[The relationship between intraocular pressure and age-related variations in ocular rigidity]. / Vzaimosvyaz' vnutriglaznogo davleniya s involyutsionnymi kolebaniyami rigidnosti glaza.

PURPOSE: This study aimed to identify the correlation between age-related fluctuations in the average values of rigidity of the fibrous tunic of the eye (FTE) and corresponding ranges of true intraocular pressure (IOP) in healthy eyes and eyes with open-angle glaucoma (OAG); using the identified ranges of FTE rigidity, to establish the appropriate IOP zones for healthy and glaucomatous eyes, taking into account the aging periods as classified by the World Health Organization (WHO). MATERIAL AND METHODS: Ocular-Response Analyzer tonometry was used according to the Koshits-Svetlova dynamic diagnostic method to examine 674 patients with healthy eyes and 518 patients with glaucomatous eyes, aged 18 to 90 years, classified according to the WHO aging periods, and a theoretical analysis was conducted to estimate clinical values of FTE rigidity, the current level of true IOP, and the calculated individual IOP level in a patient's eye during youth. RESULTS: The following IOP level zones were identified for patients with healthy and glaucomatous eyes: low IOP zone (≤13 mm Hg); medium IOP zone (14-20 mm Hg); elevated IOP zone (21-26 mm Hg); high IOP zone (27-32 mm Hg); subcompensated IOP zone (33-39 mm Hg); and decompensated IOP zone (≥40 mm Hg). CONCLUSION: The fundamental physiological criterion "rigidity" does not depend on central corneal thickness and consistently reflects the current level of true IOP. In all examined patients, both with healthy and glaucomatous eyes, healthy and glaucoma eyes with the same level of current rigidity had the same level of IOP. The ability to assign a given healthy or glaucomatous eye to a specific individual IOP zone is particularly important for the polyclinic system.

[Morpho-physiological features of the human eye sclera as the key unit in the level of intraocular pressure under normal conditions and in glaucoma].

The results of sclera investigations from the positions of morphology, physiology, biomechanics and control-system theory, are summarized. The morphological evidence was obtained supporting the physiological hypothesis stating that the specific anatomical organization and spatial displacement of elastic fiber-containing scleral layers against one another, are the key elements in formation of the individual level of intraocular pressure (IOP) in man both under normal and pathological conditions. It was shown that the elastic fibers outlined the collagen lamallae in of scleral internal layers. External scleral layer lacked elastic fibers. Scleral elastic fibers are necessary for the functioning of the mechanism of sclera microfluctuations associated with the intraocular fluid accumulation and removal, they are also important for dampening the sudden changes of IOP. Under normal conditions, age-related increase in scleral rigidity is primarily associated with the process of accelerated aging of its superficial non-elastic layers, resulting in the physiological response of the current IOP level elevation. As IOP becomes elevated under normal conditions, the internal elastic fiber-containing scleral layers are increasingly pressed against more rigid external layer. This limits the displacement capacity of internal layers against each other, resulting in the decline of the efficiency of elastic fiber work in dampening the sudden changes of IOP. In the healthy eyes, the process of scleral aging brings to a natural development of ophthalmohypertension, when IOP elevation is physiologically required for the maintenance of the volume microfluctuation mechanism ("scleral respiration"). In glaucoma, the pathological rearrangement of the scleral fibrous structures is observed, resulting in an additional abrupt increase of its rigidity, with the reciprocal significant elevation of the current level of IOP and the amplitude of its jumps. Pathophysiological mechanism of these significant changes in glaucoma remains currently unknown, however, morphological evidence indicates that it is associated with the changes in the metabolic processes in sclera.

[Evolution of Helmholtz theory on the basis of research of accommodation executive mechanisms]. / Razvitie teorii Gel'mgol'tsa po rezul'tatam issledovanii ispolnitel'nykh mekhanizmov akkomodatsii.

The authors used a profound biochemical analysis of clinical observations in different spheres of ophthalmology as well as their own many-year observations of the biomechanical intraocular systems to describe the eye accommodation system. A defined and advanced Helmoholtz accommodation theory, which from now on does not contradict the laws of mechanics in all its phases, is offered. The principles of interrelated activities of the main and auxiliary accommodation executive mechanisms are described; they enabled an explanation for a number of actual observations, which were not understood, in the past, from the standpoint of incompleted but correct in its essence Helmholtz accommodation theory. A total classification of all accommodation executive mechanisms was worked out and presented by the authors.

[Accommodation in the young age. Norm and pathology]. / Akkomodatsiia v molodom vozraste. Norma i patologiia.

The review describes the main provisions of theories and understanding related with the physiology and pathology of accommodation from the time of Helmholtz up to the present-day; besides, methods of therapy and prophylaxis in accommodation disturbances in young people are summarized.

[Morpho-functional characteristics of lens ciliary body as a key mechanism of accommodation in human eye]. / Morfologicheskie i funktsional'nye osobennosti resnichnogo poiaska khrustalika kak kliuchevogo ispolnitel'nogo zvena v mekhanizme akkommodatsii glaza cheloveka.

With the aid of ophthalmological, morphological, biomechanical and regulation theory methods the inconsistency of prevalent concepts on the functional interpretation of morphological structure of ciliary zonule was demonstrated and the scheme of functioning of its elements matching clinical and physiological observations was proposed. The role of anterior and posterior portions of ciliary zonule appears to be functionally essential and consistent with accommodation mechanism proposed by Helmholtz, while the role of cilioequatorial fibers of ciliary zonule is functionally auxiliary. Morphological and constructive peculiarities of ciliary zonule structure confirm the validity of Helmholtz concepts of accommodation mechanism.

[Laser fixation of the crystalline lens in its contused subluxation]. / Lazernaia fiksatsiia khrustalika pri ego kontuzionnom podvyvikhe.

The authors report a nontraditional effective method of treating patients with contusion semiluxation of the lens. It consists in fixation of the lens at the expense of formation of posterior synechiae because of an inflammatory process induced by laser exposure of pigmented epithelium of the iris and ciliary body. Complex clinical evaluation of the organ of vision in 132 patients, including the remote period (after 3-10 years), showed good stabilization of visual functions and of the geometrical position of the incompletely dislocated lens after its laser fixation.

[Biomechanical characteristics of interactions between the drainage and accommodation regulatory systems of the eye in health and in contusion lens subluxation]. / Biomekhanicheskie osobennosti vzaimodeistviia drenazhno i akkomodatsionnoi reguliatornykh sistem glaza v norme i pri kontuzionnom podvyvikhe khrustalika.

Biomechanical aspects of joint functioning of the accommodation system of the eye and the system regulating the discharge of intraocular fluid are considered proceeding from the concept of joint automated regulation. A multifunctional biomechanical model of the eye, created by the authors on the basis of numerous data and permitting them to quantitatively trace the relationships in the functions of the drainage and accommodation intraocular regulatory systems in health and in contusion subdislocation of the lens, is analyzed for various clinical situations. Theoretical and practical prerequisites for the development of novel methods for the diagnosis and treatment of primary open-angle and secondary phacotopic glaucoma are discussed, specifically, regulation of intraocular fluid discharge by purposeful shifting of the range of activity of the accommodation regulatory system. A detailed analysis of mutual functioning of the above ocular systems is practically important for clinical ophthalmology, for it accelerates the development of novel methods of diagnosis and pathogenetically-based therapy of a number of ocular diseases.