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
between countries, with rigid lenses accounting for over 20% of
currently-prescribed lenses in Japan, the Netherlands and Germany but less
than 5% in Scandinavia.
-wikipedia
