Contact lenses, or contacts, are thin pieces of rigid or flexible plastic that can be applied to the cornea of the eye. They can be used to serve a variety of purposes. They may be used correctively in the same way as glasses, therapeutically to treat disorders such as dry eye and keratitis and cosmetically to change the appearance of the eye.
History
Leonardo da Vinci is credited as the first person to conceptualize and sketch contact lenses. However, it wasn't until much later that his ideas became any sort of a reality. Over 350 years later, an English astronomer by the name of Sir John Herschel conceptualized making a mold of an individual person's eyes, and 50 years after that some real contact lenses were created. Contacts have gone through many phases. In the beginning, they were hard plastic and could be irritating to wear for extended periods. New technology made them lighter and easier to tolerate, but it wasn't until the 1971 launch of FDA-approved soft lenses that they became as comfortable and as popular as they are today.
Types of Lenses
There are three main types of contact lenses. Hard lenses, made from a material known as PMMA (Plexiglas) are scarcely used anymore. Soft lenses, made from plastics that are gel-like, are the most common. GP lenses, or oxygen permeable lenses, are made from rigid plastics, but they are specialized for disorders such as high astigmatism. Some contacts (daily wear contacts) must be removed each night. Others (extended wear contacts) can be worn for up to a week without being removed.
Other Varieties
Beyond their basic materials and length of wear, contact lenses can be broken into further categories. Colored contact lenses can alter the color of the eye. Disposable contact lenses can be thrown out after a certain period of time. Prosthetic contact lenses can hide eye injuries. Toric contacts are used for people with astigmatism. A person can even opt to create a custom contact lens if all available options don't have the desired attributes.
Contact Lens Safety
People who put contact lenses into their eyes should take extra care to ensure safety. Cleaning off the contact with a special solution and washing one's hands prior to touching the contact lens or the eye are particularly important steps. Furthermore, the soap being used to wash one's hands shouldn't contain fragrances, moisturizers or antibacterial substances.
Contact Lens Statistics
According to "Contact Lenses 2002: Annual Report," about 32 million (or 12 percent of) people in the United States wear contacts. Of these 32 million people, 87 percent wear soft lenses and about 13 percent wear rigid lenses. About 80 percent of soft lenses are used to correct nearsightedness and farsightedness.
