[Methods of studying deformation properties of ocular structures].

Studying ocular biomechanics presents apparent interest because of certain clinical situations when evaluation of mechanical properties can help with both diagnosis and treatment. This literature review considers the approaches to studying deformation properties of various ocular structures: dynamometric methods, elastotonometry, ophthalmic mechanography, photoelasticity method, ultrasound methods, analysis of pneumatic applanation of the cornea, atomic force microscopy, holographic interferometry, optical coherence elastography. Knowledge of the particularities of tissue deformation during examination with various methods can expand our understanding of the mechanisms of pathological changes in different structures of the organ of vision, which can help develop new methods of diagnosis and treatment.

[Pigmentary glaucoma: yesterday, today, tomorrow].

Pigment dispersion syndrome (PDS) is a condition that mostly affects young men with myopic refraction. PDS is characterized by the presence of Krukenberg spindle, peripheral iris defects, significant trabecular meshwork pigmentation, as well as convex iris configuration. Such configuration can cause friction of iris's posterior pigment layer on its ligaments, which leads to the release of pigment and its accumulation mostly in the structures of the anterior chamber.

[Transscleral laser therapy in the treatment of glaucoma].

Nowadays glaucoma is one of the leading causes of irreversible blindness worldwide. The main goal in preservation of vision in glaucoma patients is reducing intraocular pressure (IOP), which is considered the main controlled risk factor for progression of glaucomatous optic neuropathy. The article discusses the effectiveness and safety of various transscleral laser technologies in the treatment of glaucoma.

[Effects of laser operations in the iris-lens diaphragm area on the thickness of the macular region and peripapillary nerve fiber layer].

Unlabelled: All methods of laser radiation therapy currently used in clinical practice are positioned as safe in terms of possible negative effects on the eye and surrounding tissues.

Purpose: To assess possible changes in the macular region of the retina and thickness of the peripapillary retinal nerve fiber layer (RNFL) according to the results of a dynamic study of OCT parameters after laser operations in the iris-lens diaphragm area.

Material And Methods: Optical coherence tomography (OCT) was performed on 34 pseudophakic patients (43 eyes) with clinical signs of secondary cataract with best corrected visual acuity (BCVA) of at least 0.

[Retinal changes after laser interventions on anterior segment of the eyeball].

Laser surgery of the cornea, iris, angle of the anterior chamber and other parts of anterior segment of the eye sees wide application in clinical practice. The adverse effects it can cause in the anterior segment are well known and understood. At the same time, changes the treatment method can cause in the posterior segment of the eye - primarily, in macular area of the cornea, which is of great importance, have not been studied sufficiently.

[New biophotonics methods for improving efficiency and safety of laser modification of the fibrous tunic of the eye].

The article describes a newly developed and tested diffractive optical element (DOE) that converts non-uniform radiation of the laser output into a homogeneous ring. The Gerchberg-Saxton algorithm is shown to be well suited for achieving annular intensity distribution. Testing this ring transducer on threshold-plasticity cornea demonstrated the reversibility of axisymmetric changes in the cornea.

Revealing structural modifications in thermomechanical reshaping of collagenous tissues using optical coherence elastography.

Moderate heating of such collagenous tissues as cornea and cartilages by infra-red laser (IR laser) irradiation is an emerging technology for nondestructive modification of the tissue shape and microstructure for a variety of applications in ophthalmology, otolaryngology and so on. Postirradiation high-resolution microscopic examination indicates the appearance of microscopic either spheroidal or crack-like narrow pores depending on the tissue type and irradiation regime. Such examinations usually require special tissue preparation (eg, staining, drying that affect microstructure themselves) and are mostly suitable for studying individual pores, whereas evaluation of their averaged parameters, especially in situ, is challenging.

[Combined YAG-laser capsulotomy in pseudophakic patients with anterior capsular contraction syndrome].

Unlabelled: Progressive metaplastic fibrosis of the anterior capsulorhexis opening is a frequent complication of the postoperative period. There is a widely practiced method of anterior capsular contraction syndrome (ACCS) correction through radial anterior laser capsulotomy. Despite many advantages, it can be complicated by unpredictable anterior capsule tearing and intraocular lens (IOL) dislocation into the vitreous Body, which justifies the search for new technical solutions.

[Capsule contraction syndrome in pseudophakia].

This is a review of the literature on capsule contraction syndrome (CCS) in pseudophakic patients that involves severe fibrosis along the margin of the anterior capsule's opening and progressive contraction of the capsular bag. Possible causes of CCS and principles of its prevention and treatment have been analyzed.

[Hybrid (femtosecond laser-assisted) phaco surgery and the state of the macula].

The review covers different aspects of the impact of femtosecond laser-assisted cataract surgery on the state of the macular zone of the retina. Literature search has revealed inconsistency of the published data and indicated the need for a more detailed study of this problem.

Optical coherence elastography for strain dynamics measurements in laser correction of cornea shape.

We describe the use of elastographic processing in phase-sensitive optical coherence tomography (OCT) for visualizing dynamics of strain and tissue-shape changes during laser-induced photothermal corneal reshaping, for applications in the emerging field of non-destructive and non-ablative (non-LASIK) laser vision correction. The proposed phase-processing approach based on fairly sparse data acquisition enabled rapid data processing and near-real-time visualization of dynamic strains. The approach avoids conventional phase unwrapping, yet allows for mapping strains even for significantly supra-wavelength inter-frame displacements of scatterers accompanied by multiple phase-wrapping.

[Transpupillary laser photocoagulation of ocular fundus: history, the present, and the future].

The present review covers the use of chorioretinal photocoagulation, which is now a popular treatment for many diseases of the ocular fundus. The review includes a detailed 50-year history of the technology with account to both Russian and foreign achievements. The current state of the field is shown through Russian and foreign literature data.

[Photoacoustic monitoring of chorioretinal complex during laser coagulation of ocular fundus].

The effect of laser treatment on ocular fundus tissues depends on quite a number of factors, mostly uncontrollable, hence, laser output parameters may vary dramatically even within the same fundus. In classical procedure ('threshold' laser coagulation), these parameters are adjusted to ophthalmoscopically visible tissue color changes at the site of coagulation. However, this method does not work with modern subthreshold techniques, that are more tissue-saving and thus, produce no immediate and visible changes in the retina.

[Laser iridectomy and anatomical and functional parameters in primary angle-closure glaucoma].

The paper discusses literature data on the effectiveness of laser iridectomy in patients with primary angle-closure glaucoma. The main methods of anatomical and functional assessment and changes evaluation are reviewed.

Microstructural changes in sclera under thermo-mechanical effect of 1.56 µm laser radiation increasing transscleral humor outflow.

Background And Objectives: Pores in the sclera are a candidate pathway for aqueous transport and therefore can be utilized to decrease the intraocular pressure (IOP) in glaucomatous eyes. Since pore formation is a well-known mechanism for stress relaxation in solids, laser-induced creation of pores in cartilage increases hydraulic permeability and promotes tissue regeneration. The aim of this paper is to demonstrate the thermo-mechanical effect of non-destructive laser irradiation on microstructural changes in sclera, in particular pore formation, resulting in substantial increase of water permeability of eye tissues that can be a novel approach to normalize the IOP.

[Morphological and histochemical effects of subthreshold laser therapy on the chorioretinal complex].

A variety of subthreshold laser methods that enable selective and precise treatment of chorioretinal microstructures, thus decreasing the risk of negative changes in retina and choriocapillaries, is used in current ophthalmological practice. This comparative pathomorphological and histochemical study allowed characterizing structural changes and functional activity of chorioretinal cells after application of different subthreshold laser technologies.

[The study of opportunity of aqueous humor filtration increase after nondestructive laser exposure of sclera in the site of pars plana projection (experimental study)].

Increase of scleral water permeability due to formation of porous structure after exposure of pulsed periodic radiation of erbium-glass optical fiber laser with wave length 1,56 pm was demonstrated in experimental study of cadaver human eyes in vitro and eyes of experimental animals (rabbits) in vivo. Simultaneous complex laser exposure of pars plana and ciliary processes results in summation of morphological changes that provide decrease of aqueous humor secretion, uveal drainage and extension of suprachoroid space. A base for new noninvasive technology of nondestructive laser exposure in glaucoma treatment is established.

[Laser discission of a host descemet membrane after endothelial keratoplasty].

A case of YAG-laser discission of a hazy host descemet membrane left in anterior chamber after endothelial keratoplasty is presented.

[Laser cyclodestructive procedures in glaucoma treatment].

The history of development of cyclodestructive procedures is given, their advantages and disadvantages are discussed. Different techniques of laser use, relative and absolute contraindications to various laser cyclophotodestructive procedures are considered. Their potential complications and effecting mechanisms are discussed.

[Comparative experimental study of morphological and histochemical changes of chorioretinal complex after subthreshold laser exposure].

The influence of several subthreshold laser procedures on chorioretinal complex (CRC) tissues was experimentally studied in rabbits using histological and histochemical methods. Subthreshold micropulse laser radiation and transpupillar thermotherapy were found to have the most attenuated and advantageous effect on CRC structure. The feature of subthreshold laser exposure is partly reversible selective changes in CRC, that have temporary stimulating effect on cellular metabolism and local regenerative processes providing an opportunity for still viable tissues to function adequately.

[Combination of measurement of retinal vascular caliber, adaptive optics and fluorescent angiography in early diagnosis and monitoring of diabetic and hypertensive retinopathy].

15 patients with diabetic and hypertensive retinopathy are examined. Retinal vascular caliber was measured using adaptive multifocal fundus camera (AMFC), fundus camera "Topcon" TRS-NW200 and FAG. Combination of retinal vascular caliber measurement and fundus foto using AMFC in patients with ametropia and astigmatismus showed apparently lower arteriolovenular coefficient (A VC) compared with that estimated using FAG imaging.

[Current methods for the early diagnosis and monitoring of vascular pathology of the eyeground].

The paper analyzes the references given to papers in the Russian and foreign literature on the current methods of the early diagnosis and monitoring of vascular pathology of the eyeground. Their main merits and demerits are noted. Data on that adaptive optics and calibrometry may be used concurrently are given.

[The first experience in clinically using a PASCAL laser photocoagulator (OptiMedica, USA)].

A new PASCAL laser photocoagulator (OptiMedica, USA) was clinically tested. A total of 38 laser interventions were performed in 38 eyes with diabetic retinopathy (n = 25), peripheral retinal dystrophy (n = 2), retinal ruptures (n = 2), hemophthalmos (n = 3), primary open-angle glaucoma (n = 5), and ectopic pupil (n = 1). An example of successful use of the new laser unit for pupilloplasty for the ectopic pupil is given.