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Age-related macular degeneration (AMD) is the leading
cause of vision loss for people over the age of 50 in the Western world,
affecting approximately 25-30 million people.
AMD is a degenerative condition of the macula. 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 underneath the retina. However,
the new vessels are very delicate and break easily, causing bleeding and
damage to surrounding tissue.
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 and 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).
Treatment
There is no proven medical therapy for dry macular degeneration. In selected
cases of wet macular degeneration, laser photocoagulation is effective
for sealing leaking or bleeding vessels. Unfortunately, laser photocoagulation
usually does not restore lost vision, but it may prevent further loss.
Recently, photodynamic therapy has proven to be effective in stopping
abnormal blood vessel growth in some patients with wet AMD. This new type
of laser treatment is far less damaging than laser photocoagulation and
is the treatment of choice in many cases. Early
diagnosis is critical for successful treatment of wet macular degeneration.
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