Contact Lenses Overview
Contact lenses are miraculous pieces of plastic that allow you to see without glasses. In most cases, contact lenses are used as a substitute for glasses, allowing you to dispense with them. Contact lenses may also be used to treat certain eye diseases or may be used for cosmetic purposes to change the apparent color of your eyes.
Successful contact-lens wear requires a "partnership" between the fitter, that is, an ophthalmologist, an optometrist, or possibly an optician, and you, the wearer.
- The fitter must first decide if your eyes are healthy
enough to wear contact lenses. If so, the fitter then fits the correct lenses
for your eyes and your needs and teaches you how to use and care for them.
- The fitter should be available if problems develop;
if not available, the fitter must then have system in place to address those
- You must follow the instructions, care for, and wear the lenses correctly, and return as required for routine and emergency care.
A fitter can be an ophthalmologist, an optometrist, or possibly an optician.
- Ophthalmologists are doctors who have
graduated from college, and a school of medicine (MD) or osteopathy (DO), after
which three to five years of additional training are required and spent studying about eye
examinations (including fitting of contact lenses and glasses), diagnosis and
treatment of eye diseases, and performing eye surgery. Ophthalmologists perform
both conventional surgery and laser surgery.
- Optometrists have graduated from a school of
optometry (OD), where they are trained in eye examinations, fitting of contact
lenses and glasses, and depending on state licensure, treatment of certain eye
diseases. Optometrists do not perform conventional eye surgery or laser
- Opticians fit glasses based on the prescription of an ophthalmologist or an optometrist. In some states, opticians
may fit contact lenses. Opticians do not perform eye examinations, do not diagnose or treat eye diseases, and do not perform surgery.
Soft lenses and rigid gas permeable (RGP) lenses are the main lenses
available. Each has specific indications as well as a specific wear and care
regimen. The older hard (PMMA) lenses are rarely used today and have risks
similar to RGP lenses. There are larger scleral lenses available for special eye
Contact lenses are mainly used to avoid having to wear glasses in conditions
such as nearsightedness, farsightedness, and astigmatism or to avoid the use
of bifocals (multifocal lenses).
They may also be used to treat other conditions. Keratoconus is a condition
in which the surface of the eye has a very irregular shape (astigmatism). When
glasses no longer provide adequate vision, contact lenses are used.
Contact lenses are often used after refractive surgery when under- or
over-corrections occur. After surgery, and in some cases of eye diseases of the
cornea, bandage soft contact lenses may be used to allow the cornea to heal or
may be used to alleviate pain.
- Some lenses are meant for daily wear. With daily wear
soft lenses, you wear the lenses for one day and then discard them. This
allows one to dispense with solutions, cleaning, and disinfection of the
lenses. It allows intermittent wear such as weekend or occasional wear, as
desired. Most soft lenses and some RGP lenses are worn for a day and then
removed, cleaned, and disinfected each night. Soft lenses are usually replaced
on a regular basis, which varies from one week to one month to three months to
one year. RGP lenses may last for years with regular care.
- Extended wear lenses, usually soft, are worn
overnight for one week and then replaced every one to two weeks. Trying to
extend the wear of lenses beyond the recommended replacement schedule is a
false economy and an invitation to potential disaster.
- Overnight wear decreases the amount of oxygen available to the eye and increases the (rare) chance of infection
by fourfold. Because of this, some practitioners do not recommend extended wear of contact lenses. Newer lenses may be safer.
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