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Over 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.
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).
Contact 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.
Hard 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.
The 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.
Individuals 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 lens care.
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