Choroidal Neovascular Membrane (CNVM)
What is
CNVM?
Most commonly associated with
wet macular
degeneration, choroidal neovascular membrane
(CNVM) involves the development of new, abnormal
vessels below the
retina, the light-sensitive multi-layered tissue
that lines the back of the eyeball.
Macular
degeneration and other retinal diseases, like
myopic degeneration and ocular
histoplasmosis can damage the important layers
of the retina, compromising its ability to act as a
barrier to the vascular layer below the retina,
called the choroid.
Once the retinal layers are damaged by diseases like
macular degeneration, the choroid can produce new
blood vessels (neovascularization) which grow up
through the damaged layers and leak or bleed into
the retina. Once this happens, the vision can
become blurry, darkened or distorted.
Symptoms
Since the retina acts as the
"film in the camera"
of the eye, any retinal irregularities in it can cause
distortion, dark or fuzzy spots and loss of vision.
If CNVM bleeds into the retina, the patient can
experience dark or missing areas in the vision.
Using an Amsler
grid daily is usually effective at picking up any early changes
in the central
macular area -- a common location of CNVM
lesions.
Diagnosis
 CNVM is most commonly diagnosed using
Optical Coherence Tomography (OCT) or fluorescein
angiography.
Fluorescein Angiogram
This helpful
study will produce photographs of the retina that
allow Dr. Deupree to
confirm and identify the existence of and the exact location, type, shape
and size of neovascular membrane.
The fluorescein angiography results will also help
the doctor choose which treatment would be best for
the particular patient and the photos will serve as
documentation of the current state of the disease, allowing
the doctor to follow and compare future study photographs.
This series of dye tests will demonstrate the
effectiveness of treatments and help the doctor
decide if additional or alternative
treatments should be done.
Optical
Coherence Tomography (OCT)
OCT is a non-invasive technology used for imaging
the
retina,
the multi-layered sensory tissue lining the back of
the eye. This technique provides highly detailed,
high-definition maps and images of the macula and
retinal structures. The existence of CNVM
can be confirmed and followed with this non-invasive
study. This allows Dr. Deupree to make the most
accurate diagnosis possible.
Treatments
Of the two main forms of macular degeneration, wet and
dry, wet macular degeneration is the only form with
known, proven treatments. Those treatments
include:
Laser photocoagulation,
Photodynamic Therapy,
Macugen™,
Lucents™ and
Avastin™
injections.
Recently, the overwhelming treatment of choice
throughout the vitreo-retinal medical community has
been intravitreal anti-VEGF injections. These
new medications target the underlying cause of
CNVM
in the "wet" form of macular degeneration. The
abnormal blood vessels found in CNVM react to the
medication by "drying up" after multiple injection
applications. The results of these treatments
has been very encouraging for macular degeneration
patients.
Important links:
Macular
degeneration
Amsler grid
Eye anatomy
Eye healthy recipes
Macular degeneration
research
Lucentis
Injection
Avastin
Injection
Macugen
Injection
Photodynamic Therapy
Illustrations by JirehDesign.com
tmc/me/April 2008 |
