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VISUDYNE Photodynamic Therapy (PDT)
The vitreoretinal specialists at the New England
Eye Center have extensive expertise in the management of age-related
macular degeneration.
Age-related macular degeneration (AMD) is a common
eye condition that can cause significant visual loss in affected
patients. The disease is divided into a dry form and a wet form.
The dry form generally causes gradual vision loss
from deterioration of the retina. The wet form involves the growth
of abnormal blood vessels under the retina called choroidal neovascularization
(CNV); these blood vessels can leak fluid and blood and cause more
rapid deterioration in vision. The diagram above illustrates the
growth of these abnormal blood vessels under the retina in wet AMD.
AMD is the leading cause of severe, central visual
loss in individuals over the age of 50. In the US, it is estimated
that approximately 1.2% of our older population is affected by wet
AMD, as opposed to 15.6% for dry AMD. However, approximately 90%
of severe visual loss can be attributed to the wet form. Up to 200,000
new cases of wet AMD are diagnosed in the US each year.
Treatments for wet AMD are aimed at destroying
the new blood vessels to prevent further leakage and damage to the
retina. This traditionally involved the use of a conventional laser.
Laser therapy has been proven to benefit final visual outcome compared
to no intervention at all. However, the conventional laser causes
permanent scarring that damages the overlying retina when treating
these abnormal blood vessels.
The diagram to the left shows a laser beam aimed
at abnormal blood vessels growing under the retina due to wet AMD.
This therapy can effectively destroy the new blood vessels and control
the disease process.
However, the diagram on the right shows the full
effect of treatment. While the abnormal blood vessels were successfully
destroyed, so too was the sensitive retinal tissue overlying the
treated area.
This patient would benefit from control of the
leaking blood essels. However, they would also suffer vision loss
due to retinal damage in the area treated by conventional laser.
For this reason, better treatment options are desired when the center
of vision is involved by growth of abnormal blood vessels in AMD.
The goal is closure of the leaking blood vessels without immediate
loss of central vision.
The vitreoretinal specialists at the New England
Eye Center have extensive exPerience with this exciting, new treatment
for wet age-related macular degeneration (AMD). Our retina service
has been involved in the clinical research trials for this technique
and has actually taught many of the specialists throughout the country
how to perform the procedure.
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The current goal in the treatment of wet
AMD is to close leaking new blood vessels without damaging
the overlying retina. This is the precise value of photodynamic
therapy (PDT).
The first step in the PDT procedure involves
injection of a hoto-sensitizing agent (Visudyne) into an
arm vein. This substance travels through the bloodstream
and collects in the abnormal blood vessels under the retina.
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The retina is then treated with a low-energy laser
to activate the photosensitizer. (This laser does not cause permanent
scarring as in conventional laser treatment discussed above). A
chemical reaction occurs, resulting in closure of the leaking blood
vessels. There is no resulting damage to the overlying retinal tissue.
Patients have a unique opportunity to preserve or even restore vision
lost to wet AMD.
The PDT procedure is performed in the office, very
often on the same day the patient is first evaluated. The whole
procedure is quick and painless. The photo-sensitizing drug is infused
over 15 minutes, followed by an 83 second laser application.
Following the treatment, the patient must wear
special eyeglasses and avoid direct sunlight for a few days. Other
normal activities can be resumed immediately. Patients are followed
regularly and are eligible for retreatment at 3-month intervals,
should this be required.
Providing comprehensive evaluation and treatment
of age-related macular degeneration throughout eastern Massachusetts.
Office Locations
- Predominantly-classic choroidal neovascularization (>50%
of lesion)
- Subfoveal location
- Greater preservation or restoration of visual acuity compared
to natural history
- Closure of choroidal neovascular complex
- No associated retinal damage
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