Home – Home – Jornals – Combustion, Explosion and Shock Waves 2019 number 3

Based on the numerical simulation and qualitative analysis, the effect of the group velocity dispersion on the formation of light structures during self-focusing and filamentation of femtosecond titanium-sapphire laser pulses in air was studied. It was found that dispersion occurs when the dispersion length is not the smallest process scale. Based on the results of numerical solutions of the nonlinear Schrödinger equation in a Kerr-plasma dissipative dispersion medium using the method of diffraction-beam tubes, the main regularities of filamentation of femtosecond laser pulses in air at various pulse durations, initial beam radii, and peak emission powers were determined. It was shown that the relative (normalized to Rayleigh length) coordinate of the beginning of filamentation increases with increasing the dispersion distortion of the pulse. The length of the filamentation channel is reduced. For shorter laser pulses (tens of femtoseconds) the filamentation failure is observed, when the laser beam radius is increased. For this class of pulses, an increase in the size of the energy replenishing diffraction-beam tube occurs, and the angular divergence of the post-filamentation light channels also increases.

Critical evaluation of the available experimental data on the frequencies of the rotational and vibrational-rotational transitions of the OH molecule in the ground electronic state Х²Π is performed using the Ritz combination principle. The transition frequencies weighted in accordance with the experimental errors have been processed by the RITZ program code. The analysis of the dimensionless weighted deviations made it possible to exclude "bad frequencies" from consideration and to carry out processing with a standard deviation of 1.8. As a result of critical evaluation, a set of 1056 empirical RITZ energy levels is obtained with an appropriate uncertainty for each level. The empirical Ritz energy levels are compared with the calculated levels given in the HITRAN spectroscopic database.

The broadening and shift coefficients of H₂O absorption lines are compared for Ar, He, H₂, and N₂ buffer gases. The broadening and shift coefficients were derived from the analysis of the absorption spectra recorded with a Fourier spectrometer in the spectral range 8650-9020 cm^-1 with a spectral resolution of 0.01 cm^-1. Using two models of line profiles (Voigt and speed-dependent Voigt profiles) the parameters of the H₂O absorption lines were calculated. It is shown that the speed-dependent Voigt profile provides better agreement with experimental data.

The wind speed and atmospheric turbulence in the airport runway were measured using a passive optical method based on the correlation analysis of turbulent distortions of distant objects of observation. The optical path was organized in the area of the ground section of the plane descent glidepath near the start of the runway. After the aircraft passed above the line of sight of the meter, significant velocity emissions and increased turbulence, caused by the wake, against the background of a moderate side wind were stably recorded. The results indicate the practical applicability of this method for instrumental indication of the presence or absence of wake vortex tracks over the airport. This information can be useful in assessing the safe intervals in the process of organizing departure and landings of aircraft.

The results of a numerical analysis of the manifestation of the backscatter amplification effect in the regime of weak optical turbulence in dependence on diffractive size of the transmitting aperture are presented. It is shown that the magnitude and localization of the amplification of the mean power of the radiation back scattered in a turbulent atmosphere depends on the Fresnel number of the transmitting aperture. Since the Fresnel number changes with changes in the distance from which the lidar signal arrives, this must be taken into account when profiling the intensity of optical turbulence from the lidar data on the amplification of the mean power of scattered radiation.

The work presents the algorithm for determining cloud phase using the MSU-MR daily measurements on-board the Russian meteorological satellite Meteor-M N 2. The physical principles of the determination of cloud phase by using the reflectance at wavelengths of 1.6 and 3.7 mm and brightness temperatures at 11 and 12 mm are considered. The results of determining cloud phase with the algorithm presented are compared with the results of the algorithms developed for other satellite radiometers. The accuracy of the comparison is over 80%. The greatest inaccuracies are observed for thin semitransparent clouds because to additional radiation coming from the underlying surface, as well as for mixed clouds due to the specificity of the algorithm presented.

The numerical solution within the geometrical optics approximation of the light scattering matrices for ice crystals with arbitrary shape taking the absorption into account were presented. The results show that the absorption decreases the intensity of scattered light when a wavelength goes far to the IR. It was shown that the influence of absorption is less than basis points for 0.355 and 0.532 mm wavelengths, and less than several percent for 1.064 mm. For the near IR the influence of that effect could be more than several dozen percent.

The 14-channel RPG-HATPRO microwave radiometer has been operating at the Faculty of Physics, St. Petersburg State University since 2012. It performs continuous measurements of the cloud liquid water path (LWP). Along with the multiple quadratic regression (MQR) method provided by the instrument manufacturer, the “physical” retrieval algorithm, which is based on the inversion of the radiative transfer equation (IRTE), and the multiple linear regression (MLR) method are used. The estimates of the LWP retrieval errors are presented for the cases when MLR coefficients are derived from model calculations and from the experimental data (in the latter case, the IRTE results are used as reference data). It is shown that the application of the experimental data and the utilization of measurements in 7 spectral channels of the radiometer provide the LWP random error of 0.015-0.017 kg/m² which is two times lower than in case of derivation of regression coefficients from model calculations. The bias does not exceed 0.005 kg/m² in this case. It is demonstrated that the MLR results provide a reliable identification of clear-sky conditions if the criterion of minimal LWP variations is applied.

The dependence of variations in the surface ozone concentration on the absolute air humidity is studied based on measurements at the TOR station in 1994-2017. The analysis performed revealed a neutral dependence at positive temperatures and unexpectedly strong and alternating sign variability at negative temperatures. The absolute air humidity negatively affects the ozone formation in the surface air layer, decreasing the ozone concentration at temperatures of 0…-30 °C. At very low temperatures (lower -30 °C) the effect becomes positive, i.e., the ozone concentration on increases with the absolute air humidity.

A statistical analysis of the ground concentration of sulfur dioxide (SO₂) was carried out based on the measuring network of observations data in the cities of Kazakhstan. The highest concentrations are observed in large industrial cities. In large cities, the range of changes in sulfur dioxide concentrations from 0.01 to 0.09 mg/m³. In Ust-Kamenogorsk the content of dioxide varies in the range from 0.058 to 0.259 mg/m³ with a downward trend. Sulfur dioxide content analysis in the atmospheric column over the territory of Kazakhstan using reanalysis system MERRA 2. The annual sulfur dioxide average content vary from one of 2.43 to 2.73 mg/m², in 2010 this value reached to 3.16 mg/m². There is a SO₂ content decrease tendency in the atmospheric column in Kazakhstan. The total sulfur dioxide content in the atmospheric column decreased by 38% during the period from 1980 to 2018.

In 2017, at the Large Solar Vacuum Telescope of the Institute of Solar-Terrestrial Physics of SB RAS, an element base was created for developing methods for recording and correcting distortions of optical radiation passed through a layer of turbulent atmosphere; a three-stage image correction system was installed; software was developed, which provides, the statistical analysis of the quality of the formed image in BSWT and combines the work of a wavefront sensor, an image quality analyzer, and an astronomical instrument - a filter-recorder.

Laboratory simulation of the conditions for the blue “jet” beginning in the Earth’s atmosphere has been carried out. For this purpose, the diffuse “jet” formation and plasma buildup in corona and apokampic discharges on air has been studied. It is shown that “jet” is formed due to streamer breakdown, and their color depends on pressure. At atmospheric air pressures of 30-120 Torr, streamers starting from different parts of a repetitively pulsed discharge are recorded in a non-uniform electric field. It has been established that, before the breakdown, between the pointed electrodes, a corona discharge of a spherical shape is formed near a metal high-voltage electrode of positive polarity, from which streamer coronas start with increasing voltage. Data on the dimensions of the streamer head and the streamer propagation speeds in the corona and apokampic discharges are presented.

Harmful potential of bulk bottom sediments (BS) of the Yenisei River was estimated with Allium test. Sediment samples were collected in ten sites at about 100-km stretch of the middle reaches of the Yenisei affected by urban activity of the city of Krasnoyarsk and industrial plants. The samples of sediments differed considerably in concentration of potentially toxic substances (heavy metals, artificial radionuclides and organic pollutants), nutrients and physical properties. Average length of root of onion was considered as indicator of general toxicity, mitotic index - as indicator of cytotoxicity, and percent of ana-telophase cells in the root apices carrying abnormal chromosomes - as indicator of genotoxicity. Both stimulation and inhibition of indicator endpoints was revealed on sediment samples of the Yenisei relatively to control (artificial sediments). Increased genotoxicity was recorded on the sediments sample, contaminated with mixture of organic and chemical toxins. Significant positive correlation of percent of abnormal cells and concentration of copper and petrochemicals in sediment samples was revealed. Extremely strong reactions of onion endpoints to the quality of BS were not revealed, probably due to relatively low level of contamination of the sediment samples. This is in agreement with the results of chemical analyses. Based on the results of the testing we can conclude that the endpoints of the Allium test a re sensitive enough to the quality of BS of the Yenisei River and can be used for their biotesting.

During the period of study it was discovered that the general distribution pattern of species, their structure and the amount of phytoplankton were different from those recorded earlier. The most changes have undergone in the central part of the northern coast of the Neva Bay. During the eutrophication of phytoplankton in summer (late July-early August) in the Neva Bay and in the eastern part of the Gulf of Finland different groups of algae may play a prevalent role. In the Neva Bay Chlorophyta predominated in the samples. In the resort zone of the Gulf of Finland, the main share of biomass in 2011-2015 was represented by cyanobacteria.

The accumulation processes of chemical elements as well as distribution between abiotic (water, bottom sediments) and biotic (seston, zooplankton, fish) components of the Lake Bolshoy Vud’yavr ecosystem polluted by apatite-nepheline mining sewage for a long period, are analyzed. The values of the biological accumulation of the elements and their enrichment of water and bottom sediments are determined. The biogenic and terrigenous contribution of the chemical elements to the composition of bottom sediments has been estimated.

The development of novel energetic materials with highest possible performance is of current interest. Synthesis of such materials is performed at various stages of pilot plant production all over the world. However, their synthesis involves hazardous production processes. This paper discusses relatively safe and eco-friendly approaches and techniques such as microwave technology and the use of ionic liquids for the synthesis of high-performance energetic materials that can be used as explosives and propellants. In addition, the use of dinitrogen pentoxide as an efficient nitrating agent for the synthesis of energetic materials is considered.

Flame propagation in a closed vessel containing a stoichiometric propane-air mixture and partially filled with a porous medium has been experimentally studied. It has been shown that the flammability limit in the porous medium is determined by the current pressure as the flame approaches it and by the transition process occurring as the wave enters the porous medium. The phenomenon of the dynamic limit - the flammability limit in a porous medium associated with a continuous pressure drop - has been investigated. It has been found that the range of initial pressures in which the dynamic limit is observed is determined not only by the change in the number of moles in the gas phase, as during flame propagation in vessels completely filled with a porous medium, but also by gas cooling in the free space. The initial pressure range in which the dynamic limit is possible can be significantly wider than that due to a change in the number of moles. This range is mainly determined by the heat exchange of the gas with the walls of the vessel in the region free from the porous medium.

This study presents the improvement and application of a 24-element chemical reactor network (CRN) model for predicting the emission of nitrogen oxides in a lean premixed gas turbine combustor. The 24-element CRN improvement is based on the results of CFD simulations. The emission of nitrogen oxides predicted by the 24-element CRN is in good agreement with the experimental data obtained at the Korea Electric Power Research Institute. The new CRN is able to handle complex chemical mechanisms. As there are few requirements for computation time, the CRN can be used as a tool for the analysis of combustion systems and can be integrated into gas turbine combustor designs.

Kerosene concentration distributions measured in the combustion chamber of a hotshot wind tunnel in the attached pipeline regime with the input Mach number of 2.89 are reported. Kerosene is injected through 12 jet injectors at an angle to the flow from the wall upstream of a cavity. The measurements are performed in three cross sections. Data on the kerosene concentration distribution in the initial region of the combustion chamber and its dependence on the ratio of the jet and main flow momenta are obtained. It is demonstrated that the absence of intense combustion in a model combustor under these conditions is caused by the fact that the local equivalence ratios are insufficient for ignition.

The purpose of the study was to search high-informative genetic criteria of the personalized forecast at presence of the earliest feebly marked of clinical attributes of organum visus pathology development. Material and methods. The results of immunogenotypic survey of 403 persons, among which 102 patients with age-related macular degeneration (AMD) and 90 patients with diabetic retinopathy (DR), 211 patients of similar gender and age as control groups of comparison are submitted. The analysis of regulation locus polymorphism TNFA (rs361525, rs1800629 and rs1800630) , IL1B (rs1143627), IL4 (rs2243250), IL6 (rs1800795), IL10 (rs1800872 , rs1800872) genes , vascular endothelial growth factor gene VEGF (rs3025039 , rs699947), matrix metalloproteinases genes MMP (rs2438650, rs3025058, rs3918242) in this groups has been carried out. Results and discussion. Two groups of parameters have been shown through comparison of combined genetic attributes frequencies in comparable groups with/or absence AMD. One of these groups is distributed with primary frequency among patients with AMD whereas another is distributed only among elderly with absence of clinical and tool attributes of disease. On the contrary the significant prevalence of the attributes positively associated with the pathology development over negatively associated attributes has been revealed among DR. The revealed genetic attributes specify mainly inflammatory character of DR, as against AMD in which prevail degenerate and sclerogenic processes. Conclusion. Thus, the results of received genetic researches show an opportunity to personify predisposition of the significant part of elderly patients to development of ophthalmo-pathology microangiopathy or degenerate genesis with the purpose of realization of purposeful preventive actions.

Limbal epithelial stem cells are localized in the limb, which determine the regeneration of the corneal epithelium, both physiological and reparative. The aim of the study is to characterize the culture of cells isolated by different methods. Materials and methods. Limbal stem cells were isolated from the limbus region of enucleated human eyes. Cell isolation was produced by the enzymatic and explantation methods. Cell cultivation was performed on the amniotic membrane and without it, in DMEM/F12 growth media (Dullbecco’s Modified Eagle Medium/Nutrient F12 Ham) and CECBM (Corneal Epithelial Cell Basal Medium). The morphological assessment and immunophenotyping of cell cultures were performed. Results and its discussion. The obtained culture was distinguished by cell heterogeneity at the enzymatic method of isolating cells from the limbus. The presence of fibroblast-like cells was revealed in the suspension of non-adherent cells, which resembled stromal cells in appearance and growth pattern. Immunophenotyping revealed that most cells carry markers of multipotent mesenchymal stromal cells (CD90⁺/CD73⁺/CD105⁺/CD34^-/CD45^-) and a small number - markers of epithelial cells (p63α⁺, ABCG₂⁺, CK19⁺). Explant culture was more uniform. The cells had a rounded, epithelial-like shape, adhered well to the surface of the amniotic membrane and grew on it. The results of phenotyping indicated that cells are represented mainly by epithelial cells (p63α⁺, ABCG₂⁺, CK19⁺). Conclusion. The culture is represented mainly by MMSC at the enzymatic method of isolating cells from the limbal graft and cultivating them without feeder in the growth medium DMEM/F12. Isolation of limb cells by the explantation method and their cultivation in the selective medium CECBM allow us to obtain mainly the culture of epithelial stem cells.

The aim of this work was a comparative study of the ultrastructural organization of lymphatic structures in the choroid and conjunctiva of the human eye. Material and methods. Samples of the choroid and conjunctiva of the human eye, obtained perioperatively, were studied by immunohistochemical analysis using specific antibodies to endothelial cells markers of blood and lymphatic vessels, and electron microscopic studies, morphometric processing and statistical analysis of the results were performed. Results and discussion. Within simultaneous immunohistochemical staining of conjunctiva and choroid samples using antibodies to markers of lymphatic vessels (LYVE-1, Prox1, podoplanin) the positively stained typical lymphatic vessels have been revealed in the conjunctiva structure and positively stained channels with narrow elongated cells, fibroblasts and pigment cells in choriocapillar layer of the choroid and the transition zone between choroid and sclera. Electron microscopic study revealed that cells expressing lymphatic markers and forming lymphatic channels in the choroid have an ultrastructural organization that is differ from typical lymphatic vascular endothelial cells: they do not have stropic filaments, contain a greater volume density of the granular endoplasmic reticulum membranes, and a lower volume density of mitochondria and micropinocytotic vesicles. The data obtained indicate that the lymphatic pathways of the intraocular fluid outflow in the human eye choroid have organ-specific structural features.

Review highlights modern findings on molecular mechanisms of dysfunction of human corneal endothelial cells causes decline of vision. When water enters the corneal stroma, it disorganizes the regular arrangement of the collagen fibrils, which reduces corneal transparency. Corneal endothelial cells are responsible for keeping the dehydration state of the stroma by pumping out fluid. However, this layer of cells can become deficient, for example following intra-corneal surgery or because of a pathology. Corneal transplantation is currently the only treatment in order to restore vision following endothelial dysfunctions. The authors survey methodological problems and prospects for correction of endothelial cells dysfunction. Human endothelial cells do not proliferate in vivo because these cells arrest in the G1 phase of the cell cycle. Modern research showed that corneal endothelium cells could proliferate in special conditions. An alternative approach is to use human stem cells as an endothelial cells source. New methods and improved technique of storage and preservation of corneal grafts, palliative methods of surgical treatment aimed at reducing the hydration of the surface layers of the cornea are considered. The review includes consideration of works for endothelial tissue engineering using cell culture technologies. Endothelial keratoplasty limited by the technical difficulty of the procedure, a shortage of available grafts, and the potential for graft failure or rejection. These limitations are driving researchers to develop new approaches, such as methods of organ culture

Cataract surgery in eyes with glaucoma requires the most gentle manipulation during the operation including capsulorhexis and phacofragmentation. Femtolaser assistance at various stages of cataract phacoemulsification is aimed at minimizing surgical trauma. Aim of the sudy was to analyze the postoperative reactions after phacoemulsification and femtolaser-assisted phacoemulsification (FLACS) of the cataract in eyes with pseudoexfoliating glaucoma. Material and methods. Two groups of patients (30 eyes) were operated and examined (I-phacoemulsification, II-femtolaser-assisted phacoemulsification). In all cases phacodonesis was found. Results. Noted that phacoemulsification without the use of the femtolaser assistance demanded a longer intervention with large expenditure of energy ( p < 0.05). On the first day after surgery in the first group (phacoemulsification), 9 cases (66.7 %) of corneal reaction were detected. In the second group, there were 5 cases (33.3 %) of a corneal postoperative reaction that was stopped during the day. Conclusion. It has been shown that femtolaser assistance in cases of cataract associated with glaucoma and pseudoexfoliative syndrome reduced operation time, amount of ultrasonic energy expended, number of postoperative corneal reactions.

Purpose of the study was to investigate the effectiveness of selective laser trabeculoplasty (SLT) in various forms of glaucoma, in the initial, advanced and far-advanced stages of the disease. Material and methods. An analysis of the effectiveness of the treatment of 132 eyes (132 patients), who were examined and treated in the department of glaucoma diagnostics and treatment of Ekaterinburg Center of Eye Microsurgery Federal State Institution, has been performed from 2016 to 2018. The study included a group of patients with primary open-angle, pseudoexfoliation, pigment, and combined forms of glaucoma previously not operated. Laser iridotomy was previously performed in patients with pigmented and combined glaucoma. The efficacy of SLT was assessed by the level of intraocular pressure (IOP) before SLT, after three days, 1, 6 and 12 months, using the perimetric MD index and according to the need for repeated surgical interventions during the observation period. Results. By the end of the observation period after SLT in patients with initial glaucoma IOP decreased by 5.1 mm Hg (by 20.7 %), with advanced glaucoma - by 6.3 mm Hg (by 25.7 %), with far-advanced glaucoma - by 6.8 mm Hg (by 31 %) compared to baseline values. Analysis of SLT effectiveness depending on the form of the disease showed that 12 months after surgery IOP in patients with primary open-angle glaucoma decreased by 5.5 ± 1.32 mm Hg (23 %) compared with baseline figures, and in patients with combined glaucoma - by 5.5 ± 1, 5 mm Hg (22.8 %). In the follow-up period from 6 to 12 months after SLT, 88 % of patients with pseudoexfoliation glaucoma, 64 % of patients with pigmentary glaucoma and 34 % of patients with combined glaucoma underwent non-penetrating deep sclerectomy, 15 % of patients with primary open-angle glaucoma underwent repeated SLT. Conclusion. SLT is the safe and effective method of glaucoma treating. In all forms and stages of glaucoma, target IOP was obtained, as evidenced by stabilization of retinal sensitivity by automated perimetry, but the hypotensive effect after SLT in patients with pseudoexfoliation glaucoma and pigmentary glaucoma lasted less than 1 year.

Purpose of the study was to assess changes in the peripapillary retina and in patients with glaucoma associated with myopia and uncomplicated myopia by spectral domain optical coherence tomography. Material and methods. We examined 26 patients (26 eyes) with a clinically advanced of primary open-angle glaucoma on eyes with high myopia and 30 people (30 eyes) with uncomplicated myopia. Spectral domain optical coherence tomography was included in the examination. Results and discussion. A reduction in the rim area in patients with glaucoma combined with myopia, compared with patients with uncomplicated myopia ( M ± SD , respectively, 1.03 ± 0.36 and 1.60 ± 0.42 mm², p < 0.05) develops against the background of thinning of the choroid, mainly in the lower one (131.36 ± 41.98 and 226,5 ± 98.13 mm, respectively; p = 0.01) and nasal (57.63 ± 9.81 and 216 ± 122.4 mm, respectively; p = 0.0006) segments and is accompanied by an increase in the area of the peripapillary atrophy (1.94 ± 0,5 and 1.05 ± 0.15 mm, respectively; p = 0.005), which indicates the inconsistency of trophic and metabolic processes. In patients with myopia in peripapillary atrophy zone, a gamma zone was identified, in which sclera and RNFL were visualized. The Bruch’s border membrane, retinal pigment epithelium, photoreceptors, and choroid coincided. In myopia combined with glaucoma, along with the gamma zone, the beta zone was visualized, which is characterized by degenerative changes in RPE and photoreceptors against the background of choriocapillary obliteration. Conclusion. Choroidal changes and the presence of beta zone are differential diagnostic criteria for glaucoma associated with myopia and can be used for diagnosis of glaucoma in combination with myopia.

Purpose of the study was to evaluate the impact of «tight fixation» of a scleral flap with the subsequent performance of the laser suture lysis on the morphogenesis of established outflow pathways and hypotensive efficacy of trabeculectomy. Material and methods. This is a retrospective study. Seventy eyes of patients underwent trabeculectomy and LSL 1-1.5 months after it were under observation for 24 months. Comparison groups are determined by the presence of inadequate reparative regeneration syndrome. Technical nuances of trabeculectomy («tight» closure of the scleral flap) were evaluated using optical coherence tomography. The effect of LSL on the remodeling of outflow pathways was evaluated by ultrasound biomicroscopy. In the first group ( n = 22) LSL was as a mechanical adjuvant treatment, in the second ( n = 48) - as an adjuvant option. Ophthalmic tonus was evaluated by Maklakov (Pt) in mm Hg. The indices were estimated using Sstudent’s t-test, p < 0.05 was considered statistically significant. Results and discussion. The «tight» fixation of the scleral flap minimized early postoperative complications and did not detect Pt difference in the groups. LSL led to an increase in the height of the intrascleral channel and scan height in both groups ( p < 0.01). After 24 months, complete hypotensive success was 95.5 % in the 1st and 81.25 % in the 2^nd group, qualified - 4.5 and 18.75 %, respectively ( p < 0.01). Despite the difference in IOP achieved: 15.3 ± 1.9 mm Hg. after 12 months, 15.1 ± 1.2 mm Hg. after 24 months in in group 2 ( p < 0.01), more postoperative interventions in group 2 ( p < 0.01), the results of complete and qualified success in the second group were high. Conclusion. The introduction of LSL in clinical practice can improve the effectiveness of glaucomatous fistulizing operations. The use of the technique of «tight» fixation of the scleral flap and the planned implementation of LSL are an example of multimodal approaches to minimize the number of early postoperative complications and increase the hypotensive efficiency of trabeculectomy.

The aim of the study is to assess the practical significance of the use of the digital marking device «VERION™ Image Guided System» in the technology of intrastromal keratoplasty using a femtosecond laser. Material and methods. According to the developed method, 35 eyes of 27 patients with a diagnosis of keratoconus of the 2nd degree were operated. The median age was 26 years. Formation of intrastromal tunnels was performed using «Femto LDV Z8» femtosecond laser («Ziemer», Switzerland), the laser was centered in strict accordance with the markings obtained by the digital marking device «VERION™ Image Guided System» («Alcon», USA). During the implantation of the segment, this device was also used for its precise positioning in the tunnel. Setting the projection of the required axis, the surgeon intraoperatively to visualize the label that corresponds to the exact position of the end of the segment in the intrastromal tunnel, and carried out precise positioning of the intrastromal segments. Results. When performing operations using the indicated method, it was revealed that the patient’s eye at the aplanation stage of a femtosecond laser has a tendency to rotate and decentralize. Minor decentralizations relative to the pupil center were corrected by the displacement of the intrastromal tunnel pattern in the laser working program along the x-axis by 0.1 ± 0.05 mm, along the y-axis by 0.1 ± 0.04 mm. In patients in the postoperative period there was an increase in uncorrected and corrected visual acuity. By 3 months after the operation, functional parameters and keratometric data stabilized: visual acuity without correction and with maximum correction increased to 0.5 ± 0.16 and 0.7 ± 0.12, respectively, keratometry of flat and steep axis declined to 44.3 ± 1.4 and 50,8 ± 3,2 diopters, respectively. Conclusions. It was found that the applanation of the femtosecond laser aperture on the surface of the conical cornea leads to the rotation of the eye by an average of 9°. The use of femtosecond laser for forming the intrastromal tunnels in the conduct intrastromal keratoplasty requires mandatory marking of the cornea meridian the corresponding to the axis of the cutout for laser centration. Methodology of Verion-assisted femtosecond laser intrastromal keratoplasty allows to position the segments with high precision in accordance with a preoperative calculation that provides high clinical and functional results.

The aim of the study is to evaluate the effectiveness of retinal laser photocoagulation (RLC) in retinopathy of prematurity (RP) using fluorescent angiography (FAG), to identify angiographic signs of regression and progression of the disease, the features of the formation of vessels in the previously avascular retina, depending on the RP stage and the method of treatment used. Material and methods. The study included 58 preterm infants (116 eyes) with different stages of active ROP, requiring RLC. Gestational age of children ranged from 24 to 31 weeks (average 28.1 weeks), birth weight - from 680 to 1800 g (average 1100 g). All infants underwent digital retinoscopy with FAG on a retinal pediatric digital video system «RetCam-3» («Clarity Medical Systems Inc.», USA) with a built-in angiographic unit. In 94 cases, LC was performed in the pattern mode on the laser ophthalmic system «PASCAL Photocoagulator» («OptiMedica», USA) using the developed technology of early dosed coagulation optimized for energy parameters. In 12 cases, LC was performed in a single pulse mode on a laser ophthalmic device «Visulas 532s», laser type Nd:YLF («Carl Zeiss Meditec AG», Germany). In 10 cases, the RLC was conducted in the perinatal centre of the extremely premature children non-transportable diode laser «Iridex IQ 810» («IRIDEX», USA) using head ophthalmoscope. Results. The technique of dosed pattern RLC was the most optimal from the point of view of efficiency and safety for a premature baby, which was confirmed by the angiographic data obtained, indicating an active vascular germination in the coagulation zone. Angiographic picture of the regression of RP after the RLC in single pulse was not significantly different from the pattern LC. However, taking into consideration the pattern technology advantages, the single pulse technology should be used only in case of high-tech equipment absence. Postoperative angiographic monitoring after LC using a forehead ophthalmoscope showed the imperfection of this technology, which is manifested by characteristic angiographic signs, such as chaotic growth of blood vessels in the LC area. Conclusion. FAG opens wide possibilities both in the early assessment of the efficacy of LC and in the detailed assessment of the long-term results of treatment depending on the RP stage and the used LC method. The use of the results of FAG studies will contribute to the improvement of laser technologies and improve the quality of RP treatment.

Purpose of the study was to analyze and compare the outcomes of implantation of polymer micro shunt «Reper-NN» manufactured in Russia and «Ex-PRESS» shunt in surgical treatment of open-angle glaucoma. Material and methods. The results of treating 74 patients with open-angle glaucoma were analyzed. All patients were divided into 2 groups: group I consisted of 48 patients underwent micro shunt «Ex-PRESS» implantation, group II with 26 patients underwent Russian polymer micro shunt implantation. The control criteria in the early and remote postoperative period were: Maklakov tonometry, visual acuity, computer perimetry. Results and discussion. The significant reduction in intraocular pressure compared with the preoperative level has been achieved in the early and remote period as a result of implanting both shunts. The implantation simplicity and design features of polymer micro shunt «Reper-NN» provided with the relatively similar to «Ex-PRESS» shunt risks of complications such as postoperative hypotonia and ciliochoroidal detachment. Thus, the first experience of using Russian manufactured polymer shunt showed the sufficient efficacy and safety in primary open-angle glaucoma surgery and allowed recommending its further application in clinical practice.

The purpose of study is to assess the clinical significance of microalbuminuria (MAU) in pregnant women with preeclampsia in formation of vascular eye pathology in long-term postpartum period. Material and methods. In retrospect, according to medical records, analysis of somatic condition of 114 women who had preeclampsia during pregnancy was carried out, and presence / absence of MAU during pregnancy were determined. MAU was detected in the 3rd trimester of pregnancy using test strips «Woerhringer Ingelheim» (Austria), considering the test to be positive with a value of 30 mg/day and more. The age of women at time of research was from 24 to 52 years, the period after suffering preeclampsia was 12.5 ± 6.5 years. Two groups were formed: the main - 35 women with initial MAU during pregnancy; the comparison - 79 women who had no MAU during pregnancy. The controls were 36 women with physiological pregnancy and delivery. Results and discussion. In period after delivery, vascular diseases of posterior eye segment occurred in 14 people in the main group (40 %) and 15 people in the comparison group (19 %). In the control group in this period, vascular pathology of posterior eye segment was formed in 2 women. Conclusion. Statistically significant increase of frequency of formation of vascular pathology of posterior eye segment in postpartum period was revealed in women, who had pregnancy complicated by preeclampsia and MAU in the 3rd trimester, which increased through 10 and more years after delivery. The initial presence of MAU during pregnancy can be the marker of increased risk of formation of vascular pathology of posterior eye segment at different periods of the postpartum period.

Analysis of the features of surgical treatment of brown cataracts in the eyes with previously performed posterior vitrectomy. The study included 25 patients (25 eyes) with nuclear cataracts 6+ density according to LOCS III classification. All patients underwent microinvasive posterior vitrectomy more than 6 months ago. Microcoaxial (2.2 mm) phacoemulsification of cataract with implantation of flexible intraocular lens was planned for all patients. In 15 patients (60 %), a system of capsule hooks was used in order to support the capsule bag 4 in 16 % of cases and 6 in 44 % of cases. Results and discussion. Sutureless surgery were performed in 24 patients (96 %). In one case with nigra cataract despite the use of capsule hooks, due to the high risk of dislocation of the lens into the vitreous cavity, the surgery was converted into a large incision. Microcoaxial phacoemulsification is the surgery of choice in the case of a combination of dense lens and lack of vitreous support. The use of capsular hooks greatly simplifies surgery and increases the chances of sutureless surgery.

The method of bicanalicular silicone intubation of tear ducts is widely used as a stage of external and endonasal dacryocystorhinostomy, as well as during recanalization of the tear duct. The introduction of a silicone stent is the most common way to prevent rhinostoma closure. Its purpose is to maintain the permeability of the tubules or anastomoses during the healing period and can improve the results of surgical treatment if used correctly. Typically, pre-packaged kits consisting of silicone tubes attached to metal probes are used for the drainage implantation procedure. The disadvantages of using such kits are their high cost, insufficient length of metal probes when using them after dacryocystorhinostomy, and invasiveness of the procedure in the absence of visual inspection. The aim of our work was to develop a new method of silicone intubation of tear ducts, devoid of the described shortcomings. Material and methods. Silicone tubes 200 mm long were used as the lacrimal intubation kit. A line was antegradely conducted along the probe, which was then removed from the nasal cavity with a hook by endoscopic control. The procedure was repeated with the paired tear duct. Then the silicone tube was tied by both ends of the fishing line and passed to the free ends of it from the nose into the nasal cavity, where they were riveted and clipped. Results and discussion. In all cases, the drainage was performed as described. As in the case of other modifications of the drainage, holding the tube into the tear-nasal canal required more effort and more skill as compared to draining of the formed anastomosis. In all cases, the effectiveness of the method of holding the tube in the lacrimal duct depended on the severity of the obstruction. Conclusions. The method developed by us for carrying out a silicone tube into the lacrimal duct is effective, simple and does not require the use of complex technologies for the manufacture of an intubation kit.

The purpose of our study was to analyze the effectiveness of the use of Fresnel prisms for various disorders of the eye movement. Material and methods. The studied group included 40 patients with prismatic correction and was divided into 2 groups of patients depending on the type of strabismus: 25 patients with incomitant strabismus, 15 patients with comitant strabismus. Elastic Fresnel prisms (EFP) were chosen and prescribed for prismatic correction. The patients were under dynamic monitoring under conditions of continuous use of EFP and positional trainings were performed if necessary (when doubling wasn’t completely compensated by EFP). The study had a prospective character. Results and its discussion. The prismatic correction made it possible to eliminate diplopia in direct gaze position and peripheral gaze directions in all 25 patients with paretic strabismus. In 18 out of 20 cases, the prismatic correction allowed to achieve functional recovery without subsequent chemorecession or surgical treatment. In 8 patients with comitant strabismus after the first stage of surgical treatment with stable deviation, binocular vision was formed under natural conditions. In 1 year, dynamic prismatic correction contributed to the recovery of 7 patients without surgical treatment with orthophoria in vivo. Conclusion. Prismatic correction of diplopia as an independent or additional functional method of treatment contributes to the achievement of the comitance of the eye muscles.

The discussion about the safety and efficiency of the posterior capsulorhexis is still ongoing. Optical coherence tomography (OCT) can help us to study the process of capsule barrier recovering and condition of the anterior hyaloid membrane after primary posterior capsulorhexis. Aim of the study was to investigate the features of the vitreolenticular interface (VLI) after lens surgery with the primary posterior capsulorhexis. Material and methods. VLI OCT (RTVue, «Optovue», USA) was performed in 101 patients (123 eyes) after phacoemulsification with primary posterior capsulorexis. The postoperative period ranged from 1 day to 9 years. Results. We revealed a large variability of the VLI. This was due to the degree of the involutional changes in the involved structures. In the early postoperative period we observed the different variants of the relationships between the posterior capsule and the intraocular lens (IOL): from almost contact to subtotal inadhesion with a movable margin of the capsulorhexis. However, in all cases we noted the contact between posterior capsule and IOL along the optical edge of the latter. In the following days the adhesion between the lens optics and the posterior capsule progressed from the periphery to the center. The term needed for complete adhesion was 1-8 days. Three main types of VLI have been identified in the late postoperative period. Conclusion. The involutional changes of structures determine the features of the VLI in the early and late postoperative period. The contact between posterior capsule and IOL along the lens optics edge was detected from the first day, full adhesion was noted 1-8 days after surgery.

Retinal vein occlusion is the one of the most common diseases, which amounts to 60 % of all acute vascular ocular pathology, and takes second place in the severity of retinal lesions and prognosis after diabetic retinopathy. It causes the visual disability in 15 % of cases. The main reason for the decrease vision in patients with occlusion of the central retinal vein and its branches is the development of macular edema, the degree of intensity of which depends mainly on the level and severity of the retinal vascular bed lesion. The article provides a review on the current aspects of retinal vein occlusion etiology and pathogenesis, and novel methods of diagnostics. The implementation into practice of highly precise non-invasive diagnostic method - optical coherence tomography angiography was a significant progress in clinical and diagnostic studies of macular edema as a result of retinal vein occlusions. The necessity of multimodal approach to management of patients with retinal vein occlusion for improvement of the treatment clinical and functional results is emphasized. The modern techniques for the treatment of retinal vein occlusion, their advantages and disadvantages are described; data on the anatomical and functional results of the use of these techniques are given. Actual approaches to treatment are divided into laser and pharmacological methods. The prospects of further improvement and development of combined treatment for retinal vein occlusion are considered.

The review contains an analysis of the medical use of interferons - a group of signaling protein molecules that have antiviral, antitumor, and immunomodulatory activity - in ophthalmic practice. Interferons have a wide spectrum of action, including antiviral, immunomodulatory, antitumor and other types of activity. This provides a great potential for interferon use in ophthalmology, both in combination and as a first-line therapy for conjunctival papillomatosis, squamous cell neoplasia, conjunctival melanoma, keratitis caused by the herpes simplex virus, uveitis, geographical choriopathy, cystic and diabetic macular edemas, etc. There are considered mechanism of action, dosing regimens, side effects of using interferons and such their solutions as use of newly discovered interferon lambda and interferon pegylation. In contrast to the ubiquitous expression of the IFN-α receptor, IFN-λ receptor is determined mainly in the epithelial cells of the mucous membranes and skin keratinocytes, which provides a more targeted effect of the drugs. Modifying the properties of biologically active substances by combining them with low molecular weight carriers, for example, polyethylene glycol molecules (PEG), leads to a decrease in the therapeutic dose of the drug and an increase in the selectivity of its action due to changes in pharmacokinetic and pharmacodynamic parameters.

The purpose of the study is to increase the efficiency of delivering high-tech eye care to the infants of Orenburg and the Orenburg region. Material and methods. An algorithm has been developed to deliver specialized care for retinopathy of prematurity. Recently purchased «RetCam3» pediatric retinal camera made it possible to conduct dynamic screening and monitoring of preterm infants who were prematurely born at risk of retinopathy. The examination was prescribed to children at risk (gestation age up to 35 weeks, birth weight up to 2500 g). The time frame for fundoscopy varied from 3 to 7 weeks after birth depending on the infant physical condition. The number of examinations at 3th-4th weeks of life was 63 %, at 5th-6th weeks - 29 %, at 6th-7th weeks - 8 %. Screening examinations were carried out in the perinatal centre with intervals, depending on the stage of retinopathy of prematurity: preretinopathy, stage I and II from 1 to 2 weeks, III and more severe stages from several days to a week. 60 initial examinations were performed in 6 months, laser treatment was provided for 13 patients (21.7 %). Results and discussion. For 6 months, 60 initial examinations were performed; laser treatment was performed in 13 patients (21.7 %). We observed positive changes for all the infants after laser treatment, which proves high efficiency of the developed algorithm of treatment premature infants with retinopathy, which is the prevention of blindness and low vision from infancy. Repeated monitoring after laser coagulation was carried out after 2, 4 and 8 weeks. Conclusions. Thus, screening contributes to the identification of this pathology at an early stage, dynamic monitoring of the fundus changes is carried out using retinal camera, which contributes to timely laser treatment. The developed algorithm improves the quality of specialty care for premature infants at risk of developing retinopathy of prematurity, and, accordingly, improves the quality of their life.

The aim of the study was to conduct a directed analytical review of the legislative, regulatory and legal framework (RLF), of the special literature on the normative and legal regulation (NLR) and the provision of medical and organizational activities (MOA) of the sectoral and regional ophthalmological service (OphS), the medical establishment (ME) of the health system of Russia (HS). Material and methods. The federal legislative, RLF has been studied on the official websites of the government, the Ministry of Health (MH) of the Russian Federation ((RF), and the health administration authorities (HAA) of the federal subjects of RF, including subordinate regulatory and legal acts. An analytical review of the relevant periodical literature on NLR and the provision of MOA of the sectoral and regional OphS, ME industry has been carried out. Bibliographic, informational and analytical methods, expert assessment method, content analysis were used. Results and discussion. A modern RLF for the provision of MOA of the sectoral and regional OphS, MO of HS is represented by more 100 current documents - orders, decrees and directions, guidelines of MH RF and HAA of the subjects of RF, several hundreds of applications. It was established that the primary regulatory and legal basis for the activities of OphS is considered «Procedures for providing medical care (MC) to the population in case of diseases of the eye, its adnexa, and orbit for adults and children»; Requirements and guidelines for the organization and maintenance of MOA of MO branch (orders of MH of RF N 132н/27.02.2016, N 358/08.06.2016, N 182/20.04.2018). Standards for the provision of MC and clinical recommendations - auxiliary. Conclusion. Analysis of RLF support of OphS MOA in the current three-level HS, since 2012-2014 till present, has shown that the legislative and RLF on NLR and the provision of MOA of OphS the industry as a whole has been created. The main established shortcomings are the lack of a unified conceptual approach and compulsory RLF and medical-organizational mechanism for ensuring and final implementation, as declared by the regulations, in particular, resource support of the activities of regional OphS.

The purpose of the study was to evaluate the efficacy of quality indicators in the system of internal control and management of ophthalmic activities at S. Fyodorov Eye Microsurgery Federal State Institution (Institution). Material and methods. The values of quality indicators were determined and compared in dynamics over the last 5 years of the Institution (indicators of structure, indicators of technological processes, and indicators of results). The actual values of the indicators are calculated using statistical data of accounting principles on the structure, medical processes and results achieved. Target values were established on clinical recommendations results of best practices, based on the introduction of modern technologies in medicine. Results. Analysis of changes in the indicators of structure reflects a positive dynamics of realization of the potential of the Institution medical-industrial activity (over a 5 years period reduced staff turnover, increased the number of doctors and medical sisters having certification category). Indicators of medical technological processes demonstrate the stable increase of the technological level of the Institution (the proportion of implantation of toric multifocal intraocular lenses, microinvasive endovitreal interventions 25-27 G, femtosecond stages of corneal and cataract surgery were introduced). After the comparative analysis of target and actual indicators of the result, the dynamics of indicators over 5 years was evaluated and showed their growth. Conclusion. The effectiveness of quality control and safety of medical assistance in the Institution with the use of dynamic assessment system and analysis of indicators has been proven by the increase in the quantitative-qualitative indicators of health activity for the last 5 years.