Materials for contact lens are of a great variety and improvements have been made in each step from its early growth stage to its mass popularity.
As it known to all that contact lens was manufactured into hard lens, which was mainly made from polymethylmethacrylate (PMMA), in the early development, however, for its uncomfortibility and inflexibility, it has been out of use in modern society. What we now often used are soft lenses which are made from polyacrylamide, or say the HEMA. Soft lenses are more comfortable to wear as they are of similar characteristics of the acrylic fibers used to produce clothing fabrics. People who wear soft lenses hardly suffer from eye infections as they wear hard lenses for their rigid surfaces. Now HEMA is replaced by polymers that contain 80% water which are healthier for eyes. In addition, another newly researched type is the gas-permeable contact lens, which is made from HEMA, silicones and fluoropolymers. That is to say it combines merits of soft lenses and other features in one. They are fairly amiable, and one takes only one or two hours to get used to it, and that because of its special designation of permeability, air can easily go through which is good for eyes breathing.
Materials for contact lens can also be broken into two groups, namely hydrophilic and the hydrophobic, according to the moisture content. Hydrophilic refers to materials that contain more than 10% water by weight. In today's market, abafilcon A, alphabilcon A, etafilcon A, and so on so forth are made from hydrophilic. And those contain less than 10% by weight are hydrophobic, from which amefocon A, cabufocon A, dimefocon A and about 80 more in this category are made.
Therefore, from the foregoing, we may get a conclusion that great changes have always been there in the development of materials for contact lens. All those changes are made to help contact lenses wearers have a more comfortable and safer life. Thus one day when you find that materials for contact lenses alter again, do not be surprised, because all are for the benefit of the wearers.
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