The problem is related to small blood vessels of the retina that are damaged by chronic high levels of blood sugar. The damage causes increased permeability of blood vessel walls and local arterial closures. This disrupts the nutrition of retina and is followed by a formation of new blood vessels. However, the newly formed vessels are incompetent, fragile and easily break. If such blood vessel rupture occurs, the blood pours out of the affected vessel to retina causing its irreversible damage. The bleeding cause a local visual field disruption but a large hemorrhage can cause a total vision loss in the affected eye.
Diabetic retinopathy might be initially asymptomatic but sometimes it manifests by a progressive deterioration of visual quality and occurrence of dark spots in the visual field. In extreme cases, the untreated diabetic retinopathy may cause a total vision loss.
Diabetic retinopathy is the reason why every diabetic should be regularly checked by an ophthalmologist. The fundus is examined (including the retinal arteries) using an instrument called ophthalmoscope.
The prevention consists of proper treatment of the diabetes and keeping the blood sugar levels as near normal values as possible. However, diabetic complications may occur even in well-compensated diabetics. If the retinopathy occurs, it must be treated as quickly as possible to minimize the further damage.
Treatment of diabetic retinopathy involves destruction of the newly formed blood vessels. The affected retinal areas are burned by a laser destroying the blood vessels. While this prevents blood vessel breaking and retinal hemorrhage, it also damages the retina. Damage caused by the laser is much milder but repeated laser therapy may also seriously impair the vision. If vision disorder is caused by a hemorrhage of the eye fluid, the ophthalmologists perform the so-called vitrectomy – bloody eye fluid is cautiously aspirated and replace with a special clear liquid.