Репозиторий Университета

© 2020 Elsevier Ltd The purpose of this study is the mechanical characterization of the mid-to- old-age human anterior lens capsules (ALCs) obtained by capsulorhexis using Atomic Force Microscopy (AFM) and a nanoindenter at different spatial scales. The dependencies on the human age, presence or absence of pseudoexfoliation syndrome (PEX), and application of trypan blue staining during the surgery were analyzed. The measurements on both the anterior (AS) and epithelial (ES) sides of the ALC were conducted and the effect of cells present on the epithelial side was carefully accounted for. The ES of the ALC had a homogenous distribution of the Young's modulus over the surface as shown by the macroscale mapping with the nanoindenter and local AFM indentations, while the AS was more heterogeneous. Age-related changes were assessed in groups ranging from the mid-age (from 48 years) to old-age (up to 93 years). We found that the ES was always stiffer than the AS, and this difference decreased with age due to a gradual decrease in the Young's modulus of the ES and an increase in the modulus of the AS. No significant changes were found in the mechanical properties of ALCs of PEX patients versus the PEX-free group, as well as in the properties of the ALC with and without trypan blue staining.

© 2019 Elsevier Ltd The lens capsule, a thin specialized basement membrane that encloses the crystalline lens, is essential for both the structural and biomechanical integrity of the lens. Knowing the mechanical properties of the lens capsule is important for understanding its physiological functioning, role in accommodation, age-related changes, and for providing a better treatment of a cataract. In this review, we have described the techniques used for the lens capsule biomechanical testing on the macro- and microscale and summarized the current knowledge about its mechanical properties.

© 2019 Elsevier Ltd The lens capsule, a thin specialized basement membrane that encloses the crystalline lens, is essential for both the structural and biomechanical integrity of the lens. Knowing the mechanical properties of the lens capsule is important for understanding its physiological functioning, role in accommodation, age-related changes, and for providing a better treatment of a cataract. In this review, we have described the techniques used for the lens capsule biomechanical testing on the macro- and microscale and summarized the current knowledge about its mechanical properties.

© 2019 Elsevier Ltd The lens capsule, a thin specialized basement membrane that encloses the crystalline lens, is essential for both the structural and biomechanical integrity of the lens. Knowing the mechanical properties of the lens capsule is important for understanding its physiological functioning, role in accommodation, age-related changes, and for providing a better treatment of a cataract. In this review, we have described the techniques used for the lens capsule biomechanical testing on the macro- and microscale and summarized the current knowledge about its mechanical properties.

© 2019 Elsevier Ltd The lens capsule, a thin specialized basement membrane that encloses the crystalline lens, is essential for both the structural and biomechanical integrity of the lens. Knowing the mechanical properties of the lens capsule is important for understanding its physiological functioning, role in accommodation, age-related changes, and for providing a better treatment of a cataract. In this review, we have described the techniques used for the lens capsule biomechanical testing on the macro- and microscale and summarized the current knowledge about its mechanical properties.

© 2019 Elsevier Ltd The lens capsule, a thin specialized basement membrane that encloses the crystalline lens, is essential for both the structural and biomechanical integrity of the lens. Knowing the mechanical properties of the lens capsule is important for understanding its physiological functioning, role in accommodation, age-related changes, and for providing a better treatment of a cataract. In this review, we have described the techniques used for the lens capsule biomechanical testing on the macro- and microscale and summarized the current knowledge about its mechanical properties.

© 2018, Media Sfera. All rights reserved. Changes in ocular anatomy and topography that occur due to congenital development anomalies are often of complex, composite nature. Such pathologies are accompanied by not only refractive errors, but also changes in eye’s macrostructure. Careful analysis of the changes is necessary to better understand the clinical picture. Purpose - to study the specifics of structural and morphological changes of the eye in certain ocular congenital pathologies and in some orphan diseases using the results of three-dimensional ultrasound analysis and digital acoustic imaging. Material and methods. The study included 60 patients (119 eyes) with congenital ocular changes, some of which are registered as independent orphan diseases, as well as with systemic manifestations including congenital changes in eye membranes, lens and the vitreous body. The examination involved three-dimensional scanning followed by digital processing of the imaging data obtained using general medical ultrasound systems Voluson 730 Pro Kretz and Voluson E8. Results. Digital ultrasound technologies significantly expand the scope of data on eye morphology in various congenital changes obtainable in vivo. Conclusion. The advantage of this investigation method is the possibility to reliably detect congenital spatially complex morphological deformations in the eye tissues, which in some cases are impossible to observe with other methods.

The article describes a clinical case of Descemet's membrane detachment that occurred during cataract phacoemulsification with implantation of intraocular lens. Significant corneal edema developed in the early post-op period. Considering the ability of endothelium to close its own defects even with large injury area, the patient was followed-up for 2 years. Corneal edema was treated during 4 months and concluded with instillations of osmotic and anti-inflammatory drugs. At 1.5-2 months of therapy, the edema was gradually decreasing, and by the 4th month of the follow-up the cornea was practically transparent. Density of endothelial cells in central cornea, where the Descemet's membrane was absent, comprised 1000 cells/mm2. Further observation revealed cornea staying transparent for 2 years after the surgery. Complete optical recovery of patients with Descemet's membrane defect in this case study is supported by similar clinical cases briefly described in the article, and evidence that structural functional recovery of the corneal endothelial layer is possible even when it has large defects (more than 2.5 mm in diameter).

© 2018, Media Sfera. All rights reserved. At present, phacoemulsification and trabeculectomy are the most widespread surgery methods in cataract and glaucoma treatment, generally recognized as the gold standard. Among elderly patients, comorbid glaucoma and cataract are extremely prevalent, so the order of the two surgeries and the time interval between them are pivotal choices when planning treatment strategy. The reason for it is that almost any eye surgery is considered a risk factor for long-term trabeculectomy effectiveness. In attempts to solve this problem, numerous studies have been conducted on the impact of cataract surgery on filtration bleb scarring. The problem of determining the time interval between surgeries, as well as other treatment nuances, remains relevant despite the long history of research and publications. Some results are cited as general recommendations on treatment tactics (increasing the time interval between operations, using antimetabolite and anti-inflammatory therapy, minimizing intraoperative traumatism). However, currently there are no specific recommendations for one of the most important factors - the time interval between cataract extraction and trabeculectomy.

© 2018 Ophthalmology Publishing Group. All rights reserved. Purpose: creation of working classification of morphologic variations of postoperative lens capsule opacity after Micro-Invasive cataract surgery. Material and methods: Morphologic study of the lens capsule (LC) has been conducted on 4 artiphakic cadaveric eyes. A specimen of an isolated anterior lens capsule, obtained during the repeated operation with changes characteristic for anterior capsular contraction syndrome has been studied too. The obtained specimens have been researched with the method of semithin sections. Results: The analysis of the morphologic cadaveric LC specimens revealed the polymorphism of secondary cataract (SC). Besides well known "classic" SC forms, which were caused by fibroplasias processes or pseudo-regeneration a new type of postoperative LC opacity not represented in the available literature before has been revealed. The given variant of opacities was called "pseudo-hyaloid" form and characterized by the absence of clear LC borders, changes of its normal structure, the appearance of loose fibrillar structure with microslit spaces and exfoliations, that possibly was the consequence of acustic cavitation, arising in the result of ultrasonic effect. As a result the LC lost characteristic for it the role of the dense bed and made impossible adhesion and migration on its changed surface the proliferative fibrocellular elements characteristic for "classic" SC forms. The microscopy results of the isolated anterior LC specimen in the area of capsulotomic aperture showed the presence of altered abundant loose fibrillar tissue with microporous structure and expressed forming of folds. Making layers of fibrous tissue exceeded the thickness of the normal anterior LC in 10 and more times and considerably reduced the diameter of capsulotomic aperture. Conclusion: The variety of postoperative LC opacities confirmed by the results of morphologic studies afforded to suggest a new working classification in which all possible morphologic variants and the stages of the secondary pathologic changes forming of anterior LC. The suggested classification is convenient for the understanding and must promote to make a right algorithm in the choice of optimal and safe technology of laser reconstructive interventions.

© 2018 Media Sfera. All rights reserved. Bioinorganic chemical composition of the lens of human and experimental animals (cows, dogs, rats, rabbits) have been analyzed in various studies. In most cases, the studies employed different methods to determine the gross (total) composition of chemical elements and their concentrations in the examined samples. Less frequently, they included an assessment of the distribution of chemical elements in the lens and correlation of their concentration with its morphological changes. Chemical elements from all groups (series) of the periodic classification system were discovered in the lens substance. Despite similar investigation methods, different authors obtained contradicting results on the chemical composition of the lens. This article presents data suggesting possible correlation between inorganic chemical elements in the lens substance with the development and formation of lenticular opacities. All currently employed methods are known to only analyze limited number of select chemical elements in the tissues and do not consider the whole range of elements that can be analyzed with existing technology; furthermore, the majority of studies are conducted on the animal model lens. Therefore, it is feasible to continue the development of the chemical microanalysis method by increasing the sensitivity of Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS) with the purpose of assessing the gross chemical composition and distribution of the elements in the lens substance, as well as revealing possible correlation between element concentration and morphological changes in the lens.

© 2018, Media Sfera. All rights reserved. Throughout the history of pediatric ophthalmology, pathophysiological state has always played an important role. It’s characterized by reduced central vision, often paired with disruption of binocular vision, which is interpreted as amblyopia. Central vision is necessary for social integration, so its disorders cause great quality of life changes in patients limiting their professional activities and complicating everyday life. Despite large number of proposed methods of treatment, amblyopia still remains a pressing problem and its prevalence has not changed significantly over the years.