Diabetic retinopathy is the commonest cause of blindness in people of working age in Australia. It is a condition affecting the blood vessels in the retina. The retina is the light sensitive lining of the back of the eye responsible for vision. In diabetes, high blood sugar levels damage the retinal blood vessels causing them to become blocked, leak fluid or bleed into the retina, potentially leading to loss of vision.
Blindness due to diabetic retinopathy is usually preventable with regular eye examinations and early treatment when sight threatening diabetic retinopathy is detected.
Anybody who has type 1 or type 2 diabetes is at risk of developing diabetic retinopathy. The longer the duration of diabetes, the greater the risk. Diabetic people with poor blood sugar control or high blood pressure are at particularly high risk of developing diabetic retinopathy.
In the early stages of the condition, diabetic retinopathy causes no symptoms so it is vital that all people with diabetes have regular eye examinations including assessment of their retinas to detect and treat diabetic retinopathy before loss of vision occurs.
Diabetic retinopathy may cause loss of vision due to the following problems;
This is a swelling of the macula due to fluid leaking from blood vessels in the retina. The macula is the central part of the retina which is responsible for fine vision (reading, watching TV, and recognising faces). In the early stages, there may be no symptoms. However, if the swelling of the macula increases, central vision will become blurred. If macular oedema is present for a long time, it may cause permanent damage to the macula and severe loss of vision.
Proliferative diabetic retinopathy:
Diabetic damage to the retinal blood vessels causes the retina to become starved of oxygen. The body responds by growing abnormal blood vessels on the retina and the front of the eye. These abnormal blood vessels are called ‘new vessels’ and are very fragile. They often bleed, causing a sudden loss of vision. Scar tissue may form on the retina, leading to a retinal detachment and permanent blindness. New vessels can block drainage channels in the eye, causing raised eye pressure (this is called neovascular glaucoma). This can lead to severe pain which in the worst cases may require removal of the eye
High blood glucose and blood pressure levels cause diabetic retinopathy to progress so it is important that these factors are controlled as much as possible usually under the supervision of a family doctor or endocrinologist
A laser beam is used to treat areas of diseased retina to reduce leakage from blood vessels and growth of new vessels. The aim of laser treatment is to prevent severe loss of sight.
Medicines such as steroids, bevacizumab (Avastin) or ranibizumab (Lucentis) can be injected into the eye to reduce swelling of the retina and prevent new blood vessels growth. This often leads to an improvement in vision.
Keyhole surgery is used to remove the jelly within the eye (called the vitreous gel). This leads to improved oxygen supply to the retina. Scar tissue and blood is also removed from the eye to improve vision. Combinations of these treatments are often very effective in reducing vision loss from diabetic retinopathy.