Retinopathy is a common complication of long-term diabetes and refers to damage to the back of the eye (the retina), which is caused by prolonged periods of high blood sugar levels.

This is what is known as diabetic retinopathy and what we will look at in detail in this guide.

How common is diabetic retinopathy?

Diabetes is a common cause of retinopathy and diabetic retinopathy is the leading cause of new cases of blindness in American adults.

In 2010, the Centers for Disease Control and Prevention (CDC) found that 4.2 million adults in the U.S. had diabetic retinopathy and of those, 655,000 had the more severe, vision-threatening form of the disease.

Prevalence of diabetic retinopathy and vision-impairing diabetic retinopathy is particularly high among both African-Americans and Mexican-Americans.

How your eye works – what is the retina?

When you look at something, light passes through the front of your eye and onto your retina – a delicate layer of tissue that coats the inside of your eye. The retina converts the light into electrical signals that your brain interprets to “see” the world around you.

As with other parts of the body, uncontrolled diabetes can, over time, damage the retina and put your eyesight at risk. This damage is referred to as diabetic retinopathy and is the most common diabetes-related eye disorder.

By keeping blood glucose levels and blood pressure under control, the risk of developing diabetic retinopathy can be reduced or its progression slowed.

What causes diabetic retinopathy?

Diabetic retinopathy develops as a result of high blood glucose levels. Over time, this can weaken and damage the network of tiny blood vessels (capillaries) on the surface of the retina, which in turn can lead to a number of problems. These include:

  • Swelling of capillaries (Microaneurysms)
  • Small leaks of fluid from damaged capillaries (Exudates)
  • Bleeding from damaged capillaries (Hemorrhages)

Prolonged high blood sugars can also starve the retina of blood and oxygen by blocking the blood vessels.

What are the risk factors?

In addition to poor diabetes management (or poor blood glucose control), the following also raise the risk of retinopathy developing:

  • High blood pressure
  • Having had diabetes for over 10 years
  • High triglycerides
  • Genetic susceptibility

If any of these apply to you, ask your doctor for a retinopathy screening examination as soon as possible.

Are there different types of diabetic retinopathy?

Yes there are. The extent of damage to the retina determines the type of retinopathy a person has. The greater the damage, the higher the risk of vision loss.

  • Background retinopathy
    Tiny swellings in the walls of the retinal capillaries are referred to as background retinopathy, simple retinopathy or non-proliferative retinopathy. Vision is impaired through small dots that form on the retina, which are usually accompanied by yellow patches of exudates (blood proteins). Over time, background retinopathy can advance from mild to moderate and severe stages of retinopathy.
  • Diabetic maculopathy
    Maculopathy is when background retinopathy progresses into the small central part of the retina called the macula. The macula is vital for seeing fine detail (focus) and things directly in front of you (central vision), so any damage to this part of the eye can cause serious vision problems. If fluid leaks into the macula, causing it to swell, vision can become blurry or be lost entirely.
  • Proliferative retinopathy
    Proliferative retinopathy is an advanced stage of retinopathy that develops when retinal blood vessels become so damaged they close off. Blockages prevent oxygen and blood from reaching the retina and the body responds to this by growing new, weak capillaries which can break and bleed into the eye, obstructing vision. Loss of vision can be instant if blood leaks into the vitreous humor – the central part of the eye. In severe cases, the abnormal blood vessels can distort your retina or cause it to detach (retinal detachment), putting you at serious risk of blindness.

What are the signs of diabetic retinopathy

The typical symptoms of retinopathy include:

  • Sudden changes in vision – blurred vision, double vision, etc
  • Eye floaters and spots
  • Pain in the eye

The early stages of diabetic retinopathy can, however, develop without warning,  or in some cases, symptoms may only become noticeable in the later stages.

The earlier diabetic retinopathy is detected and treated, the lower your risk of permanent vision damage will be.

How is retinopathy treated?

Mild or background retinopathy does not usually require any treatment. Instead, patients are advised to undergo regular eye health checks and to keep blood glucose, blood pressure, and cholesterol levels well controlled.

For later stage cases of retinopathy, however, laser surgery is usually required to prevent further eyesight deterioration and loss of vision. Special lasers are used to make tiny burns on the retina or in the macula to seal leaking blood vessels.

While this form of treatment cannot restore lost vision, it can prevent further eyesight deterioration and blindness in most people, especially in those with early stage retinopathy where sight is still largely unaffected.

Other forms of treatment include:

  • Medications that can be injected into the eye to slow the growth of new blood vessels and reduce or stop the leakage of fluid.
  • Surgery – eye surgery (vitrectomy) is usually only used in cases of retinal detachment.  The operation is often successful at removing scar tissue that forms on abnormal retinal capillaries and cloudy fluid from inside the eye. However, surgery to reattach a retina to the eye is only successful in about 50% of cases.

The earlier treatment for retinopathy begins, the less chance retinopathy has to cause long term damage to the eyes.

Can diabetic retinopathy be prevented?

Keeping blood glucose levels and blood pressure well controlled in the long-term helps to lower the risk of diabetic retinopathy or slow the progression from mild to more severe, vision impairing forms of the disease.

Other steps you can take to lower retinopathy risk include:

  • Taking a dilated eye examination once a year (eye checks)
  • Having regular cholesterol checks
  • Quitting or avoiding smoking