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FAQ's
ABOUT EYEWEAR and EYE-CARE
Q. What is the difference between bifocals, multifocals, and
trifocals?
A. Bifocals are lenses that have two parts - the upper part is
used for distance vision, and the lower part is used for such
close vision tasks as reading or sewing. Even though bifocals
can technically be considered multifocals (because they have
more than one focus), the term "multifocal" is generally
used interchangeably with the term "trifocal", because
they have three or more segments. In trifocals, the upper part
helps view distant objects, the intermediate segment is effective
for arms-length vision, and the lower section is for reading-distance
vision.
Q. Are anti-reflective coatings really worth the added expense?
A. Many people who use lenses with an anti-reflective coating
would wholeheartedly agree that they are worth every cent. Recent
research showed that approximately 14% of all lenses sold in
the U.S. have anti-reflective coatings. In Europe, however, more
than 60% of all lenses are "A-R" coated. Anti-reflective
lenses make use of metallic oxides that "coat" lens
surfaces and help to reduce annoying reflections. A-R coatings
also help to improve vision by reducing "ghost" images
and light reflections that are both irritating and distracting.
The "clear" appearance that A-R coatings give makes
the process particularly popular among TV personalities.
Keep in mind however, that if you ask a former A-R user, they
may warn you against the coating, which was once prone to crack
and delaminate. But rest assured, newly developed techniques
have dramatically improved the quality, reliability, and performance
of A-R coatings.
Q. What does it mean if I have astigmatism?
A. In astigmatism, the eye's surface is shaped somewhat like
a football (more oval), rather than like a baseball (round).
Astigmatism causes the eye to focus on objects in two planes,
only one of which is able to focus on the retina. In this case,
out-of-round cylindrical lenses, opposite in design to those
of the astigmatic eye, are prescribed to "neutralize" the
defect.
Q. How safe is laser corrective surgery?
A. The procedure has proved quite safe thus far. There have been
no reported cases of blindness in relation to either of the two
most common procedures, PRK and LASIK. However, the FDA is aware
of a few cases of severe eye injury requiring cornea transplant.
Q. How effective is laser eye surgery?
A. Most physicians agree that the treatment is generally effective.
According to an article printed in the July-August '98 issue
of the FDA Consumer Magazine, the treatment does seem to be permanent,
although as people age and their eyes change, re-treatment may
be necessary. It is also difficult to predict how your eyes will
respond to the surgery, which means that you may still need corrective
lenses for good vision, even after undergoing the procedure.
In some cases, patients will need to undergo a second procedure.
Unfortunately, some patients even find that after refractive
surgery, their best obtainable vision with corrective lenses
is worse than it was before being operated on. This can occur
as a result of irregular tissue removal or the development of
cornea haze. In others, the effect of the surgery can be gradually
lost over several months. Again, re-treatment is an option.
"
Halo Effect" is also a risk. The halo effect is noticed
in dim light. As the pupil enlarges, a second faded image is
produced. For some patients who have undergone the PRK or LASIK
procedures, this can interfere with night driving.
The FDA also reports that even when everything goes perfectly,
there are effects that might cause some dissatisfaction. Older
patients should be aware that they cannot have both good distance
vision and good near vision in the same eye without corrective
lenses.
Finally, if one eye is being treated at a time, the eyes may
not work well together between treatments. If a contact lens
won©£t be tolerated on the eye not yet operated on,
work and driving can be difficult or even impossible.
Q. What is the difference between an ophthalmologist, an optometrist,
and an optician?
A. For this answer, we looked to Jeffrey Anshel, author of Smart
Medicine for Your Eyes (Avery Publishing Group, 1999): There
are three different kinds of professionals involved with the
care of the eyes, so it may not come as a surprise to you that
there is some confusion over who does what. An ophthalmologist
is a medical doctor (MD) who specializes in eye health and disease.
After graduating from medical school, an ophthalmologist spends
three more years learning about the diseases and surgeries of
the eye (all ophthalmologists are surgeons). In order to become
a board certified ophthalmologist, the MD must pass a written
and practical certifying examination in the specialty of ophthalmology.
In telephone directories, ophthalmologists are listed under the
general heading of "physicians". An optometrist is
a doctor of optometry (OD). Optometrists are defined as healthcare
professionals trained and state licensed to provide primary eyecare
services. These services include; comprehensive eye health and
vision examinations, diagnosis and treatment of eye diseases
and vision disorders, detection of general health problems, the
prescription of glasses and contact lenses, low vision rehabilitation,
vision therapy and medication, the performance of certain surgical
procedures, and the counseling of patients regarding their surgical
alternatives and vision needs. Optometrists complete pre-professional
undergraduate education at a college or university and four years
of professional education at a college of optometry. Some optometrists
also complete residencies. An optician is a technician trained
to fill prescriptions for lenses written by optometrists and
ophthalmologists. Opticians are trained to make glasses, fit
eyeglass lenses into frames, and adjust frames to people's faces.
In some states, they are also allowed to do fittings of contact
lenses. Opticians generally have an associate college degree,
which is awarded for completing a two-year undergraduate program.
Q. How does diabetes affect the eye?
A. Diabetes, a disease that prevents your body from making or
using insulin to break down sugar in your bloodstream, can cause
changes in nearsightedness, farsightedness, and premature presbyopia.
In fact, the early signs of diabetes are often detected during
eye examinations. Diabetes can lead to cataracts, glaucoma, and
decreased eye-muscle coordination and cornea sensitivity. Symptoms
include fluctuating or blurred vision, occasional double vision,
loss of visual field, or flashes and floaters within the eyes.
However, the most serious diabetes-related eye problem is diabetic
retinopathy.
Q. What is retinopathy?
A. Diabetic retinopathy is a weakening or a swelling of the tiny
blood vessels in the retina of the eye, which can result in blood
leakage, the growth of new blood vessels, as well as other changes.
If left untreated, diabetic retinopathy can lead to blindness.
Once damage has occurred, it is usually permanent, so it is important
to control your diabetes as much as possible to reduce the risk
of developing retinopathy. Frequent visits to your eyecare physician
are also essential, since early detection is crucial.
Q. Do certain things put me at risk for developing retinopathy?
A. Several factors can increase the risk of developing retinopathy,
including; smoking, high blood pressure, alcohol use, and pregnancy.
(Source: http//www.virtualcity.com/dvc/diabetes.html)
Q. What is presbyopia? And what causes it?
A. Presbyopia is a vision condition in which your eyes have difficulty
focusing on close objects due to a loss of flexibility in the
crystalline lens of the eye. Although our eyes stop growing at
age 10, the lens continues to produce cells. Due to this growth,
as well as the aging process, the lens can lose some of its elasticity
and, therefore, its ability to focus.
Q. At what age does presbyopia become a problem?
A. It's different for everyone. Actually, presbyopia doesn't
have a sudden onset; it develops over a number of years. The
condition will usually become noticeable in your mid-40s.
Q. What are the symptoms of presbyopia?
A. If your arms are too short to see reading materials anymore,
that's a pretty good sign. At normal reading distance, you will
notice blurred vision, while close work will fatigue your eyes
and bring on a headache. An optometric examination that tests
your near-vision ability can determine presbyopia. Once diagnosed,
you will need glasses for reading or general close vision - although
you may find that wearing your glasses all the time is best.
Because the effects of presbyopia will continue to change through
your 60s, periodic lens changes will most likely be necessary. |
