Diabetic Retinopathy-
The "blinding"
effect
of diabetes on the eye
What is diabetic
retinopathy?
The retina lines the
inside of the eye and acts rather like
the film
in a camera. The macula
is the small central part
of the retina that you
use to see things clearly and is the
part you are using now to read. You use
the rest of your retina to see things
around you and to see in the dark.
Blood vessels bring
oxygen and nourishment to your retina.
These blood vessels may
be damaged in a number of ways if you
have diabetes. Severe
changes to the retinal blood vessels
will
affect the health of your
retina and this can damage your sight.
Why is diabetic
retinopathy important?
•
Diabetic retinopathy
can affect your sight and is still a
significant cause of blindness in
the working population.
•
Laser treatment for
sight-threatening retinopathy
reduces
the risk of you
losing your sight but needs to be
given at the
appropriate stage and
ideally before your vision has been
affected.
Who gets diabetic
retinopathy?
All people with diabetes
are at some risk of getting diabetic
retinopathy. This is true
whether your diabetes is controlled by
diet, tablets or insulin.
You are at greater risk if:
•you
have had diabetes for a long time;
•your
diabetes is poorly controlled;
•you
have high blood pressure; or
•you
are on insulin treatment
What does diabetic
retinopathy look like?
The earliest changes are
called background retinopathy.
Small
changes develop on the blood vessels and
look like tiny red
dots. These are called microaneurysms.
Larger red dots are called
retinal haemorrhages. They lie within the retina and are very like a
bruise on your skin. Background
retinopathy does not affect your sight
and does not need treatment. However,
you should make sure that you go
for screening every year and control
your diabetes well.
As time goes by, your
blood vessels may become constricted and
the retina may become starved of oxygen
and nutrition. Different signs can be
seen in the retina at different stages
during this progression. These are
called
pre-proliferative
retinopathy
and requires more frequent follow ups.
Eventually you may
develop new blood vessels on the retina.
This
is called proliferative diabetic
retinopathy. At this stage
your sight is at risk as the vessels may
bleed or may develop
scar
tissue. This can pull the retina away
from the underlying layers of the eye,
causing a traction retinal detachment.
If the new vessels bleed, you may
see a sudden shower of floaters or
cobwebs in your sight, or your sight may
be completely blurred. This is called a
vitreous
haemorrhage.
If
you develop proliferative retinopathy or
if you are very close to
developing proliferative
retinopathy, you will be
advised to have laser treatment.
You may also suffer from
changes in the blood vessels at the
macula. The commonest change is that the
blood vessels become
leaky. Fats and fluid that are normally
carried along in the bloodstream may
then leak into the macula. Fats that
have leaked into the retina are called
exudates. Fluid leaking causes
waterlogging in the retina and is called
"oedema".
Oedema at the centre of the
macula (
Diabetic Maculopathy or Macular Oedema
) will cause you to lose some sight
and you
may need gentle
laser treatment
or an
injection in the back part of the
eye
( Intravitreal
Triamcinolone , Intravitreal Anti VEGF or
Macugen)
.
How will I know if I have
diabetic retinopathy?
Diabetic retinopathy does
not usually cause a loss of sight
until it has reached an advanced stage.
Even sight-threatening
retinopathy that is close to affecting
your sight may not cause
symptoms.
Diabetic retinopathy is
best detected by examining the back of
your
eyes to look at your
retina as a part of routine screening
yearly or more frequently as outlined
above.This is done by indirect
ophthalmoscopic examination and slit
lamp biomicroscopy. When required
photographic documentation, retinal
angiography, scanning of the retina
(OCT), sonography has to be done to know
the disease severity and plan the
management accordingly.
You must seek urgent
retina evaluation if
• you
get a sudden increase in floaters in
your vision.
• your sight suddenly
gets worse, distorted or you loose
all or part of your vision
Do's and
don'ts
Diabetic retinopathy can
get worse over time, but the following
measures can help you to
reduce your risks of developing
diabetic retinopathy and to slow the
progress of sight-threatening
retinopathy.
•Control
your blood glucose as effectively as
possible
•Keep
your regular screening appointment.
•Get advice if you
have a problem with your sight.
•For your eyes and
general health, you should also have
your cholesterol levels checked
regularly and not smoke
Acknowledgements
Last Reviewed by Dr Vikram Mehta
10th April,2008
