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 Dr.
Fry Continues to Update Advances in Treatment of Vision Problems.
Macular
degeneration is the most common uncorrectable cause of vision
loss in the United States. Although it affects only central vision
and never makes a person go entirely blind, it can cause
considerable visual difficulty.
In
the last issue, I promised to talk about new advances in the treatment
of macular degeneration. These include; Photdynamic Therapy (PDT),
Transpupillary Thermotherapy (TTT), Macular Translocation Surgery,
and Retinal Pigment Epithelium Cell Transplant. In this issue,
we will talk about Visudyne Photdynamic Therapy, which was just
approved by the FCA in May of 2000.
Macular
degeneration comes in two types; "wet" and "dry".
The dry type is much more common and progresses very slowly. The
wet type tends to progress rapidly. Photodynamic Therapy is a
treatment for the wet type only.
In
the wet type, new blood vessels form beneath the retina. These
blood vessels leak fluid and bleed, causing rapid loss of vision.
Previously, treatment involved destroying the vessels with a laser
beam. Unfortunately, this also destroyed the retina over these
vessels, causing an immediate loss of vision in the involved area.
This
new PDT involves an intravenous injection of photosensitizing
agent, followed by shining a low power laser on the involved blood
vessels. The photosensitizing agent (Visudyne, from CIBA Pharmaceuticals
is the one recently approved) is absorbed into the involved blood
vessels, making them susceptible to damage from this low powered
laser. This allows destruction of these vessels without
damage to the retina.
This
is a treatment for only the less common wet type. Also, only a
minority of patients with the wet type have vessels which are
amenable to treatment with this new therapy. Recurrence is common;
however re-treatment is possible. To determine if you are likely
to be helped, your retinal specialist will do a fluorescent angiogram.
This involves injection of a special dye into a vein in your arm,
followed by pictures of the retina.
If
you have sudden decrease in central vision, or increasing distortion
of central vision, it might mean your dry type of macular degeneration
has developed into the wet type. A visit to your eye doctor will
tell you whether or not this has happened. If the wet type has
developed, you eye doctor will refer you to a retinal specialist
to determine if you would benefit from this new therapy.
It
appears we are finally developing some promising treatment for
macular degeneration. There is still a long way to go, but we
will keep you up to date on new developments.
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