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A two-dimensional computer model was developed to describe hydraulic flows inside the human eye. The flow field was described by coupled Navier-Stokes and Darcy equations. The velocity and pressure profiles in the chambers, the wall, and the vitreous body of the normal eye were obtained using the finite-element method. The model includes the filtration of fluid from the retinal capillary and its drainage through the choroid. The applications of this model include the investigation of the contribution of convection and diffusion to the transport of drugs and study of the kinetics of biodistribution in the eye.

A classification of diabetic retinopathy and diabetic maculopathy as well as treatment schemes for each stage, which were worked out by the authors, are described in the paper. A stage free of any diabetic changes in the eye fundus is isolated, within the suggested classification, as well as the notion of a high-risk diabetic retinopathy is defined with more precision and in accordance with the modern understanding of importance of the vitreous-retinal interaction and of compensation of carbohydrate metabolism in the disease pathogenesis. Finally, an original classification of diabetic macular edema was introduced.

The hemostasis system was analyzed in 106 patients with diabetes mellitus, including 86 patients with diabetic retinopathy. Parameters of coagulogram and thromboelastogram as well as platelets aggregation, stimulated by collagen, were examined in all patients. Besides, the fibrinolytic activity of blood plasma as well as the concentration of plasminogen, fibrinogen and of fibrin-degradation products were evaluated. Essential changes were detected, which correlated with an intensity of diabetic changes in the eye fundus, i.e. generalized hypercoagulation caused by a lower activity of the system antithrombin III-heparin, a higher activity of fibrinogen and activation of the fibrinolytic system. The obtained data denote an important role of impaired hemostasis in the pathogenesis of diabetic retinopathy.

Thrombolytic enzymes are widely used in the treatment of vascular diseases of the eyes and of intraocular hemorrhages. We studied the pharmacokinetics of recombinant prourokinase (proRUK) in ocular structures after its intravitreal administration and subtenon's implantation of collagen infusion system (SICIS). Kinetic parameters of accumulation of labeled proRUK in ocular structures were obtained. After intravitreal administration, the proRUK half-life (T1/2) was 7.9 +/- 1.44 h, with proRUK losing none of its enzymatic activity while in the vitreous body. The maximum accumulation of proRUK in the vitreous administered by the SICIS is observed after 4-5 h and is 1.5-2.0% of the dose administered. In the sclera the maximum accumulation of proRUK is 10-15% (4-6 h after administration), in the vascular membrane 0.8% (4 h after administration). We believe that combination of intravitreal and SICIS-aided administration of proRUK to patients with extensive hemorrhages (subtotal and total hemopthalmia) will improve the efficacy of therapy.

Results of clinical and laboratory examinations of 161 diabetics are presented. The main factors or risk of nonproliferative diabetic retinopathy are the duration and degree of compensation of diabetes mellitus, development and stage of diabetic nephropathy, the latter factor replacing in experiments with simulation of diabetic retinopathy the level of arterial hypertension, and the blood serum content of high-density lipoprotein cholesterol and ratio of total cholesterol to high-density lipoprotein cholesterol. The factors of risk of proliferative diabetic retinopathy are duration and degree of compensation of diabetes mellitus, development and stage of diabetic retinopathy with this latter factor replacing in simulation of diabetic retinopathy the level of arterial hypertension, and the blood serum levels of triglycerides, low-density lipoprotein cholesterol, fibrinogen, soluble fibrin-monomer complexes, as well as fibrinolytic activity.

The hemodynamics of both eyes was examined before and after surgery in patients with detachment of the retina. The depression of uveal blood stream was transitory in extrascleral ballooning, in contrast to that in cerclage and filling, when the hemodynamic characteristics of both eyes are significantly reduced.