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Contact Lens Definitions and Factiods
Contact Lenses 2
PMMA lenses
Rigid or "hard" contacts were the first lenses; they were developed in the 1960's. They are made of a type of plastic called PMMA (polymethyl methacrylate), which is very durable, but does not allow oxygen in the air to directly reach the cornea.
When the eye blinks, the lens moves, which allows the oxygen dissolved in the tears to reach the cornea. Rigid lenses are the least comfortable type of contacts and are not really used anymore. However, some people still prefer them for their durability and lower cost.
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