Diabetic retinopathy is when uncontrolled blood sugar levels cause damage to the blood vessels in your eye (the retina). These blood vessels can swell and leak. Or they can close up, stopping blood from passing through. Sometimes abnormal new blood vessels grow on the retina to compensate for the closed off vessels. All these diabetic changes can steal your vision.

NPDR (non-proliferative diabetic retinopathy)

This is the early stage of diabetic eye disease.

It is initially characterized by micro aneurysms (microscopic blood-filled lumps in the arteries) which may burst and leak into the retina. Tiny spots of blood may build up in the retina, but they usually do not create noticeable symptoms in the early stages of the disease. As the disease progresses, hard exudates (buildup of fluid that has leaked from blood vessels), abnormalities in the growth of new blood vessels in the retina, and bleeding from the veins that feed the retina may occur.

While non-proliferative diabetic retinopathy is not itself a sight-threatening condition, it can trigger macular oedema or macular ischaemia, which are other forms of diabetic retinopathy that may cause rapid vision loss at any stage of non-proliferative disease.

Macular oedema is a sight-threatening condition that occurs as a consequence of the vascular changes of diabetic retinopathy. Macular oedema is the most common cause of diabetes-associated vision loss. It occurs when abnormal new blood vessels burst and bleed into the macula (the area of the eye that enables central, clear, sharp vision), which reduces your vision.

Macular ischaemia or known as ischaemic maculopathy is an untreatable form of diabetic retinopathy characterised by the loss of capillaries (tiny blood vessels) that provide blood flow to the macula.

PDR (proliferative diabetic retinopathy)

PDR is the more advanced stage of diabetic eye disease. It is characterized by neovascularisation. Neovascularisation is when the retina starts growing new blood vessels. The retina wants to grow new blood vessels when your blood vessels start closing off in NPDR. These fragile new vessels often bleed into the vitreous (fluid in the back of the eye) causing either floaters or when it bleeds a lot it can obscure your vision completely.

These new blood vessels can also form scar tissue on your retina. Scar tissue can cause problems with the macula or lead to traction on your retina causing a retinal detachment.

Glaucoma is also another complication of diabetic eye disease. Glaucoma is an eye disease in which there is progressive damage to the optic nerve. As neovascularisation takes place in PDR, it greatly raises the eye pressure, which damages the optic nerve. If left untreated, PDR can cause severe vision loss and even blindness.

PDR is very serious and can steal both your central and peripheral (side) vision.

It is very important for diabetic patients to have their eyes checked yearly in order to monitor your retinal health.