A contact lens is a corrective, cosmetic, or therapeutic lens usually placed on the cornea of the eye. Leonardo da Vinci is credited with describing andsketching the first ideas for contact lenses in 1508, but it was more than 300 years later before contact lenses were actually fabricated and worn on the eye. Modern soft contact lenses were invented by theCzech chemist Otto Wichterle and his assistant Drahoslav Lím, who also invented the first gel used for their production.
Contact lenses usually serve the same corrective purpose as glasses, but arelightweight and virtually invisible—many commercial lenses are tinted a faint blue to make them more visible when immersed in cleaning and storage solutions. Some cosmetic lenses are deliberatelycolored to alter the appearance of the eye. Some lenses now have a thin surface treatment which is a UV coating; this helps to reduce UV damage to the eye's natural lens.
It has been estimated that 125million people use contact lenses worldwide (2%), including 28 to 38 million in the United States and 13 million in Japan. The types of lenses used and prescribed vary markedly between countries, withrigid lenses accounting for over 20% of currently-prescribed lenses in Japan, the Netherlands and Germany but less than 5% in Scandinavia.
People choose to wear contact lenses for many reasons,often due to their appearance and practicality. When compared with spectacles, contact lenses are less affected by wet weather, do not steam up, and provide a wider field of vision. They are moresuitable for a number of sporting activities. Additionally, ophthalmological conditions such as keratoconus and aniseikonia may not be accurately corrected with glasses.
* Leonardo DaVinci → 1508 Codex of the eye, Manual D
In 1888, Adolf Fick was apparently the first to successfully fit contact lenses, which were made from blown glass
René Descartes → proposed... [continua]
Cite este ensayo
(2010, 08). Articulo cientifico en ingles. BuenasTareas.com. Recuperado 08, 2010, de http://www.buenastareas.com/ensayos/Articulo-Cientifico-En-Ingles/656882.html
"Articulo cientifico en ingles" BuenasTareas.com. 08 2010. 2010. 08 2010 <http://www.buenastareas.com/ensayos/Articulo-Cientifico-En-Ingles/656882.html>.
- MLA 7
"Articulo cientifico en ingles." BuenasTareas.com. BuenasTareas.com, 08 2010. Web. 08 2010. <http://www.buenastareas.com/ensayos/Articulo-Cientifico-En-Ingles/656882.html>.
"Articulo cientifico en ingles." BuenasTareas.com. 08, 2010. consultado el 08, 2010. http://www.buenastareas.com/ensayos/Articulo-Cientifico-En-Ingles/656882.html.