Diabetic retinopathy is one of the most common causes of blindness in the RSA. Retinopathy means damage to the tiny blood vessels (capillaries) that nourish the retina, the tissues in the back of the eye that deal with light. Damage to these vessels causes blood leakage (haemorrhage), which may be small and confined to the retina or may extend forward into the jelly that fills the main cavity of the eye (the vitreous gel). This can seriously affect your vision.
Another feature of diabetic retinopathy is that new, fragile blood vessels grow on the surface of the retina, particularly around the head of the optic nerve (the optic disc). These new vessels bleed easily.
The main cause of diabetic retinopathy is diabetes. It can occur as a result of all types of diabetes and if left untreated can lead to blindness.
It is important to have regular routine eye examinations because if new blood vessel formations are detected early, they can be treated effectively. Any new blood vessels can be dispersed by applying multiple laser burns to the periphery (outside edges) of the retina.
There are three main types of diabetic retinopathy:
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Although diabetic retinopathy is entirely painless, it often causes sudden blindness. It does this when the fragile new blood vessels bleed into the vitreous gel (jelly that fills the eye). This appears as a dark cloud within your eye which can obscure your vision. The blood may slowly be absorbed, so that after a period of time – sometimes weeks or months – your vision may be restored.
Other symptoms of diabetic retinopathy can include:
Severe bleeding into the vitreous gel can lead to the growth of new blood vessels and fibrous strands. This can be very serious because these fibrous strands can contract and pull off the retina – a form of retinal detachment that is difficult to correct. Treatment can sometimes repair this damage but, in other cases, blindness may be permanent.
Diabetic retinopathy is caused by diabetes. You are more likely to develop diabetic retinopathy if you do not control your diabetes closely.
Having a high blood sugar level and high blood pressure can cause your blood flow to increase. This thickens a membrane in your eye, preventing the flow of essential fluids in and out of your retina. Damaged cells then begin to release special chemicals that encourage the formation of new blood vessels. These new blood vessels tend to leak more fluid.
If left untreated, these growing vessels will begin to obscure your vision and perhaps lead to complications within the eye structure.
You are at increased risk of diabetic retinopathy if:
National Screening Programme
The Department of Health has set up a national screening (testing) programme for diabetic retinopathy. If you are over 11 years of age, and you have diabetes, you should be offered screening annually.
The screening programme was introduced because if diabetic retinopathy is detected early enough it can then be treated effectively by using laser treatment.
Often, by the time diabetic retinopathy begins to cause noticeable symptoms, it can be much harder to treat.
You should receive a letter from your GP, or other health professional, inviting you to a screening appointment. If you think you are over-due for a screening appointment, contact your GP.
During screening, eye drops are used to make your pupils large, and then photographs are taken of your retina. As the photographs are being taken, you will see flashes of bright light, but it is not normally uncomfortable.
The eye drops can cause a slight stinging, and your vision may become blurred about 15 minutes after the screening ends. The blurring can last between two and six hours, depending on what sort of eye drops are used.
The blurring will affect your ability to drive, so you will not be able to drive from your screening appointment. You will also find that everything looks very bright during this time, so you may want to take sunglasses with you to your appointment.
Very rarely, the eye drops can cause a sudden rise in pressure within your eye. However, this only occurs in people who are already at risk of developing the condition. It will require prompt treatment in an eye unit.
If, after screening, you experience any of the symptoms outlined below, contact your screening centre or go to an accident and emergency department:
You will not receive the results of your screening straight away, as the pictures need to be studied by a team of professionals. The screening staff should tell you how long this will take.
You will be called back for further assessment if:
You do not have to attend your screening programmes, but if you have diabetes, then it is the single best way to prevent sight loss.
Treatment for diabetic retinopathy will vary depending on which particular type you have:
A course of laser treatment involves one, or more, visits to a laser treatment clinic.
Treatment is normally available on an out-patient basis.
Drops are put into your eyes to numb the surface. Then a special contact lens is placed on your eye to hold your lids open and focus the laser beam on your retina.
The treatment involves focusing a laser to burn the abnormal blood vessels to prevent further growth. The laser is not targeted directly at the blood vessels but to the outer part of your retina. This is the part of the retina than allows you to see to the side (peripheral vision) and in the dark.
The treatment is usually not painful, but you may feel an occasional sharp pricking feeling when certain areas of your retina are treated.
If you have had a number of laser sessions in the past, you may feel some discomfort during the treatment. If you have felt discomfort in the past, ask the doctor to give you painkillers or a mild sedative. Alternatively, take these yourself an hour before the appointment.
Your vision will be blurred after treatment, but this should return to normal after a few hours. A lot of treatment can cause your eyes to ache. Over-the-counter painkillers such as paracetamol should ease the pain.
Because of the damage to the outer retina there is some chance that your night and peripheral vision may be affected. Over 50% of people treated noticed some difficulty with their night vision, and 25% noticed some loss of peripheral vision.
You should get medical advice if you have any new eye problems after the treatment.
Laser treatment for early proliferative retinopathy will prevent severe sight loss in 90% of cases.
In rare cases, eye surgery may be considered if there is severe bleeding into your eye. This is usually the case if proliferative retinopathy has been diagnosed at a late stage. Eye surgery may also be an option if laser treatment has proved ineffective.