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MACULAR DEGENERATION
Overview
What is the macula?
What
is degeneration of the macula?
Why does macular degeneration occur? What can
be done to prevent macular degeneration?
How is macular degeneration treated?
What should I watch for?
Newest Treatments for AMD
Dr.
Yoken's Patient Handouts
Overview
All physicians
at EyeHealth Northwest are trained to diagnose and care for patients
with Macular Degeneration. In addition, we also have a fellowship
trained vitreoretinal specialist on our staff, Dr.
Jonathan Yoken who is a Fellowship trained Retinal Specialist
available for Macular Degeneration disease treatments, surgery and
consultations.
What
is the macula?
The macula is a specific area of the retina. It is at the center
of the visual field-when looking directly at an object, you are
seeing it with the macula, while the rest of the retina provides
peripheral vision. Although it represents only a small fraction
of the total size of the retina-about the size of the capital letter
"O" on this page-the macula is crucial for visually demanding
tasks like reading, driving a car, and color vision. Diseases of
the macula may interfere with "detail vision", making
these activities more difficult. Macular problems can also cause
images to appear distorted, or may cause an area of cloudiness or
darkness to form at the center of the visual field. Fortunately,
many diseases that affect the tiny macula may spare the rest of
the retina, thereby preserving peripheral vision. Therefore, diseases
such as Age Related Macular Degeneration (ARMD) rarely result in
complete loss of sight.
What
is degeneration of the macula?
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"Dry
AMD", Drusen
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In some individuals,
tiny dot-like deposits (known as drusen) slowly accumulate beneath
the macula. While these deposits usually do not cause visual loss
directly, they indicate that the patient is at risk for developing
further problems with the macula. Usually, these deposits would
not be apparent before the age of 50.
Visual problems
in macular degeneration take two basic forms. The first, milder
problem occurs as the cells of the macula slowly lose sensitivity
and may become less numerous. This may result in fluctuating vision-the
sight is clearer on some days than others-and slowly (typically
over months to years) vision may worsen. This is referred to as
the "dry" form of macular degeneration.
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| Vision
change in "Wet" AMD |
The second type
of problem occurs more suddenly and may cause a more serious drop
in vision. Tiny clusters of abnormal blood vessels may begin to
grow beneath the macula. These vessels "leak" and blood
or watery fluid may accumulate beneath the macula. This can result
in irreversible damage to the macula, resulting in loss of the central
detail vision. The presence of leaks is often referred to as the
"wet" form of macular degeneration.
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"Wet"
AMD with new blood vessels in the macula.
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If these vessels
can be identified at an early stage, it may be possible to seal
them with laser treatment. In many cases, however, laser cannot
be used because the vessels have already spread too far, or the
exact location of the leak cannot be found.
Fortunately,
newer treatments have been developed which can be used to treat
the wet form of the disease even when it has developed under the
center of the macula, or in cases when the vision has recently declined.
"Wet" AMD. New blood vessels visible with
Fluorescein Angiography.
Why
does macular degeneration occur? What can be done to prevent macular
degeneration?
While the most
important risk factor for macular degeneration is age, it is not
yet understood why macular degeneration occurs in some seniors and
not in others.
There may be some inherited factor which predisposes individuals
to have this condition, and research to identify the genes which
are associated with macular degeneration is ongoing. The development
of drusen, and the slow loss of retina cells that sometimes occurs,
is not preventable by any means yet identified. However if the genetic
basis of macular degeneration was identified, it might be possible
to correct the defect before macular degeneration can begin. Many
researchers are working on this question, but it remains a difficult
problem.
If a person
has macular degeneration, it appears that keeping the entire body
healthy-control of blood pressure, control of cholesterol, good
nutrition, and avoiding cigarettes-helps to reduce the risk of developing
visual loss. The Age-Related Eye Disease Study (AREDS) was a major
study sponsored by the National Eye Institute (NEI). In the study,
scientists looked at the effects of zinc and antioxidants (vitamin
C, vitamin E & beta carotene i.e. provitamin-A), on patients
with cataracts and age-related macular degeneration (AMD). Patients
with intermediate to advanced AMD, as determined by the doctor,
who were taking the anti-oxidant and zinc combination had a demonstrable
decrease in the incidence of developing wet AMD.
While most patients in the study experienced no serious side effects
from the doses of zinc and antioxidants used, a few taking zinc
alone had urinary tract problems that required hospitalization.
Some patients taking large doses of antioxidants experienced some
yellowing of the skin. The long-term effects of taking large doses
of these supplements are still unknown. Previous studies have shown
that individuals who smoke and take beta-carotene are at an even
greater risk of developing lung cancer, and therefore current
and recent smokers should not take beta-carotene.
If you have intermediate (or advanced macular degeneration in one
eye only), talk to your physician about taking nutritional supplements.
Your doctor can help you determine if they may be beneficial-and
safe-for you, and what types and doses of supplements to take. The
doses used in the study were: Vitamin C 500 mg, Vitamin E 400 IU,
Beta-carotene 15 mg, Zinc 80 mg, as zinc oxide, Copper 2 mg, as
cupric oxide (copper should be taken with zinc, because high-dose
zinc is associated with copper deficiency).
An additional
factor that may aggravate macular degeneration is unprotected exposure
to the sun's UV rays. While this is not yet proven, in my practice
most patients find that sunglasses (with UV protection) are more
comfortable in bright sunlight.
See article
entitled "Vitamin
and Mineral Supplementation" for more information.
How is macular degeneration treated?
There is no
treatment for dry AMD, except for vitamin supplementation as described
above if recommended by your doctor. There are now a variety of
treatments for wet AMD, but whether or not you are a candidate for
treatment depends on the type and location of the leak, its progression
over time and its affect on your vision and macula. Some of the
newest treatments finally offer the hope of restoring some lost
vision, if treatment is started in the early stages, and in
most cases vision can at least be stabilized.
I recommend
reading the article entitled "Newest
Treatments for Age Related Macular Degeneration" for a
more detailed explanation.
What
should I watch for?
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Amsler
Grid
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Your doctor
will schedule regular follow-up appointments to monitor your condition.
In addition, we strongly recommend monitoring your vision with an
Amsler grid at least twice a week, so that any changes in vision
will be recognized as early as possible. Instructions on how to
use the grid will be provided.
Any
changes on the Amsler grid-waviness of the lines, blank or missing
lines, or blurring of the lines-should be reported to your doctor
promptly. Early detection is our best defense against visual loss
in macular degeneration!
Return to Top
Dr.
Yoken's Printable Handouts
What is the Retina?
Flashes and Floaters
Diabetic Retinopathy
Retinal Tears and
Detachment
Central Serous Retinopathy
(CSR)
Macular Degeneration
Vitamin and Mineral
Supplementation - ARMD
Newest Treatments
for ARMD
Macular Hole
Macular Pucker
Photodynamic Laser
Treatment (PDT) and Visudyne™
Retinal Artery
or Vein Occlusion
Cystoid Macular
Edema
Fluorescein
and Indocyanine Green (ICG) Angiography
Headace, Migraine
and Ocular Migraine
Uveitis
Endophthalmitis
Retained Lens Material
After Cataract Surgery
Monitoring For
Plaquinil-Induced Retinal Toxicity
How to Apply Eyedrops
and Your EyeDrop Schedule
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