Thursday, 9 June 2011

Contact Lens

Contact Lens

A contact lens (also known simply as a contact) is a corrective, cosmetic, or therapeutic lens usually placed on the cornea of the eye. Leonardo da Vinci is credited with describing and sketching 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. Rigid ones were produced and marketed first. Modern soft contact lenses were invented by the Czech chemist Otto Wichterle and his assistant Drahoslav Lím, who also invented the first gel used for their production.


Some soft contact lenses are tinted a faint blue to make them more visible when immersed in cleaning and storage solutions. Some cosmetic lenses are deliberately colored to alter the appearance of the eye. Some lenses now have a UV protection surface treatment to reduce UV damage to the eye's natural lens.

It has been estimated that 125 million 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 among countries, with rigid 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 more suitable for a number of sporting activities. Additionally, ophthalmological conditions such as keratoconus and aniseikonia may not be accurately corrected with glasses.

What are contact lenses?

Contact lenses are small visual devices made with curved pieces of plastic shaped in a way to conform directly to the wearer’s eye. They provide an artificial refracting surface to the human eye and are used to correct vision problems like myopia and hypermetropia. Contact lenses aid in eye focusing in the same manner as spectacles do. Apart from these corrective measures, contact lenses can also be used for cosmetic and therapeutic reasons.

There have been many modifications and improvements to the original idea of contact lenses, conceptualized first by Leonardo Da Vinci, through centuries. About 35 million people in the U.S. wear contact lenses today.

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