Diabetic retinopathy (DR) and diabetic macular oedema (DMO) are both eye conditions that can affect people with diabetes.

Diabetic retinopathy is a condition where the blood vessels that supply the retina — the part of your eye responsible for forming images — are damaged. Diabetic macular oedema may then develop as a result of this damage, causing fluid to accumulate in the macula. The macula is the part of the retina responsible for making sure our vision is clear and sharp. If left untreated, either condition can potentially lead to severe vision loss and blindness. 

It can be quite overwhelming to be diagnosed with a diabetic eye disease. The good news is that tests can detect these conditions before they affect your eyesight, and there are treatments available that can prevent further damage from occurring. This article will help you understand the link between diabetic retinopathy and diabetic macular oedema, and what to do if you suspect you have either condition. 

Causes and symptoms of diabetic retinopathy

Diabetic retinopathy is caused by changes in the tiny blood vessels that supply the retina. These changes occur due to chronically high blood glucose levels. Therefore, people with longstanding diabetes and poorly-controlled blood sugar levels are more likely to develop DR. The condition usually affects both eyes and can occur with both type 1 and type 2 diabetes1.

In the early stages, DR may not cause any symptoms. As the condition progresses, however, symptoms may start to occur. These may include blurred vision, floaters (spots or strings floating in the vision), impaired colour discrimination, dark areas in the visual field, fluctuating vision, and vision loss (in advanced stages of the condition)1.

Causes and symptoms of diabetic macular oedema

Diabetic macular oedema refers to a build-up of fluid (oedema) in a part of the eye called the macula. The macula is an area in the centre of the retina that has a very high concentration of light receptor cells. The macula is responsible for ensuring our central vision (what we see straight ahead, in front of us, as opposed to in our periphery) is clear, sharp, and correctly detailed. For example, the macula would be at work if we were to thread a needle or read small print. When there is swelling and thickening in the macula, this causes our vision to distort. This occurs due to damaged blood vessels in the surrounding retina. 

Symptoms of DMO include wavy or blurry vision in the centre of the visual field, and colours may appear faded or washed out. The severity of DMO symptoms can range from a slight blurring of vision to noticeable vision loss. If only one eye is affected, changes in vision may go unnoticed until the condition is quite advanced2.

Worsening vision due to diabetic retinopathy and/or diabetic macular oedema can have a considerable impact on daily life, leading to difficulties reading or at work, participating in leisure activities, and completing household and personal care tasks.

Is diabetic macular oedema the same as diabetic retinopathy?

No, but the two conditions are intimately linked: diabetic retinopathy is a common cause of diabetic macular oedema, and DMO is the most common cause for vision loss in people who have DR. Macular oedema typically develops as retinopathy worsens, but it can occur at any stage of DR. However, not everyone with diabetic retinopathy will necessarily develop diabetic macular oedema. Experts estimate that around 10% of people with DR also have DMO2.

Prevention of diabetic eye disease

Eye complications of diabetes can be prevented by keeping blood sugar levels under control. This can be accomplished by taking medications as prescribed, eating a healthy diet, and participating in regular physical activity.

 Diabetic eye disease often goes unnoticed until vision loss occurs. In the early stages, there may be no symptoms or very mild problems with vision, so the affected person may not realise that damage to the retina is occurring. Yet, early detection and timely treatment of diabetic retinal changes can protect against vision loss. That’s why people with diabetes should undergo a diabetic screening test at least once a year.

Diagnosis and treatment of diabetic eye complications

If you have diabetes and are wondering whether it has affected your eye health, a visit to the optometrist can help you identify any issues and make a plan for managing them. Some of the tests that may be performed include:

  • Visual acuity testing with an eye chart
  • Tonometry to measure the pressure inside the eye
  • Dilated eye exam to examine the optic nerve and retina
  • Digital retinal photography
  • OCT (optical coherence tomography) to capture 3D images of the eye

These tests will show any changes in the retinal blood vessels that indicate damage due to diabetes. If intermediate or advanced stages of DR or DMO are discovered, more frequent dilated eye examinations may be recommended and treatment may be started. 

Therapies for DMO include drugs that prevent the growth of abnormal blood vessels. Corticosteroids (steroids) can help in the short-term, but they can increase the risk of other complications such as glaucoma and cataracts. Laser surgery can also help to slow down the leakage of fluid from the damaged retinal blood vessels. These treatments can be used alone or in combination.

Want to learn more about diabetic retinopathy or diabetic macular oedema? Browse through our educational resource or book an appointment with one of our Specsavers optometrists.

References

  1. Mayo Clinic. (no date). Diabetic Retinopathy. [Online]. Available at: https://www.mayoclinic.org/diseases-conditions/diabetic-retinopathy/symptoms-causes/syc-20371611#targetText=Diabetic%20retinopathy%20(die-uh-,or%20only%20mild%20vision%20problems. [Accessed 20 August 2019].
  2. National Eye Institute. (no date). Facts About Macular Edema. [Online]. Available at: https://nei.nih.gov/health/macular-edema/fact_sheet [Accessed 20 August 2019].