[Influence of corneal curvature and peripheral thickness on tonometry readings]. / Vliyanie krivizny i perifericheskoi tolshchiny rogovitsy na rezul'tat tonometrii.

PURPOSE: This study investigates the influence of peripheral corneal thickness (PCT) and its curvature on tonometry readings. MATERIAL AND METHODS: The study included 49 patients (49 eyes) who were indicated for glaucoma surgery. Using bidirectional applanation tonometry, the following parameters were obtained: IOPcc, IOPg - intraocular pressure (IOP) corrected for corneal compensation, taken as the most reliable indicator; IOP converted to Goldmann measurement, taken as the result of applanation tonometry, ΔIOP (IOPcc-IOPg), CH and CRF (corneal hysteresis and corneal resistance factor). During corneal topography, the corneal thickness was studied in the center, PCT at 1.5; 2, 3, 4 and 5 mm from the center in four meridians, as well as ΔPCT (PCT 3 mm - PCT 1.5 mm), the curvature of the anterior and posterior surfaces of the cornea and the depth of the anterior chamber. Aberrometry was used to obtain refractometry data and the curvature of the anterior surface of the cornea. The influence of the studied parameters on ΔIOP was evaluated. RESULTS: ΔIOP correlated with CRF (r= -0.652), CH (r= -0.873), central corneal thickness (r= -0.293), PCT at all distances except 5 mm (r= -0.297; -0.287; -0.302; -0.303), with the strong and weak meridians of the anterior surface of the cornea (r=0.328; r=0.315), with the strong and weak meridians of the posterior surface, as well as the average curvature of the posterior surface (r=0.307; r=0.332; r=0.328). After step-by-step selection of the above parameters for creating a linear regression model for ΔIOP calculation, CH, CRF and PCT1.5mm remained in the model. The model describes ΔIOP with high accuracy (R2=0.974). CONCLUSION: Biomechanical parameters of the cornea are the leading factor of applanation tonometry error. Individual linear dimensions of the cornea (thickness, curvature) have a lesser effect.

[Effect of refractive surgery on Maklakov tonometry results]. / Vliyanie keratorefraktsionnoi khirurgii na rezul'taty tonometrii po Maklakovu.

PURPOSE: The study investigates the influence of changes in keratometric parameters after refractive surgery on the results of Maklakov tonometry. MATERIAL AND METHODS: The study examined a total of 61 people (121 eyes). The patients were divided into a control group with no history of surgery (16 people, 31 eyes), a LASIK group (13 people, 26 eyes), a femtosecond-assisted LASIK (FS-LASIK) group (16 people, 32 eyes), and a photorefractive keratectomy (PRK) group (16 people, 32 eyes). The patients underwent standard examination, keratometry (Km), Maklakov tonometry with a 10 g weight, and elastotonometry with 5, 7.5, and 15 g weights. RESULTS: In the LASIK group, the indentation diameter with 5 and 7.5 g weights correlated with Km in the central and near-paracentral zone (r=0.3-0.5). Tonometry with a 10 g weight did not correlate with anything. Tonometry with a 15 g weight inversely correlated with Km in the paracentral points (4 mm) of the strong meridian (r= -0.5 ... -0.7). In the FS-LASIK group, a significant inverse correlation with Km was observed only for the indentation diameter with a 10 g weight in the paracentral (3-4 mm) zone (r= -0.4 ... -0.5). In the PRK group, weak (r<0.4) correlations were found between Km and the indentation diameter of the 7.5 and 10 g weights for the central zone (1-2 mm). No significant correlations were found for 5 and 15 g weights.In the control group, there were practically no correlations for 5 and 7.5 g weights. The indentation diameter of the 10 g weight evenly correlated with Km at all points (r= -0.38 ... -0.60), the indentation of the 15 g weight correlated mainly with the curvature of the horizontal meridian (r= -0.37 ... -0.49). CONCLUSION: Tonometry readings with the 10 g weight are the most dependent on Km in different groups, and the readings with the 5 g weight are the least dependent. LASIK is characterized by the largest scatter of dependencies for weights of different masses, FS-LASIK - by the smallest. Tonometry readings with the 5 g weight correlated with Km only in the LASIK group, and this was the only direct correlation. Considering the inverse nature of most correlations, higher Km may be associated with an overestimation of tonometry results, and lower Km - with its underestimation.

[Role of point-by-point light sensitivity in the assessment of glaucoma progression]. / Rol' potochechnoi svetochuvstvitel'nosti v otsenke progressirovaniya glaukomy.

PURPOSE: This study analyzes changes in light sensitivity in each test point of the visual field in patients with different stages of glaucoma. MATERIAL AND METHODS: The data of a prospective analytical case-control study were analyzed. All patients underwent assessment of retinal light sensitivity and its variability in 54 points corresponding to the 24-2 program. Mean light sensitivity values were calculated in each point. Intergroup analysis was performed to evaluate changes in light sensitivity in each point. RESULTS: The range of light sensitivity decrease in the early glaucoma group compared to the control group was from 1.5 to 3.6 dB. The range of light sensitivity decrease in the moderate glaucoma group compared to the control group was from 2.1 to 11.5 dB, and compared to the early glaucoma group - from -0.9 to 7.9 dB. The most frequent decrease in light sensitivity was detected in the nasal sector and along the horizontal line in the upper half of the visual field. This trend persisted within the central 10 degrees of the visual field. The range of light sensitivity decrease in the advanced glaucoma group compared to the control group was from 14.1 to 28.0 dB, and compared to the early glaucoma group - from 11.35 to 26.08 dB, compared to the moderate glaucoma group - from 9.1 to 23.5 dB. The most frequent and severe decrease in light sensitivity was detected in the paracentral zone in the lower half of the visual field. CONCLUSION: The study analyzed the trends in the development of glaucoma from the early to the advanced stage. The most frequent and severe defect in light sensitivity in cases of verified advanced glaucoma was found in the lower half of the visual field. Points No. 32, 33 and 40 can be indicated as the area of interest in assessing the progression of glaucoma, as they were found to have the most profound changes in light sensitivity as glaucoma progressed.

[Thresholds and variability of retinal light sensitivity in each point of the examined visual field]. / Porogovye znacheniya i variabel'nost' svetochuvstvitel'nosti setchatki v kazhdoi tochke issleduemogo polya zreniya.

PURPOSE: This study assesses the light sensitivity and its variability in each point of the visual field in patients without glaucoma and with different stages of glaucoma. MATERIAL AND METHODS: The data of a prospective analytical case-control study involving 500 patients were analyzed. The initial examination of all patients was performed using basic ophthalmological methods, including static perimetry. Retinal light sensitivity and its variability were assessed in 54 points corresponding to the Humphrey 24-2 program. Mean deviation and pattern standard deviation of light sensitivity were calculated for each point. RESULTS: The lowest light sensitivity values in patients with moderate glaucoma were found in the periphery of the nasal sector, at point No. 27 - 14.4 dB, and at points No. 24-26 along the horizontal axis from the nasal side - from 17.7 to 22.7 dB. The maximum variability of light sensitivity was found in the nasal sector on both sides of the horizontal line - from 10.7 to 11.5 dB. The average light sensitivity above the horizontal axis in patients with advanced glaucoma was 10.8 dB, which is 2 dB higher than in the lower half of the visual field - 8.8 dB. The highest light sensitivity values were found at points No. 24 - 17.7 dB and No. 31 - 16.78 dB, the lowest - at point No. 32 - 4.5 dB. The average variability values of light sensitivity in the upper half of the visual field were 9.6 dB, which is 1 dB less than in the lower half of the visual field - 10.6 dB. CONCLUSION: According to our data, points No. 32 and No. 40 are of particular interest in the diagnostic plan. In these loci, the highest light sensitivity values were determined in early and moderate glaucoma. However, the values in these points decrease significantly in advanced glaucoma. It can be assumed that changes in light sensitivity in these loci at the early stages of glaucoma may be a predictor of glaucoma progression.

[Static automated perimetry in the diagnosis of glaucoma. Assessment of disease progression]. / Staticheskaya perimetriya v diagnostike glaukomy. Sposoby otsenki progressirovaniya.

There are several ways to assess glaucoma progression using standard automated perimetry. Most often, ophthalmologists evaluate the stability of visual functions manually when comparing several study protocols. The advantages of clinical assessment are ease of implementation and the ability to interpret data from any device. The main disadvantage of this method is its subjectivity. There are many available automated methods for assessing disease progression involving Humphrey Field Analyzer and Octopus perimeters. Event analysis allows determining glaucoma progression at the time of examination, with consideration of the possible physiological fluctuations in light sensitivity. Trend analysis of perimetric indices makes it possible to assess the rate of glaucoma progression and forecast the trend of changes in visual functions over the next five years. All these methods for assessing progression have certain advantages and disadvantages and cannot be considered ideal. Pointwise and cluster trend analysis are more sensitive in early glaucoma and are being actively researched and developed. These methods have great potential, although they are not yet sufficiently available in clinical practice.

[Modern achievements in the diagnosis and treatment of glaucoma]. / Sovremennye dostizheniya v diagnostike i lechenii glaukomy.

Glaucoma is one of the most difficult and significant ocular conditions. The chronic asymptomatic course of glaucoma progression leads to irreversible deterioration of visual functions. Many aspects of its pathogenesis, the features of its clinical presentation, diagnosis and treatment have been identified in recent years. The results of diagnostic methods: tonometry, perimetry, optical coherence tomography - with glaucoma do not have high specificity due to the large diversity of the population. When determining the target intraocular pressure (IOP), we look at the indicators of the choroidal blood flow and biomechanical stress of the cornea and sclera (fibrous membrane of the eye). Studying visual functions is important in the diagnosis and monitoring of glaucoma. The creation of a modern portable device based on a virtual reality helmet allows examination of patients with low central vision. Structural changes in glaucoma affect the optic disc and the inner retinal layers. The proposed classification of atypical discs allows determining the earliest characteristic changes in the neuroretinal rim for glaucoma in cases of difficult diagnosis. The complexity of the diagnosis of glaucoma is also associated with concomitant pathologies in elderly patients. In cases with comorbidity of primary glaucoma and Alzheimer's disease the structural and functional changes revealed by modern research methods for glaucoma are explained by both the process of secondary transsynaptic degeneration and the death of neurons as a result of an increased IOP. The starting treatment is and its type are fundamentally important for preserving visual functions. Drug therapy with prostaglandin analogues contributes to a significant and persistent decrease in the level of IOP, and mainly by utilizing the uveoscleral outflow pathway. Surgical treatment of glaucoma is an effective way to achieve the target IOP values. However, postoperative hypotension affects the bloodstream both in the central and peripapillary retina. Optical coherence tomography angiography helped establishe that the strongest factor that determines postoperative changes is the difference in IOP, not its absolute level.

[The effect of body position on the results of central and paracentral rebound tonometry]. / Vliyanie polozheniya tela na rezul'taty tochechnoi kontaktnoi tonometrii v tsentre i na periferii rogovitsy.

PURPOSE: This study analyzes the fluctuations of intraocular pressure (IOP) and clarifies the error of paracentral rebound tonometry associated with change in body position. MATERIAL AND METHODS: The study included 45 healthy volunteers aged 25.4±2.1 years. First we performed rebound tonometry in the sitting position in the center of the cornea and 3-4 mm from the temporal and nasal sides (Icare-c, Icare-n, Icare-t, respectively) and bidirectional applanation tonometry (IOPcc - corneal compensated, IOPg - Goldmann tonometry). Then we measured Icare-c, Icare-n, Icare-t in the supine position, and after 5 minutes repeated Icare-c in the supine position. After this, we measured Icare-c, IOPcc and IOPg in the sitting position. RESULTS AND DISCUSSION: Initial IOPcc and IOPg were 4.6±2.8 and 14.8±2.8 mm Hg. Initial Icare-c, Icare-t, and Icare-n measurements amounted to 15.0±1.9, 15.7±1.5 and 16.3±1.3 mm Hg; in the supine position the measurements were 16.4±2.1, 17.2±1.7 and 17.1±1.9 mm Hg. Paracentral measurements differed from Icare-c in both sitting and supine positions; only between Icare-t and Icare-n measured in the supine position there were no significant differences. The results of Icare-c, Icare-t, and Icare-n in body position change were comparable. Icare-c measured after 5 minutes in the supine position increased up to 16.6±2.4 mm Hg. Final IOPcc and IOPg did not differ from the initial measurements. Final Icare-c was lower than the initial result by 0.8±0.2 mm Hg, and lower than both supine Icare-c measurements by 2.1±0.2 and 2.6±0.2 mm Hg. CONCLUSION: Paracentral rebound tonometry findings exceed those of rebound tonometry in central cornea, but in body position change the alteration of measurements in the same points on the cornea are comparable. In the supine position IOP increases on average by 1.0-1.5 mm Hg compared to the sitting position.

[The effect of phacoemulsification of age-related cataract on intraocular pressure and iridocorneal angle parameters in primary open-angle glaucoma]. / Vliyanie fakoemul'sifikatsii vozrastnoi katarakty na uroven' oftal'motonusa i parametry iridokorneal'nogo ugla pri pervichnoi otkrytougol'noi glaukome.

Cataract phacoemulsification with intraocular lens implantation significantly affects the morphology of the anterior chamber angle (ACA) and contributes to a reduction of intraocular pressure (IOP). PURPOSE: This study investigates the changes in anterior chamber angle configuration and IOP level before and after cataract surgery in primary open-angle glaucoma (POAG) eyes, and assesses its possible relationship with the axial length of the eye. MATERIAL AND METHODS: The study included 38 patients with immature senile cataract and compensated unoperated stage I-II POAG. Patients underwent anterior segment optical coherence tomography (AS-OCT) with measurement of the angle opening distance (AOD750) and trabecular-iris space area (TISA750) before and six weeks after the surgery, as well as axial length and corneal-compensated IOP (IOPcc). RESULTS: After the surgery 92.11% of patients showed a decrease in IOPcc an average of 1.84±1.95 mm Hg (by 12.33±10.21% of the baseline); the maximum decrease in the IOPcc level was 8.35 mm Hg (by 40.97% of the baseline). AS-OCT data indicates that cataract phacoemulsification causes an increase in anterior chamber angle width: AOD750 increased from 0.510±0.175 to 0.771±0.156 mm, and TISA750 increased from 0.266±0.090 to 0.494±0.096 mm2. The strongest correlations were found between the axial length, postoperative TISA750 increase (Δ%TISA750) and postoperative IOPcc reduction (Δ% IOPcc). Postoperatively, specific changes could be observed in the trabecular meshwork in 28.95% of cases in the form of elongation and strain of the membrane. CONCLUSIONS: Cataract extraction contributes to a significant reduction in IOP due to anterior chamber angle expansion, trabecular meshwork stretching, and improved aqueous outflow.

Investigation of genetic polymorphism of Russian rape and turnip rape varieties using SSR and SRAP markers.

Rapeseed (Brassica napus L.) and turnip rape (B. rapa L. subsp. campestris (L.)) are important agricultural plants widely used for food, fodder and technical purposes and as green manure. Over the past decades, a large number of perspective varieties that are being currently cultivated in every region of Russia have been developed. To increase the breeding eff iciency and facilitate the seed production, modern molecular-genetic techniques should be introduced as means to estimate species and varietal diversity. The objective of the presented research study was to investigate DNA polymorphism of the rapeseed and turnip rape varieties developed at Federal Williams Research Center of Forage Production and Agroecology and detect informative markers for varietal identif ication and genetic certif ication. To genotype 18 gDNA samples, 42 and 25 combinations of respective SSR and SRAP primers were used. The results obtained demonstrate that SRAP markers were more effective for polymorphism analysis: 36 % of the tested markers revealed genetic polymorphism compared with only 16.7 % of microsatellite loci. Molecular markers to detect differences at interspecif ic and intervarietal levels have also been found. For the investigated set, such microsatellite loci as Na12A02, Ni2C12, Ni02-D08a, Ra02-E01, Ni03H07а and SRAP-marker combinations as F13-R9, Me4- R7, F11-Em2, F10-R7, F9-Em2 and F9-R8 proved to be informative. Application of the two marker techniques made it possible to detect a higher level of DNA polymorphism in plants of different types (spring and winter varieties) if compared against the intervarietal differences within a species or a group. According to Nei's genetic diversity index, in the cluster of winter rapeseed, VIK 2 and Gorizont varieties had the longest genetic distance, and in the spring cluster, these were Novosel and Veles. A high level of similarity was found between Vikros and Bizon winter rapeseed varieties. The results obtained have a high practical value for varietal specif ication of seed material and genetic certif ication of rapeseed and turnip rape varieties.

[Modern capabilities of ophthalmic tonometry in pathologically altered corneas]. / Sovremennye vozmozhnosti oftal'motonometrii pri patologicheskikh izmeneniyakh rogovitsy.

Changes in intraocular pressure have great influence on the course of various processes in ocular tissues. Presently, the scientific discussion has returned to the theoretical issues of tonometry and the creation of models that would allow assessing the influence of various ocular parameters on IOP values. Some of the modern tonometers (Icare, Tono-Pen) are convenient and effective when measuring IOP in eyes with damaged, uneven or edematous cornea. It is necessary to analyze the results of ophthalmic tonometry by modern methods in accordance with the data of direct intracameral manometry in pathological conditions of the cornea and after keratoplasty.

[Coefficient of biomechanical stress in assessment of the degree of intraocular pressure compensation]. / Koeffitsient biomekhanicheskogo napryazheniya v otsenke stepeni kompensatsii vnutriglaznogo davleniya.

Intraocular pressure is the one modifiable factor, which correct assessment and normalization initiates the treatment of glaucoma. The accuracy of its measurement by traditional methods depends on biomechanical properties of the fibrous tunic of the eye, which in modern clinical practice are most successfully studied by the method of bidirectional applanation of the cornea using the Ocular Response Analyzer (ORA). Mathematical integration of the parameters it measures makes it possible to calculate the coefficient of biomechanical stress (Kbs) that characterizes changes in the fibrous tunic of the eye induced by intraocular pressure, and serves as a criterion for intraocular pressure compensation. PURPOSE: To determine the range of normal values of the Kbs coefficient, and to evaluate its specificity and sensitivity as a criterion for the degree of intraocular pressure compensation. MATERIAL AND METHODS: Two consecutive studies on representative clinical material were used to determine the range of normal Kbs values in patients without significant ophthalmic pathologies (400 patients, 800 eyes) and establish the sensitivity and specificity of the coefficient in the diagnosis of glaucoma in patients with newly diagnosed glaucoma (673 patients, 1346 eyes). The age and gender composition of patients in both study groups was similar. RESULTS: The cut-off value for Kbs is 1.0. In the range of values from 1.0 to 1.09, additional risk factors for glaucoma progression must be taken into account to assess intraocular pressure compensation. In cases when Kbs is equal to or exceeds 1.1, the intraocular pressure is considered elevated and a high risk of disease development or progression is predicted. In glaucoma patients with uncompensated intraocular pressure, the specificity of Kbs is 81.5%, the relative specificity (including the borderline range) is 98%. With Kbs values over 1.1, its specificity reaches 100%. CONCLUSION: The performed clinical and statistical analysis demonstrates high sensitivity and specificity of the biomechanical stress coefficient in the diagnosis and treatment of glaucoma.

[Static automated perimetry in the diagnosis of glaucoma. Part 1: Basic principles]. / Staticheskaya perimetriya v diagnostike glaukomy. Chast' 1. Bazovye printsipy.

Static automated perimetry is an indispensable tool in the diagnosis of glaucoma. It is used to study the differential light sensitivity of the retina in different points of the visual field. The most important is the central zone of the visual field, many perimetric programs and strategies have been developed for its examination. Using standard background brightness, we can vary sizes, location methods and the type of stimulus delivery. The proper use of standard achromatic perimetry is crucial for the correct management of glaucoma patients. This review analyzes literature on the basic principles of static perimetry in the examination of differential photosensitivity of the retina.

[Static automated perimetry in the diagnosis of glaucoma. Part 2: Research protocol, glaucoma classifications, perimetric defects through the prism of structural-functional correlation]. / Staticheskaya perimetriya v diagnostike glaukomy. Chast' 2. Protokol issledovaniya, klassifikatsii glaukomy, perimetricheskie defekty cherez prizmu strukturno-funktsional'noi korrelyatsii.

Examination of the central visual field is currently required for glaucoma diagnosis. Modern computer perimeters make it possible to qualitatively and quantitatively evaluate defects of light sensitivity. Perimetric indices are calculated showing the severity of the defects. This allows the use of perimetric results to create universal classifications of glaucoma. Recently, new perimeter programs based on optical coherence tomography data have appeared. The possibility of personalizing perimeter programs are being tested. This review attempts to systematize data on the capabilities of computer perimeters in assessing functional defects, presents the widely used glaucoma classifications, and describes ways of developing static perimetry programs for earlier diagnosis of glaucoma with respect to structural and functional correlations.

Molecular-statistical theory of elasticity in nematic liquid crystals composed of polar and nonpolar molecules.

A molecular-statistical theory of the orientational elasticity of nematic liquid crystals has been developed employing the orientational deformation tensor which describes the rotation of the director. An explicit expression for the general elasticity tensor of the nematic phase has been obtained and the Frank elastic constants are expressed in terms of the three independent parameters of this tensor. Explicit expressions for the Frank elastic constants have been derived in the molecular field approximation in terms of the orientational order parameters and the corresponding coefficients of expansion of the intermolecular potential in spherical invariants. Frank elastic constants have been calculated numerically for nematic liquid crystals composed of both polar and nonpolar molecules together with the orientational order parameters using the classical Gay-Berne model interaction potential and the two of its popular modifications. The polarity of the uniaxial molecular shape has been directly introduced into the model potential by modifying the distance of closest approach. The elastic constants are presented as functions of temperature for different values of the molecular elongation, the anisotropy of the potential well and the molecular shape polarity. It has been shown that the elastic constants are much more sensitive to the details of the intermolecular interaction potential in comparison with the orientational order parameters. In particular, a relatively weak polarity of the molecular shape may result in an unusual decrease of the splay constant K_{11} which may vanish at some temperature leading to the instability of the homogeneous nematic phase. This may represent a mechanism of the formation of the splay-bend phase.

Biomineralization of Trabecular Meshwork in Open-Angle Glaucoma.

A new form of open-angle glaucoma has been identified, in which calcification and silicification of the trabecular meshwork is a potentially significant component of outflow obstruction. It is noted that the mineralization of this area is promoted by various disturbances in the acid-base balance in the tissue. The role of melanosomal enzymes in the initiation of the formation of mineral calcium phosphate in trabecular tissue in open-angle glaucoma is considered.

[Is the health care system ready to apply gene therapy preparations?]

The gene therapy is totally new approach to treatment of patient. It has significant therapeutic potential for wide range of diseases, including those caused by genetic disorders. The in vivo therapy is one of types of gene therapy meaning that impact on gene apparatus of somatic cells occurs straight within organism of patient. Among significant advantages of of this kind of therapy is potential opportunity of treatment of diseases which previously had no effective therapy or only supportive symptomatic therapy was administered. The article describes international approaches to classification of gene therapy preparations. The review of in vivo gene therapy preparations currently registered in different countries. Also, the features of their development, production and registration are analyzed. For many in vivo gene therapy preparations, due to small number of patients, clinical evidence base is limited, especially in terms of long-term clinical effect that complicates process of registration and economic evaluation for subsequent their inclusion in the system of state funding. It should also be noted that gene preparations currently registered abroad have extremely high cost that limits their widespread implementation into clinical practice. The production of gene therapy preparations requires a number of additional measures targeted to supporting product quality that complicates process of their production and registration. Due to absence of necessity in large production capacities, gene therapy preparations are produced centrally that results in their logistic complexities. It is actual to analyze international experience of distribution of in vivo gene therapy preparations in order to optimize approaches to regulation, assessment and financing of gene technologies in the Russian Federation.

[On the question of progressive hyperopia correction after radial keratotomy]. / K voprosu o korrektsii progressiruyushchei gipermetropii posle radial'noi keratotomii.

Progressive hyperopia development in the long-term period after radial keratotomy (RC) is associated with not only surgical effects, but also individual biomechanical features of the fibrous tunic of the eye, its age-related changes, and hydrodynamic disturbances. When choosing a method of correction, one should take into account a number of features characteristic of this induced refractive disorder: instability and irregularity of refraction, coexisting presbyopia, and, in some cases, anisometropia. Correction of progressive hyperopia after RC can be achieved with eyeglasses, or contacts, or intraocular lenses depending on the subjective factor - the so-called patient adherence. The most effective in terms of functionality is contact correction with scleral rigid gas-permeable lenses, and in the presence of pronounced lens opacities - intraocular correction.

[Accumulation of sulfur and phosphorus in the eye's drainage system in primary open-angle glaucoma]. / Nakoplenie sery i fosfora v drenazhnoi zone glaza pri pervichnoi otkrytougol'noi glaukome.

PURPOSE: To analyze the chemical composition of the sclera and trabecular meshwork in patients with primary open-angle glaucoma (POAG) and to assess the impact of corneal-compensated intraocular pressure (IOP) on the chemistry of the drainage area. MATERIAL AND METHODS: Biopsy specimens of the trabecular meshwork (89 specimens) and sclera (41 specimens) obtained from patients with POAG on maximal medical therapy were analyzed to determine the content of certain chemical elements - carbon (C), nitrogen (N), oxygen (O), aluminum (Al), calcium (Ca), chlorine (Cl), potassium (K), magnesium (Mg), sodium (Na), phosphorus (P), silicon (Si) and sulfur (S). The elements were selected based on chemical structure target tissue and sensitivity of the method used for analysis. Visualization was performed using the «EVO LS 10¼ (Zeiss, Germany) scanning electron microscope (SEM), and the chemical composition was studied with the «Oxford-X-MAX-50¼ (Oxford, UK) energy-dispersive spectrometer (EDS). Statistical analysis was performed using the Spearman correlation. RESULTS: The IOP of patients with POAG was found to have positive correlation with the total amount of S, P, and Ca in the trabecular meshwork. The accumulation of sulfur-containing compounds associated with pigment granules in trabecular meshwork's tissue was identified. A correlation was determined between the organic and inorganic (mineral) phosphorus content in the trabeculae, and the IOP values. The organic component of phosphorus was better represented than the mineral component in patients with increased IOP. CONCLUSION: In patients with POAG, an increase in the IOP level causes the amount of S associated with pigment granules and the proportion of organic P to increase in the trabecular meshwork, which should be taken into account in the further search for drug therapy that would potentially affect pathologically altered tissue.

[Current state of ophthalmic tonometry]. / Sovremennoe sostoyanie oftal'motonometrii.

Currently, the level of intraocular pressure (IOP) can be assessed with a large number of tonometers, which differ in the principle of action, the place of application and the degree of invasiveness. All the methods in use - except for direct manometry - allow only indirect judgement of the level of ophthalmotonus. The quality of tonometric measurement is influenced by many factors, from the choice of tonometer to the analysis of the results obtained by the doctor. The use of complex methods for assessing the level of intraocular pressure provides additional information that increases its diagnostic value. This article summarizes current information about modern methods of tonometry, and describes their features.

Molecular theory of the tilting transition and computer simulations of the tilted lamellar phase of rod-coil diblock copolymers.

Symmetric rod-coil diblock copolymers have been simulated using the method of dissipative particle dynamics in the broad range of the Flory-Huggins parameter. It has been found that the tilted lamellar phase appears to be the most stable one at strong segregation. The rod-coil copolymer tilt angle and orientational order parameters have been determined as functions of the segregation strength. The density functional theory of rod-coil diblock copolymers has been generalized to the case of the tilted lamellar phase and used to study the stability of the orthogonal lamellar phase with respect to tilt. The orthogonal phase indeed appears to be unstable in the broad region of the parameter space in the case of relatively strong segregation. It has also been shown that the transition into the tilted lamellar phase is determined by a strong coupling between two independent tilt order parameters.