Macular Disease

Risk Factors

Approximately 1.7 million Australians have diabetes. This includes 1.2 million Australians have diagnosed (known) diabetes.

Of these, over 300,000 (beween 25-35% of people) have some degree of diabetic retinopathy, and about 65,000 have progressed to sight-threatening eye disease.

Most people with diabetic retinopathy should keep most, if not all vision, providing it is diagnosed early and all steps are taken to keep it under control.

If you have diabetes:

Inform your optometrist or ophthalmologist that you have the disease and how long you have had it.

Visit an eye specialist (ophthalmologist) or an optometrist at least every two years for a comprehensive, dilated eye exam.

If you are at high risk of diabetic retinopathy, have an eye check at least every 12 months, even if your vision appears to be perfect.

Be guided by your eye specialist, and do not cancel or delay appointments unless absolutely essential.

The longer you have had diabetes, the more important it is to have regular eye tests, even if the tests have always been clear in the past. This is because the risk of eye disease is strongly related to the duration of diabetes.

Uncontrollable risk factors

  • Duration of diabetes: The duration of diabetes is the strongest risk factor for developing retinopathy. This means that it is very important to keep getting regular eye checks, even if all previous checks have been clear.
  • Ethnicity: Aboriginal and Torres Strait Islander Australians are two to four times more likely than the general population to develop diabetes and are therefore at a much higher risk of developing vision problems related to diabetes. Other groups including some Middle Eastern and Asian populations and Pacific Islanders are also at higher risk.
  • Genetics: Studies have found that many genetic factors can influence the onset of complications in diabetes, including the severity and speed of onset of diabetic retinopathy.
  • Medical history: Women who have previously been diagnosed with gestational diabetes (or a condition known as polycystic ovary syndrome) are at increased risk of developing type 2 diabetes, and hence retinopathy, later in life.

Controllable risk factors

High blood glucose

People who have persistently high blood glucose levels are at risk of serious vision loss and blindness.

People with diabetes whose blood glucose is not at target levels are almost eight times more likely to develop diabetic retinopathy.

Regular follow-ups with healthcare professionals are essential to help preserve vision. It important to speak to your GP or diabetes specialist about your personal target blood glucose range, which can depend on age, medical condition and other risk factors. If there is already some degree of diabetic retinopathy, the goal is to get glycated haemoglobin (HbA1c) level to 7% or less (53 mmol/mol). (HbA1c is a measure of the blood glucose control over the preceding few months. Note that the HbA1c target is different to the target for blood glucose at any particular time). A periodic test of HbA1c is therefore recommended.

For some people, continuous blood glucose monitoring may be recommended. Guidance should be sought from a diabetes specialist.

High blood pressure

People with diabetes and high blood pressure are more likely to develop diabetic retinopathy and it will also progress more rapidly. High blood pressure will also aggravate any macular edema (fluid leakage). If there is already some degree of diabetic retinopathy, the aim should be to get systolic blood pressure (the bigger number) to 130 mm Hg or less.

Blood lipids

People with abnormal blood lipids are at greater risk of developing diabetic retinopathy. It is important to get blood lipids to normal levels. Guidance should be sought from a GP or diabetes specialist.

Weight and exercise

People who carry excess weight, especially around the waist, are at substantially increased risk of their diabetes progressing. Regular exercise helps insulin to work better, lowers blood pressure, helps reduce weight and reduces stress. A relatively small weight loss of even 5 to 10% of current weight can result in a significant reduction of risk. This makes it important to incorporate exercise into a daily routine.

Discuss any changes in your diet or exercise program with a GP or diabetes specialist before you start. A diabetes educator can support the increase of exercise into daily routine.

Smoking

Smoking significantly increases the risk of diabetes and its related conditions. It also increases blood pressure and blood sugar levels, making it harder to control diabetes. Speak to a GP for help about quitting smoking and the many options available.