Eye
Facts> Eye Diseases
Diseases & Conditions: Age
Related Macular Degeneration (AMD)
Overview
Age-related macular degeneration (ARMD) is a degenerative
condition of the macula (the central retina). It is the
most common cause of vision loss in the United States in
those 50 or older, and its prevalence increases with age.
AMD is caused by hardening of the arteries that nourish
the retina. This deprives the sensitive retinal tissue
of oxygen and nutrients that it needs to function and thrive.
As a result, the central vision deteriorates.
 Macular
degeneration varies widely in severity. In the worst cases,
it causes a complete loss of central vision, making reading
or driving impossible. For others, it may only cause slight
distortion. Fortunately, macular degeneration does not
cause total blindness since it does not affect the peripheral
vision.
What is the difference between wet and dry macular degeneration?
AMD is classified as either wet (neovascular) or dry (non-neovascular).
About 10% of patients who suffer from macular degeneration
have wet AMD. This type occurs when new vessels form to
improve the blood supply to oxygen-deprived retinal tissue.
However, the new vessels are very delicate and break easily,
causing bleeding and damage to surrounding tissue.
 Dry
macular degeneration, although more common, typically results
in a less severe, more gradual loss of vision. The dry
type is much more common and is characterized by drusen
and loss of pigment in the retina. Drusen are small, yellowish
deposits that form within the layers of the retina.
 Patient
with wet macular degeneration develop new blood vessels
under the retina. This causes hemorrhage, swelling, and
scar tissue but it can be treated with laser in some cases.
What causes macular degeneration?
Macular degeneration may be caused by variety of factors.
Genetics, age, nutrition, smoking, and sunlight exposure
may all play a role.
Signs & Symptoms
- Loss of central vision. This may be gradual for those
with the dry type. Patients with the wet type may experience
a sudden decrease of the central vision.
- Difficulty reading or performing tasks that require
the ability to see detail.
- Distorted vision (Straight lines such as a doorway
or the edge of a window may appear wavy or bent.)
Detection & Diagnosis
Eye physicians usually diagnose AMD. Vision testing, Amsler
grid test, ophthalmoscopy, fundus photography and fluorescein
angiography are some common tests performed during a retinal
exam.
Treatment
There is no proven medical therapy for
dry macular degeneration. However there are several
treatments for Wet macular degeneration.
Treatments options for Wet Macular
Degeneration
The Wet form of ARMD need to be treated
as soon as it has been detected. There are several .
Dr. Campbell will discuss all the optins that are out
there for you. In fact at times he will suggest a combination
of treatments. These different forms of therapy are
for those who experience central vision loss from the
classic form of Wet ARMD, the leading cause of blindness
in people over age 50 in the Western world.
These Therapies include:
Laser Photocoagulation
While this process cannot restore lost vision, it seals
the abnormal blood vessels. This prevents further vision
deterioration in certain types of Wet Macular Degeneration.
In laser photocoagulation, a laser is used to destroy
the abnormal blood vessels under the retina. Since the
heat of the laser also destroys overlying healthy retinal
tissue, a permanent blind spot will result anywhere
the laser is applied. Thus, laser photocoagulation is
useful if the abnormal blood vessels are not in the
center of vision. If they are in the center however,
laser to this area will lead to permanent loss of vision.
Photodynamic
Therapy with Visudyne
There is a way to treat abnormal blood vessels in the
center of the eye. It’s called Visudyne Therapy.
Even with Visudyne Therapy there may be some loss of
vision. However, it’s less severe that laser photocoagulation
or no treatment at all. Visudyne therapy cannot restore
lost vision.
In Visudyne Therapy, a light-activated drug known as
Visudyne (verteporfin for injection) is injected in
to the bloodstream. The drug travels in the bloodstream
and collects in the abnormal blood vessels, where it
is activated by a non-thermal laser (a laser that does
not burn the retina). This produces a reaction that
closes the abnormal vessels without causing damage to
the overlying retina.
Visudyne Therapy is a multi-course treatment. The desired
result cannot be achieved with just one or two treatments.
Multiple treatments are necessary because leakage often
reoccurs and the abnormal blood vessels may return after
treatment. However, Visudyne can be reapplied at up
to three-month intervals, if necessary. A typical treatment
schedule for eligible AMD patients is three treatments
in the first year, two times in the second year, and
one to two treatments in the third year.
Macugen
Injection
Macugen works differently from all other treatments.
Macugen blocks a key signal that causes abnormal vessels
to grow and leak. By helping to slow the growth of these
abnormal blood vessels, Macugen can slow the damage
they do to your site.
The goal of therapy with Macugen is to help slow the
progression of your disease and preserve your vision.
In clinical trials, patients receiving macugen lost
less vision on average than patients who did not receive
Macugen. However, results may vary from person to person.
This medicine is injected into the eye by Dr. Campbell
every 6 weeeks. The medicine has shown to slow the growth
of abnormal blood vessels, slowing the damage to your
sight. Results may very from patient to patient. Refer
to the Macugen website above for further details.
|
Nutrition and Macular Degeneration
Several recent studies have indicated a strong link between
nutrition and the development of macular degeneration.
It has been scientifically demonstrated that people with
diets high in fruits and vegetables (especially leafy green
vegetables) have a lower incidence of macular degeneration.
More studies are needed to determine if nutritional supplements
can prevent progression in patients with existing disease.
Read Our Disclaimer |
