When diabetes blinds

One of my patients was diagnosed with diabetic macular oedema this week - and she's terrified. She said she had no idea that complications of type 2 diabetes could be so serious. I've been on a crusade for decades to help spread the word that type 2 diabetes is NOT a 'mild' kind of diabetes. 

One of my patients was diagnosed with diabetic macular oedema this week - and she's terrified. She said she had no idea that complications of type 2 diabetes could be so serious. I've been on a crusade for decades to help spread the word that type 2 diabetes is NOT a 'mild' kind of diabetes - without good control, it can blind and, make no mistake, kill.

In many respects type 1 and type 2 diabetes are very different conditions. Type 1 diabetes is an autoimmune disease not linked to lifestyle or weight, while type 2 diabetes is (almost) all about weight and lifestyle. But in terms of long-term complications there are many similarities. They're both diagnosed on the basis of raised blood glucose, and that raised glucose can cause similar complications in both - kidney problems; eye disease; and nerve damage which can lead to ulcers or even amputation of the foot. People with type 1 and type 2 diabetes are also at increased risk of heart attack.

High blood sugars over several years can weaken and damage the blood vessels at the back of the eye, which supply blood to the retina (the layer of cells that send messages about what you're seeing to your brain). This is known as diabetic retinopathy. It can result in leakage of fluid from the blood vessels, tiny bleeds, little bubbles of weakened vessel walls (called microaneurysms) and problems with the blood supply to the retina. New blood vessels grow to try to improve the blood supply, but these blood vessels are easily damaged and can harm your eyesight.

The macula is a small part near the middle of your eyesight that is tightly packed with light-sensitive cells. It allows you to see in fine detail. In severe diabetic retinopathy, fluid and scar tissue can build up on the macula, causing a condition called macular oedema. Diabetic macular oedema affects about 50,000 people in the UK - it's the commonest preventable cause of blindness in adults of working age.

In the past, there was little or no treatment for diabetic retinopathy or macular oedema, other than using tight glucose control to try to stop it worsening. That's still important today, but now we have two main options for treatment, depending on how bad your symptoms are. The first is laser surgery to seal off the abnormal new blood vessels growing on the back of the eye .

The second is the injection of vascular endothelial growth factor (VEGF) inhibitor medicines - Lucentis® is licensed for treatment of diabetic macular oedema, and now the National Institute for Health and Care Excellence (NICE) has approved a new drug for some people. Eylea® has already been approved by NICE for another condition affecting the macula, called age-related macular degeneration but this new approval increases the options available for people whose eyesight is threatened by diabetic macular oedema.

But these treatments are only needed if the condition develops in the first place, and prevention is always better than cure. In both type 1 and type 2 diabetes, a healthy diet, regular exercise and tight control of your blood pressure, cholesterol and blood sugar can all help cut your risk of complications. But regular eye checks are also essential.

We're incredibly lucky in this country - the NHS Diabetic Eye Screening Programme is the envy of the world. Virtually no other country has a system for annual eye screening for everyone with diabetes over 12 years old - once a year, you'll be offered a 30-minute appointment which involves dilating your pupils with drops and taking photographs of the retina at the back of your eye. This checks for diabetic retinopathy and if early signs and symptoms are found, you'll either be called back for follow-up sooner or referred on to a specialist with a view to assessing you for treatment.

Both problems get more likely with increasing length of diabetes - few people have any diabetic retinopathy if they've had diabetes for under five years, but up to one in person in three who has had diabetes for 25 to 30 years will have some degree of macular oedema. That doesn't mean you can ignore it until then - by taking preventive steps and getting regular eye checks from an early stage, you could just avoid becoming a statistic.

Dr Sarah is unable to provide medical advice or respond directly to questions concerning your health. If you have health concerns we recommend contacting your GP.