Diabetic retinopathy (DR) is a disease that affects the small vessels of the retina, the part of the eye responsible for the images that are formed and sent to the brain.
The onset of DR is mainly related to the duration of diabetes and uncontrolled glycemia. When diabetes is not controlled, hyperglycaemia triggers several changes in the body that, among other damages, leads to dysfunction of the retinal vessels.
Diabetes is associated with several complications and the eye is one of the main organs that is affected. As far as ocular complications are concerned, DR is the most common microvascular complication and the main cause of blindness in adults in the western world, between the ages of 20 and 74.
DR usually affects both eyes and, if not diagnosed and treated early, can lead to irreversible blindness. However, the onset or progression of the disease can be prevented by proper control of blood glucose levels. In addition, regular eye exams are essential to detect eye complications resulting from diabetes and, therefore, permitting treatment to begin as early as possible, when the chances of controlling the disease are greater.
According to the location, extent and degree of various clinical features observed during the diagnosis, DR can be classified as non-proliferative or proliferative.
Non-proliferative DR is the least advanced stage of the disease. At this stage, microaneurysms (small vascular dilations), haemorrhages and obstructed blood vessels can be found, causing several areas of the retina to be without oxygen and nutrients (known as ischemia).
If the macula (small area in the centre of the retina responsible for central vision) is not affected, this stage of DR may present no symptoms or loss of vision. However, when there is an accumulation of fluid in the macula causing macular oedema, vision may appear blurred, and the risk of visual loss or blindness is significantly increased.
On the other hand, proliferative DR, is the most advanced stage of the disease, characterised by the appearance of new blood vessels (also known as neovessels) on the surface of the retina.
Neovessels are fragile and grow without causing any symptoms or loss of vision. However, they can rupture and cause bleeding, leading to severe vision loss and even blindness. Frequently, the new vessels are accompanied by a kind of scar, whose contraction can lead to another serious complication called retinal detachment.
DR prevention lies in controlling blood glucose levels, which significantly reduces the risk of long-term vision loss, while its treatment depends on the stage of the disease.
In the most severe cases (such as proliferative DR), or in the presence of complications such as diabetic macular oedema, treatment is necessary, such as laser surgery or photocoagulation, which, while not curing DR, allows “drying” of the neovessels, thus reducing macular swelling.
Another option is vitrectomy surgery, when severe vitreous haemorrhage occurs. Blood and scar tissue around the neovessels of the eye is removed. Vitrectomy often prevents further bleeding by removing the neovessels that caused the bleeding. In some cases, laser surgery may be performed along with vitrectomy surgery.
Article submitted by the HPA Group
