[Confocal microscopy in the diagnosis of acanthamoeba keratitis]. / Vozmozhnosti konfokal'noi mikroskopii v diagnostike akantamebnogo keratita.

Acanthamoeba keratitis (AK) is a dangerous disease of the cornea, its prevalence has increased significantly due to widespread usage of contact lenses. The similarity of the clinical manifestations of AK to other infectious keratitis (especially herpetic keratitis) requires introduction of a rapid diagnosis method into clinical practice. PURPOSE: To evaluate the capabilities of corneal confocal microscopy (CCM) in the diagnosis of acanthamoeba keratitis. MATERIAL AND METHODS: We examined 33 patients (35 eyes) with suspected acanthamoeba keratitis using light and laser confocal microscopy of the cornea (ConfoScan and HRT devices, respectively). RESULTS: CCM was technically feasible in 23 of 35 cases (65.7%). Acanthamoeba cysts were detected in 16 cases (69.6%); trophozoites were visualized in 17.4% of cases; signs of keratoneuritis were detected in 12 eyes (52.2%); in 7 cases (30.4%), hyporeflective honeycomb-like cavities were observed in the stroma; deep stromal striae were observed in 9 cases (39.1%); activated keratocytes were detected in 11 patients (47.8%), and Langerhans cells were detected in 19 cases (82.6%). CONCLUSIONS: The main diagnostic value of confocal microscopy is the detection of direct markers of AK - cysts and trophozoites of Acanthamoeba. Both light and laser CCM techniques are suitable for the diagnosis of AK, but the resolution of laser confocal microscopy is higher. The non-invasive nature of this method and the possibility of multiple subsequent examinations make it possible to verify the diagnosis of acanthamoeba keratitis and monitor the treatment.

[Corneal confocal microscopy in Fabry patients with cornea verticillata]. / Konfokal'naya mikroskopiya rogovitsy u patsientov s vikhrevidnoi keratopatiei pri bolezni Fabri.

PURPOSE: To study the changes in corneal microstructure and nerve fibers in patients with cornea verticillata in Fabry disease. MATERIAL AND METHODS: The study included patients with a confirmed diagnosis of Fabry disease. All patients underwent standard ophthalmological examination. Corneal confocal microscopy was performed when slit-lamp examination revealed cornea verticillata. RESULTS: Cornea verticillata was found in 64.5% of patients. Corneal microscopy revealed hyperreflective deposits in the basal cell layer of corneal epithelium in all patients with cornea verticillata. Characteristic features were desquamation of epithelial cells with islands of epithelial cells deficiency, as well as hyperreflective intracellular deposits in the basal layer. Changes in keratocytes in the form of perinuclear white microdots were found in the stroma of 25.8% of patients. Endothelial layer was not changed and had normal cell density, reflectivity and morphology in all patients with cornea verticillata. CONCLUSION: Corneal confocal microscopy is a valuable diagnostic tool in patients with Fabry disease and may be important in evaluation of disease progression and monitoring of treatment efficacy.

[Possibilities of increasing contact lens tolerance in keratoconus (a clinical case study)]. / Vozmozhnosti povysheniya perenosimosti kontaktnoi korrektsii pri keratokonuse (klinicheskoe nablyudenie).

Optical correction of keratoconus (KC) is intended to simultaneously solve two tasks: elimination of myopic defocus and irregular astigmatism. In terms of the latter, hard contact lenses (HCL) should be considered as the first-choice method for optical correction of KC. HCL are currently the most effective means of optical correction of refractive errors induced by KC. Despite this, it should be noted that adherence of patients to this method of correction does not always correspond to results. Most often, limitations of HCL use in KC are associated with the so-called intolerance of correction. The term «correction intolerance¼ should be considered as a general complex of potential subjective symptoms and clinical manifestations that limit the possibility of using a particular method of optical correction. In this clinical observation, subjective discomfort when wearing lenses was practically eliminated by changing the design of the lens and switching from corneal to scleral HCL. The second problem was caused by clinical manifestations of corneal hypoxia (growth of newly formed vessels in the limbal region of the cornea) and attempts to solve it were associated with improved tear production and increased oxygen permeability of the material HCL are made of. The observed stabilization of the growth of newly formed vessels should be considered as a positive (although in need of dynamic evaluation) result of these therapeutic measures.

[Results of confocal microscopy of the cornea after bandage therapeutic-optical keratoplasty in keratoconus]. / Rezul'taty konfokal'noi mikroskopii rogovitsy posle bandazhnoi lechebno-opticheskoi keratoplastiki pri keratokonuse.

Bandage therapeutic-optical keratoplasty (BTOK) is one of the modern methods of surgical treatment of keratoconus (KC) that allows to improve visual functions by changing keratotopographic and pachymetric parameters of the cornea in the zone of ectasia. Long-term results show that changes also affect the central part of the cornea, which tends to flatten. PURPOSE: To compare the light confocal microscopy appearance of the cornea before and after BTOK surgery. MATERIAL AND METHODS: We examined 15 patients (15 eyes) with progressive keratoconus (7 eyes with Amsler stage I KC and 8 eyes with Amsler stage III KC), who subsequently underwent BTOCK surgery. Using the Confoscan-4 confocal light microscope (Nidek, Japan), we studied the structure of central and paracentral cornea. The exact zone of interest was determined individually depending on the location of the graft. RESULTS: In all cases, morphological changes in the cornea characteristic of the stage II and III KC were detected. Twelve months after the operation, there was an increase in the transparency of intercellular substance of the stroma with a clearer visualization of keratocyte nuclei in the optical zone as well as at the site of the graft. In the area of interface, tissue compaction in the form of diffuse fibrosis with local scar formation could be seen. Neither significant changes in the cell structure, nor a decrease in cell density were found in the central part of ectasia and the areas of clear visualization of the endothelium under the graft. Additional postoperative assessment of the level of corneal light scattering indicated a tendency towards restoration of stromal transparency and optical uniformity. CONCLUSION: As a result of interlayer graft implantation in the zone of corneal ectasia, a tendency to structural improvement in its central and paracentral parts was revealed. Local fibrosis in the interface area can indirectly indicate biomechanical «strengthening¼ of this zone.

[On the question of progressive hyperopia correction after radial keratotomy]. / K voprosu o korrektsii progressiruyushchei gipermetropii posle radial'noi keratotomii.

Progressive hyperopia development in the long-term period after radial keratotomy (RC) is associated with not only surgical effects, but also individual biomechanical features of the fibrous tunic of the eye, its age-related changes, and hydrodynamic disturbances. When choosing a method of correction, one should take into account a number of features characteristic of this induced refractive disorder: instability and irregularity of refraction, coexisting presbyopia, and, in some cases, anisometropia. Correction of progressive hyperopia after RC can be achieved with eyeglasses, or contacts, or intraocular lenses depending on the subjective factor - the so-called patient adherence. The most effective in terms of functionality is contact correction with scleral rigid gas-permeable lenses, and in the presence of pronounced lens opacities - intraocular correction.

[Modern options for non-surgical correction of keratoconus]. / Sovremennye vozmozhnosti «nekhirurgicheskoi¼ korrektsii keratokonusa.

The article reviews data on the so called non-surgical methods of keratoconus (KC) correction. The combined approach to KC treatment entails three main tasks: prevention of progression, optical correction of induced refractive disorders, and structural repair. Measures taken to accomplish the first two tasks should be regarded as symptomatic treatment, while addressing the last task requires pathogenetically oriented solutions. Corneal cross-linking and optical correction of refractive disorders with rigid gas permeable (RGP) scleral contact lenses should be regarded as the first choice for symptomatic non-surgical correction of keratoconus.

[Rational strategy for studying microbiome of the ocular surface of people using hard contact lenses by method of 16S rRNA gene metabarcoding]. / Ratsional'naya strategiya izucheniya mikrobioma glaznoi poverkhnosti pol'zovatelei zhestkikh kontaktnykh linz metodom metabarkodinga po genu 16S rRNK.

The study is based on the hypothesis that high taxonomic diversity of bacteria detectable on the eye surface by molecular genetic methods is attributed to the high level of its contamination by skin microflora. Such contamination would make it problematic to identify the fractions of real ocular surface microbiome, which remains behind the one-percent cut-off threshold adopted in the metagenomic analysis. Hard contact lenses for long-wearing act as a physical filter preventing DNA contamination from random microorganisms, and at the same time providing adhesion to the living cells of bacteria and fungi. To confirm this assumption, a detailed analysis of references was carried out, supplemented by original laboratory research. MATERIAL AND METHODS: The analysis included 16 hard contact lenses obtained from 11 patients with impaired refraction (myopia). Additionally, conjunctival mucosa scrapings were collected from 42 patients. Samples were cross-analyzed by 16S rRNA gene sequencing using 454 GS Junior (Ion Torrent) and Illumina MiSeq platforms. RESULTS: Results obtained by the Illumina platform (analysis of the V3-V4 variable region of the 16S rRNA gene) showed better convergence with the data of culture tests reported in the literature. The major microorganism groups found were: Acinetobacter (39%), Gluconacetobacter (10.8%), Propionibacterium (9.3%), Corynebacterium (9.3%), Staphylococcus (7.2%), Streptococcus (7%), Pseudomonas (4.1%), Micrococcus (3.3%), Yersinia (3%), Chondromyces (2.4%), Serratia (2.3%), and Bacillus (2.1%). Analysis of the samples obtained directly from the mucosa revealed dominance of typical skin-associated microorganisms. CONCLUSION: The present study proposes a contamination-reduction algorithm for microbiological testing of the ocular surface using hard contact lenses for prolonged wearing as a carrier for microbial DNA.

[Clinical and morphological changes in the eye in Fabry's disease (a clinical case study)]. / Kliniko-morfologicheskie aspekty izmeneniia glaza pri bolezni Fabri (klinicheskii sluchai).

The article presents a clinical case of Fabry's disease accompanied by changes in the eye and gives detailed description of standard ophthalmological examination and results of some modern methods of assessing macro- and micro-structure of certain ocular tissues. Fabry's disease (also known as Anderson-Fabry disease, diffuse angiokeratoma of the body, hereditary dystonic lipidosis) is a progressive hereditary multi-systemic disease; more specifically, it is a progressive congenital defect in the metabolism of tissues of the human body. It is included in the list of orphan diseases. One of its local manifestations is development of dystrophic changes in the structure of the cornea with tendency to progress. Early diagnosis of Fabry's disease is crucial, but its extensive and 'mixed' symptoms often mask the true causes of pathological changes, which leads to late diagnosis.

[Secondary dry eye syndrome after keratorefractive surgeries and approaches to its treatment and prevention]. / Vtorichnyi sindrom 'sukhogo glaza' posle keratorefraktsionnykh vmeshatel'stv i podkhody k lecheniiu i profilaktike.

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. Therefore, intensive and early treatment of secondary DES during the early follow-up period after refractive surgery may significantly reduce risks of tear dysfunction and neurotrophic epitheliopathy development in the long term.

[Topical cyclosporine for the treatment of ocular surface changes in contact lens wearers].

OBJECTIVE: To assess opportunities for the use of cyclosporine emulsion 0.05% for the treatment of dry eye syndrome in long-term contact lens wearers. MATERIAL AND METHODS: A total of 25 long-term contact lens wearers (50 eyes) with signs of dry eye syndrome and corneal epitheliopathy of different degree, unresponsive to conventional artificial tears therapy, were observed. All of them were prescribed cyclosporine emulsion 0.05% twice daily at 12-hour intervals 10 min before inserting contact lenses or after removing. Biomicroscopy with fluorescein eye stain test, determination of the tear film break-up time (Norn's test), optical coherence tomography of tear meniscus (OCT-meniscometry), Jones test, impression cytology, and corneal confocal microscopy (Confoscan-4, "Nidek", Japan) were used to evaluate the treatment effect. RESULTS: The treatment resulted in better contact lens tolerance, significantly increased mean values of tear film break-up time (by 13.2% at 1 month, 62% at 3 months, and 37.3% at 6 months as compared with the baseline) and basal tear secretion (by 29%, 32%, and 82.4% at 1, 3, and 6 months correspondingly). Confocal microscopy revealed restitution of corneal superficial epithelial structure and cell density. Goblet cells were present in impression cytology specimens. CONCLUSION: Topical use of cyclosporine emulsion 0.05% has a positive effect on morphofunctional parameters of ocular surface and promotes basal tear secretion and precorneal tear film stability.

[Intralamellar bandage keratoplasty for the treatment of progressive keratoconus (draft report)].

The article discusses surgical options currently available for different stages of keratoconus. Indications and possible complications of each method are described in detail. So called intralamellar bandage keratoplasty, a new surgical procedure developed in the Research Institute of Eye Diseases and aimed at stabilizing the disease, is presented. Preliminary results suggest that the procedure is a promissing method for corneal thickness restitution and early stabilization of progressive keratoconus.

[Corneal protection in contact lens users].

PURPOSE: To evaluate the efficacy of corneoprotective agents (Corneregel and Solcoseryl) in contact lens users. MATERIAL AND METHODS: A total of 66 long-term contact lens wearers with dry eye symptoms and varying degrees of corneal epitheliopathy were monitored. All patients used artificial tears, which, however, were not effective enough to suppress manifestations of corneal epitheliopathy and to release the associated discomfort. The therapy was supplemented with Corneregel. The following examination methods were applied: biomicroscopy with fluorescent staining, Norn test, Schirmer's test, advanced tearscopy with digital image analysis of the precorneal tear film lipid layer, corneal confocal microscopy. In all cases the assessment was performed prior to starting Corneregel and repeated in 7 days, 14 days and 1 month. RESULTS: Complete corneal re-epithelization and restoration of the most superficial layer of the epithelium were achieved within 7-14 days. In case of severe initial epitheliopathy the effect of Corneregel was not sufficient and epithelium defects remained. These patients additionally received Solcoseryl Eye Gel. After the treatment course the condition of corneal epithelium ameliorated and contact lens wearing comfort increased. A longer precorneal tear film break-up time indicated an increase of tear film stability. The total tear production did not change significantly. The moistening effect of Corneregel and low-viscosity artificial tears together with intensive regeneration of corneal epithelium enables structural recovery of the epithelial membrane and considerable improvement of the anterior corneal stroma. CONCLUSION: At the first stage of corneoprotective treatment it is appropriate to use preservative-free artificial tears of low and high viscosity. If the effect of tear substitutive therapy is unsatisfactory it is recommended to prescribe Corneregel and Solcoseryl. The regimen is to be adjusted individually.

[Clinical significance of modern methods of corneal assessment].

The article observes the application experience of modern methods of corneal refraction and structure evaluation. Comprehension of computer-assisted videokeratography is high enough to diagnose corneal astigmatism, keratoconus, early-stage corneal dystrophies, and corneal topography changes resulting from a variety of factors. Scanning projecting keratography provides information on both anterior and posterior corneal topography and elevation, as well as corneal thickness in each point of central area. Aberrometry can be used for estimation of the impact of different factors on corneal optical properties and assess the possibility for correction of resultant disturbances. Confocal microscopy allows to evaluate morphological changes in keratoconus and corneal dystrophies and also diagnose acanthamoeba keratitis. Optical coherence tomography provides the possibility of whole cornea assessment, however, with much less magnification in comparison to confocal microscopy. Improved tearscopy with computed analysis of interference digital images ("Lacrima" software) enables evaluation of lipid layer thickness and structure in normal and impaired tear film (like in dry eye syndrome), as well as the influence of different factors and therapeutic measures. Topographical pachymetry data is the most valuable for diagnostics and monitoring of keratoconus.

[Potential of impression cytology in diagnosis and evaluation of efficacy of pharmacological correction of dry eye syndrome associated with contact lens wearing].

Potential of impression cytology in diagnosis and evaluation of efficacy of pharmacological correction of dry eye syndrome (DES) associated with contact lens wearing was studied. When wearing contact lenses for a long time DES with tear film instability and reduction of tear production occurs in more than 50% patients. Morphological changes of epithelium of tarsal and bulbar conjunctiva manifest consequently. Impression cytology reveals structural damage of epithelium with keratinization signs and decrease of goblet cells density down to total absence. After tear substitution therapy tear break-up time increased by 65,3% and total tear production by 11,4%. In control impression cytology of tarsal and bulbar conjunctiva during tear substitution therapy the following changes were revealed: recovery of goblet cells density and differentiation, recovery of epithelial structure and reduction of epithelium keratinization.

[Diagnostic value of confocal microscopy in primary corneal ectasia].

Diagnostic value of confocal microscopy in subclinical corneal ectasia is analysed. Morphological changes were revealed in 71.2% of cases with subclinical keratoconus. Results of the study let us reveal typical morphological abnormalities in subclinical keratoconus, although these changes are not specific for this condition. The method is also not informative for detecting of early signs of pellucid marginal degeneration. Confocal microscopy may be considered an additional specifying method in diagnostic algorithm of subclinical corneal ectasia.

[Improvement and estimation of tearscopy potentials].

New potentials of improved tearscopy technique based on photoregistration of colour interference phenomenon are presented. A new softwear "Lacrima" was developed in order to objectivate the results and to get more detailed data, it allows to reveal data on lipid layer thickness (LLT), estimate relative area of examined zone (in %) with certain LLT as well as regularity of lipids distribution. Digital images of interference picture of precorneal tear film of 13 healthy objects (26 eyes) and 20 patients with exogenous dry eye syndrome were analyzed. In eyes with dry eye syndrome compared to normal eyes increase of uncertainty zone and zone with minimal LLT were revealed for 13,2 and 12,8% respectively. Relative area of zones with increased LLT decreased for 16,7 and 56,3 % respectively. Computer analysis of interference picture of precorneal tear film using softwear "Lacrima" allows to extend capabilities of tearscopy and get additional data on lipid layer status.