24 million people choose contact lenses to correct vision. When used with care
and proper supervision, contacts are a safe and effective alternative to
eyeglasses. And with today's new lens technology, many people who wear
eyeglasses can also successfully wear contacts.
are thin, clear discs that float on the tear film that coats the cornea, the
curved front surface of the eye. Contacts correct the same refractive
conditions eyeglasses correct: myopia (nearsightedness), hyperopia
(farsightedness) and astigmatism (an oval- rather than round-shaped cornea).
lenses can be made from a number of different plastics. The main distinction
among them is whether they are hard or soft. Most contact lens wearers in the United States
wear soft lenses. These may be daily wear soft lenses, extended wear lenses or
disposable lenses. Toric soft lenses provide a soft lens alternative for people
with slight to moderate astigmatism.
lenses are usually not as comfortable as soft lenses and are not as widely
used. However, rigid gas permeable lenses provide sharper vision for people
with higher refractive errors or larger degrees of astigmatism.
majority of people can tolerate contact lenses, but there are some exceptions.
Conditions that might prevent an individual from successfully wearing contact
lenses include dry eye, severe allergies, frequent eye infections, or a dusty
and dirty work environment.
who wear any type of contact lens overnight have a greater chance of developing
infections in the cornea. These infections are often due to poor cleaning and