Age Related Macular Degeneration
What is age-related
macular degeneration (ARMD)?
Age-related macular degeneration (ARMD)
is a condition that occurs when cells in
the macula degenerate(the central, and
most sensitive part of the retina at the
back of the eye), that is, they become
damaged and die. Damage to the macula
affects your central vision which is
needed for reading, writing, driving,
recognising people's faces and doing
other fine tasks.
This disorder results in the loss of
central vision only -- peripheral fields
are always maintained. Although loss of
ability to read and drive may be caused
by macular degeneration, the disease
does not lead to complete blindness.
Who gets
age-related macular degeneration?
ARMD is the most common form of macular
degeneration and develops in older
people. The disease becomes increasingly
common amongst people in each succeeding
decade over 50. By age 75, almost 15% of
people have this condition (There are
other rare types of macular degeneration
which occur in younger people). If you
develop ARMD in one eye, you have a high
chance that it will also develop in the
other eye too.
There are two main types of AMD: the
"dry" form and the "wet" form, based on
the absence or the presence of abnormal
growth of blood vessels under the
retina.
“Dry ARMD” is the most common form and
occurs in 85% of cases. In this type the
cells in the retinal pigment epithelium
of the macula gradually become thin
(they 'atrophy') and
degenerate thus causing reduction in
vision. Typically, dry-ARMD is a very
gradual process and it usually takes
several years for vision to become
seriously affected. Many people with
dry-ARMD do not totally lose their
reading vision.
“Wet ARMD”- Approximately 15% of
patients with AMD have the “wet form”,
where there is a growth of abnormal
blood vessels under the retina, which
can cause leakage, bleeding, and
scarring, resulting in more rapid and
severe vision loss. About 80% of severe
vision loss is due to the wet form as
compared to 20% due to the dry form.
What are
the symptoms of age-related macular
degeneration?
The main early symptom is blurring of
central vision despite using any glasses
that you need. In the early stages of
the condition you may notice that:
You need brighter light to read.
Words in a book or newspaper may
become blurry.
Colours appear less bright.
You have difficulty recognising
faces.
What
happens to Vision :
Some people with macular degeneration
may notice that straight lines in a
landscape - such as telegraph poles, the
sides of buildings or streets, appear
wavy.
Other symptoms include blurring of type
or a page of print, with dark or empty
spaces that may block the centre of the
field of vision.
Take The
Online Macular Degeneration Test to
find out if you need help.
What can
you do to reduce the risks
Diet :
Eat
foods rich
in lutein and zeaxanthin (or
supplements). high quantities of
dietary supplements that contain the
antioxidant vitamins A, C, E,
beta-carotene and the minerals zinc and
copper, such as citrus fruits,
cauliflower, broccoli, nuts, seeds,
orange and yellow vegetables, cherries,
blackberries, and blueberries.
Consuming fish (like tuna) more than
once per week may be beneficial
Reduce alcohol consumption (alcohol may
deplete antioxidants and carotenoids in
the body)
General Health :
Decrease cardiovascular risk
factors (hypertension, obesity,
fats, cholesterol)
Gentle exercise is
good for you -
but don't overdo it
Quit
Smoking :
Overall
smoking
accounts for 32% of ARMD.
Even stopping at the
age of 80 will reduce the risk of
developing the disease.
STOP or NEVER START
smoking.
Eye
protection :
Wear
uv-blocking glasses/sunglasses (and
preferably large or wrap-around
types)
Wear hats or caps.
Is there
any treatment for age-related macular
degeneration?
For the common ‘dry-ARMD’ - there is no
treatment (apart from taking dietary
supplements). However, remember that in
this type of ARMD the visual loss tends
to be very gradual, over 5-10 years or
so.
For the less common ‘wet-ARMD’ - in some
cases treatments like photodynamic
therapy and treatment with drugs may
halt or delay the progression of visual
loss. Some newer treatments may even be
able to reverse some of the visual loss.
Photodynamic Therapy,is where a light is
shone on to the eye to activate a
medicine that destroys the abnormal
blood vessels. It is effective only if
the condition is caught early. The
process takes about half an hour.
Drugs
that can treat macular degeneration :
In recent years a group of drugs
(medicines) called anti-VEGF drugs have
been developed. VEGF stands for
'Vascular Endothelial Growth Factor'.
This is a chemical that is involved in
the formation of new blood vessels in
the macula in people with wet-ARMD. By
blocking the action of this chemical, it
helps to prevent the formation of the
abnormal blood vessels that occur in
wet-ARMD thereby preventing its
complications.
Anti-VEGF drugs include ranibizumab
(trade name, Lucentis),
pegaptanib (Macugen), and
bevacizumab (Avastin). These drugs
are injected directly into the vitreous
of the eye by a fine needle, and
injections may be needed more than once
at few weeks interval to keep on with
their effect.
The main aim of treatment with Anti-VEGF
drugs is to prevent wet-ARMD from
getting worse. However, it seems that in
some cases these drugs may actually
restore some of the vision that has been
lost.
How can
you take care of your vision now that
you have AMD?
Dry AMD
:
If you have dry AMD, you should have a
comprehensive dilated eye examination at
least once a year. Your ophthalmologist
can monitor your condition and check for
other eye diseases and at the same time
he may suggest that you take the
products containing high levels of
antioxidants and zinc.
Wet AMD
: If you have wet AMD and your doctor
advises treatment, do not wait. After
treatment with laser or injection, you
will need frequent eye exams to detect
any recurrence of leaking blood vessels
What can
you do if you have already lost some
vision from AMD?
If you have lost some sight from AMD,
don't be afraid to use your eyes for
reading, watching TV, and other routine
activities. Normal use of your eyes will
not cause further damage to your vision.
If you have lost some sight from AMD,
ask your ophthalmologist about
low
vision services and devices that may
help you make the most of your remaining
vision.
Acknowledgements
Last Reviewed by DrMudit Bansal
18th April,2008
