People with diabetes are more likely to suffer a condition that may damage their eyesight
The eye, the retina and the macula
Your retina is the tissue at the back of your eye that enables you to see. It contains cells called photoreceptors that convert light coming into your eye into signals that your brain can understand. There are two types of photoreceptors: rod cells, which are sensitive to low light levels; and cone cells, which allow you to see colour.
Cone cells are most tightly packed in a region of the retina called the macula, which gives you your central vision – necessary for reading, for example, or driving a car.
How does diabetes damage the eye?
The retina also contains many small and delicate blood vessels (capillaries) that supply oxygen and nutrients to the photoreceptors.
In diabetes, the amount of sugar in the blood is higher than normal. If not controlled, high blood sugar can damage the capillaries in the retina.
Damaged capillaries cause release of a protein called vascular endothelial growth factor, or VEGF. VEGF causes capillaries to leak fluid into the macula. It also makes new blood vessels grow (neovascularisation), which can also leak fluid.
What is DME?
The leaked fluid causes swelling (edema) – known as diabetic macular edema (DME) – that distorts the macula, resulting in blurred vision. If not treated, DME can result in complete loss of central vision.
About one in every three people who have had diabetes for 20 years or more will develop DME.
How can I prevent DME happening to me?
If you have diabetes, the most important thing you can do is to ensure that your blood sugar level is well-controlled, to avoid damaging the fragile capillaries in your eye. Your physician will be able to advise you if you have concerns about your diabetes treatment.
It is also important to visit an eye specialist regularly, so that any signs of capillary damage in the retina can be picked up and treated, as early as possible. If you experience blurred vision, you should immediately report this to an eye specialist.
How is DME treated?
Many patients with DME are treated with a special laser that seals leaky capillaries and reduces swelling. Others are treated with steroids, injected directly into the eye, to reduce inflammation.
Recently, a new class of medicines that targets VEGF became available (anti-VEGF therapies). When injected into the eye, these medicines stop VEGF from acting and allow existing swelling to reduce. Anti-VEGF therapies are more effective than laser or steroid treatment for DME.
We have developed an anti-VEGF therapy that rapidly reduces edema and restores central vision. The substance is approved and effective in a number of eye diseases and can be an effective treatment for many people with DME.
Advice for patients
Each body reacts differently to medicines. Therefore it is impossible to tell which medicine works best for you. Please consult your physician.