Many diabetics – particularly those with poor diabetic control which results in too-high blood sugar levels over long periods of time – have damaged blood vessels in the retina, the tissue lining the back of the eye that detects light and allows us to see. This condition, called diabetic retinopathy, affects up to eight out of 10 patients who have had diabetes for 10 years or more.
Many people with mild diabetic retinopathy have good vision, but there are two types of sight-threatening diabetic retinopathy: diabetic macular oedema (DMO) and proliferative diabetic retinopathy (PDR).
In DMO, fluid leaks out of the tiny damaged blood vessels in the back of the eye, and accumulates in the macula, the central part of the retina which is responsible for seeing fine details and central vision. This leads to swelling of the tissue and blurred vision. Eventually, patients with diabetic macular oedema can develop poor central vision and be unable to read or drive, but the vision to the side usually remains normal.
Proliferative diabetic retinopathy is when the retinal blood vessels close resulting in the retina being starved of blood. This causes abnormal and very fragile blood vessels to grow on the surface of the retina which can lead to permanent loss of vision from bleeding into the eye, retinal scarring and retinal detachment.
Regular eye checks are essential for all diabetics, so signs of diabetic retinopathy can be detected as early as possible. If you diabetic and experience blurred vision, you should visit an eye specialist immediately.
If you develop DMO, you might require laser photocoagulation, which involves placing tiny laser burns in the area of leakage in the retina which slow the leakage of fluid and reduce the fluid in the eye. This may not significantly improve vision for some patients – although it can stop your vision from getting worse. Other treatments are available and have been shown to benefit patients with DMO, including injections of anti-VEGF drugs such as bevacizumab and ranibizumab. Ask your specialist if these treatments are suitable for you or available to you.
Laser treatment is used to treat new blood vessels at the back of the eyes in the advanced stages of diabetic retinopathy. This is done because the new blood vessels tend to be very weak and often cause bleeding into the eye.
In some cases of diabetic maculopathy, injections of a medicine called anti-VEGF may be given directly into your eyes to prevent new blood vessels forming at the back of the eyes.
The main medicines used are called ranibizumab (Lucentis) and aflibercept (Eylea). These can help stop the problems in your eyes getting worse, and may also lead to an improvement in your vision.
Surgery may be carried out to remove some of the ‘jelly’ inside the eye. This is the transparent, jelly-like substance that fills the space behind the lens of the eye.
The operation, known as vitreoretinal surgery, may be needed if:
Vision loss occurs when the fluid reaches the macula (the centre of the retina that provides sharp vision) and builds up, causing swelling. At first, you may not notice changes to your vision. Over time, diabetic macular oedema can cause your central vision to become blurred. A healthy macula is essential for good vision.
All people with type 1 and type 2 diabetes are at risk of diabetic macular oedema.
Large studies have shown that people who have well-controlled blood sugar, blood pressure and cholesterol levels, and do not smoke are less likely to develop diabetic macular oedema.
Diabetic macula oedema may be detected during your annual eye screening visits, which are offered to all patients with diabetes. Digital photographs of your retina may show signs of early diabetic macular oedema. You may not notice any changes in your vision at this stage.
If diabetic macular oedema is detected, you will be referred to the medical retina clinic at Moorfields for further assessment. If you are attending clinics at Moorfields, you do not need to attend your local diabetes eye screening programme. If you do not require treatment or when your treatment is complete, you will be discharged from Moorfields. After being discharged, it is important to resume attending your annual local diabetes eye screening appointments.