Diabetic retinopathy is one of the most serious complications of diabetes for the eyes. The little vessels at the back of the eye become blocked or leak fluid in the retina which can possibly affect the eyesight.

Forty per cent of people with type 1 diabetes and 20 per cent of people with type 2 diabetes will develop some sort of diabetic retinopathy.

Background diabetic retinopathy

This is the earliest stage of diabetic retinopathy. The blood vessels are only  

mildly affected. They may leak blood or fluid. As long as the macula (the central part at the back of the eye) is not affected, vision is normal and you will not notice that anything is wrong.

The diabetic retinopathy screening test will keep a close check on these changes and detect any signs of progression early.

Pre-Proliferative diabetic retinopathy

This is the next stage in the progression of diabetic retinopathy. The damage at the back of the eye is more extensive than background retinopathy. There is more leaking of blood and fluid at the back of the eye. The blood flow becomes more restricted and the retina becomes starved of oxygen and nutrition.

Proliferative diabetic retinopathy

If diabetic retinopathy progresses, it can cause the blood vessels in the retina to become blocked. As the retina becomes starved of oxygen, the eye is stimulated into growing new vessels on the surface of the retina.

This is called proliferative diabetic retinopathy.

If this happens the sight will be at risk as these new vessels may bleed or may develop scar tissue.

If the new vessels bleed into the jelly (vitreous) inside the eye you may see a sudden shower of floaters or cobwebs, or your sight may become completely blurred. This is called a “vitreous haemorrhage”.

The scar tissue may pull the retina away from the underlying layers. This is called a “retinal detachment” resulting in serious sight loss.

Diabetic maculopathy

Diabetic maculopathy means that the macula is affected by diabetes. This can occur with any stage of diabetic retinopathy.

The commonest cause is the blood vessels becoming leaky. As a result there is water-logging in the macula which makes it swollen.

Because the macula is used for detailed vision this will make the central vision blurred.

Occasionally, the blood vessels in the macula become so constricted that the macula is starved of oxygen and nutrition which also makes the central vision blurred.

   Treatment for diabetic retinopathy

   Most sight-threatening problems caused by diabetic retinopathy can be managed by laser treatment. The aim of laser treatment is to stabilise the changes caused by diabetes. Laser treatment can control but not cure diabetic retinopathy and it is likely that it will need to be repeated.

Laser treatment does not generally improve sight, although in some cases it might. However if the changes are not treated it is likely that some, or all, of the eyesight will be lost.

Localised Laser Treatment

When individual vessels or small groups of vessels are leaking, the laser can seal them. This stops the bleeding and helps reduce the swelling of the retina.

This type of treatment is used when maculopathy has been detected.

Pan Retinal Laser Treatment

In cases where new vessels have started to grow at the back of the eye (proliferative diabetic retinopathy) more extensive laser is needed. The treatment aims at stopping the release of factors in the eye that stimulate the growth of the new vessels.

If the treatment is successful, the new vessels shrink and disappear over a few months.

Because large areas of retina are treated the effects on vision may be significant. Some peripheral vision may be lost and night vision may be affected.

Intravitreal injections for Diabetic Macular Oedema

When there is leaking of fluid affecting the macula, laser treatment can reduce the leakage and prevent any more blurring of vision. However, when the centre of the macula is affected, then laser treatment offers no benefit.

In these cases anti-vascular endothelial growth factor (anti-VEGF) treatment has been shown to be effective in reducing the amount of fluid at the back of the eye therefore reducing the blurred central vision.

This treatment is given by an injection into the white of your eye and more than one injections may be needed over a period of months.