New Treatment
Options for Wet Age-Related Macular Degeneration
by Andrew Davidson,
MD
Davidson Eye Clinic, PA
Age-related
macular degeneration (ARMD) is one of the leading causes of legal
blindness in this country. There are two major forms of ARMD. The
first,
"dry" ARMD,
is characterized by drop-out of visual cells which are replaced by
pigment spots. In extreme cases, large areas of central visual cells
die off, leaving large patches of atrophy, sometimes referred to as
geographic atrophy.
Even though 80-85%
of ARMD falls into the "dry" form,
and there probably is a genetic tendency in the extreme form, very
little is known about the cause, or how to treat this slow loss of
central visual cells. There is, however, statistical
evidence that a diet high in antioxidants, vitamins, luteins, and
xanthophylls, can help slow progression of the deteriorative process.
More and more eye care professionals are recommending dietary
supplementation, especially where good dietary habits are doubtful. At
Davidson Eye Clinic, we
offer OculaRx and MaculaRx by
Science Based Health. There are a number of other over-the-counter
products available as well.
"Wet"
ARMD is
characterized by the development of nets of weak blood vessels
referred to as choroidal neovascularization (CNV) beneath the macula.
The vessels of CNV are thin-walled, weak and can leak fluid or break
and hemorrhage easily, causing sudden loss of central vision.
Anatomically, the macula consists of the fovea- the absolute center,
and the parafovea macula. The location of the fluid or hemorrhage is
important when "wet" ARMD is suspected. A fluorescein
angiogram is performed. In this procedure, a sterile dye, which
fluoresces in blue light, is injected into a small vein on the back of
the hand or forearm. Through the dilated pupil, photos are taken using
a special fundus camera and will show areas of neovascular nets. At
Davidson Eye Clinic, we are proud
to have the latest Topcon Digital Imaging System,
so photos can be seen
immediately,
reviewed with the patient and treatment recommendations made (at the
time of the angiography).
Over the past
12-15 years, the only treatment for the neovascular nets in
"wet" ARMD was conventional heat laser photocoagulation,
essentially "welding" shut the leaking vessels. The results
scarred the vessels down, but also damaged and scarred retinal visual
cells. Therefore, traditional laser treatments were limited to
parafoveal nets because to treat foveal nets would destroy what we
wanted to preserve.
In the past several
months, the FDA has
approved Photo Dynamic Therapy (PDT) for use against foveal
neovascular nets.
Once the diagnosis of "wet" foveal ARMD has been made by
fluorescein angiography, PDT can be performed. In this procedure, the
patient receives an intravenous injection of a photosensitizer,
verteporfin (Visudyne). This chemical accumulates in neovascular nets
and is activated by illumination from a diode laser source. The wave
length of this laser source is not strong enough to create the damage
once experienced through traditional laser therapy. However, a patient
may require 2-3 treatments to produce complete closure of the
neovascular net.
This new
treatment modality has added significantly to the retinal specialist's
ways of treating "wet" ARMD. It does have limitations and
cannot help (stop...reverse) a disease process that is very extensive
or includes old scarred-down areas from previous traditional laser
therapy.
Dr. Jeffrey S. Taylor,
a retina specialist trained at the Boston Retina Foundation, is
available in New Bern to treat "wet" ARMD by the traditional
laser photocoagulation for parafoveal neovascular nets, and with PDT
for foveal neovascularization. If you feel you may be a candidate, we
urge you to contact Davidson Eye Clinic at 252/514-2155, or your own
local eye care professional.
252.514.2155
Email: macular@davidsoneyeclinic.com
Email is for
information purposes only.
Call our office for appointments and eye care emergencies.
