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Optics And Refraction
Contacts and Cosmetics
Contact lens wearers who wear
cosmetics on a daily basis may be especially vulnerable
to eye problems. Misuse of products and adverse
reactions to ingredients used in cosmetic formulas cause
lens deposits, eye irritation, allergy, dryness, injury
and infection. Knowing which products to use and how to
use them is important for long-term, problem-free
contact lens wear.
Before handling lenses, wash your hands with a mild soap
such as Neutrogena, Ivory or a clear glycerin soap. Or,
use one of the specialty soaps for contact lens wearers
such as AOSoap or Optisoap. Avoid soaps containing
cream, deodorant, antiseptics, or heavy fragrances.
Contact lenses should be inserted before any cosmetics
are applied to prevent contaminating the lens by makeup
and disrupting makeup by tears. Mascara should be used
sparingly and only on the outer half of the lashes.
Besides being a potential irritant, mascara is
frequently a source of infection. Even with the best of
care, mascara and eyeliner should be replaced every
three months. Use a light touch with eyeliners and
shadows, as they may cause blepharitis, an infection of
the eyelid that can lead to styes and chalazion. Don't
use eye liner pencils inside the lower eyelid. Color
pigments can cause irritation, damage contact lenses, or
lodge underneath the contact lens and scratch the
cornea.
Prevent contamination of your makeup by keeping it dry
and avoiding contact with fingers. Keep applicators
clean and replace them after approximately three months.
Hair spray, deodorant, cologne, mousse, nail polish and
nail polish remover should be used before inserting your
lenses. If one of these products gets into your eye it
can cause permanent damage to the contact lens surface.
If you must use hair spray while wearing contacts, close
your eyes tightly while spraying and then leave the area
quickly. Aerosol mist lingers in the air for some time
after spraying.
Never wear contacts when using hair dyes, permanent wave
lotions, or medicated shampoos.
Use cosmetics labeled "hypoallergenic," "for contact
lens wearers," or "for sensitive eyes." Approximately
one in ten women have either a respiratory or skin
allergy to perfume. Hypoallergenic brands are designed
be free of irritants such as perfumes and lanolin.
Lanolin may be used in cosmetics and soaps and is one of
the most common allergens, causing redness, itching, and
blotchy skin spots.
Wash your hands and remove contact lenses before
removing make-up. Your fingers are less likely to be
contaminated by pigments, creams and oils from cosmetic
products when the lenses are removed first. |
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Extended-Wear Contact Lenses
Some people do not consider wearing
contact lenses because they think the required cleaning,
disinfecting, storing, and inserting are too much
trouble. They may also want the option of occasionally
napping or sleeping with their contacts in their eyes.
Extended-wear contacts are designed to appeal to these
people. They require less maintenance than daily wear
lenses and because they are thinner and allow more
oxygen to reach the eyes, they may be left in the eye
overnight.
To use extended-wear contact lenses, you must be free of
external eye disease, have normal tear function, and be
motivated to take care of them.
Infection is the most significant complication of
extended-wear contact lens use. They must be removed at
least once a week and thoroughly cleaned and
disinfected. Many studies show the cornea is put at
increased risk of infection by wearing contact lenses
overnight. The risk of developing an infection in the
cornea is 10-15 times greater for those who wear
extended-wear contacts overnight than for those who use
daily wear soft lenses. This risk increases with the
number of consecutive days the contacts are worn
overnight. Infections may range from simple
conjunctivitis to blinding endophthalmitis, which is a
serious infection that travels through all layers of the
eye.
The decision to accept the risks and benefits of
extended-wear contacts requires a process of evaluation
between you and your doctor. Once you are carefully fit
for your contact lenses, follow-up exams with your
ophthalmologist to ensure continuing eye health is
important. As with any contact lens, extended-wear
contacts should be removed at the first sign of redness
or discomfort.
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Eyeglasses
Sixty percent of the 161 million
Americans who wear prescription eyewear choose eyeglasses.
Wearing eyeglasses is one of the simplest ways to correct
vision problems.
To see images clearly, light rays must focus directly on the
retina, the light-sensitive nerve layer that lines the back
of the eye. There are different kinds of focusing problems,
called refractive errors, which may require corrective
lenses. In the case of myopia or nearsightedness, the eye is
too long. Light rays focus before reaching the retina and
images appear blurry. In hyperopia or farsightedness, the
eye is too short, so light rays have not yet focused when
they reach the retina. Astigmatism describes an eye with a
cornea that is oval shaped instead of round, causing light
rays to hit the retina in more than one place.
Eyeglass lenses compensate for an eye that is too long or
too short by adding or subtracting focusing power. The
lenses create just the right amount of focusing power so
light rays focus directly on the retina.
A plus (+) in front of the first number of the eyeglass
prescription means the lens corrects farsightedness. A minus
(-) in front of the first number means the lens corrects
nearsightedness. If a second and third number are present in
the prescription, they indicate astigmatism. The higher the
first number in the prescription, the greater the correction
in the lens.
Lenses are available in glass, regular and high index
plastic, and polycarbonate. Although they scratch less
easily, glass lenses tend to be heavier and often slide down
the nose. Plastic and polycarbonate lenses are lighter and
safer than glass but scratch easily. Scratches cannot be
removed but they can be avoided or minimized with
appropriate care. Scratch resistant coatings can be applied
to plastic and polycarbonate lenses but some of these
coatings crack if exposed to extreme heat or cold.
Frames come in many shapes and sizes, so it is important to
pick a frame that is best for you. Factors to take into
consideration when selecting a frame include facial
features, age, activities and the prescription itself. Often
a strong prescription requires thicker lenses, which can
affect your choice of frames.
Ask about the quality and expected lifetime of the frame and
if there is a frame guarantee. |
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