information for patients
Laser Treatment for Diabetic Retinopathy
Diabetes can cause problems with the small blood vessels in your eyes
and this in turn leads to problems with the retina which lines the eye and
contains the light sensitive nerves which help you to see. The blood
vessels can either leak which causes the retina to become swollen
(oedema) or become blocked which prevents blood and oxygen reaching
the nerves (ischaemia).
If large areas of the retina have no blood supply due to blockages then the
retina is stimulated to grow new vessels, this is called neo-vascularisation.
These new blood vessels are fragile and can bleed very easily. If there is a
large bleed this can totally obscure the vision as the blood goes into the
jelly of the eye (vitreous) and blocks light passing into the eye. This can
clear with time but sometimes takes weeks or months.
If there are extensive haemorrhages then scar tissue can form which can
pull and distort the retina. In extreme cases the retina may become
detached leading to loss of sight.
In some cases the new blood vessels can grow on the coloured part of the
eye (iris) and this can lead to glaucoma. This is a raise in pressure in the
eye which can cause progressive sight loss.
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Most sight threatening problems caused by diabetic retinopathy can be
managed by laser treatment if detected early enough. The aim of the
treatment is to reduce the risk of visual loss by preventing growth of new
vessels and so preventing bleeding.
What is laser and how does it work?
A laser beam is a tiny but concentrated light energy. When applied to the
retina it causes a reaction in the tissues to stop vessels leaking and in
most cases prevents new vessels growing. Each application of laser lasts
for a fraction of a second but the number and strength of the “burns”
depends on the type of treatment needed for the retinopathy.
Localised or focal laser
When individual vessels or small groups of vessels are leaking, the laser
can seal them to stop the swelling and bleeding. This is used in early
proliferative retinopathy or maculopathy.
Pan-retinal laser
If neo-vascularisation is seen then more extensive treatment may be
needed. The aim is to treat large areas of the peripheral retina to stop the
retina producing the growth factor which stimulates the new blood vessels
to grow. If the treatment is successful then the new vessels will shrink and
may disappear over a period of time.
What is involved in laser treatment?
The treatment is carried out in the out-patient department and you should
expect to be in the department for about an hour. After you have your
vision tested you will have drops instilled to dilate the pupils of your eyes.
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These take about 20 minutes to work and will cause blurred vision and
sensitivity to light for 4-6 hours. Because of the drops you should not drive
yourself to clinic on that day and if possible have a friend or relative to
come to the clinic with you.
The laser takes 10-20 minutes to perform-depending on the type of laser
given- and often more than one session is needed.
Prior to the treatment your eye will be numbed with anaesthetic drops and
a small contact lens may be put into your eye. As the procedure takes
place you will be asked to look in various direction so that the laser can
reach where it is needed.
Is laser painful?
Localised treatment to seal vessels does not usually cause discomfort
although the bright laser light can be dazzling.
Pan-retinal treatment can be uncomfortable. Don’t be afraid to tell the
doctor if the treatment is causing you discomfort. Also, if you need further
treatments, inform the doctor before each session that you have found it
uncomfortable.
Does laser treatment have any side effects?
Initially after treatment your vision will be blurred due to the eye drops used
and you should not drive following treatment.
Due to the brightness of the laser, there may be a temporary reduction in
your sight which will fade over a few hours following the treatment.
Sometimes may notice small black spots in your vision, these may improve
with time.
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The local treatment has little long-term effect as only a very small area of
the retina is treated. However, if treatment is to the macula then your
central vision may deteriorate and you may find it more difficult to see to
read.
As pan-retinal treatment is more extensive it can have more lasting effects
on your vision.
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It is common for you to lose some of your peripheral (side) vision.
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You may find your night vision is not as good as it was before
treatment.
These changes in your vision may affect your ability to drive safely. If you
have had laser treatment in both eyes, then you must inform the DVLA.
They may require you to have a special eye examination to check that
your vision is good enough for you to continue driving.
Occasionally fluid may develop in the macula after peripheral laser
treatment which may resolve on its own or may require further treatment.
Although there are risks with having the treatment, it is worth remembering
that the risks of having the treatment are fewer than the risks of NOT
having treatment and having worsening retinopathy.
Also, the earlier the treatment is given the more successful the result. If
you need treatment ask the doctor to explain what they plan to do, how
they expect it to help and the risks to your vision after treatment.
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What if my eye becomes painful after treatment?
If you have a long treatment session you may develop a headache. This is
usually relieved with your usual headache tablets.
If the pain is severe or if you notice your vision getting worse you should
seek help immediately. Contact the eye clinic or, if this isn’t possible,
attend your nearest Accident and Emergency department.
We hope you have found this information useful. If you have any
questions please contact the Chesterfield Eye Centre on 01246 513937.
Laser Treatment for Diabetic Retinopathy, version 1: February 2015
Review date: February 2017
Directorate: Ophthalmology (Surgical Specialties)
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