Diabetic retinopathy is a disease due to diabetes mellitus, diabetes-induced disease of the retina of the eye. The increasing damage of small blood vessels (microangiopathy) causes an initially undetected damage to the retina. This may lead to blindness.
The numbers speak a clear language and are terrifying: after twenty years of type 1 diabetes up to 95 percent of patients will have damage to the retina, among type 2 diabetic patients, this rate is around 60 percent. In the industrialized nations is diabetic retinopathy, the most common cause of blindness in the working age. As with other micro-circulation disorders is the increased blood sugar, the most important factor causing retinopathy, but other factors may also play a role, such as increased blood pressure, hormonal changes during puberty and pregnancy, high blood fat levels.
We distinguish two forms of diabetic retinopathy:
- The nonproliferative retinopathy
- Proliferative retinopathy
The nonproliferative retinopathy
The nonproliferative form is occurring in the earlier stage and may turn into a proliferative form. The first symptoms are small, reddish spots on the retina, known as microaneurysms.
These vessels disorders occur due to weak wall cabinets. An increase in the number of microaneurysms is a harbinger for the occurrence of further changes.
From the damaged vessel walls, it can come to an escape of blood into the retina, also may form fatty deposits on the retina (“hard exudates”).
The retinal vessels have first variations of their diameter and then locks on with increasing lack of oxygen supply.
The reduced blood supply (ischemia) of the retina by the nonproliferative retinopathy often triggers a highly undesirable «repair mechanism” of the eye. New vessels start to form to supply the retina, this mechanism is known as vascular proliferation. This results in the second, more dangerous stage, the proliferative retinopathy.
The pathological changes remain no longer limited to the level of the retina. These newly formed abnormal blood vessels and the accompanying vascular tissue grow into the vitreous (the gel-like filling of the eye between the retina and lens) into it. These new vessels often tend to bleed.
The patient notices this as a sudden “dark cloud” in the view field.