Sunday, July 19, 2009

What Is In Contact Lenses

Two of the major types of contact lenses are corrective contact lenses and cosmetic contact lenses. Corrective lenses are made from soft polymers having 60 to 70 percent of water. Dry eyes contact lenses have very less or almost zero moisture which makes the contact lenses comfortable for dry eyes. RGP lenses are made of a special polymer that contains no moisture at all and is specifically used in making dry eyes contact lenses.

Many of the people are perplexed about the fact that what is in contact lenses? It is very important to know before purchasing the contact lenses that which type of material is used to make these lenses. In early days, the lenses were made from glass which caused pain and irritation in the eyes. Such contacts could not be worn as extensive wear and were supposed to be discarded after a trial period. Then there were hard contact lenses that had plastic in them. Although these lenses were better than glass but they did not allow oxygen to pass through them. Oxygen is very necessary for the eyes. Then in the late 19th century, rigid material contact lenses were introduced that were oxygen permeable. These polymers are called rigid gas permeable lenses polymers. They are non porous in nature and therefore cannot absorb any fumes or chemicals.