Glasses, also known as eyeglasses (formal) or spectacles, are frames bearing lenses worn in front of the eyes. They are normally used for vision correction or eye protection. Safety glasses are a kind of eye protection against flying debris or against visible and near visible light or radiation. Sunglasses allow better vision in bright daylight, and may protect against damage from high levels of ultraviolet light. Other types of glasses may be used for viewing visual information (such as stereoscopy) or simply just for aesthetic or fashion purposes.
Historical types of glasses include the pince-nez, monocle, lorgnette, and scissor or scissors-glasses.
Modern glasses are typically supported by pads on the bridge of the nose and by temple arms (sides) placed over the ears. CR-39 lenses are the most common plastic lenses due to their low weight, high scratch resistance, low dispersion, and low transparency to ultraviolet and infrared radiation. Polycarbonate and Trivex lenses are the lightest and most shatter-resistant, making them the best for impact protection.
An unpopular aspect of glasses is their inconvenience. Though modern frames can be both lightweight and flexible, and new lens materials and optical coatings are resistant to breakage or scratching, glasses can still cause problems during rigorous sports. Visibility can be significantly reduced by becoming greasy, trapping vapour when eating hot food, swimming, walking in rain or rapid temperature changes (such as walking into a warm building from cold temperatures outside). Scraping, fracturing, or breakage of the lenses require time-consuming and costly professional repair.
Read more about Glasses: Redistribution
Other articles related to "glasses":
... Cat eye glasses are a form of women's eyewear ... They are horn-rimmed glasses with flared outer edges where the arms join the frame ... They preceded the large bug-eye glasses of the '70s, '80s and '90s ...
... Some organizations like Lions Clubs International, Unite For Sight and New Eyes for the Needy provide a way to donate glasses and sunglasses ... Unite For Sight has redistributed more than 200,000 pairs ...
... Glasses Malone Birdman) 411 2 ... Glasses Malone) 304 4 ... Glasses Malone Butch Cassidy) 403 8 ...
... Scissors-glasses (or binocles-ciseaux) are eyeglasses, normally used to correct distance-vision, mounted on scissoring stems rather than on temple stems as modern eyeglasses are ... The invention of scissors-glasses solved the problem of the single lensed monocle or "quizzing glass", thought to be tiresome to the eye, by providing two lenses on a "Y" shaped frame ... George Washington, Lafayette and Napoleon used scissors glasses ...
... Some glasses have a peculiar property called anomalous partial dispersion ... oxide and oxides of other rare earth elements in borate glasses, greatly expanding the available range of high-index low-dispersion glasses ... Borate glasses have lower wavelength-refraction dependence in the blue region of spectrum than silicate glasses with the same Abbe number ...
Famous quotes containing the word glasses:
“Nothing in Nature’s sober found,
But an eternal health goes round.
Fill up the bowl, then, fill it high,
Fill all the glasses there—for why
Should every creature drink but I?
Why, man of morals, tell me why?”
—Abraham Cowley (1618–1667)
“Altruism is selfishness out with a pair of field glasses and imagination.”
—Christina Stead (1902–1983)
“There has always been the same amount of light in the world. The new and missing stars, the comets and eclipses, do not affect the general illumination, for only our glasses appreciate them.”
—Henry David Thoreau (1817–1862)