[Alternative methods of surgical treatment of keratoconus]. / Al'ternativnye metody khirurgicheskogo lecheniya keratokonusa.

The introduction of early diagnostic methods for keratoconus into clinical practice has become the basis for the development of surgical treatment techniques for this pathology, such as corneal collagen crosslinking and interlamellar keratoplasty with implantation of intrastromal segments. The article analyzes the results of research by Russian and foreign specialists in these areas and presents the data on the combination of SMILE surgery and corneal crosslinking, the Rome protocol of corneal crosslinking, modifications of interlamellar keratoplasty, the use of femtosecond laser technologies, and some pilot studies. Modern requirements for ophthalmological care require a personalized approach to each patient, and therefore the surgeon should have a wide range of surgical methods of treatment applicable to different patient cohorts. The described methods of treatment, according to the authors, are the most promising.

[Right ventricle free wall rupture during transcatheter occluder implantation in a patient with postinfarction rupture of the interventricular septum and COVID-19-associated myocarditis. Case report].

Intraventricular septum rupture is a rare mechanic complication of myocardial infarction associated with high mortality. This case describes STEMI in recovered patient after COVID 19 associated pneumonia, which was complicated by ventricular septum rupture followed by cardiogenic shock. It was managed by percutaneous occluder implantation. The procedure was complicated by right ventricular wall rupture. Postmortem examination of myocardium showed the signs of inflammation infiltrate and myocyte necrosis, according to histopathological Dallas criteria diagnosis of COVID-19 associated myocarditis was established. The COVID-19 pandemic has contributed to increasing cardiovascular mortality. This is typically attributed to diminishing resources for timely and appropriate medical care, and patients' late presentations for fear of contracting the infection. Cardiovascular complication of COVID-19 may be another contributing factor. Further research is needed to improve our understanding of the mechanisms and long-term sequelae of myocardium damage in COVID-19, to optimize treatment strategy and subsequent follow-up in such patients.

[Primary vitrectomy in the treatment of retinopathy of prematurity with unfavorable progression]. / Pervichnaya vitrektomiya v lechenii retinopatii nedonoshennykh neblagopriyatnogo tipa techeniya.

PURPOSE: The study aims to determine the indications and evaluate the results of primary vitrectomy in unfavorable progression of stage III active retinopathy of prematurity (ROP). MATERIAL AND METHODS: The control group consisted of 17 patients (28 eyes) with unfavorable progression of stage III ROP, who had the disease progress after coagulation of the avascular retina and underwent the second stage of treatment - vitrectomy. The main group consisted of 5 patients (10 eyes) with unfavorable progression of stage III ROP, who underwent primary vitrectomy. Gestational age at birth was 24-30 weeks, body weight ranged from 680 to 1250 g. According to spectral optical coherence tomography (SOCT) and OCT angiography (OCT-A), the initial state of the retina and vitreoretinal interface in patients of the main and control groups were identical. RESULTS: A retrospective analysis of control patients, according to SOCT and OCT-A data, showed the spread of neovascularization beyond the retinal plane, its interaction with the posterior hyaloid membrane and vitreous body structures in the early stages of the disease, traction changes in the underlying retina, areas of retinoschisis, as well as thickening of the posterior hyaloid membrane. The tactics of treating patients with unfavorable progression of stage III ROP has changed since 2020. Primary vitrectomy was performed in case the signs listed above were identified. The transition of the disease to the inactive stage was recorded in all cases one month after primary vitrectomy. After one year the pathological process did not reactivate in any of the cases, and no pathological changes were found in the projection of the former proliferation ridge. CONCLUSIONS: Extraretinal retinovitreal neovascularization, according to multimodal preoperative diagnostics, indicates the need for vitreoretinal surgery as a pathogenetically substantiated method of treatment for unfavorable progression of stage III active ROP.

[Morphological evaluation of orbital implants in postenucleation reconstruction (an experimental study)]. / Morfologicheskaya otsenka orbital'nykh implantatov v postenukleatsionnoi rekonstruktsii (eksperimental'noe issledovanie).

About 12 thousand surgeries for eyeball removal are performed every year in the Russian Federation. Formation of the supporting stump and implantation of the proper orbital implant is essential for successful cosmetic prosthesis. PURPOSE: Comparison of materials biocompatibility, design of different orbital implants and morphological condition of formed postenucleation stumps in an in vivo experiment. MATERIAL AND METHODS: In the course of the study 24 rabbits were operated, divided into three comparable groups. Enucleation with primary implantation of an orbital implant was performed in all subjects. The following implants were used: polymeric orbital implant - in the main (experimental) group, polytetrafluorethylene insertion implant - in the control group 1, and silicone endoprosthesis - in the control group 2. We assessed features of the implantation process, implant design, general condition of the operated animals, condition of the postenucleation stumps, passive motility of the stumps, and reaction of the surrounding tissues to the implants. RESULTS: Performed surgeries did not negatively affect the general condition of the rabbits, and there was no significant local tissue reaction to the implants. The structural and design features of the implants used in the main group were found to be more convenient for implantation, ensured stable fixation and position in the orbit. Postenucleation stump motility was comparable in all groups during the early postoperative period. This parameter decreased at later follow-up times mostly in the control group 2. When extracting the implants, it was revealed that in the main group it had secure fixation to the orbital tissues and stable position, did not cause abundant proliferation of connective tissue. Pathomorphological examination revealed that tissue reaction to the implants was less prominent and was reversed soon with fine connective tissue capsule formation in the main group and control group 2. In the control group 1 tissue reaction increased progressively, and capsule formation was delayed. CONCLUSION: Polymeric implant is the most suitable orbital implant for postenucleation orbital reconstruction.

"Design of a Suspension Lever Mechanism in Biomedical Robotic System".

The article discusses the design of a suspended lever mechanism with elastic elements, which is used as a safety device in a robotic system for the rehabilitation of the lower limbs. The article analyzes the existing mechanical structures of devices for rehabilitation, identifies the problems of operation, design, and safety systems and suggests a new design of the device. The process of reverse development of a lever mechanism scheme to ensure safety during rehabilitation of the lower limbs is presented. The design of the lever mechanism consists of movable levers connected by elastic elements. The device allows you to dampen the force during active rehabilitation. The power calculation of the lever mechanism in the rehabilitation system was carried out. The article addresses the issues present in the current mechanical designs with a brief discussion on the system architecture.

[Botulinum therapy for acute esotropia]. / Botulinoterapiya v lechenii ostro voznikshei ezotropii.

PURPOSE: To determine the effectiveness of the use of botulinum toxin type A in the treatment of acute esotropia in children. MATERIAL AND METHODS: A retrospective analysis of the results of using botulinum toxin type A in the treatment of acute convergent strabismus in 16 children was performed. Children's ages ranged from 3 to 15 years. Botulinum toxin was injected into the medial rectus muscles. In 6 patients with acute esotropia, botulinum toxin was injected into the internal rectus muscle of both eyes, in the rest of patients the toxin was injected into one eye. Two patients underwent chemodenervation of extraocular muscles twice. The injected dose of botulinum toxin (from 1 to 5 U) was chosen depending on the strabismus angle, the patient's age, and the duration of the disease. In order to form binocular vision, all patients underwent orthopto-diploptic treatment. The observation period lasted 12 to 18 months. RESULTS: One month after chemodenervation, the orthoposition of the eyes was persistently restored in 7 children (43.75%). Esodeviation angle decreased steadily to 2 degrees in 4 patients (25%). A second injection of botulinum toxin was required to achieve orthotropy in 2 patients (12.5%) 4-6 months after chemodenervation. An increase of esodeviation angle was recorded in 3 patients (18.75%), which required classical surgical treatment of strabismus. One month after the injection, unstable binocular vision developed in 11 children (68.75%). After 1 year, binocular vision was successfully formed 13 patients (81.25%). CONCLUSION: Chemodenervation in the majority of children with acute esotropia led to persistent orthoposition of the eyes. This created favorable conditions for the restoration of binocular vision during subsequent orthopto-diploptic treatment.

[Venous blood flow in ocular vessels of patients with active retinopathy of prematurity]. / Osobennosti venoznogo krovotoka v sosudakh glaza pri aktivnoi retinopatii nedonoshennykh.

PURPOSE: To study the characteristics of venous circulation in the eyes with retinopathy of prematurity (ROP) observed in examination of blood flow in the central retinal vein and superior orbital vein in patients with different forms, stages and state of the disease. MATERIAL AND METHODS: Color duplex scanning of the central retinal vein and superior orbital vein was performed using color Doppler imaging and pulsed Doppler sonography in 55 premature babies (55 eyes) with active ROP and 8 premature babies (8 eyes) with no signs of ROP. All babies included in the study were born at 25-32 weeks of gestation, their birth weight was 680-1760 g. RESULTS: A characteristic feature of hemodynamic parameters in the central retinal vein at stages 1-3 of active ROP was a decrease in both the maximum and minimum blood flow velocities (Vmax and Vmin), indicating a serious disorder of ocular hemodynamics in this category of patients. An increase in Vmax in the central retinal vein was recorded for patients with aggressive posterior ROP, which occurs in response to venous stasis that is common in this form of the disease. The performed statistical assessment of the prognostic significance of hemodynamic parameters of the central retinal vein in relation to the type of active ROP revealed a high information content of Vmin, which is promising for early detection of unfavorable course of the disease helping to ensure timely treatment. The blood flow in the superior orbital vein showed distinctive absence of any correlations with the course of the disease, disallowing any immediate conclusions on the informativeness and predictive value of its parameters. CONCLUSION: The revealed features of venous blood flow in patients with active ROP help expand the understanding of vascular changes in this pathology, and can also be applied in clinical practice to improve the accuracy of predicting the course of the disease.

Valence tautomeric transition of bis(o-dioxolene) cobalt complex in solid state and solution.

Valence tautomer transition occurs mainly in 3d metalorganic complexes with redox-active ligands and makes them potential candidates for single-molecular switches. The transition occurs under temperature, pressure, or light-induced stimuli and is strongly affected by the intermolecular interactions. However single-crystal x-ray diffraction is not always applicable to such systems when crystal structure is destroyed upon transition or system is studied in the solution. Such an example is bis(o-semiquinonato) cobalt complex with TEMPO-functionalized iminopyridine ancillary ligand. In this work we apply two complementary techniques-ligand-sensitive Fourier transform infrared spectroscopy (FTIR) and metal sensitive Co K-edge x-ray absorption spectroscopy (XAS). In a solid state, a temperature hysteresis of magnetization larger than 40 K was observed upon cyclic cooling-heating. So, the temperature of phase transition upon cooling is about 40 K lower than that upon heating. In solution, the x-ray absorption spectra for high-temperature and low-temperature states were similar to that in the solid form, but the hysteresis was absent. Two methods are can probe valence tautomer transition, but XAS has an advantage for the liquid phase analysis and FTIR has larger sensitivity to the ligand related interactions in solid.

[Surgical treatment of vertical strabismus. Part 2. Indications, scheduling, methods]. / Khirurgicheskoe lechenie vertikal'nogo kosoglaziya. Chast' 2. Pokazaniya, sroki provedeniya, metody.

Treatment of vertical strabismus will almost inevitably involve surgery when it is associated with hyperfunction of the inferior oblique muscle due to the weakness of vertical fusion (3.0-4.0 ave dptr), the presence of cyclotropy and torsional diplopia. Many operations aimed at weakening the lower oblique muscle have been described. However, they have a number of negative aspects associated with high invasiveness, difficulty of technical implementation due to the need for manipulations in the inaccessible area of the eye in proximity to the optic nerve, macular area, large vessels, as well as long duration of the operation, inability to dosage the result of the operation, low functional results. They are, to a large extent, absent in the operation of anterior transposition in which the neurofibrovascular bundle serves as the axis of rotation of the lower oblique muscle changing the vector of its action and increasing the effectiveness of treatment. Despite all the advantages of that technique, its use is still limited due to the lack of methods for controlling the amount of anterior transposition for the treatment of hyperfunction of the inferior oblique muscle, especially of small degrees.

[Surgical treatment of vertical strabismus. Part 1. Classification and diagnostics]. / Khirurgicheskoe lechenie vertikal'nogo kosoglaziya. Chast' 1. Klassifikatsiya patologii, diagnostika.

Vertical strabismus caused by hyperfunction of the inferior oblique muscle is a common oculomotor disorder. It is found in one third of all patients with strabismus, and in 70% of cases it is combined with esotropia. To date, there is no single approach to determining the degree of hyperfunction of the inferior oblique muscle, and the most common classifications are very subjective and inaccurate. Thus, in connection with the need to understand the severity of the disease, as well as to determine the tactics of treatment and prognosis of the surgical outcomes, it is necessary to standartize the classification of this pathology. The mechanism of action of the inferior oblique muscles of the eye is very complex and depends on the position of the eyeball at the time of their contraction. In addition to horizontal and vertical movements, they provide torsional movement. Any impairment of these muscles leads to the development of not only vertical strabismus, but excyclotropia that reduces the effectiveness of strabismus treatment. To identify all the symptoms associated with hyperfunction of the inferior oblique muscle, taking into account the peculiarities of its triple action, it is necessary to conduct a thorough diagnostic study.

[Experimental justification of the use of a polymeric implant in reconstructive and regenerative surgery of the sclera and tarsal plate]. / Éksperimental'noe obosnovanie ispol'zovaniia polimernogo implantata v rekonstruktivno-vosstanovitel'noi khirurgii sklery i tarzal'noi plastinki.

INTRODUCTION: Congenital and acquired diseases, as well as traumatic injuries of the sclera and tarsal plate can lead to serious complications up to the complete loss of visual functions and loss of the eye as an organ if not treated timely. Due to that, it becomes necessary to use biological and synthetic materials during reconstructive and regenerative surgeries to replace the defects and reinforce the carcass properties of the sclera and tarsal plate. PURPOSE: To compare experimental and morphological features of the response of the eye and surrounding tissues to implantation of the synthetic polymeric implant for reconstructive and regenerative surgery (PERRS) 'Reperen-6' and biological xenopericardium implant taken from cattle on the sclera in animal experiment. MATERIAL AND METHODS: The studies were conducted on 12 chinchilla rabbits. PERRS 'Reperen-6' was implanted on the surface of the sclera (into the subtenon space) of left eyes of 6 rabbits from the main group. Similar surgeries with biological xenopericardium implant taken from cattle were performed on the left eyes of 6 rabbits from the comparison group. The right eyes of each animal from both groups remained intact. After the surgery, we performed examination of the animals and acquisition of the material (the eyes and surrounding tissue) in 16, 34 and 68 days. Enucleated eyes were fixed in 10% buffered formalin solution with subsequent preparation of histologic specimen according to standard procedure. CONCLUSION: The experimental and morphological studies showed that the postoperative period went smoother in the main group of animals. Thanks to its structure, PERRS 'Reperen-6' fixed tightly to the sclera and surrounding structures forming a firm 'own tissue-implant' complex. The polymeric implant 'Reperen-6' can be recommended for reconstructive and regenerative surgeries to reinforce the connective tissue structures in pathological conditions of sclera and appendages of the eyes.

Chirality-Induced Phonon Dispersion in a Noncentrosymmetric Micropolar Crystal.

Features of the phonon spectrum of a chiral crystal are examined within the micropolar elasticity theory. This formalism accounts for not only translational micromotions of a medium but also rotational ones. It is found that there appears the phonon band splitting depending on the left- and right-circular polarization in a purely phonon sector without invoking any outside subsystem. The phonon spectrum reveals parity breaking while preserving time-reversal symmetry, i.e., it possesses true chirality. We find that hybridization of the microrotational and translational modes gives rise to the acoustic phonon branch with a "roton" minimum reminiscent of the elementary excitations in the superfluid helium-4. We argue that a mechanism of this phenomena is in line with Nozières' reinterpretation P. Nozières, [J. Low Temp. Phys. 137, 45 (2004)JLTPAC0022-229110.1023/B:JOLT.0000044234.82957.2f] of the rotons as a manifestation of an incipient crystallization instability. We discuss a close analogy between the translational and rotational micromotions in the micropolar elastic medium and the Bogoliubov quasiparticles and gapful density fluctuations in ^{4}He.

[Clinical forms of ocular dirofilariasis]. / Klinicheskie formy glaznogo dirofiliarioza.

The prevalence of dirofilariasis in Russian Federation has been increasing in recent years. Diagnosis of ocular dirofilariasis is difficult due to polymorphism of its clinical manifestations. Systematized data on this disease in literature is virtually absent. The study included 142 cases of ocular dirofilariasis registered in Russian Federation and the former Soviet Union, which were described in the literature of 1915-2016 years. An analysis of the registered cases of dirofilariasis allowed the following classification points to be defined: localization-based - subcutaneous soft tissue, subconjunctival, orbital, scleral, intraocular; in terms of clinical forms - capsular (with perifocal inflammation, asymptomatic disease course, with fixed or unfixed capsule) and acapsular/migrating (with or without infiltration of surrounding tissues). The most difficult to diagnose are the capsular forms. In such cases, ultrasonography is used to reach final diagnosis. The developed working classification of ocular dirofilariasis enables to refine the approaches to diagnosing this pathology, which will undoubtedly improve the quality of medical care.

[Complications of the Catheter Treatment of Atrial Fibrillation: Stenosis of All Pulmonary Veins after Radiofrequency Ablation].

Radiofrequency ablation is the "gold standard" in atrial fibrillation treatment. The frequency of complications is about 3.5-3.9 %. The symptomatic pulmonary vein stenosis is one of the most severe complications. In this report we present a clinical case of stenosis of all four pulmonary veins after redo catheter ablation of atrial fibrillation in 61year-old patient, and discussion of possible causes, specific features of diagnosis, and possible approaches to treatment of this complication.

Rate of Complications at Early Removal of Compression Bandage After Transradial Coronary Angiography.

PURPOSE: to compare rates of access site complications at early (after 4 hours) and traditional (after 24 hours) removal of a compression bandage after diagnostic transradial (TR) coronary angiography (CA) in patients not receiving anticoagulants. MATERIALS AND METHODS: We included into this study 392 patients (mean age 63±8.7 years, 62.8% men) who underwent transradial coronary angiography. Patients were divided into 2 groups. In group 1 patients (n=221) compression bandage was removed from puncture site in 4 hours after procedure with subsequent control of radial artery patency using presence of pulse metric curve during ulnar artery compression (the reverse Barbeau test with pulse oximeter). In patients of group 2 (n=171) compression band was removed after 24 hours. In both groups control of radial artery patency was carried out after 24 hours using the reverse Barbeau test. Upon detection of radial artery occlusion (RAO) ultrasound imaging of the forearm arteries was performed. RESULTS: No RAO was detected in group 1 while in group 2 number of detected RAO was 15 (8.8%) (р<0.05). Rates of hematomas at puncture site were not significantly different. Puncture site bleeding after band removal requiring repeated banding occurred in 1 patient of group one (0.6%); no such cases were registered in group 2 (p>0.05). CONCLUSION: Compared with traditional method early removal of compression bandage after TR CA was associated with lower rate of RAO.

[Ophthalmic manifestations of facial nerve palsy]. / Oftal'mologicheskie proiavleniia paralicha litsevogo nerva.

Facial nerve palsy is a common pathology that develops due to various diseases, traumas and medical interventions. The most common peripheral type of facial paralysis leads to acute unilateral involvement of facial muscles along with the development of paralytic lagophthalmos. The absence of adequate and timely medical treatment in patients with paralytic lagophthalmos can lead to severe corneal complications such as cornea perforation causing loss of eye and consequently restricted professional ability, work capacity and significant decrease of patient's life quality. Patients with paralytic lagophthalmos require timely, complex, planned treatment involving various correction methods aimed at protection of the cornea, as well as anatomical and functional recovery of the eyelids. Chemodenervation of the upper eyelid muscles is a pathogenetically substantiated method that can help restore the protective function of the upper eyelid and prevent corneal complications; it can be recommended for early stages of the disease.

[Vitrectomy technique in aggressive posterior retinopathy of prematurity]. / Tekhnika vitrék-tomii pri zadnei agressivnoi retinopatii nedonoshennykh.

AIM: to develop the methodology of early primary vitrectomy for aggressive posterior retinopathy of prematurity. MATERIAL AND METHODS: The study included 10 preterm infants (20 eyes; gestational term - 26-30 weeks, post-conceptual age - 34-39 weeks) with severe forms of aggressive posterior retinopathy of prematurity (AP-ROP). All patients underwent a complex ophthalmic examination. Their results were compared with retrospective data of earlier treated AP-ROP patients (10 preterm infants, 20 eyes), in whom laser photocoagulation (LC) was done first (gestational period at the time of LC ranged from 26 to 30 weeks, post-conceptual age - from 34 to 39 weeks). In all cases, the disease progressed despite LC, thus, second-stage vitrectomy was required. Taking into account the similarity between clinical and morphometric data of the study group and retrospective patients, laser treatment was voted inexpedient as predictably inefficient and, therefore, a decision was made to perform vitreoretinal surgery. For that, an original technique of vitrectomy without preliminary LC was designed. Follow-up periods were up to 6 months. RESULTS: In all cases, AP-ROP regression to inactive stage was diagnosed 1 month after vitrectomy. According to digital retinoscopy findings, initial sings of blood vessel growth into the previously avascular retina appeared on day 20-26 after surgery. This was confirmed by the results of fluorescein angiography. In general, complete retinal reattachment was obtained in 16 eyes (80%), partial - in 3 eyes (15%). In 1 case, the retina failed to reattach (5%). CONCLUSION: The proposed method of primary vitrectomy enables optimization of the treatment approach to severe AP-ROP and can be regarded as promising.

[Step-by-step creation of internal limiting membrane fragment for surgical treatment of large idiopathic macular holes]. / Metodika poetapnogo formirovaniya fragmenta vnutrennei pogranichnoi membrany v khirurgicheskom lechenii bol'shikh idiopaticheskikh makulyarnykh otverstii.

AIM: to develop a surgical procedure for large idiopathic macular holes (MH) that would involve creation of an original internal limiting membrane (ILM) flap to close the hole with. MATERIAL AND METHODS: Nineteen patients aged from 59 to 71 years with stage 3 idiopathic MH (by J. Gass) were enrolled. Besides standard ophthalmic examination, spectral optical coherence tomography and microperimetry were performed in all cases. The patients were followed up 2 weeks and then 1 and 3 months after surgery. Surgical procedure was notable for an original ILM flap created in a way that resembles removing petals from a flower. The new method implies that the ILM is peeled off all the way round the MH except for the foveolar area and one particular ILM fragment, which is only partially separated from the retina, from the periphery towards the MH, stopping at some 0.1-0.2 mm from its margin. This last fragment is then inverted to cover the MH. RESULTS: All surgeries were completed without complications. Visual acuity has gradually increased over the follow-up period in all patients: from 0.1-0.4 to 0.3-0.7 (0.39±0.15 on the average; Sivtsev-Golovin chart). Foveal anatomy has also improved: complete closure of the MH was achieved in 8 patients, partial - in 11. Moreover, all patients demonstrated a shift of the retinal fixation point towards the center of the fovea for 153-369 mm, at that, their fixation has stabilized and absolute central scotomas disappeared. CONCLUSION: The method developed is a promising treatment for large idiopathic macular holes. Further studies are required.

[Triggering factors and pathogenesis of radiation cataract].

Cataract is one of the most common eye diseases in the world. Many factors, including genetic, metabolic, nutritional, and environmental, are involved in its formation. It is necessary to know main causal agents and cellular mechanism of cataractogenesis. The tissue of the lens is considered radiosensitive, thus, lens opacities are possible late effects of exposure to ionizing radiation. The use of medical radiation for both diagnostic and therapeutic purposes grows worldwide. At the same time, there continues to be much confusion regarding the actual threshold dose of radiation exposure for cataract formation. Eye safety and the risk of cataract development are not entirely clear. However, with an ever-widening range of interventional procedures, one should take attempts to reduce the risk for radiation cataract.