What is diabetic retinopathy?
Most people with diabetes see well and have no major eye problems. Some people develop 'cataracts'. These cause misty vision, and can be removed with a relatively quick operation.
If your diabetes has been a little more severe, you may develop 'retinopathy
', a disease of the retina of your eye. If your sight has already been damaged, it can be very difficult
coping with everyday life. For information that may help a little, see Coping with Poor Vision.
What is the retina?
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The 'retina' is the film at the back of your eye, like the film in a camera. This is shown in the picture.
Light enters your the eye ... from the left in this picture. and then passes through the eye to reach the retina.
The messages about what you see are then passed on to the brain.
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What
is retinopathy?
Retinopathy is the name given to 'disease of the retina' due to diabetes, and is described below. Blindness from retinopathy can
in theory be prevented, and has in Iceland. See.This has been done by regular eye checks and people controlling
their diabetes.
Types of retinopathy
There are four main types of retinal damage that can occur if
you are diabetic. Unfortunately the condition may progress from
no or mild retinopathy to a much more severe type.
- No retinopathy…. many people have a basically healthy
retina. If you can control your diabetes and blood pressure at
this stage it will help prevent or slow down any harmful changes.
- background retinopathy ….
early changes.
- maculopathy ….this
is more serious. Eventually your sight may become reduced. Laser
and blood pressure control help.
- pre-proliferative or non-proliferative
stage before the new blood vessels start growing.
- proliferative retinopathy … when
the new vessels grow. These blood vessels are very delicate and
can bleed easily. Laser is very effective in stopping the new
vessels grow.
There are other conditions that may be present:
However, if you have 'no' retinopathy you should still look after
your diabetes, because this reduces your chance of getting it,
and you may even feel better for it.
Many people with diabetes do go on to develop retinopathy, and
this can damage the sight severely. The different types of retinopathy
are described in adjacent pages.
Controlling your diabetes and blood pressure also helps to prevent
other problems such as neuropathy and kidney damage.
Such matters are discussed briefly below, but in more details in
other sites such as the Diabetes
UK site.
If you have been diabetic for ten years or more, especially if
you have type 2 diabetes (NIDDM: basically non-insulin dependant),
you may have a combination of maculopathy and proliferative disease.
Preventing
Eye disease: recent progress
You cannot tell if your eyes have been damaged by diabetes; your eyes have
to be checked by a doctor or optometrist who is expert at finding the condition.
This check needs to be carried out every year.
What can you do to stop retinopathy developing? More details are discussed
in Preventing problems, but basically you
need as far as possible to
- keep to a healthy diet
- have regular exercise
- have regular checks of your eyes (with dilated pupils)
- have regular checks or your glucose, HbA1C, & blood
pressure,
- attend your annual diabetic review where your urine protein, feet, and
other checks are carried out
- keep your blood sugar, blood pressure, and fat levels as normal as possible
as below
- keep a diary of glucose readings
- record your lipids and blood pressure in the comments section of your glucose
diary or in your shared care card.
- remember if you have (but are not yet diabetic) impaired glucose tolerance
(pre-diabetes in the US) you may progress to diabetes. A healthy diet, not
being overweight, having lots of exercise, can delay or prevent this progression.
- see epidemiology
- we need to
pay attention ot improving control
- See the Prevention Movie, and
Prevention Pages
Is your diabetes controlled?
If your parents had heart or another type of vascular disease you may be more prone to complications also.
Where
are you on the graphs below? Is your HbA1c below 7%? Is yourblood pressure below 130/80?
The rise in blood pressure after 8 units of alcohol
(4 pints of beer)
enlarge
Blood
pressure control is discussed in more detail. Exercise,
a healthy diet, avoiding obesity, low salt, and less than
one drink of alcohol a day help. This graph shows the effects
of 8 units of beer in one evening. Your weight is very important:
the lighter you are, the less insulin you need. Sometimes losing
weight can therefore make the diabetes disappear; losing
weight (if you are overweight) certainly makes your diabetes
easier to control.
Causes
of type 1 diabetes
Type one diabetes usually begins in young people. The body's
immune system attacks the islet cells in the pancreas where
insulin is made.
As the damage increases, less less insulin is made, and diabetes
develops.
This inflammation may be started off by an infection; your
immune system reacts against a virus (the virus acts as a 'trigger'),
but becomes 'misdirected', and attacks the islet sells instead.
Thus type 1 diabetes is caused by a 'faulty' immune system. Why
do some people get diabetes and others do not? ......because we
all have inherited different immune systems and slightly different
coatings on the different cells of our body. It is a certain combination
of virus/immune system/coating on cells that makes diabetes develop.
Type 1 diabetes is much commoner in Western Countries such as parts
of Scandinavia than other countries. Why this is remains a mystery,
but breast feeding up to six months of age is said to reduce the
incidence.
This type of diabetes is also increasing in the UK.
It occasionally occurs in relations: occasionally the twin of a
young person with diabetes has had tests that detect the inflammation
before there is too much islet cell damage, and drugs have been
given to stop the inflammation. A lot of research is taking place
in this area.
Causes
of type 2 diabetes
This
type of diabetes is also called late-onset on non-insulin
dependent (although eventually people often do need insulin). Type
2 diabetes runs in families.
It occurs at a younger age if people
have little exercise, smoke, have an unhealthy diet, or get overweight.
Conversely, even if you have the genes likely to make you diabetic,
it will be delayed many years or indefinitely with a healthy lifestyle.
Some people's genes program them to develop diabetes at a young
age, others at a very old age, but it is much more common in the
elderly. This is because the islet cells shrink and make less insulin
as you get older.
Worryingly, it is increasing at a rate of 10% a year, and is occurring
at an ever younger age.
As a community exercise and lifestyle measures are needed to prevent
more people developing the condition, starting as children.
Remember, if you have diabetes, there is a direct relationship between
diabetic control (sugar and blood pressure and smoking) and likely
damage.
Also, there is a direct relationship between alcohol and blood pressure.
The World Health Organisation recommend the relations of people
with diabetes should take lifestyle precautions, as doing so will prevent or
delay diabetes:
- not smoke
- exercise
- have a healthy diet
- lose weight if overweight if they want to avoid diabetes
The World Health Organisation recommends If you have type 2 diabetes
your relations should be tested every 3 years with a fasting blood
sugar.
In a few years blood tests (testing insulin resistance) may be recommended.
Mechanisms
of Retinopathy
How does retinopathy develop? This is explained in more detail (mechanisms). Each
retinal vessel is lined by endothelial cells, which form the wall of
the cell. The endothelial cell rests on a foundation layer of basement
membrane.
In diabetic retinopathy, high sugar and blood pressure levels cause blood flow
to increase. The basement membrane layer then becomes thick. The thickened basement
membrane then stops the flow of essential chemicals into and out of the retina.
Next the damaged cell releases special chemicals (growth factors such as VEGF
and FGFb) that make fresh new blood vessels grow, and also make the blood vessel
leak even more fluid. It is these new blood vessels and leaky areas that a doctor
can see looking into your eye.
Eventually there may be so much damage that the vessel closes up and the retina
stops working.
In several years it may be possible to take a tablet that stops
the growth chemicals working, and much research is taking place
around the world. No drug is currently in regular use.
Your eye
examination
For
the examination, you should bring |
- a list of tablets/medication you use
- your diabetic diary with a recent blood pressure, HbA1c result, blood sugars, and any problems you are having
- you should never drive home from the eye clinic, so never drive
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The examination will include |
Once the doctor
has examined your eyes, he will decide with you whether
or not laser treatment is need. This will be based on
the type of retinopathy you
have.
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Some
visits extra tests/procedures may be needed
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Dilating
you pupils
- Your pupils need to be dilated. Standard drops are tropicamide 1% and phenylephrine 2.5%.
- generally these work for 1-2 hours, with some residual effect for the rest of the day.
- Rarely the phenylephrine component may cause the pupils tostay dilated for 3 days (mention this to your doctor if it happens
to you).
- You can be allergic to either of the drops, usually the phenylephrine.
If this happens your eyes will be red and itchy for a week after
the drops. Again, mention this to your doctor if it happens to
you.
- It is dangerous and illegal to drive after the drops. Some
people find they can drive, but you are strongly advised not
to. You must wait until they wear off. Drops are used for every
retinopathy examination.
See
Consultation and the doctor..for professionals
This paper notes
- The level of satisfaction after initial photocoagulation
treatment was high; 46.4% of patients with proliferative retinopathy
and 53.1% with maculopathy scored 31 or higher.
- Although 69.5% of all patients reported that their expectations
of treatment corresponded to their final 9-month visual results,
only 8.7% of these patients reported an improvement in visual
acuity after 9 months.
- The number of unwanted actions performed by the patients
during treatment were significantly related to the number of
unclear instructions given by the physician
- [By using these improved consultation techniques], a high level
of satisfaction was observed, despite the minimal improvements
in visual acuity. Attempts to further improve patient satisfaction
might focus on improved education of patients on the possible
benefits of laser treatment, greater care in communicating information
during treatment, additional nursing support, and additional
clerical time to communicate with patients before each appointment.
- decisions should be shared with
patients
Good news in Birmingham and many other places
In Europe retinopathy is reducing in all areas, especially those without much poverty. It is
increasing in developing countries as diabetes and obesity increase.
