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The Curious Bag
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There are two major types of contact lens: soft lenses and hard gas permeable (GP) contacts. Each type of lens is made out of different material.
Soft Contacts
Soft contacts are made from hydrogels, a type of plastic that can absorb high levels of moisture. According to Allaboutvision.com, the water content hydrogel lens can be anywhere between 38 to 75 percent depending on the type of lens.
New Science
Newer soft lenses use a material called silicone hydrogel that include silicon in the hydrogel to allow oxygen to be more transmissible.
History of Hard Lenses
GP lenses were developed in the 1970s and do not contain water. However, GP lens have microscopic pores in the lens to allow oxygen to pass through.
Function of Hard Lenses
GP lenses are made from a plastic polymer called fluorosilicone/acrylate. Fluorine is added to the lens to prevent them from drying out.
Benefits of Hard Lenses
GP lenses provide better visual acuity than soft lenses. However, most people find wearing rigid GP lenses uncomfortable and opt for the softer lenses.
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