of the scientist Antoine Lavoisier, who worked with amplified sunlight.
[15] From the late 19th century, short references of sunglasses have been found in reports, such as one from 1866 by Walter Alden, who wrote of soldiers using, during the American Civil War (1861-1865), "shell spectacles" ("verres de cocquille") to protect against sunlight on long marches, or by the British T. Longmore reporting in The Optical Manual (1885) of soldiers in Egypt being equipped with tinted glass "eye protectors."
The most widespread protection is against ultraviolet radiation, which can cause short-term and long-term ocular problems such as photokeratitis (snow blindness), cataracts, pterygium, and various forms of eye cancer.
[28] More recently, high-energy visible light (HEV) has been implicated as a cause of age-related macular degeneration;[29] before, debates had already existed as to whether "blue blocking" or amber tinted lenses may have a protective effect.
[34] One survey even found that a $6.95 pair of generic glasses offered slightly better protection than expensive Salvatore Ferragamo shades.
In addition to filtering, the standard also lists requirements for minimum robustness, labeling, materials (non-toxic for skin contact and not combustible) and lack of protrusions (to avoid harm when wearing them).
The main purpose of these glasses are to protect the wearer from dust and smog particles entering into the eyes while driving at high speeds.
They need shatterproof and impact-resistant lenses; a strap or other fixing is typically used to keep glasses in place during sporting activities, and they have a nose cushion.
In addition to the features for sports glasses, water sunglasses can have increased buoyancy to stop them from sinking should they come off, and they can have a vent or other method to eliminate fogging.
[57] Mountain climbing or traveling across glaciers or snowfields requires above-average eye protection, because sunlight (including ultraviolet radiation) is more intense in higher altitudes, and snow and ice reflect additional light.
During space walks, the visor of the astronauts' helmets, which also has a thin gold coating for extra protection, functions as strong sunglasses.
[62] NASA research primarily by scientists James B. Stephens and Charles G. Miller at the Jet Propulsion Laboratory (JPL) resulted in special lenses that protected against the light in space and during laser and welding work.
With the introduction of office computing, ergonomists may recommend mildly tinted glasses for use by display operators, in order to increase contrast.
There are two styles of frameless glasses: those that have a piece of frame material connecting the two lenses, and those that are a single lens with ear stems on each side.
The model saw more limited use throughout the 1980s and 1990s, aided by a 1982 product placement deal, featured most notably in Top Gun and Cobra, with both films causing a 40% rise in 1986.
Based on the eyeglass design of the same name, browline glasses have hard plastic or horn-rimmed arms and upper portions joined to a wire lower frame.
Analogous to Inuit goggles (see above), the principle is not to filter light, but to decrease the amount of sun rays falling into the wearer's eyes.
Pop icons such as Mick Jagger, Roger Daltrey, John Lennon, Jerry Garcia, Boy George, Liam Gallagher, Suggs, Ozzy Osbourne, Duckie (Jon Cryer) in Pretty in Pink and Jodie Foster's character in the film Taxi Driver all wore teashades.
The original teashade design was made up of medium-sized, perfectly round lenses, supported by pads on the bridge of the nose and a thin wire frame.
"Teashades" was also used to describe glasses worn to hide the effects of recreational drugs such as marijuana (conjunctival injection) or heroin (pupillary constriction) or just bloodshot eyes.
Introduced in 1952, the trapezoidal lenses are wider at the top than the bottom (inspired by the Browline eyeglasses popular at the time), and were famously worn by James Dean, Roy Orbison, Elvis Presley, Bob Marley, The Beatles and other actors and singers.
