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.
- 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].
- 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].