[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.

[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.

[Reducing cytotoxic action of the preservative employed in ophthalmic hypotensive medications with tear replacement therapy]. / Snizhenie tsitotoksicheskogo deistviia konservanta v sostave oftal'mogipotenzivnykh preparatov s pomoshch'iu slezozamestitel'noi terapii.

PURPOSE: to assess the possibilities of reducing the cytotoxic effect of benzalkonium chloride (a preservative used in ophthalmic hypotensive drugs) with the help of tear replacement therapy. MATERIAL AND METHODS: The study included 28 patients (56 eyes) who had been using antiglaucomatous drugs containing benzalkonium chloride as a preservative for various periods (from 2 months to 17 years). The examination was performed in the setting of compensated IOP. In addition to hypotensive topical medication regimen, all patients were prescribed Stilavit eye drops. Subjects were examined prior to the prescription of artificial tears and after 1, 3 and 6 months of its usage. Effectiveness of the treatment was evaluated with biomicroscopy, Norn's test, Jones test, tearscopy, OCT-meniscometry, confocal microscopy, and impression cytology. RESULTS: The use of 'Stilavit' artificial tears in combination with antiglaucoma drugs led to an improvement of the corneal epithelium condition in 85% of cases, a statistically significant increase in the mean values of precorneal tear film rupture time after 1, 3 and 6 months by 26%, 61.2% and 85.8% respectively. Maximum increase of main tear production level was achieved after 3 months of treatment (increased by 43.5%), and was accompanied by 18.6% rise of the lower tear meniscus height after 3 months; in 6 months it raised by 29.4%. A tendency for restoration of the lipid layer of the tear film was observed. According to confocal microscopy and impression cytology, positive dynamics in the condition of corneal epithelium and conjunctival epithelial layer were present. CONCLUSION: The study results justify the use of tear replacement therapy, in particular the tear substitute Stilavit, as an additional protective agent for glaucoma treatment regimen.

[Reasons to reconsider interpretation of densitometry for corneal transparency]. / O neobkhodimosti peresmotra interpretatsii dannykh densitometricheskoi otsenki prozrachnosti rogovitsy.

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). Light scattering intensity was measured with Pentacam (USA). The densitometric curve and brightness maxima of the epithelium and neighboring stroma as well as the mid and upper stroma were recorded for each patient. RESULTS: A physico-mathematical model of the interaction between a light beam and the two-layer epithelium-stroma system was created. The study confirmed our theoretical CONCLUSION: on the effect size of light scattering intensity on the apparent densitometric brightness of the stroma. CONCLUSION: Direct densitometry of multilayered spherical objects, of which each layer possesses its own optical properties, has been proved inaccurate. Complex optical interactions in a multilayered model cause a false increase in brightness of more transparent layers that lie behind those with pronounced light scattering properties. The function that describes the false increase in scattering ability of the layer that is more transparent rises sharply at the border between the layers.

[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.

[Keratoconus. Diagnostic and monitoring methods].

Up-to-date methods for diagnosis and monitoring of keratoconus are reviewed. Main advantages and drawbacks in early keratoconus diagnosis are analyzed for such methods as videokeratography, ultrasound corneal pachymetry, aberrometry, scanning projection corneal topography, confocal microscopy.

[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.

[Intrastromal corneal segments implantation in keratoconus].

Comparative analysis of intrastromal corneal segments Keraring implantation using either femtosecond laser or manual technique to create corneal tunnel in 47 patients (47 eyes) with keratoconus stage II-III is presented. Refractional and functional results in groups with femtosecond laser and manual technique did not show significant difference. The main advantage of femtosecond laser revealed in the study is technical simplification of intrastromal tunnels creation.

[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.

[Functional results of contact lens correction and penetrating keratoplasty in keratoconus. Report 1. Analysis of resolution ability of the eye].

Comparative analysis of functional results of contact lens correction and penetrating keratoplasty (PKP) in keratoconus are presented. To assess resolution ability we considered visual acuity and contrast sensitivity. 117 patients (219 eyes) with stage I-IV keratoconus, wearing rigid gas-permeable contact lenses (RPCL), and 60 patients (64 eyes) after PKP were examined. In 69% patients after PKP non-corrected visual acuity (NCVA) was 0.1 or more and mean best corrected visual acuity (BCVA) was 0.63, that is similar to efficacy of contact lens correction in stage III-IV keratoconus. In 31% patients NCVA after PKP was less than 0.1 due to significant refractive arrow, visual rehabilitation of these patients required use of RPCL or refractive surgery. Contrast sensitivity in medium frequencies after PKP was almost similar to that of contact lens correction in stage III keratoconus, and in high frequencies it was close to that of stage IV.

[Functional results of contact lens correction and penetrating keratoplasty in keratoconus. Report 2. Wavefront analysis].

Comparative analysis of optic aberrations in contact lens correction and after penetrating keratoplasty (PKP) in keratoconus are presented. 117 patients (219 eyes) with stage I-IV keratoconus, wearing rigid gas-permeable contact lenses (RPCL), and 60 patients (64 eyes) after PKP were examined using OPD Scan (NIDEK, Japan) to assess aberration characteristics. Total optic aberrations and higher-order aberrations of ocular and corneal wavefront were significantly increased after PKP compared to those in patients with I-III stage keratoconus wearing RGCL. Astigmatic aberrations after surgery are increased compared to that in patients wearing RGCL regardless of keratoconus stage. Generally, according to objective aberrometry efficacy of PKP is similar to that of contact lens correction in IV stage keratoconus.

[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.

[Confocal microscopy of the cornea. Communication 1. The normal morphological pattern].

The paper presents the results of life-time confocal microscopy using a Confoscan-4 confocal microscope (Nidek). The study was conducted on 10 healthy volunteers (20 eyes), which evaluated the specific features of the normal morphological pattern of the cornea. The morphological features of three types of anterior corneal epithelial (basal, wing, and spiny) cells were revealed. The possibilities of visualizing subbasal and stromal nerve fibers were assessed. Corneal stromal layers (these being anterior, anteromedian, median, and posterior) differing in the density of cellular elements, their shape, and orientation) were conventionally identified. In health, Bowman's and Descemet's membranes were not visualized as they were transparent and failed to reflect light. The posterior corneal epithelium was microscopically presented by a layer of light hexagonal or polygonal squamous cells with well-defined outlines. Thus, life-time corneal confocal microscopy is a highly informative noninvasive study.

[Confocal microscopy of the cornea. Communication 2. Morphological changes in keratoconus].

The paper presents the results of studying morphological changes in keratoconus by life-time confocal microscopy. A total of 50 patients (100 eyes) with grades 1-to-4 keratoconus were examined. The most pronounced changes were found in the corneal areas involved in an ectatic process. Four grades of epitheliopathy were conventionally identified in relation to the desquamation of superficial epitheliocytes, the change of their shape, impaired adhesion with the underlying layers, and transparency disorders. The indirect signs of altered Bowman's membrane were revealed. In early keratocons, the stroma showed hyperreflectivity of anterior layers, higher activated keratocytes, their changed shape and spatial orientation. The emergence of microstrium in the posterior stromal layers with their gradual spread to the midstroma and anterior stroma, abnormal transparency, and scarring were typical of the progress of the disease. There were processes of homogenization and fibrotization of stromal structure and fewer keratocytes. There might be changes in Descemet's membrane (undulating folds) and posterior epithelium (polymegatism, polymorphism, enlarged intercellular spaces, and cell apoptosis). Thus, confocal microscopy reveals certain regularities of a pathological process in keratoconus at different stages of the disease.

[Influence of long-term contact lens wear on the cornea according to the data confocal microscopy].

The paper presents the results of a comparative study of corneal morphological changes by lifetime confocal miscroscopy in the long-term use of various types of contact lenses (CLs). Twenty-two patients (44 eyes) were examined, of them 8 patients (16 eyes) had worn soft CLs (SCLs) for 10-25 years (mean 17 years). 8 (16 eyes) had used hard CLs (HCLs) made of polymethyl metacrylate for 17-30 years (mean 23 years), 6 (12 eyes) had worn HCLs for 15 to 30 years (mean 20 years), hard gas-permeable CLs (HGCLs) over the past 5-15 years. The findings suggest that long-term wear of corrective CLs may lead to significant structural impairments in different corneal layers. The most characteristic changes are different types of epitheliopathies and the emergence of the signs of stromal degeneration with formation of deposits. According to our evidence, the likelihood of the detected changes increases with the long use of SCLs and reduces with the wear of HCLs, HGCLs in particular, which allows the authors to recommend that SCLs be changed to HGCLs after long (more than 10-15-year) contact correction.