Diabetic retinopathy is a severe and widespread eye disease. In fact, it is the leading cause of legal blindness for the working age population (between 20 and 64) in western countries. Diabetic retinopathy is a complication of diabetes mellitus and its prevalence increases with the duration of the disease. After 15 years of diabetes, the prevalence lies near 98%, so nearly all diabetic patients are affected by this disease after some time. Although not all the forms of the disease coincide with vision alteration, about 2% of the diabetic patients are blind and 10% suffer from vision loss after 15 years of diabetes .
This shows that diabetic retinopathy is a very frequent eye disease, but the situation shall become even worse in the future. The number of diabetics in the world is strongly increasing; a number of 300 millions of diabetic patients is expected for the year 2025. Hence, diabetic retinopathy is a major problem for an increasing number of persons, and also for the national health systems. According to , blindness due to diabetic eye disease produces costs of about 500 millions dollars a year in the United States.
Diabetic retinopathy is a silent disease, i.e. in its early stages, it is asymptomatic and vision is not altered. Vision impairment and blindness are the consequences of the complications of this disease, not of the disease itself. The starting point of the disease is the elevation of glucose in the blood which results in alterations of the vascular walls, like microaneurysms, the first unequivocal sign of the disease (see Fig. 7.2). This first abnormality causes two phenomena:
• Capillary occlusions due to modifications in the capillary walls result in local ischemia (a region in the retina which is no longer supplied with blood) accompanied by hemorrhages. If this ischemia is relatively large, it may give rise to new vessels which proliferate on the surface of the
Microaneurysm Exudate Optic disk
Macula (centre de la vision) Retinal Vessel Hemorrhage Choroidal vessel
Figure 7.2: Image of the fundus.
retina. These new vessels are normally weak and may cause vitreous hemorrhages, which are one of the main reasons for irreparable vision impairment and blindness due to diabetic retinopathy.
• Because of alterations of the vascular walls, the vessels become hyperper-meable. As a consequence, extracellular liquid can pass the wall and may accumulate under the retina building a retinal edema. If situated in the macula, the center of vision, it is called macular edema; it is accompanied by exudates in the macular region (intraretinal deposits made of serum lipoproteins, see Fig. 7.2) and it represents one of the main reasons for vision loss.
Both of these two main complications can be prevented by an adapted treatment if the disease is detected early enough. Hence, early diagnosis of diabetic retinopathy is essential for the prevention of vision impairment and blindness threatening a large number of patients.
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Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...