[Glaucoma surgery: from traditional filtration techniques to modern principles of bioengineering]. / Khirurgicheskoe lechenie glaukomy: ot klassicheskoi pronikaiushchei khirurgii do primeneniia metodov tkanevoi inzhenerii.

The article reviews the history of glaucoma surgery and analyses the connection between the accumulation of knowledge on glaucoma progression and the emergence of effective surgical treatment methods based on glaucoma pathogenesis. It also describes modern principles of preventing filtering bleb scarring. Particular attention is devoted to biodegradable collagen matrix implants.

[Bandage keratoplasty therapeutic-optical in treatment of progressing pellucid marginal corneal degeneration (a preliminary report)]. / Bandazhnaia lechebno-opticheskaia keratoplastika pri progressiruiushchei pelliutsidnoi marginal'noi degeneratsii rogovitsy (predvaritel'noe soobshchenie).

PURPOSE: To provide preliminary estimation of the effectiveness of bandage therapeutic-optical keratoplasty (BTOK; previously called inralamellar bandage keratoplasty) in patients with pellucid marginal corneal degeneration (PMD). MATERIAL AND METHODS: The study included 7 patients (8 eyes) with PMD aged 35 to 55 years operated with intralamellar bandage keratoplasty, the follow-up period comprised 3, 6, and 12 months after the surgery. RESULTS: All patients with PMD operated with intralamellar bandage keratoplasty showed increase in visual acuity to an average of 0.55±0.35 a year after the surgery; by that time, the maximum refractive power of the cornea decreased to an average of -44.5±3.0 D. The area of stromal thinning was thickened by donor corneal flap. No signs of rejection were detected over the entire observation period. CONCLUSION: Intralamellar bandage keratoplasty may be the method of choice to stop further progression of PMD with improvement of optical properties of the cornea.

[Compensating the Descemet's membrane defect (a clinical case study)]. / Kompensatsiia defekta destsemetovoi membrany (klinicheskoe nabliudenie).

The article describes a clinical case of Descemet's membrane detachment that occurred during cataract phacoemulsification with implantation of intraocular lens. Significant corneal edema developed in the early post-op period. Considering the ability of endothelium to close its own defects even with large injury area, the patient was followed-up for 2 years. Corneal edema was treated during 4 months and concluded with instillations of osmotic and anti-inflammatory drugs. At 1.5-2 months of therapy, the edema was gradually decreasing, and by the 4th month of the follow-up the cornea was practically transparent. Density of endothelial cells in central cornea, where the Descemet's membrane was absent, comprised 1000 cells/mm2. Further observation revealed cornea staying transparent for 2 years after the surgery. Complete optical recovery of patients with Descemet's membrane defect in this case study is supported by similar clinical cases briefly described in the article, and evidence that structural functional recovery of the corneal endothelial layer is possible even when it has large defects (more than 2.5 mm in diameter).

[Polishing of Bowman's membrane with diamond burr in the treatment of recurrent corneal erosion syndrome]. / Abrazivnaia shlifovka boumenovoi membrany almaznym borom v lechenii retsidiviruiushchei érozii rogovitsy.

PURPOSE: To study the effectiveness of polishing Bowman's membrane with a diamond burr (DBPBM) in the treatment of recurrent corneal erosion syndrome (RCES). MATERIAL AND METHODS: The study included 22 patients (22 eyes) with RCES aged 20-56 years who underwent our original modification of DBPBM. All patients had keratotopography examined, endothelial cell density measured, and optical coherence tomography (OCT) of the cornea taken before and after the procedure. Additionally, conjunctival scraping, blood test for types I and II herpes (fluorescent antibody method) were performed before the surgery. Post-operative treatment included 1-2 weeks of anti-inflammatory and anti-bacterial steroid therapy, and 6 months of artificial tear Cationorm usage. RESULTS: Rehabilitation of all patients after the procedure went quickly, and no relapses were noted during the follow-up. Complete epithelialization of the area of surgical intervention under soft contact lens occurred over 2-3 days. Epithelial thickness was measured with OCT including epithelial mapping; after the surgery, it was almost even over the entire corneal surface. No complications such as induced post-operative refractive error or corneal haze were registered during the course of the study. Disruption of basal epithelial layer and epithelial basal membrane in the area of erosion relapse detected with scanning electron microscopy confirmed the need for their removal in the course of the surgery. CONCLUSION: Conservative treatment of RCES rarely yields results. Removal of inadequate epithelium and following DBPBM using our original method is a highly effective and accessible procedure for RCES treatment with low risk of complications and relapse.

[Clinical results of aphakia correction with multifocal intraocular lenses]. / Klinicheskie rezul'taty korrektsii afakii mul'tifokal'nymi intraokulyarnymi linzami.

AIM: to assess visual functions and ergonomics after bilateral versus unilateral implantation of Lentis Comfort LS-313 MF15 multifocal intraocular lenses (MIOL) in aphakic eyes. MATERIAL AND METHODS: A total of 20 patients with М LENTIS LS-313 MF15 MIOLs were followed up. Group 1 consisted of 12 patients after bilateral symmetric implantation, group 2 - of 8 patients after unilateral procedure. The following parameters were examined: uncorrected binocular visual acuity at far, near, and intermediate distances under photopic and mesopic conditions, the range of pseudoaccommodation, spatial contrast sensitivity to achromatic sinusoidal gratings, lens stability with account to its optical design, and patient satisfaction with the resultant vision. RESULTS: In both groups, distance visual acuity was high under any lighting conditions. At near and intermediate distances as well as at 5-6 m, binocular visual acuity in group 1 was higher than in group 2, regardless of the lighting conditions. The range of pseudoaccommodation was 3.5 D and 3.25 D in groups 1 and 2, respectively. Spatial contrast sensitivity function appeared typical, with maximum values at intermediate frequencies and lower values at higher frequencies. None of the patients required distance correction. Of 32 eyes, 7 exhibited MIOL rotation of 10-25 degrees at 1 month after surgery, however, none of the patients presented complaints characteristic of IOL decentration. CONCLUSION: Bilateral symmetric implantation of М LENTIS LS-313 MF15 MIOLs has the advantage over a unilateral procedure, since it enables a wider range of pseudoaccommodation and less dependence on lighting conditions with no compromise of high visual acuity at far and intermediate distances.

[Objective assessment of donor material for penetrating corneal transplantation]. / Ob''ektivizatsiia otsenki donorskogo materiala dlia skvoznoi peresadki rogovitsy.

Reliable suitability evaluation of donor material is the crucial issue of penetrating corneal transplantation. The main parameter to be considered is endothelial cell density (ECD). However, when it comes to practice, one has to admit significant variation in ECD readings of cadaver corneas obtained by different methods. AIM: to investigate discrepancies in ECD measurements and to define objective criteria for the evaluation of a donor cornea before full-thickness grafting. MATERIAL AND METHODS: In a hundred cadaver eyes, discrepancies in ECD measurements by different methods (specular microscopy, confocal microscopy, and keratoanalyzer) were studied and objective evaluation criteria developed along with an optimal algorithm of pretransplantation assessment. Digital fluorescence microscopy was chosen as the reference method. RESULTS: It has been established that a triple measurement average obtained with any of the tested methods is informative enough as to the state of the donor cornea. CONCLUSION: The highest ECD values were obtained with specular microscopy, the lowest - with confocal microscopy. For reliable evaluation of donor corneas, we recommend that the average of a triple ECD measurement be taken using one of the mentioned methods.

[Mechanisms of corneal neovascularization and modern options for its suppression]. / Mekhanizmy rogovichnoi neovaskuliarizatsii i sovremennye vozmozhnosti ee podavleniia.

Quite a number of pathological factors exist that can disturb the balance between anti-angiogenic and proangiogenic mechanisms, thus causing vascularization of the cornea. The neovessels are immature, ill-formed, and show increased permeability, which is dangerous of corneal edema, lipid deposition, and opacification. Moreover, as known, corneal neovascularization (CNV; preexisting or postoperative) may contribute to immune response against the transplant. Suppression of neovascularization is able to decrease the risk of corneal transplant rejection. In order to identify the principal strategy for struggling against CNV, we should first get a better understanding of its etiology, pathogenesis, and role in transplant immunity as well as mechanisms of action of available treatment methods.

[Intraocular pressure, ocular blood flow, and corneal biomechanics changes after LASIK surgery for myopia]. / Vliyanie operatsii LASIK pri miopii na pokazateli oftal'motonusa, ob''emnogo glaznogo krovotoka i «biomekhaniki¼ rogovitsy.

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 9.0 D were examined before and after LASIK. Ocular Blood Flow Analyzer (OBFA) was used to measure IOP and OBF as well as pulse amplitude and volume. Ocular Response Analyzer (ORA) was also employed to provide the following data: Goldmann-equivalent IOP, corneal compensated IOP, corneal hysteresis, and corneal resistance factor. The eyes were then divided into two groups: group 1 - 15 eyes with less than 70-µm deep ablation of the cornea and group 2 - 17 eyes with more than 70-µm deep ablation. RESULTS: Group 1 demonstrated a statistically reliable decrease in IOP values provided by either method and biomechanical parameters of the cornea (p<0.005), but no difference in pre- and postoperative OBF, or pulse amplitude, or pulse volume (p>0.05). In group 2, all the parameters changed reliably, except for the pulse volume (p>0.05). In particular, a decrease was recorded for IOP (with no dependence to the method of measurement; p<0.001), pulse amplitude (p<0.01), corneal hysteresis (p<0.001), and corneal resistance factor (p<0.001); an increase - for OBF (p<0.05). CONCLUSION: One should allow for possible mismeasurement of IOP and OBF as well as biomechanical parameters of the cornea in post-LASIK patients, keeping in mind that the extent of error depends on the depth of ablation. Shallow ablation (no more than 70-µm deep) has no statistically significant effect on OBF readings, while IOP seems to decrease considerably. In deep ablation (more than 70-µm deep), both parameters are reliably lower than at baseline.

[Clinical results of aphakia correction with bifocal intraocular lenses].

AIM: To evaluate the effect of symmetrical vs. asymmetrical and bilateral vs. unilateral implantation of M LENTIS LS-312 MF 30 multifocal intraocular lenses (IOLs) on visual functions and ergonomic parameters. MATERIAL AND METHODS: A total of 44 patients (68 eyes) with lens opacities of different intensity were enrolled. Group 1 included 24 patients who underwent symmetrical bilateral multifocal IOLs implantation, group 2--20 patients who received unilateral procedure. Binocular uncorrected near and intermediate visual acuity (VA) under photopic and mesopic conditions, amplitude of pseudoaccomodation, and spatial contrast sensitivity to achromatic sinusoidal gratings were evaluated. Patient's satisfaction with visual results was also analyzed. Taking into account the peculiar design of multifocal IOLs optics, lens rotational stability in the postoperative period was also assessed. RESULTS: Regardless of lighting conditions binocular distance VA was similarly high in both groups, while binocular near and intermediate VA was higher in group 1 as compared with group 2. The amplitude of pseudoaccomodation in groups 1 and 2 was 3.75 and 3.5 diopters correspondingly. Contrast sensitivity function was of typical shape peaking at intermediate frequencies and gradually decreasing toward higher frequencies. None of the patients from either group required optical correction for distance vision. Two patients from group 2 (and none from group 1) at times were in need of reading vision correction. Another patient from group 2 used spectacles for intermediate work. To evaluate lens rotational stability in the postoperative period, the alignment of axis marks on the IOL with the horizontal meridian of the eye was checked under maximum mydriasis. At the 1-month follow-up, rotation of 10-15 degrees was found in 31 eye, however, none of the patients presented complaints characteristic of IOL decentration. CONCLUSION: Symmetrical bilateral implantation of M LENTIS LS-312 MF 30 multifocal IOLs provides advantages over unilateral procedure because not only does it allow to retain high distance VA, but also ensures larger amplitude of pseudoaccomodation at near and intermediate distances.

[Abnormal distribution of trace elements in keratoconic corneas]. / Pereraspredelenie mineral'nykh elementov v rogovitse pri keratokonuse.

UNLABELLED: Our understanding of etiology and pathogenesis of many disorders, corneal included, greatly relies on existing knowledge in human biochemistry and biophysics. This study was aimed at chemical mapping of normal and keratoconic corneas. MATERIAL AND METHODS: Modern methods of analytical chemistry, such as X-ray fluorescence and energy-dispersive X-ray spectroscopy on the basis of scanning electron microscopy, were adapted to the needs of cornea research. Normal human corneas obtained postmortem and corneal buttons obtained during penetrating keratoplasty were analyzed. RESULTS: In keratoconus, abnormal accumulation of iron, copper, and zinc was found in the periphery of the buttons, i.e. in the zone of visible pigmentation (Fleischer ring), while the center - the ectatic zone - demonstrated a total deficiency of trace elements. This data suggests that keratoconus pathogenesis is associated with impaired mineral metabolism and formation of a physicochemical barrier in corneal tissues with subsequent keratectasia. The authors discuss several possible vicious circles involved.

[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.

[Effects of blood flow properties on ocular hemodynamics].

AIM: to study the effects of blood rheology on ocular blood flow (OBF) parameters and estimated individual normal range of intraocular pressure (IOP). MATERIAL AND METHODS: A total of 15 patients (15 eyes) taking warfarin were enrolled. Volumetric parameters and linear velocity of OBF under warfarin treatment and after its cessation were obtained by means of flowmetry (Paradigm's Blood Flow Analyzer) and color Doppler flow mapping (Voluson 730), respectively. On the basis of flowmetry results an individual normal range of IOP was calculated in all patients. RESULTS: Pulsatile OBF does not appear to correlate with warfarin-induced changes in blood rheology (p = 0.09), however, depends on IOP fluctuations (p = 0.02). Resistance index of retinal vessels is found to rise significantly with increasing blood viscosity (p < 0.05). CONCLUSION: The use of warfarin, an indirect thrombin inhibitor, has no effect on estimated individual normal range of IOP, which is crucial for glaucoma diagnosis and monitoring.

[Tomography findings in optic nerve head and retina in differential diagnosis between normal-tension glaucoma and ischemic optic neuropathies].

AIM: to determine tomography findings in optic nerve head (ONH) and retinal nerve fiber layer (RFNL) that may be valuable for differential diagnosis between normal-tension glaucoma (NTG) and ischemic optic neuropathy (ION) outcome. MATERIAL AND METHODS: Group 1 consisted of 17 patients (32 eyes) with NTG, group 2--17 patients (24 eyes) with ION outcome. The control group included 22 patients (22 eyes) with no sighs of optic neuropathy. Optic nerve head and retina assessment included scanning laser ophthalmoscopy (HRT 111) and optical coherence tomography (Stratus OCT 3000). Statistical analyses were performed using Statistica 10 software suite. RESULTS: Statistically significant changes in HRT parameters, namely, the mean RNFL thickness, retinal height variation along the contour line, and RB discriminant function, were observed in both study groups as compared to the controls. NTG patients also showed lower rim indices, larger cups, smaller values of the FSM discriminant function, and lower GPS (glaucoma probability score) than both ION patients and the controls. OCT findings included a statistically significant decrease in RNFL thickness in both study groups as compared to the controls. As for the difference between the groups, it was unreliable. Quadrant comparisons of RNFL thicknesses revealed that lower quadrant RNFL thinning was more significant in NTG patients, while temporal quadrant RNFL thinning--in ION patients. CONCLUSION: Both conditions are associated with a similar degree of RNFL thinning, as confirmed by OCT, however, HRT changes are much more pronounced in NTG than in ION patients.

[Ocular blood flow and carotid artery malfunction].

AIM: to evaluate ocular hemodynamics and informativity of estimated individual normal range of intraocular pressure (IOP). MATERIALS AND METHODS: A total of 12 patients (22 eyes) with carotid artery malfunction were examined. Ocular blood flow (OBF) and IOP were measured with Ocular Blood Flow Analyzer. Actual OBF was then compared with what is considered normal for a given axial length (AL). Individual normal range of IOP was calculated according to an original formula (described in previous publications). Doppler imaging of ocular vessels enabled blood flow velocity measurement. Morphological parameters and functional status of the retina and optic nerve were judged on automated perimetry (Octopus 900) and optical coherence tomography (Cirrus HD-OCT) findings. Statistical analyses were performed using Statistica 10 software. RESULTS: Generally, OBF showed no correlation with the grade of carotid artery stenosis (p < 0.05), however, was significantly reduced as compared to its AL-dependent norm in patients with greater than 85% narrowing of the internal carotid artery, which can cause misestimating of their individual normal range of IOP. A negative relationship was established between the blood flow velocity in short posterior ciliary arteries and the grade of internal carotid artery stenosis (p < 0.005). Ocular blood flow deficit relative to the AL-dependent norm correlated with ophthalmic artery resistance index. CONCLUSION: OBF-based estimation of individual normal range of IOP is inexpedient in patients with greater than 80% carotid artery stenosis due to its possible influence on ocular hemodynamics. In most cases of less than 80% carotid artery stenosis OBF is adequate or slightly reduced as compared to its AL-dependent norm and thus, has no significant impact on estimated individual normal range of IOP.