Dynamic viscosity of the wall of the lacrimal sac in disorders of the patency of the lacrimal ducts.

PURPOSE: To assess the dynamic viscosity of the lacrimal sac wall in patients with various origins of lacrimal duct obstruction. METHODS: The study was performed in 35 cases: 21 cases with primary nasolacrimal duct obstruction (PANDO) and 14 cases with secondary nasolacrimal duct obstruction after radioiodine therapy (SALDO). The study of biomechanical properties of the lacrimal sac was carried out using a test bench. The principle of the study was to indent the sample at a given speed and record the data obtained from the sensor of the force transmitted to the sample. The area under the curve (AUC) and the peak viscosity were calculated. A qualitative characteristic of the obtained curve was given. RESULTS: Median AUC in patients with PANDO was 17 × 106 [6 × 106; 19 × 106] N/m2 × s, in patients with SALDO 21 × 106 [13 × 106; 25 × 106] N/m2 × s. Intergroup differences were statistically significant (p = 0,048). The median peak viscosity in PANDO patients was 29 × 106 [25 × 106; 35 × 106] N/m2, in patients with SALDO 32 × 106 [21 × 106; 41 × 106] N/m2. The qualitative characteristics of the obtained curves differed. CONCLUSION: Biomechanical properties of the lacrimal sac may vary depending on the cause of obliteration of the lacrimal ducts. The integrated dynamic viscosity is significantly higher in SALDO patients due to exposure to radioiodine compared to that in PANDO patients.

[Methods for assessing the microbiological diversity of the ocular surface]. / Metody otsenki mikrobiologicheskogo raznoobraziya glaznoi poverkhnosti.

This review compares data from scientific studies on the microbial community of the ocular surface (OS) in conditionally healthy individuals using cultural methods (including culture-dependent diagnostic tests), microscopic and molecular genetic methods, and assesses the influence of research methods and sample preparation on the results. Concordance and discordance of the sets of identified microorganisms were analyzed using overlapping and non-overlapping methods of studying the microbial community of a healthy OS. The article presents tables showing the names of microorganisms that were identified in different sources. Cross-verification in taxa of different ranks helped confirm the following most frequently found microorganisms on healthy OS: coccomorphic microorganisms of the genera Staphylococcus, Micrococcus, Kocuria, Streptococcus, Enterococcus; gram-positive spore-forming bacilli of the genera Bacillus and Paenibacillus; gram-positive non-spore-forming rod-shaped bacteria, including Corynebacterium, but excluding Propionibacterium and Microbacterium; gram-negative non-spore-forming rod-shaped microorganisms of the genera Moraxella and Serratia. The study also assessed the effect of wearing soft contact lenses on the composition of the microbial community of the OS.

[Study of the growth temperature of ocular surface microorganisms in norm and in infectious keratitis]. / Izuchenie temperaturnykh uslovii rosta mikroorganizmov glaznoi poverkhnosti v norme i pri infektsionnykh keratitakh.

Standard bacteriological examinations, which involve culturing microorganisms at 37 °C, are commonly used in clinical practice for diagnosing infectious diseases. However, the growth temperature of microorganisms on the ocular surface (OS) during infectious keratitis (IK) may not coincide with the laboratory standard, which is due to the characteristic features of heat exchange in the eye. PURPOSE: This exploratory study examines the distribution and properties of OS microorganisms isolated under different temperature cultivation conditions in patients with IK and healthy volunteers without ophthalmic pathology. MATERIAL AND METHODS: Fifteen participants were divided into two groups. Group 1 (n=10) consisted of patients with signs of unilateral infectious keratitis, while group 2 (n=5) served as the control group. A novel microbiological method was employed to isolate pure cultures of microorganisms. This method involved cultivating microorganisms at two temperature regimes (37 °C and 24 °C) and subsequently identifying them using biochemical, immunological, and physicochemical techniques, including mass spectrometry. Scanning electron microscopy (SEM) with lanthanide staining used as the reference method. The temperature status of the ocular surface was assessed using non-contact infrared thermography. RESULTS: The study demonstrated the presence of psychrotolerant microorganisms on the ocular surface, which exhibited growth at a relatively low temperature of 24 °C. These psychrotolerant microorganisms were found to be isolated from the ocular surface displaying signs of temperature dysregulation. Among such microorganisms are Acinetobacter lwoffii, Achromobacter xylosoxidans, Bacillus licheniformis, Enterococcus faecalis, Klebsiella oxytoca, Klebsiella pneumoniae, Micrococcus luteus, Pseudomonas luteola, Streptococcus spp. CONCLUSION: When identifying the causative agent of infectious keratitis, it is crucial to consider the divergence of growth temperature of ocular surface microorganisms. The presence of psychrotolerant microorganisms on the ocular surface, which can effectively grow at room temperature, should be taken into account, especially in cases of temperature dysregulation.

Impact of azole antifungal treatment on outcome in acute invasive fungal rhinosinusitis with orbitocranial involvement: a surgical perspective.

PURPOSE: To provide real-life data on azole treatment outcomes and the role of surgery in the current management of invasive fungal rhinosinusitis complicated by orbitocranial fungal infection (OCFI). METHODS: Data was collected retrospectively from a chart review from four participating centers and a systematic literature review. The study group included patients with OCFI treated with azole antifungals. The control cases were treated with other antifungal agents. The cranial and orbital involvement degree was staged based on the imaging. The extent of the surgical resection was also classified to allow for inter-group comparison. RESULTS: There were 125 patients in the azole-treated group and 153 in the control group. Among the patients with OCFI cranial extension, 23% were operated on in the azole-treated group and 18% in the control group. However, meninges and brain resection were performed only in the controls (11% of patients) and never in the azole antifungals group. Orbital involvement required surgery in 26% of azole-treated cases and 39% of controls. Despite a more aggressive cranial involvement, azole-treated patients' mortality was significantly lower than in controls, with an OCFI-specific mortality rate of 21% vs. 52%. A similar, though not statistically significant, trend was found for the extent of the orbital disease and surgery. CONCLUSION: Despite less aggressive surgical intervention for cranial involvement, OCFI patients treated with azoles had a higher survival rate. This finding suggests we may improve morbidity with a more conservative surgical approach in conjunction with azole treatment. The same trend is emerging for orbital involvement.

[The effect of keratoconus-associated refractive errors on the results of tomographic methods of studying the posterior structures of the eye]. / Vliyanie opticheskikh narushenii pri keratokonuse na rezul'taty tomograficheskikh metodov issledovaniya struktur zadnego segmenta glaza.

PURPOSE: The study assesses the potential influence of refractive errors in keratoconus (KC) on the results of tomographic methods of studying the structures of the posterior eye segment. MATERIAL AND METHODS: The study included 30 patients with bilateral stabilized KC of stages I-IV in classification by M. Amsler. Spherical and cylindrical components of refractions were determined using automatic refractometry, keratometry measurements - based on scanning keratotopography with Scheimpflug analyzer. Aberrometry was performed to evaluate corneal wave front according to the following parameters: root mean square for lower order aberrations (RMS LOA), root mean square for higher order aberrations (RMS HOA), vertical trefoil, vertical coma, horizontal coma and spherical aberrations. Optical coherence tomography (OCT) and laser confocal scanning ophthalmoscopy (HRT 3) data was used in morphometric analysis of the optic nerve head and peripapillary retina. The following morphometric parameters were analyzed: optic nerve head (ONH) area, optic disc cup area, optic disc cup volume, ratio of optic disc cup area to ONH area, neuroretinal rim area, neuroretinal rim volume, peripapillary retinal nerve fiber layer (RNFL) thickness. All studies were performed first without correction, and 30 minutes after installing customized scleral hard contact lenses (SHCL). RESULTS: Compensation of the refractive errors characteristic for KC was achieved as expected with contact correction. OCT revealed a general trend for reduction in the area and volume of the optic disc cupping, ratio of area to volume of the optic disc cupping, as well as an increase in other parameters. As such, with correction the values for area and volume of the neuroretinal rim according to OCT were 2.2 and 13%, HRT 3 - 18 and 51.6%; comparable increase in mean RNFL thickness - 2.8 and 28.5%, respectively (p<0.001). According to HRT 3 data, the area and volume of optic disc cupping statistically significantly decreased (by 21 and 28%, respectively), while OCT showed statistically significant decrease only in cupping area (by 5.7%). The ratio of cupping to ONH area decreased by 6.6 and 23% relative to the initial data obtained with OCT and HRT 3, respectively. Significant decrease in ONH area amid SHCL correction was observed only with HRT 3. The revealed changes in morphometric parameters were analyzed using the fundamental principles of physiological optics. Changes in interference pattern and, consequently, morphometric parameters of structures of the eye fundus in KC are of multifactorial nature, and are mostly associated with refractive and wave artefacts occurring when the rays pass through the irregular corneal surface and cannot be optically compensated by the device. The use of SHCL as means for making the optic system relatively regular can significantly decrease the artefacts in morphometric measurements. CONCLUSION: The results obtained in this study demonstrate the practicality of tomographic examination in KC with contact correction. The optimal choice is custom-fit SHCL, which along with proper correction of refractive errors also ensures stable position of the lens on the cornea. In standard examination specialists should take into account the «false¼ decrease in parameters of the peripapillary retinal nerve fiber layer and increase in ONH cupping.

[Features of accumulation of chemical elements in the volume of the lens in senile cataract]. / Osobennosti nakopleniya khimicheskikh elementov v ob"eme khrustalika pri senil'noi katarakte.

PURPOSE: This study provides a detailed analysis of the bioinorganic chemical composition of lens substance in patients with senile cataract using classical and spatial statistics methods. MATERIAL AND METHODS: The study included 30 isolated human lenses. The light scattering ability (LSA) of the lens substance was evaluated using an original method. Additionally, distribution of chemical elements in the lens substance was analyzed using a scanning electron microscope with energy dispersive spectrometer (SEM/EDS). Measurements by all methods were carried out in a single coordinate space, which made it possible to compare the spatial correlation of different parameters. RESULTS: Small-angle light scattering of the lens substance has been quantitatively characterized for the first time. In contrast to the conventional norm, in senile cataract the accumulation fields of the majority of ion-forming elements (including Na, P, K, Cl) are distributed along the lines repeating the geometry of the lens capsule. At the same time, the light scattering ability of certain areas of the lens is significantly correlated with changes in the concentrations of Na, P, K, Ca in these areas. In particular, one ion-forming element can be distinguished - Na: spatial change of its concentration in senile cataract is strongly associated with a local change in LSA of the lens with opacities clustering of any degree. Thus, a change in the nature of the Na accumulation in the lens volume can be considered the main marker of senile cataract formation. CONCLUSION: The distribution pattern of ion-forming elements indicates that the loss of barrier properties in the capsule plays a significant role in the development of senile cataract.

[Morphological evaluation of the results of laser activation of scleral hydropermeability in the treatment of glaucoma]. / Morfologicheskaya otsenka rezul'tatov operatsii lazernoi aktivatsii gidropronitsaemosti sklery v lechenii glaukomy.

PURPOSE: The study attempted to experimentally substantiate the possibility of using the laser activation of scleral hydropermeability (LASH) technique in glaucoma treatment by morphological evaluation of treatment outcomes. MATERIAL AND METHODS: The pulsed-periodic radiation from an Er-glass fiber laser (λ=1.56 µm) was used. The model experiment consisted of evaluating ultrafiltration of fluid through the tissues of human sclera autopsy specimen according to the original technique using neodymium chloride-based labeling agent and scanning electron microscopy. The clinical part of the study consisted of optical coherence tomography (OCT) and laser confocal microscopy of the sclera and conjunctiva (CMSC) performed in vivo immediately after laser treatment in the laser application sites in 5 patients (5 eyes) aged 57 to 68 years with uncompensated advanced (IIIb-c) stage of glaucoma who had previously underwent LASH surgery. RESULTS: Results of morphological evaluation after LASH revealed structural changes indicating increased transscleral ultrafiltration: increased intrastromal hyporeflective areas in the sclera, thinning of collagen fibers, formation of porous structures. Using an original technique involving neodymium chloride-based labeling agent and scanning electron microscopy, we were able to prove the enhancement of transscleral ultrafiltration. The results of the experiment were confirmed by in vivo OCT images of the sclera and CMSC performed in 5 patients with advanced glaucoma after LASH surgery, in which tissue decompaction in the laser-exposed areas was clearly visualized. CONCLUSION: The revealed structural changes indicate the possibility of reducing intraocular pressure after LASH by the means of forming scleral porous structures and increasing transscleral ultrafiltration. Experimentally selected optimal mode of laser exposure (0.66 W with total exposure time of 6 seconds) during LASH helps avoid gross destructive changes in the eye tissues, making the proposed intervention a sparing approach to the treatment of glaucoma.

[Express-diagnosis of the diseases of the eye and its appendages by scanning electron microscopy with supravital staining]. / Skaniruyushchaya elektronnaya mikroskopiya s supravital'nym kontrastirovaniem v ekspress-diagnostike zabolevanii glaza i pridatochnogo apparata.

This review describes the history of development of a new line of chemical reagents that prompts to significantly reevaluate the application of scanning electron microscopy (SEM) in medical and biological studies, particularly in ophthalmology; considers the establishing of SEM as an analytical method; covers the problems in its application associated with the needs of clinical medicine and the complexities of biological sample preparation for electron microscopy. The article also presents in chronological order the technical solutions associated with creating a unique line of reagents for supravital staining. The multitude of technical solutions allows considering SEM as a method of express diagnostics. The review discusses examples of practical application of these methods for solving certain cases in clinical ophthalmology. The niche of SEM is considered among other methods of clinical diagnostics, as well as its future development involving the use of artificial intelligence.

[Age prediction based on the examination of bone tissue elemental composition using energy dispersive X-Ray spectroscopy]. / Prognozirovanie vozrasta na osnovanii izucheniya elementnogo sostava kostnoi tkani s pomoshch'yu energodispersionnoi rentgenovskoi spektroskopii.

THE AIM OF THE STUDY: Was to assess the possibility of using chemical analysis of bone mineral content by the means of an energy dispersive X-Ray spectroscopy to determine the age of unidentified corpses for forensic identification. A semi-quantative chemical microanalysis of bone fragments of 85 male and female corpses aged between 21 and 91 was done through the use of energy dispersive X-Ray spectrometer. The association of bone tissue apatite mineral composition with age is confirmed and a formula, connecting age and chemical composition change, is proposed. The possibility of using quantitive evaluation of chemical elements content in the normative mineral to determine the unidentified corpse's age in a standard laboratory, equipped with an energy dispersive X-Ray spectrometer, was proved.

Post-genomic platform for development of oligonucleotide vaccines against RNA viruses: diamond cuts diamond.

The coronavirus pandemic has starkly demonstrated the need to create highly effective vaccines against various viral diseases. The emerging new platforms for vaccine creation (adenovirus vectors and mRNA vaccines) have shown their worth in the fight against the prevention of coronavirus infection. However, adenovirus vectors and mRNA vaccines have a serious disadvantage: as a rule, only the S protein of the coronavirus is presented as an antigen. This tactic for preventing infection allows the ever-mutating virus to escape quickly from the immunity protection provided by such vaccines. Today, viral genomic databases are well-developed, which makes it possible to create new vaccines on a fundamentally new post-genomic platform. In addition, the technology for the synthesis of nucleic acids is currently experiencing an upsurge in demand in various fields of molecular biology. The accumulated experience suggests that the unique genomic sequences of viruses can act as antigens that trigger powerful humoral and cellular immunity. To achieve this effect, the following conditions must be created: the structure of the nucleic acid must be single-stranded, have a permanent 3D nanostructure, and have a unique sequence absent in the vaccinated organism. Oligonucleotide vaccines are able to resist the rapidly changing genomic sequences of RNA viruses by using conserved regions of their genomes to generate a long-term immune response, acting according to the adage that a diamond cuts a diamond. In addition, oligonucleotide vaccines will not contribute to antibody-dependent enhanced infection, since the nucleic acid of the coronavirus is inside the viral particle. It is obvious that new epidemics and pandemics caused by RNA viruses will continue to arise periodically in the human population. The creation of new, safe, and effective platforms for the production of vaccines that can flexibly change and adapt to new subtypes of viruses is very urgent and at this moment should be considered as a strategically necessary task.

Anti-coronavirus vaccines will not accelerate the transition of humanity to a non-pandemic period, but the pandemic will take fewer victims.

The vaccination rate worldwide has reached enormous proportions, and it is likely that at least 75% of the world's population will be vaccinated. The controversy is that, while people aged 65 and older suffer a significantly higher mortality rate from COVID-19, plans are being made to vaccinate young people under the age of 20. Equally thorny is the question of vaccinating people who already have antibodies to SARS-CoV-2, as well as B and T memory cells, because they contracted and survived the virus. The possible consequences of large-scale vaccination are difficult to predict, when some people do not have access to the vaccine at all and others have already received 3 doses of the vaccine. SARS-CoV-2 will circulate through the human population forever and continue to mutate, as viruses do. Therefore, in the coming years, the need to develop and use effective vaccines and medicines for the prevention and treatment of COVID-19 will remain urgent in view of the high mortality rate from this disease. To date, three vaccine platforms have been most used: adenoviral vector, inactivated, and mRNA. There is some concern about the side effects that occur after vaccination. Whether modern anti-coronavirus vaccines can raise the safety threshold, only time will answer. It is obvious that the pandemic will end, but the virus will remain in the human population, leaving behind invaluable experience and tens of millions of victims. This article is based on search retrieves in research articles devoted to COVID-19 mainly published in 2020-2021 and examines the possible consequences of the worldwide vaccination against SARS-CoV-2 and suggests that, while anti-coronavirus vaccines will not magically transport humanity to a non-pandemic world, they may greatly reduce the number of victims of the pandemic and help us learn how to live with COVID-19.

Age-related changes in cationic compositions of human cranial base bone apatite measured by X-ray energy dispersive spectroscopy (EDS) coupled with scanning electron microscope (SEM).

One of the most common scientific methods to study the chemical composition of bone matter is energy-dispersive X-ray spectroscopy (EDS). However, interpretation of the data obtained can be quite complicated and require a thorough understanding of bone structure. This is especially important when evaluating subtle changes of chemical composition, including the age-related ones. The aim of current study is to create a method of processing the obtained data that can be utilized in clinical medicine and use it to evaluate the age evolution of bone chemical composition. To achieve this goal, an elemental composition of 62 samples of cadaver compact bone, taken from the skull base (age: Me = 57.5; 21/91(min/max); Q1 = 39.5, Q3 = 73.75), was studied with EDS. We used the original method to estimate the amount of Mg2+ cations. We detected and confirmed an increase of Mg2+ cation formula amount in the bone apatite, which characterizes age-related resorption rate. Analysis of cation estimated ratio in a normative bone hydroxylapatite showed an increase of Mg2+ amount (R = 0.43, p = 0.0005). Also, Ca weight fraction was shown to decrease with age (R = - 0.43, p = 0.0005), which in turn confirmed the age-dependent bone decalcification. In addition, electron probe microanalysis (EPMA) and X-ray diffraction analysis (XRD) were performed. EDS data confirmed the EPMA results (R = 0.76, p = 0.001). In conclusion, the proposed method can be used in forensic medicine and provide additional data to the known trends of decalcification and change of density and crystallinity of mineral bone matter.

[Potential risk factors of atrial fibrillation recurrence after cryoballoon ablation].

Aim      To identify risk factors for recurrence of atrial fibrillation (AF) following cryoballoon ablation (CBA).Material and methods  This prospective study included patients with paroxysmal AF who had undergone CBA (141 patients, median age 60 years, 3% men). The evaluation prior to CBA included clinical instrumental parameters (electrocardiography (ECG), 24-h ECG monitoring, echocardiography, contrast-enhanced cardiac multispiral computed tomography). Also, possible intraoperative indexes that could affect the CBA effectivity, were evaluated. The postoperative follow-up duration was 12 months. Effectivity was assessed during in-person visits at 3, 6, and 12 months, when questioning of patients and 24-h ECG monitoring were performed. CBA was considered ineffective if the patient had recurrences of any atrial tachyarrhythmia longer than 30 sec after the end of the 3-month "blind" period.Results During the 12-month follow-up, recurrences of atrial tachyarrhythmia were observed in 46 (32.6 %) patients. Patients with ineffective CBA more frequently had AF during the first 3 months (71.7 % vs. 11.6 %; р<0.001). Such patients had a history of multiple ineffective treatments with antiarrhythmic drugs (AAD), common pulmonary venous (PV) collector (41.3 % vs. 20.0 %; р=0.008), and stroke/recurrent ischemic attacks (15.2 % vs. 5.2 %; р=0.047). Multifactorial regression analysis showed that the factors of AF recurrence included common PV collector (relative risk (RR) 2.35; 95 % confidence interval (CI) 1.29-4.25; р=0.005), multiple ineffective AADs (RR 1.42; 95 % CI 1.08-1.86; р=0.011), and early AF recurrence (RR 7.57; 95 % CI 3.84-14.90; р<0.001).Conclusion      Common PV collector and multiple ineffective AADs are risk factors of ineffective CBA. Early recurrences during the first 3 postoperative months are a significant risk factor of long-term AF recurrences.

[Optical properties of the cornea after different modifications of penetrating keratoplasty]. / Opticheskie svoistva rogovitsy posle razlichnykh modifikatsii skvoznoi keratoplastiki.

PURPOSE: Comparative analysis of optical properties of the cornea after different modifications of penetrating keratoplasty. MATERIAL AND METHODS: The study included 56 patients (56 eyes) divided into three study groups according to the surgery technique. Group I included 17 patients (17 eyes) after one-piece mushroom keratoplasty, group II - 21 patients (21 eyes) after two-piece mushroom keratoplasty and group III - 18 patients (18 eyes) after penetrating keratoplasty. In addition to standard examination methods, before surgery and in the course of the follow-up all patients underwent software-powered corneal densitometry on the anterior segment analyzer (Pentacam HR, "Oculus", Germany), as well as an assessment of the degree and regularity of postoperative astigmatism. RESULTS: Comparison of the obtained results revealed with a high degree of confidence higher values of the total specific light scattering after two-piece mushroom keratoplasty throughout the entire observation period (p<0.05). At the same time, there was no statistically significant difference in visual acuity between the three study groups (p>0.05). A statistically significant increase in the level of induced astigmatism was revealed after penetrating keratoplasty. CONCLUSION: The observed increase in light scattering after two-piece mushroom keratoplasty does not lead to a decrease in visual acuity. The interface in the optical zone of the cornea formed by a microkeratome does not affect the degree and regularity of induced astigmatism.

[Prospects for early detection of keratoconus based on systems built for computer-assisted diagnostics of structural changes in the cornea]. / Perspektivy rannego vyyavleniya keratokonusa na osnove postroeniya sistem mashinnoi diagnostiki strukturnykh izmenenii rogovitsy.

The article is devoted to the problem of diagnosing subclinical keratoconus (KK). The need to identify early signs of KK is primarily associated with the potential for the development of iatrogenic keratoectasia in cases of underdiagnosis of the disease when determining the conditions for laser keratorefractive surgery involving a decrease in the thickness of the cornea. Today generally accepted algorithms for early computer-assisted diagnosis of KK are mainly based on the analysis of various morphometric parameters of the cornea, reflecting changes in its shape and thickness induced by structural abnormalities. Direct detection of structural changes in the cornea characteristic of early KK requires the use of high-tech imaging methods that are not always applicable in everyday clinical practice. The promising approach proposed in this study is based on the fact that a digital image of a corneal «slice¼ obtained using serial analyzers such as the Scheimpflug camera widely used in clinical practice provides indirect information about the structure of the epithelial layer, the local thickening of which takes place in the initial stages KK. It is this criterion that underlies the proposed system of computer-assisted diagnosis of KK. The carried out studies have shown the high sensitivity of this algorithm, and its specificity can be increased by involving the known diagnostic indicators of KK.

[Visualization of normal ocular surface microflora via impression cytology sample using scanning electron microscopy with lanthanide contrasting]. / Vizualizatsiya normal'noi mikroflory glaznoi poverkhnosti posredstvom impressionnoi proby s ispol'zovaniem skaniruyushchego elektronnogo mikroskopa i lantanoidnogo kontrastirovaniya.

PURPOSE: To determine the possibilities of impression cytology (IC) with subsequent visualization of the sample on a scanning electron microscope in assessment of normal microflora of the ocular surface. MATERIALS AND METHODS: The article presents a visual characteristic of the microorganisms of the ocular surface (OS) captured during impression cytology (IC) in individuals without signs of inflammatory and degenerative eye diseases. The original method of staining the sample with heavy metal salts made it possible to identify the individual signs of the microorganisms in their subsequent visualization by scanning electron microscopy (SEM). RESULTS: The paper presents photomicrographs of the microorganisms most common for the OS obtained with the help of SEM, confirming and supplementing the data of non-visual methods of studying the ocular microflora. It was shown that the detection frequency of the microbial component of the OS by the visual method presented in this study is comparable with the detection frequency when using the microbial cultivation method (<80%). Coccoid and rod-shaped microorganisms were detected with relatively equal frequency, with the coccoid organisms mainly represented in association with epithelial cells. The morphological diversity of rod-shaped microorganisms is shown. CONCLUSION: The results of the study can be used as a visual reference for the normal microbiome of the eye.

Ultrafast Magneto-Optics in Nickel Magnetoplasmonic Crystals.

Here, we report on ultrafast all-optical modulation of the surface-plasmon (SP)-assisted transverse magneto-optical Kerr effect (TMOKE) and the reflectance in a one-dimensional nickel magnetoplasmonic crystal (MPC). A 50 fs nonresonant laser pump pulse with 7 mJ/cm2 fluence reduces the magnetization by 65%, which results in the suppression of TMOKE in the SP-resonant probe from 1.15% to 0.4%. The differential reflectance of SP-resonant probe achieves 5.5%. Besides this, it is shown that electron thermalization and relaxation in MPC are several times slower than those in the plane nickel.

[Scanning electron microscopy results of the vitreous body in asteroid hyalosis]. / Rezul'taty skaniruyushchei elektronnoi mikroskopii steklovidnogo tela pri asteroidnom gialoze.

PURPOSE: To evaluate the structure of vitreous body in asteroid hyalosis by low vacuum scanning electron microscopy. MATERIAL AND METHODS: The material of the study was samples of the vitreous body obtained from 7 patients aged from 62 to 72 years with vitreomacular traction syndrome during vitrectomy. In all cases, clinical manifestations of asteroid hyalosis (the presence of multiple point-like echo-positive inclusions) were identified during the preoperative examination. Samples for scanning electron microscopy and chemical microanalysis were prepared without using fixation elements, total dehydration, staining or centrifugation, and according to the so-called principle of bougienage, which consists in partial separation of fractions of the gel-like tissue with a stream of saline. RESULTS: The conducted examinations made it possible to identify various types of local accumulations of mineral elements in the vitreous body in asteroid hyalosis - called asteroid bodies - that is, multiple complex rounded formations consisting of needle-shaped crystals of a radial fibrous structure. CONCLUSION: The developed algorithm, which includes intraoperative sampling of the vitreous body in conditions of its minimal hydration and a special technique for preparing samples for scanning electron microscopy and chemical microanalysis, provides the capability for the in vivo assessment of morphological changes in hyaloid elements of the vitreous body. With that, asteroid bodies can be considered as markers of the vitreous structures that are difficult to visualize.

[Effectiveness of anti-VEGF therapy for neovascular age-related macular degeneration in different types of exudative fluid localization]. / Effektivnost' anti-VEGF-terapii neovaskulyarnoi formy vozrastnoi makulyarnoi degeneratsii pri razlichnykh tipakh lokalizatsii ekssudativnoi zhidkosti.

PURPOSE: To assess the effectiveness of anti-VEGF therapy in different types of fluids localization in neovascular age-related macular degeneration (AMD). MATERIAL AND METHODS: The study included 16 people (16 eyes) with exudative AMD. The study included patients with fibrovascular detachment of the retinal pigment epithelium (RPE), subretinal and intraretinal fluid. The patients were divided into two groups: in the first group, fibrovascular RPE detachment was combined with subretinal fluid (9 eyes); in the second group, fibrovascular RPE detachment was accompanied by both sub- and intraretinal fluid (7 eyes). All patients underwent standard ophthalmological examination, which included visometry, biomicroscopy, and ophthalmoscopy under conditions of drug-induced mydriasis. Additionally, OCT of the macular region and OCT-angiography were performed. RESULTS: Over the entire observation period, the first group of patients received an average of 5.11 intravitreal injections (IVI), the second group - 5.14 IVI. Visual acuity was comparable in both groups at the beginning of the study. Subsequently, the treatment resulted in an increase in visual acuity after 3 months in the first (p=0.066) and second (p=0.043) groups, as well as after 12 months in both groups (p=0.043). In the first group of patients, after 12 months, an increase in RPE detachment was observed (p=0.942), which suggests that the disease activity remains underestimated on OCT when RPE detachment and subretinal fluid are combined. In the first group, complete resorption of subretinal fluid occurred in 2 people. In the second group, resorption of subretinal and intraretinal fluid occurred in 6 people. CONCLUSION: Regardless of the subtype of fluid, anti-VEGF therapy is an effective method for treating exudative AMD. Intravitreal injections are necessary both in the presence of intra- and/or subretinal fluid, and fluid under RPE. The greatest difficulty is assessment of the fluid under the RPE.

[Assessment of age-related changes in lens capsule biomechanics using atomic force microscopy]. / Otsenka vozrastnykh izmenenii «biomekhaniki¼ kapsuly khrustalika na osnove atomno-silovoi mikroskopii.

Studies devoted to the assessment of lens capsule biomechanics can be divided into fundamental and applied. The former are oriented towards analysis of various indicators characterizing elasticity of the capsule as a basal membrane that maintains and changes the shape of the lens, and the latter deal with widespread introduction of modern microinvasive methods of phaco surgery into clinical practice. PURPOSE: To assess age-related changes in lens capsule biomechanics based on atomic force microscopy (AFM). MATERIAL AND METHODS: The study included 50 central fragments of the anterior capsule of the human lens obtained intraoperatively during ultrasonic phacoemulsification by continuous circular capsulorhexis. The measurements were carried out in the Fast Force Volume (FFV) mode. The force curves were processed in the Nanoscope Analysis software (Bruker, USA) using the Hertz model that allows calculating the Young's modulus of the capsule sample based on the dependence of the force on the puncture depth. RESULTS: There was no statistically significant difference in the «stiffness¼ of the inner and outer surfaces before and after removal of the subcapsular epithelium (p=0.25). In all cases, the inner surface of the capsule turned out to be «harder¼ than the outer one. In this case, the ratio of Young's modulus of the inner and outer surfaces has a significant dependence on age (p<0.001). With an increase in age from 50 to 90 years, this ratio decreased from ~7 to ~1.5. This was due to a simultaneous change in Young's modulus of the opposite nature: an increase in the stiffness of the outer surface and its decrease in the inner one. CONCLUSION: It is possible to assess lens capsule biomechanics using AFM if the subcapsular epithelium is present. In this case, the objects of study are the areas of the capsule free of epithelium, and the epithelial cells themselves can be used to identify the inner surface of the capsule. Regardless of age, the stiffness of the inner surface of the anterior lens capsule significantly exceeds that of the outer surface.