In 1960, experiments to make contacts out of water-absorbing (hydrophilic) plastic began, and the first soft lens made of such material became available commercially in the U.S. in 1971. The water content of today’s soft lenses ranges from just under 40 percent up to about 80 percent. They normally cover all of the cornea and part of the sclera (white of the eye).
Rigid Gas Permeable (RGP) Lenses
The first RGP lenses were introduced commercially in 1979. Also called oxygen permeable lenses, RGP contacts are made of a variety of silicone-acrylate combinations. They normally cover about two-thirds of the cornea. Some contacts use a combination of soft and RGP materials to accommodate unique fitting cases. For example, there’s a lens made with an RGP center surrounded by a soft periphery. Read more about RGP lenses.
The first lenses to hit the market in 1945 were what are now known as hard lenses. Until 1945, these lenses were made from hard glass before Plexiglass was discovered. This material is now better known as Plexiglass. Hard lenses are still manufactured in this manner due to history and quality but their use has tapered off significantly, largely due to the discomfort and lack of oxygen flow to the eye.
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