Diabetes is a very common disease that is caused by elevated blood sugar levels. These prolonged elevated blood sugar levels can damage the tiny blood vessels in the eye (capillaries)and cause the disease, diabetic retinopathy. Diabetes can affect many other organs such as the kidneys, blood vessels, nerves and heart.
Diabetic retinopathy occurs when the retina in the back of the eye becomes damaged by diabetes. The longer a person has diabetes, the greater their chance of developing diabetic retinopathy. Diabetic retinopathy is the leading cause of preventable blindness in working age Australians.
Types of Diabetic Retinopathy
Background diabetic retinopathy
Minor diabetic eye changes that do not cause significant loss of vision.
Diabetic macular oedema
Macular oedema refers to swelling of the macula (the central part of the retina). Leaking blood vessels leak fluid and fatty material, lipid, into the retina. The resultant swelling can severely impair vision.
Proliferative diabetic retinopathy
Proliferative diabetic retinopathy is caused by the development of abnormal blood vessels in the retina. This can cause bleeding into the eye and detachment of the retina. Proliferative retinopathy is a very serious complication of diabetes that can lead to permanent visual impairment.
- Dilated examination
- Retinal photography
- Ocular coherence tomography/OCT
- Fluorescein angiography, now only performed infrequently
Traditional laser treatment, also known as retinal laser photocoagulation, though effective, is used less frequently nowadays because new drugs that work inside the eye are better at ensuring vision is not lost and is maintained long term. In some circumstances, focal laser photocoagulation can be useful when directed away from the macular area from specific sites of leakage from diseased blood vessels.
In this situation, laser treatment prevents the spread of fluid into the macular area where it can result in vision loss.
In advanced diabetic retinopathy, new blood vessels can grow into the retina and because they are diseased vessels, they can bleed into the eye, causing severe vision loss. Also they can cause a form of retinal detachment, leading to severe vision loss. If these new vessels are seen, a form of laser known as panretinal photocoagulation, can be applied to cause the new vessels to shrink and disappear.
When the centre of the retina, a part of the retina known as the macula, becomes swollen due to leaky, diseased blood vessels, the vision is reduced. This condition is known as diabetic macular oedema. Injections of medications into the eye, intra-vitreal injections, can reduce or eliminate the swelling resulting in improved vision.
The medication injected is anti-vascular endothelial growth factor (anti-VEGF) into the back of the eye (the vitreous). A protein called vascular endothelial growth factor or VEGF, is responsible for leaking of abnormal blood vessels.
To stop or slow this process, various drugs that block the protein, called anti-VEGF agents, can be injected into the eye. To get these drugs into the eye an injection is given with a tiny needle. An anaesthetic is given before the injection and very little pain, if any, should be experienced during the procedure. It is a quick procedure and usually occurs in the clinic.