[Role of local factors in the pathogenesis of diabetic retinopathy]

The pathogenesis of diabetic retinopathy includes the following components actual at a local level: diffuse retinal hypoxia leading to increase in the retina of anaerobic energy processes, development of local acidosis causing venous congestion, increased permeability of retinal capillaries and veins, impairment of the structure of vascular walls, development of foci of deep retinal hypoxia and of proliferative changes. These disorders develop in succession and mutually aggravate each other. A noticeable role belongs to deteriorated evacuation of the products of abnormal metabolism which depends on the existence of a solid barrier (pigmented epithelium, Bruch's membrane) between the retina and choroid and on the venous congestion and impaired liquid circulation in the vitreous body. A dichotomic type of division of the central retinal artery and absence of anastomoses between its branches facilitate the appearance of foci of retinal hypoxia. Local pathogenetic therapy of diabetic retinopathy should be aimed at removal of at least one out of three factors: hypoxia, acidosis, or venous congestion. This does not make less important the treatment of general metabolic disorders characteristic of diabetes mellitus.