Contact Lenses Health Article

Contact Lenses

Clear or slightly colored plastic lenses worn directly on the eyeball to correct vision problems, held in place over the cornea by a thin layer of tears.

The concept of corrective lenses that sit directly on the eyeball was developed in the ninth century, but it was not until the late 20th century that manufacturing and grinding techniques for contact lenses were perfected. Originally contact lenses were made of glass, then later of hard plastic, and still later of flexible, highly oxygen-permeable soft plastic. Today, the majority of lenses worn are of two basic types: rigid gas permeable (so-called "hard" lenses) and soft lenses. Hard lenses are smaller and more durable, but require a longer period of adjustment for the wearer. Hard contact lenses can correct some vision problems, like astigmatism, that the soft lenses cannot. The soft lenses are slightly larger than hard lenses. They are more comfortable and less expensive, but can be easily torn. The latest generations of contact lenses are extended wear and disposable soft lenses. Extended wear lenses are intended to be worn for several weeks at a time, while disposable lenses are thrown away every day or every few weeks, or in the newest versions, every day. The Contact Lens Council reports that 26 million Americans wear contact lenses. Among contact lens wearers, approximately 80% wear the soft type and 18% wear rigid gas-permeable lenses. The Council reports that about 11 % of contact lens wearers, approximately 2.8 million people, are under 18.

Infants

There are few instances when corrective lenses—eyeglasses or contacts—are prescribed for infants. However, when an infant develops cataracts, a condition known as infantile aphakia, contact lenses may be prescribed following surgery. In 1993, the Journal of the American Medical Association reported that contact lenses were safe and effective for use with infants following cataract surgery. Routine care of the lenses was easily learned by the baby's parents or caregivers.