What is diabetic retinopathy?
Diabetic retinopathy is a serious eye disease, which is usually associated with long-term diabetes and, if left untreated, can lead to blindness. There are three distinct forms of the disease:
- Background retinopathy
- Proliferate retinopathy.
The very best way to treat retinopathy is to prevent it, and with good long-term management of diabetes, it should be possible to reduce the number of cases of retinopathy in this country.
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What causes it?
Diabetic retinopathy is always associated with diabetes, and the longer a person is diabetic, the higher their chances of developing this disease. Medical evidence shows that prolonged periods of high blood sugar levels cause damage to the small blood vessels in the retina at the back of the eye. Initially these blood vessels become leaky and sometimes they may even become blocked off. The leaking from the blood vessels causes haemorrhages and leakage of fats from the vessels to the retina, and it may also cause swelling (oedema) of the retina itself.
The blocked blood vessels can starve the retina of vital oxygen which it needs and this, in turn, can lead to the growth of new abnormal vessels from the retina and a diagnosis of diabetic retinopathy.
This occurs in connection with leaky blood vessels in the retina. Medical examination will show up tiny swellings in the blood vessel walls; blots of haemorrhage on the retina itself and tiny yellow patches of hard exudates (liquid containing protein and white blood cells).
While this type of retinopathy does not in itself threaten the sight, it needs to be closely monitored by a doctor or optician to ensure that it does not become worse.
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The symptoms are the same as those for background retinopathy, but this condition is much more sight-threatening because it occurs in the central area of the retina, known as the macula. The macula is the area of the retina which allows us to have clear and detailed vision and any damage to this will affect vision.
The haemorrhages, swelling and exudates which are a feature of diabetic retinopathy may interfere with vision, particularly for reading and for seeing fine details.
The disturbing thing about this condition is that it causes virtually no symptoms until it is very advanced. It occurs as a result of the complete blockage of tiny blood vessels in the retina, and is characterised by the growth of new, abnormal blood vessels. These blood vessels may bleed into the eye giving rise to what is known as a vitreous haemorrhage, or they can stimulate abnormal supporting tissue which can cause the retina to detach itself 9retinal detachment).
This type of retinopathy eventually leads to blindness if left untreated. The first indication of the disease is usually a sudden loss of vision caused by a vitreous haemorrhage into the eye.
How is it diagnosed?
In all cases of diabetic retinopathy the vision is not usually affected until the disease is at a very advanced stage. Therefore, it is of the utmost importance that all diabetes sufferers have their eyes examined on a regular basis. The only way to diagnose retinopathy is by carrying out an examination of the back of the eye, and this should be done regularly so that treatment can be carried out before vision is affected.
How often should the eyes be checked?
Diabetes sufferers should have their eyes checked once a year. This can be carried out by their own GP or at an Eye Clinic.
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How is the disease treated?
Laser treatment is often used in the treatment of retinopathy and is very effective at improving vision. It is carried out on an outpatient basis with no anaesthetic and the side effects are minimal.
In rare cases, surgery to the eye is necessary. This may be the case where there is bleeding into the eye from abnormal blood vessels (vitreous haemorrhage), or if laser treatment proves to be ineffective. The medical term for this type of surgery is vitrectomy, and it involves removing the jelly from the back of the eye and removing any bleeding at the same time.
What are the future prospects?
In cases where diabetic retinopathy has been diagnosed before it has reached an advanced stage, very strict control of blood glucose levels will normally prevent it from progressing any further. Advanced cases of the disease will usually have to be treated either by laser or surgery, and vision may be adversely affected.
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