[Changes in the precorneal tear film at various stages of keratoconus].

Unlabelled: The combination of keratoconus (KC) with signs of dry eye disease (DES) has been described in numerous scientific publications. At the same time, there is a relationship between KC stage and an increase in the severity of DES symptoms, however, there is still no common understanding of the severity of xerotic process depending on the clinical course of keratectasia.

Purpose: This study assesses the changes in the state of the precorneal tear film in KC relative to the stages of the disease.

[Effect of conventional and orthokeratological hard contact lenses on anatomical and functional characteristics of the cornea].

Unlabelled: Contact lenses are widely used for correction of myopia due to their accessibility, effectiveness and relative safety.

Purpose: This study evaluated the potential effects of conventional hard contact lenses (HCL) and orthokeratological contact lenses (OKL) on anatomical and functional condition of the cornea in myopia correction.

Material And Methods: The study included 80 patients (159 eyes) with low, moderate and high myopia.

[Changes in precorneal tear film and ocular surface in keratoconic patients after corneal collagen cross-linking].

The article reviews the current available data on the signs and symptoms of dry eye syndrome (DES) in patients with keratoconus (KC), describes the clinical features of DES in KC patients and the morphological features of this type of keratectasia that lead to manifestations of the «dry eye», and highlights the risk factors, consequences of therapeutic measures, concomitant ophthalmological and general somatic diseases that contribute to the development of DES in KC.

[Prospects for early detection of keratoconus based on systems built for computer-assisted diagnostics of structural changes in the cornea].

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.

[Precorneal tear film after corneal collagen cross-linking in keratoconus (preliminary report)].

Purpose: To study the condition of precorneal tear film in keratoconus patients after corneal collagen cross-linking (CXL).

Material And Methods: The study enrolled 24 patients (30 eyes) with stages I-III progressive keratoconus. All study patients underwent standard (Dresden) protocol CXL.

[The effects of corneal collagen cross-linking on the corneal structure in keratoconus].

The article reviews the key information regarding morphological changes in keratoconic corneas and dramatic alterations of the corneal tissue induced by corneal cross-linking according to data obtained with corneal confocal microscopy, presents basic information on keratoconus visualization techniques widely used for diagnosis, monitoring of ectasia, as well as efficacy assessment of its treatment, and lists basic principles of corneal cross-linking procedure and confocal microscopy with consideration of morphology specifics of keratoconic corneas. The article also discusses prospective benefits of further research and longitudinal studies aimed to define the origin of keratoconus and to develop advanced corneal cross-linking protocols.

[Changes in biomechanical properties of the cornea after keratorefractive surgery].

Biomechanical properties of the cornea are important for the functioning of the ocular optical system. They affect such qualities of the system as correct diffraction and resistance to different external action. Keratorefractive surgery widely used in clinical practice nowadays significantly upsets corneal biomechanics, which introduces a margin of error for IOP measurements done by different methods.

[Biomechanical properties of the cornea and tonometry measurements].

Purpose: To study peculiarities of intraocular pressure (IOP) measurement by different methods in patients with changes in corneal biomechanical properties.

Material And Methods: The study enrolled 154 patients (290 eyes) divided into 3 groups according to the condition of their corneas in terms of biomechanical properties. Group I consisted of 84 patients (168 eyes) with conditionally 'normal' cornea and corneal thickness ranging from 470 to 660 μm.

[Secondary dry eye syndrome after keratorefractive surgeries and approaches to its treatment and prevention].

The article reviews the particularities of development and pathogenesis of secondary dry eye syndrome (DES) after refractive surgeries including a complex of problems related to changes in tear film content, damage of eye surface and neurotrophic epitheliopathy. Additionally, modern algorithms of treatment and prevention of secondary DES in patients after refractive surgeries are described. Despite the transient nature of the changes, excimer-laser surgery can lead to lasting deficiencies of eye surface in some patients.

[Structural changes in the ocular anterior segment against elevation of intraocular pressure after repeated intravitreal injections].

Unlabelled: Numerous studies have demonstrated the efficacy of anti-VEGF medications for exudative (wet) age-related macular degeneration (AMD). Significant IOP elevation is one of the side effects of anti-VEGF intravitreal injection.

Purpose: To study the changes in the parameters of anterior segment of the eyeball against acute IOP elevation after repeated intravitreal injections (IVI) of anti-VEGF medication.

[Modern methods of treatment of amblyopia].

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.

[Changes in intraocular pressure after intravitreal injections].

Unlabelled: At present, intravitreal drug injections are used for treatment of various diseases of posterior segment of the eye. Among its side effects is significant rise of intraocular pressure (IOP).

Purpose: To study the changes in IOP levels after two intravitreal injections.

[Reasons to reconsider interpretation of densitometry for corneal transparency].

Aim: To assess the effect of light scattering in the corneal epithelium on densitometric brightness of the stroma through mathematical modeling of the interaction between a light beam and the two-layer epithelium-stroma system.

Material And Methods: In order to study the scattering behavior of a plane-parallel non-coherent beam at the epithelium-stroma interface, a multi-age group was formed (87 patients, 174 eyes) that comprised two subgroups with equal number of assign participants: healthy patients with no systemic changes and mixed patients with undisturbed corneal transparency that, nevertheless, were under instillation therapy. In the first subgroup, the assessment of light scattering was done at random times, while in the second subgroup - within the first 200 seconds after the instillation in order to avoid a reaction of the ocular surface structures, including epithelium (rapid response of epithelial cells to instillations).

[Intraocular pressure, ocular blood flow, and corneal biomechanics changes after LASIK surgery for myopia].

Aim: to study changes in intraocular pressure (IOP), volumetric ocular blood flow (OBF) rate, and biomechanical properties of the cornea after excimer laser ablation in patients with myopia of different degrees.

Material And Methods: A total of 16 patients (32 eyes) with myopia ranging from 2.75 to 9.

[Long-term efficacy of corneal collagen cross-linking in patients with progressive keratoconus].

Aim: to study the efficacy of corneal collagen cross-linking in patients with progressive keratoconus over longer (up to 2 years) follow-up periods.

Material And Methods: A total of 52 patients (104 eyes) aged 23-34 years with stage I-III progressive keratoconus were enrolled. Besides routine examinations (automatic refractometry, uncorrected and best corrected visual acuity (UCVA and BCVA) evaluation, pneumatic tonometry), Pentacam keratotopography and pachymetry ("Oculus", Germany) were performed in all cases.

[Variability in biomechanical properties of the fibrous tunic of the eye in a healthy population].

Unlabelled: Studying biomechanical properties of the fibrous tunic of the eye meets current clinical demands. Previous studies have proved bidirectional corneal applanation suitable for this purpose. The so called corneal elasticity coefficient is more informative in terms of corneal elastance than the two other parameters measured during bidirectional corneal applanation, namely, corneal resistance factor and corneal hysteresis.

[Clinical and experimental aspects of investigation of biomechanical properties of corneoscleral shell].

The article summarizes the results of long-term clinical and experimental studies on biomechanical properties of corneoscleral shell performed over the last few years in the Research Institute of Eye Diseases of the Russian Academy of Medical Sciences. A total of 2432 patients (4775 eyes) were assessed. Dynamic bidirectional pneumatic corneal applanation, dynamic pneumatic corneal impression, and elastotonometry were used for in vivo evaluation.

Experimental study on the mechanical strain of corneal collagen.

Currently, investigations of biomechanical properties of the fibrous tunic are becoming even more topical, especially for diagnosis of corneal ectatic disease, as well as correct interpretation of intraocular pressure (IOP) parameters, particularly in patients with prior surgery on cornea. The study principle is based on the ability of substances to change optical anisotropy depending on mechanical strain applied to them. An experimental set-up was constructed which allows assessment of polarization degree of light which is emitted during luminescence of strained collagen.

[Fibrous tunic biomechanics and biometric indicies. Report 2. The impact of topographic features in keratoconus].

The potential relation of biomechanical indices with topographic features in keratoconus was studied using multifactor correlation analysis. Topographic features in keratoconus were found to have influence on biomechanical measurements in the central zone of the cornea. If the zone of ectasia is distant from the central part of the cornea the central biomechanics can remain normal.

[Fibrous tunic biomechanics and biometric indicies. Report 1. The impact of axial length, thickness and corneal curvature].

The degree of impact of several fibrous tunic biomechanical parameters on biomechanical indices was studied using multifactor correlation analysis. In patients with "normal" cornea corneal thickness was found to be the most significant factor influencing corneal hysteresis, corneal resistance factor, elasticity coefficient and elasticity rise, hence values of corneal biomechanical properties prevail over all other biomechanical indices studied in this work. However influence of significant changes in scleral biomechanics (e.

[Biometry of anterior segment structures: comparative study].

We studied different methods of biometry (spatial ultrasonography, ultrasound biomicroscopy, optical principles) of anterior segment structures: lens, anterior chamber and its angle. 20 patients (40 eyes) with immature cataract were examined. Ultrasonography showed to be the most informative method.

[Corneal biomechanics: clinical importance, evaluation, possibilities of sistemization of examination approaches].

The study of corneal biomechanics meets several clinical needs: diagnosis and monitoring of corneal ectatic diseases, accurate calculating of parameters for keratorefractive surgery, proper IOP measurement for glaucoma diagnosis and monitoring. Comparison of different studies and subsequently wide practical use of this knowledge are strongly limited mostly due to lack of unitary terminology and biomechanics classification. We developed classification of biomechanics based on the diagnostic approaches and evaluation methods depending on the principle of examination.

[Efficacy of catalin eyed drops in age-related cataract agents].

The present investigation studied the efficacy of Catalin eye drops (Senju Pharmaceutical Co, Osaka, Japan) in patients with early senile cataract. An objective procedure for the densitometric analysis of lens transparency images with a Pentacam apparatus (Oculus GmbH, Germany) was used to assess the results of the investigation. Unlike the control group, the patients using Catalin had a lower optical density in the anterior and posterior cortical lens layers and beneath the posterior capsule in the first months of therapy.

Determination of corneal elasticity coefficient using the ORA database.

Purpose: To propose a new approach for the study of corneal biomechanics using the Reichert Ocular Response Analyzer (ORA) database, which is based on changes in velocity retardation in the central cornea at the peak of flattening.

Methods: The ORA applanation curve was analyzed using a mathematical technique, which allowed calculation of the elasticity coefficient (Ke), which is primarily characteristic of the elastic properties of the cornea. Elasticity coefficient values were obtained in patients with presumably different biomechanical properties of the cornea: "normal" cornea (71 eyes, normal group), keratoconus (34 eyes, keratoconus group), LASIK (36 eyes, LASIK group), and glaucoma with elevated and compensated intraocular pressure (lOP) (38 eyes, glaucoma group).