Age-Related Macular Degeneration
See also: Macular Degeneration
What is it?
Age-related macular degeneration is a condition
in which the cells of the macula, the center part
of the retina, progressively degenerate, causing
blurred central vision.
Who gets it?
Age-related macular degeneration affects
middle-aged individuals and occurs more often in
females than males. The risk for developing
macular degeneration increases with age, and may
be higher in people who smoke, have high
cholesterol, light-colored eyes, or a family
history of the disease.
What causes it?
The retina is a light-sensitive membrane that
lines the inner part of the eye and is connected
to the brain by the optic nerve. The macula is the
central part of the retina. It contains cells that
are responsible for sharp central vision. What
causes damage to these cells is not known for
sure, but it could be caused by hardening of the
arteries that supply blood to the retina. Most
people develop a form called dry age-related
macular degeneration where the cells of the macula
gradually disappear, so the macula becomes thin.
As little as 10 percent develop wet age-related
macular degeneration. With this form, blood
vessels grow in the layer of tissue under the
macula. As they grow toward the macula, they may
leak blood and other fluids under the macula,
damaging it.
What are the symptoms?
The main symptom of age-related macular
degeneration is blurred central vision, which
looks like a blind spot right in the middle of
your vision. You might first notice it when
reading, driving, or watching TV. Macular
degeneration does not affect peripheral (side)
vision or the ability to see colors. Dry
age-related macular degeneration usually begins in
one eye, but may affect the other eye at a later
time, or it can occur in both eyes at the same
time. The dry type progresses slowly until central
vision is very poor. Wet age-related macular
degeneration causes the same symptoms, but they
occur more rapidly. Lines that should be straight
may also look wavy or distorted.
How is it diagnosed?
Age-related macular degeneration is diagnosed
through an eye exam. Your doctor will test your
vision by having you read an eye chart. He or she
will also show you a card with a grid pattern and
a dot in the center. This is called an Amsler grid
and is used to test central vision. You will stare
at the dot and tell the doctor if there is any
distortion in any area of the grid. He or she may
also dilate your pupils for a better view of the
retina. Yellow deposits, called drusen, on the
retina can be a sign of the disease. Your doctor
may want to perform a procedure called fluorescein
angiography. A healthcare professional will inject
a dye into a vein, then photograph the retina.
These photos will help your doctor determine if
there are any leaky blood vessels behind the
retina.
What is the treatment?
There is currently no treatment for dry
age-related macular degeneration, which progresses
so slowly. You can improve your vision with
special lenses called low vision aids. Wet
age-related macular degeneration can be treated
with laser surgery. The laser is used to destroy
the abnormal blood vessels behind the retina and
stop further loss of vision. Right after the
surgery, vision will be blurry and you may feel
some discomfort in the eye. Your doctor will
continue to monitor your condition with
fluorescein angiography during routine visits. It
is not unusual for more new blood vessels to grow
after existing ones have been destroyed. Your
doctor may recommend another type of laser
surgery, called photodynamic therapy. With this
procedure, you receive an injection of a
photosensitive dye that affects the abnormal blood
vessels. They become sensitive to a special laser
light, which then destroys only the blood vessels
and no other tissues of the retina. Research into
anti-angiogenic drugs may hold promise for
treating wet macular degeneration. This treatment
would disable the molecules that stimulate the
growth of blood vessels.
Self-care tips
Everyone should see an eye care professional
for a regular eye exam. If you are at risk for
age-related macular degeneration, your doctor may
give you an Amsler grid to check your central
vision periodically at home. Contact your doctor
any time you notice a change in vision. People
with dry age-related macular degeneration may
benefit from a diet low in saturated fats and high
in antioxidants, found in vitamins C and E and
beta-carotene, as well as zinc and copper. Talk to
your doctor before changing your diet or taking
supplements. Not smoking can reduce your risk of
age-related macular degeneration and of recurrence
of the wet type after laser surgery.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
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