DIABETIC RETINOPATHY (LITERATURE REVIEW)

Аннотация

Retinal damage is one of the specific complications of diabetes mellitus, which is the main cause of blindness in this category of patients. Currently, there are 5 million blind people and 180 million with low vision in the world. Presumably, by 2030, the number of blind people will increase by 27%, and people with low vision by 45% (WHO, 2002). Diabetic retinopathy (DR) was first described more than 100 years ago by Mac Kenzi in 1879, however, today this complication of diabetes mellitus is a major problem for health care. Despite the widespread introduction of new effective drugs and instrumental methods for diagnosis and treatment, DR still remains the main cause of vision loss. Different figures are given for the prevalence of DR in type 1 and type 2 diabetes in different countries. In patients with undiagnosed type 2 diabetes, signs of DR are detected at the time of diagnosis in 7-30% of patients. Moreover, proliferative DR is not a big problem for them, in contrast to type 1 diabetes, while diabetic maculopathy becomes the main cause of visual acuity deterioration. Among the factors causing DR progression are the degree of compensation of carbohydrate metabolism, duration of diabetes, age, arterial hypertension, nephropathy, pregnancy, and smoking. DR is characterized by the presence of specific vascular anomalies andRetinal damage is one of the specific complications of diabetes mellitus, which is the main cause of blindness in this category of patients. Currently, there are 5 million blind people and 180 million with reduced vision in the world. Presumably, by 2030, the number of blind people will increase by 27%, and people with reduced vision by 45% (WHO, 2002). Diabetic retinopathy (DR) was first described over 100 years ago by Mac Kenzi in 1879, however, this complication of diabetes mellitus still represents a major health problem today. Despite the widespread introduction of new effective drugs and instrumental methods for diagnosis and treatment, DR remains the main cause of vision loss. Different figures are 98,7:ROTCAFTCAPMI .SECNEICSLACIDEM,5202,yaM,5emuloV gro.srehsilbupcimedaca.www given for the prevalence of DR in diabetes mellitus types 1 and 2 in different countries. In patients with undiagnosed DM 2, signs of DR are detected at the time of diagnosis of the disease in 7-30% of patients. Moreover, proliferative DR is not a big problem for them, in contrast to DM 1, while diabetic maculopathy becomes the main cause of visual acuity deterioration. Among the factors causing DR progression, the degree of compensation of carbohydrate metabolism, duration of diabetes, age, arterial hypertension, nephropathy, pregnancy, and smoking are distinguished. DR is characterized by the presence of specific anomalies of the vessels and tissues of the retina. It is characterized by a change in the caliber and tortuosity of the retinal vessels, the appearance of microaneurysms, hemorrhages, edema, hard and soft exudates, newly formed vessels, glial proliferation, and vitreoretinal traction. The study of the morphological picture of DR revealed thickening of the basement membrane, loss of capillary pericytes, and as a result, the development of capillary acellularity, which leads to the fact that the microcapillaries are represented by tubes consisting of the basement membrane. Oxygen perfusion through the wall of the latter deteriorates and retinal ischemia and hypoxia develop. All this leads to the development of neovascularization, the newly formed vessels, in turn, are functionally defective and become a new source of hemorrhages. According to the authors, the retina may be especially sensitive to damage, since it has the highest rate of glucose and oxygen utilization per unit weight than any other tissue, and has a high activity of the glycolytic and anaerobic pathological pathway ofglucosemetabolism. It is an undeniable fact that chronic hyperglycemia plays themain rolein the development of DR.There are data obtained as a result ofmulticenter studies performed in diabetes mellitus, confirming the primary importance of normoglycemia. Maintaining the state of normoglycemia in patients with type 1 diabetes confirmed a significant reduction in the risk ofprogression of microvascular complications. The results of the international study –Diabetes Control and Complication Trial showed that maintaining satisfactory glycemic control in a group of people without vascular complications contributed to a decrease in the risk of developing: diabetic retinopathy – by 76%, diabetic neuropathy – by 60%, microalbuminuria – by 30%, albuminuria – by 54%. A multicenter study conducted in patients with type 2 diabetes in the UK and its results were presented in 1998. Normoglycemia reduces the risk of complications of diabetes by 12%, myocardial infarction by 16%, microvascular complications by 25%. BP control reduces all complications by 24%, strokes by 44%, heart failure by 56%, microvascular complications by37%, morta