Diabetes, when poorly-controlled, results in multiple complications. Diabetes is a leading cause of kidney failure, blindness, limb amputation, heart attack and stroke. Diabetes complications can be broadly divided into those affecting the small blood vessels (microvascular) and those affecting the large blood vessels (macrovascular).


Microvascular (Complications of small blood vessels)

Macrovascular (Complications of large blood vessels)

Eye (Blindness)Heart (Heart Attacks)
Kidney (Kidney Failure)Brain (Strokes)
Nerve (Amputations)Limbs (Amputations)

How diabetes can affect your​ eyes

Diabetic eye disease (diabetic retinopathy) results from reduced blood flow to the light-sensing nerve layer of the eye (retina). Over time, there is formation of fragile and leaky new blood vessels and nerve layer swelling. These changes can progress to blindness if not identified early and treated, say doctors at the Surgical Retina Department, Singapore National Eye Centre (SNEC), a member of the SingHealth group.

Diabetes affects the peripheral and central retina in different ways:

  • Non-proliferative diabetic retinopathy, also known as background diabetic retinopathy, is the early stage of diabetic retinopathy and occurs when the small retinal blood vessels become affected and start to leak and bleed. At this stage, vision is usually not affected.
  • Proliferative diabetic retinopathy is associated with a high risk of permanent loss of vision. There is growth of abnormal new blood vessels in the retina. These abnormal new vessels can rupture, causing significant bleeding that will lead to loss of vision. Progressively, the scar tissues that form can cause retinal detachment. The abnormal blood vessels can grow on the iris and block the outflow of fluid from the eye. Neovascular glaucoma can occur, with risk of optic nerve damage and blindness.

What puts you at risk of diabetic retinopathy?

All individuals with diabetes are at risk of developing diabetic retinopathy. After 20 years, most people will develop this complication to some degree. Those who have poorly-controlled diabetes are at higher risk of developing diabetic retinopathy earlier and at more severe stages.

What you can do to protect your eyes

Reduce your risk of diabetic retinopathy by:

  • Keeping your blood glucose levels in check
  • Treating and keeping other medical conditions such as high blood pressure, high cholesterol and heart disease under control
  • Quitting smoking and exercising regularly

Although you cannot completely prevent diabetic retinopathy, vision loss can be prevented with early detection. Diabetic retinopathy often has no warning signs, hence it is important to get a comprehensive dilated eye examination annually even if you have no eye symptoms.

If you develop a gradual blurring of vision or hazy vision, please see your doctor immediately.

Eye checks can be done by taking a photo of the back of your eye, in a process known as retinal photography, at SingHealth polyclinics and hospitals. If further consultation with an eye specialist is required, you will be referred to an eye specialist at the Singapore National Eye Centre (SNEC).

Treatments available at Singapore National Eye Centre

In most cases, laser surgery can prevent significant vision loss associated with diabetic retinopathy.

Laser photocoagulation can be performed to seal or destroy growing or leaking blood vessels in the retina:

  • Panretinal photocoagulation (PRP) – to treat the peripheral retina to prevent or stop the growth of abnormal new vessels
  • Focal laser– to treat the macular oedema to reduce swelling

In general, each eye requires 2-3 sessions for a PRP to be completed. You will be expected to go for regular treatments over a period of 6-12 months before diabetic retinopathy is controlled adequately.

In patients with loss of central vision due to diabetic macular oedema, intravitreal injections of medication into the centre of the eye can reduce the macular swelling and improve vision.

Medications which are injected into the eye for diabetic macular oedema include Anti-Vascular Endothelial Growth Factor (VEGF) drugs such as Avastin, Lucentis and Eylea, as well as steroids.

Often, multiple injections at intervals of 1 month or longer are required to achieve resolution of the swelling. Repeated injections at longer intervals may also be required to maintain the visual improvement. In some people with diabetic retinopathy, the abnormal blood vessels in the retina may also result in massive bleeding into the centre of the eye (vitreous humor), causing sudden severe loss of vision. A surgical procedure called a vitrectomy can be used to remove the blood that has leaked into this part of the eye.

See next page to learn more about diabetes complications of the kidney, nerves, heart and blood vessels.

Ref: O17