Scientific Journal of KubSAU

The dramatic lowering of intraocular pressure (hypotony) is developing during glaucomatous surgery due to the formation of the new aqueous humor outflow. The calculations of the flow in the fluid balance parameters have shown, that for the normal intraocular pressure maintenance in the postoperative period the fluid flow out of the anterior chamber should not exceed 0,04 microliter in minute. The intensity of the aqueous humor outflow through the shunts with different parameters does not depend on the shunt length. The shunt with the inner hole radius 0,025 mm is the most safe as it provide the less outflow. The experimental comparative study of the static viscosity of the most widely used viscoelastics in ophthalmological surgery was carried out. It was stated that used in eye surgery viscoelastics on the basis of 1%, 2% and 3% sodium hyaluronate possess the viscosity, that differs in 10 and 100 times and has significant influence on the flow intensity out of the anterior chamber when the new outflow tracts are formed. The mathematically based choice of the most optimal relationship between the viscoelastics physical parameters and the inner hole size of the shunt type glaucoma drainage devices was established. Shunt with the inner hole radius 0,05 mm and simultaneous use of 2% and 3% sodium hyaluronate solution is the most safe for the maintenance of the eye tonus during the first 5 days after glaucoma surgery. The presented correlation allows to increase the safety of the surgical treatment of the patients with the refractory glaucoma

Acceptable values of the drainage hole parameters in the shunt glaucoma surgery were calculated by means of mathematical modeling of different conditions of eye hydrodynamics. The operation method was designed with provision for pressure gradient, rate of the aqueous humor outflow, and the values of intraocular pressure in early and late postoperative period. The balance of liquid in eye was calculated in mathematical model as ordinary differential equation in accordance with flow resistance of every section. The data received by using mathematical model has shown that allowable rate of aqueous humor outflow is gained with the hole diameter of 0,025 mm. This mathematical model should assist to the better understanding of physical processes describing the eye hydrodynamics, should benefit to the operation quality and should create the base to the clinical studies

The retrospective study of patients with retinal vein occlusion and frequency of pseudoexfoliation syndrome is made in this study. Retinal vein occlusion is the second most common type of retinal vascular disorder, after diabetic retinal disease, and may develop with a consequent reduction in visual acuity. Pseudoexfoliation syndrome is an age-related disease characterized by the production and accumulation of a fibrillar extracellular material in several ocular tissues We have analyzed data of 73 patients with retinal vein occlusion. It was detected that risk of central vein occlusion is higher in patients with pseudoexfoliation syndrome (23,3% of patients were diagnosed as having pseudoexfoliation syndrome). In the branch retinal vein occlusion group only 9,3% of patients had pseudoexfoliation syndrome. In control group only 8,6% of patients had this syndrome. Control group was made of 80 patients similar in age without any retinal and cardiovascular abnormalities, patients with episodes of ocular hypertension, glaucoma, and those who had undergone cataract surgery were excluded from the study. Pseudoexfoliation syndrome may be considered as an independent risk factor for development of central retinal vein occlusion

The dramatic lowering of intraocular pressure (hypotony) is developing during glaucomatous surgery due to the formation of the new aqueous humor outflow. The calculations of the flow in the fluid balance parameters have shown, that for the normal intraocular pressure maintenance in the postoperative period the fluid flow out of the anterior chamber should not exceed 0,04 microliter in minute. The intensity of the aqueous humor outflow through the shunts with different parameters does not depend on the shunt length. The shunt with the inner hole radius 0,025 mm is the most safe as it provide the less outflow. The experimental comparative study of the static viscosity of the most widely used viscoelastics in ophthalmological surgery was carried out. It was stated that used in eye surgery viscoelastics on the basis of 1%, 2% and 3% sodium hyaluronate possess the viscosity, that differs in 10 and 100 times and has significant influence on the flow intensity out of the anterior chamber when the new outflow tracts are formed. The mathematically based choice of the most optimal relationship between the viscoelastics physical parameters and the inner hole size of the shunt type glaucoma drainage devices was established. Shunt with the inner hole radius 0,05 mm and simultaneous use of 2% and 3% sodium hyaluronate solution is the most safe for the maintenance of the eye tonus during the first 5 days after glaucoma surgery. The presented correlation allows to increase the safety of the surgical treatment of the patients with the refractory glaucoma