About Eyeglasses

Eyeglasses are lenses with frames worn around the eyes. Corrective lenses have been around since time of Ancient Rome. The first recorded use of corrective lenses may have taken place around 1st century AD when Roman Emperor Nero watched the gladiator games through and emerald. Since then, eyeglasses have taken on many forms, but they continue to be used for vision correction, safety, UV protection and as forms of personal expression.

History
The first uses of wearable glasses may date back to 1285 in Italy. Magnifying lenses were mounted into an inverted V-shape and balanced on the bridge of the nose. Opticians then began making lenses out of glass. In 1450, Johann Gutenberg’s invention of the printing press prompted a significant rise in the demand for reading glasses. By the end of the 15th century, spectacle peddlers became commonplace. In 1730, London optician Edward Scarlett perfected temple spectacles, which allowed glasses to be worn above the ears. In the 1870s, Benjamin Franklin invented bifocals, solving the problem of having to switch between reading and distance glasses.

Function
Eyeglasses have several functions, both aesthetic as well as practical. Glasses have been used for vision correction, eye protection and protection from UV rays. Yet they also serve as fashion statements. Famous figures such as Elton John, Groucho Marx and Dame Edna Everage have used eyeglasses as forms of personal expression. Others such as Senator Barry Goldwater and British soap star Anne Kirkbride were unrecognizable without their trademark glasses. While figures such as Princess Diana used eyeglasses to disguise herself from paparazzi, superheroes such as Superman and Wonder Woman used them as a form of cover under their alter-egos.

Types
There are several types of eyeglasses. Corrective glasses are used to correct myopia (nearsightedness), hyperopia (farsightedness) and astigmatism. These lenses work by modifying the focal length of the eye. Safety glasses or goggles are used to protect the eyes in the laboratory or in sporting games. Shatterproof plastic frames protect the eyes from flying debris. Many workers use eye-wear with different color coatings to enable eyesight in different lighting conditions. Welders also use safety glasses to provide protection from welding flash. Athletes tend to use goggles with nylon frames because of the flexibility. Sunglasses protect the eyes from UV rays. They can either come in prescription or non-prescription lenses.

Features
Although glasses have historically been made of glass, modern glasses tend to be made from metal plastics such as CR-39 and polycarbonate. These materials are lighter and less likely to break. The plastics allow the possibility of thinner lenses for high prescriptions. They also allow for better transmission of light and absorption of UV rays. Other features such as scratch resistant coatings, hydrophobic coatings and anti-reflective coatings can be applied to the lenses. CR-39 lenses are better for low transparency for UV and infrared radiation while polycarbonate lenses are more shatterproof. Eyeglass frames tend to be made from either metal or plastic.

Considerations
There are several factors to take into consideration about eyeglasses, both from a social and a pragmatic standpoint. Although eyeglasses have been used as a fashion statement, there is sometimes a social stigma attached to glasses. Those who wear glasses tend to be pigeonholed as either intelligent (positive connotations) or nerdy (negative connotations). Kids and teens may feel peer pressure to wear contact lenses instead of glasses. From a practical aspect, glasses can be inconvenient under weather conditions such as rain, snow, extreme heat or cold weather. Eyeglasses also tend to become greasy or fogged up while eating hot foods. And when glasses break or scratch, repair can be expensive. Still, corrective eyeglasses are valuable for those who are unable or unwilling to have Lasik surgery or wear contact lenses.
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