How Diabetes Causes Other Complications

Diabetes, when poorly-controlled, can cause multiple complications such as blindness. Doctors from the Surgical Retina Department at Singapore National Eye Centre (SNEC), a member of the SingHealth group, explains.

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).

How diabetes affects the 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.

Related article: How diabetes can affect the kidneys, nerves and heart

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.

Related article: Beware the "silent thief" that steals your eyesight

What you can do to protect your eyes

To reduce your risk of diabetic retinopathy:

  1. Keep your blood glucose levels in check
  2. Treat and keep other medical conditions such as high blood pressure, high cholesterol and heart disease under control
  3. Quit smoking (if you are still smoking) and exercise 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.

Related article: Have pre-diabetes? Here's how you can reverse it


Articles on are meant for informational purposes only and cannot replace professional surgical, medical or health advice, examination, diagnosis or treatment.