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Given the prevalence of refractive surgery in modern ophthalmological practice, when preparing a patient for this type of surgery, it is important to understand the multifactorial mechanism of the development of dry eye syndrome in this group of patients. Analysis of the literature data made it possible to identify key factors in the disruption of the tear formation process after refractive surgery, which include the intersection of the nerve endings of the cornea, which in turn reduces the frequency of blinking and the distribution of the tear film over the ocular surface, and also causes a violation regarding neurotrophic factors secreted by the nerve endings of the cornea . The presence of a postoperative inflammatory reaction, which has a specific course, manifested in a change in the biochemical properties of the tear, damage to the goblet cells of the conjunctiva during the creation of a vacuum during LASIK and SMILE, leading to a subsequent deficiency of mucin in the tear, changes in the curvature of the cornea caused by laser refractive surgery are factors influencing the development of dry eye syndrome after refractive surgery. When preparing a patient for refractive surgery, to reduce the risk of developing severe forms of dry eye syndrome, including corneal ulceration, it is necessary to take into account a history of systemic diseases and allergic reactions, especially in patients with high myopia. The influence of cosmetic procedures, such as eyelash extensions, eyelid tattooing, blepharoplasty, and the use of botulinum toxin in the periorbital area on the course of the postoperative period during refractive surgery, has been poorly studied. Research in this area opens up a new range of opportunities to reduce the incidence of dry eye syndrome in patients after refractive surgery and improve the quality of life of patients and patient satisfaction with the surgical intervention.

Relevance. Today, the problem is particularly relevant for cases of keratoconus combined with high refractive ametropia. An extensive review of protocols for the combined use of corneal cross-linking (CXL) in combination with photorefractive keratotomy (PRK), phototherapeutic keratectomy (FTC), IRS, and phakic intraocular lens implantation shows that these protocols require further research to prove the best treatment options. Purpose. To evaluate the effectiveness of the fourstage model of surgical treatment of keratoconus in combination withhigh refractive ametropia. Material and methods. Between 2016 and 2019, 16 patients (22 eyes) aged 18 to 40 years were operated on using the four-step procedure including intrastromal corneal segments (ICRS) implantation, CXL the next day after the surgery, phakic toric lens implantation (Visian ICL STAAR, implantable collamer lens) 8 months after the surgery, and transepithelial topographic PRK 6 months after the surgery. The study group included patients with keratoconus stage II–III according to the classification of Amsler M. (1961). Patients were examined before, 10 days, 1, 3, 6, 8 and 12 months after the surgery according to a unified program, including determination of visual acuity without (NCVA) and with maximum correction (MCVA), autorefractometry (TOMEY RC-5000), non-contact tonometry (TOMEY FT-1000), Pentacam corneal topography, Wavelight Oculyzer (ALCON), Topolyzer VARIO tomography (ALCON), OCT of the anterior segment Cirrus HD-OCT 5000 (Zeiss, Germany). Results. Indicators of NCVA (M±SD) before and after the 1st operation were 0.02±0.015 and 0.08±0.022 (p=0.05). After the 2nd operation, the NCVA (0.10±0.025) didn’t change significantly, after the 3rd operation its value increased more than 4 times (0.42±0.11). After the 4th operation, a statistically significant increase in NCVA was observed (0.58±0.12). Conclusion. In patients aged 18 to 40 years with progression of keratoconus, with high myopia, due to the inexpediency of excimer laser operations and where the depth of the anterior chamber isn’t less than 3 mm, the combined four-stage method of treating keratoconus can be performed as a more effective method. This method allows to avoid keratoplasty, preserving and correcting the irregularity of the own cornea

Purpose: to evaluate the clinical and functional results of the operation the FemtoLASIK by excimer lasers with frequency more 1000 Hz in patients with low to moderate myopia.Patients and methods. The 84 eyes of 84 patients with low to moderate myopia who had undergone FemtoLASIK procedure using with excimer lasers: Schwind Amaris 1050 Hz (Germany) and Microscan Visum 1100 Hz (Russia) were included in the study. The “Schwind Amaris 1050 Hz” and “Microscan Visum 1100 Hz” groups were comparable in terms of pre-operative data (age, sex, corneal curvature, central thickness of the cornea, sphere, cylinder, SE) (p > 0.05). All patients underwent complete ophthalmological examination before refractive laser surgery, and also patients were examined on the 1st day and 1 month after FemtoLASIK.Results. One month postoperatively, in the “Schwind Amaris 1050 Hz” group the UDVA 1.0 or better (20/20 or better by Snellen) was achieved in 100 %, in the “Microscan Visum 1100 Hz” group — in 100 % (p > 0.05). There wasn’t observed a loss of the CDVA lines in both groups. In the “Schwind Amaris 1050 Hz” group gain of one or more lines of the CDVA was 14 %, in the “Microscan Visum 1100 Hz” group — in 12.2 % (p > 0.05). In the “Schwind Amaris 1050 Hz” group the predictability of targeted refraction within ±0.5 D was in 90.7, within ± 1.0 D — in 100 %, in the “Microscan Visum 1100 Hz” group — in 90.2 % and 100 %, respectively (p > 0.05).Conclusions. The FemtoLASIK procedure using with different high-frequency excimer lasers is an effective, safe and predictable method for correcting low to moderate myopia.

Purpose. To evaluate the corneal biomechanical properties using the CORVIS ST device (Oculus, Germany) in patients with myopia and myopic astigmatism with intact cornea as well as in patients with myopia and myopic astigmatism who underwent excimer laser refractive surgery using femtolaser or microkeratome.Material and methods. Totally the study included 65 patients aged 18 years to 56 years with myopia and myopic astigmatism of various degrees were examined. They were scheduled for excimer laser refractive surgery after laser refractive surgery in different periods from 5 days to 5 years. Among the additional methods of examination, all patients were measured the biomechanical properties of the cornea using a CORVIS ST device (Oculus, Germany).Results. After excimer laser refractive surgery performing for myopia and myopic astigmatism correction, indicators of the corneal biomechanical properties, namely indicators describing stiffness and elasticity were changed, as well as IOP i ndicators.Conclusion. The biomechanical properties of the cornea, such as stiffness and elasticity, can be assessed using the CORVIS ST device (Oculus, Germany). After excimer laser vision correction of myopia and myopic astigmatism, corneal stiffness and elasticity decreases. IOP value in patients after excimer laser correction of myopia and myopic astigmatism decreases. It is associated with a decrease in corneal thickness but is not associated with a true decr ease in IOP.

Purpose. To evaluate the effectiveness of dry eye syndrome (DES) treatment in patients with meibomian gland dysfunction (MGD) before refractive surgery.Materials and methods. We examined 48 women (aged 29.6 ± 3.9 years) with myopia, DES, and MGD of noninfectious etiology before performing LASIK. Group 1 of these patients received presurgical correction of DES for 2 months, including instillation of 3 % trehalose as a bioprotector (Thealoz®; 3–4 times a day); application of 5 % dexpanthenol in the conjunctival cavity (before going to bed); eyelid hygiene (2 times per day), which included cleaning (Theagel®), warm compresses on eyelid area, massage of eyelid margin (Blephaclean wipes). Group 2 only received bioprotective and reparative therapy for 2 months. Testing included a standard ophthalmological examination; assessment of DES symptoms (OSDI scale, points); BUT test (sec) and Schirmer-1 test (Sh-1, mm); measuring the height of the lower tear meniscus (optical coherence tomography, μm); lissamine green staining with calculation of xerosis index by Bijsterveld (points); assessment of MGD severity (points). Processing of the results included calculation of M ± s; Wilcoxon t-test, Mann Whitney U-test.Results. A positive change of OSDI (decrease from 31.9 ± 2.9 to 8.71 ± 1.1 points), xerosis index (decrease from 4.71 ± 0.5 to 2.1 ± 0.3 points) and BUT test (increase from 4.14 ± 0.53 to 8.66 ± 0.93 sec) was significantly stronger in patients of group 1 (p < 0.05) in comparison with patients of group 2 (decrease in OSDI from 33.2 ± 3.1 to 15.6 ± 2.4 points; decrease of xerosis index from 4.75 ± 0.50 to 3.7 ± 0.5 points; BUT increase from 4.21 ± 0.47 to 6.05 ± 0.73 sec). Apparently, this was caused by a significant decrease in the severity of MGD (from 2.1 ± 0.3 to 0.9 ± 0.2 points) and a decrease in the severity of lipid deficiency due to eyelid hygiene in patients of group 1. In group 2, MGD severity change proved unreliable. Change of Sh-1 and the height of the lower tear meniscus was unreliable in all cases. Conclusion. The inclusion of eyelid hygiene (Theagel and Blephaclean) in the pre-surgery preparation of patients with DES and MGD leads to a more significant correction of eye surface condition compared to isolated bioprotective and reparative therapy, thus providing an opportunity of more favorable conditions for carrying out surgical correction of ametropia.

Refractive surgery is a dynamically developing field of ophthalmic surgery, which requires studying new approaches for determining indications and contraindications for refractive surgery.Purpose. To investigate the possibility of expanding indications for refractive surgery in conditions related to contraindications on the example of four clinical cases.Material and methods. The study included 4 clinical cases of photorefractive operations in patients with relative contraindications who underwent refractive surgery (Femto-Lasik, photorefractive keratectomy (PRK), phototherapeutic keratectomy (PTK)).Results and discussion. Follow-up period of patients after Femto-Lasik, PRK and PTK was 1 year. During this period, stabilization of such parameters as intraocular pressure (IOP), progression of diabetic retinopathy, visual acuity was detected on all operated eyes. There were no postoperative complications. In the first clinical example, to avoid flap injury pneumotonometry was performed 72 hours after the surgery. IOP indices differed from preoperative ones and were 15 mm Hg because of the flap cut and the removal of part of the corneal tissue as a result of laser ablation. In the second clinical example, BCVA OU was 1.0 throughout the whole follow-up period. In the third clinical example recurrence of retinal detachment and any formations of new zones of peripheral vitreochorioretinal were not observed. BCVA improved up to 0.9–1.0. In the fourth clinical example, 3 months later, the patient complained for “misting” in the right eye. On examination, subepithelial fibroplasia of the 1st degree was revealed. After the course of treatment, the transparency of the cornea was restored. The data of the diagnostic examination after the surgery at the period of 1 month, 3 months did not differ and corresponded to preoperative ones. Diagnostic examination data 1 year after the operation: visual acuity: OD — 1.0; OS — 0.4 sph + 1.0Dcyl + 1.5Dax 45 = 0.8.Conclusion. The presented clinical examples allow us to reconsider the list of relative contraindications for performing refractive operations for compensated diabetes mellitus, glaucoma, retinal detachment, corneal opacities, as it can be performed safely and effectively with good refractive results.

Purpose: This study assesses the treatment outcomes of patients with thin corneas and/or borderline corneal topography who underwent combined refractive surgery using the SMILE Xtra technique., Material and Methods: The study included 53 patients (105 eyes) with myopia and a risk of developing keratectasia according to the Randleman criteria. All patients underwent prophylactic crosslinking following the SMILE procedure by introducing riboflavin solution into the corneal pocket, followed by ultraviolet irradiation according to the SUB-400 protocol with additional acceleration. The results were evaluated using data from Scheimpflug analyzer, analysis of corneal biomechanical properties, optical coherence tomography (OCT), and standard ophthalmological examinations. Follow-up lasted up to 12 months., Results: The preoperative spherical equivalent of refraction was -4.09±1.30 D, and postoperative measurements on day 1, day 7, and at 1, 3, 6, and 12 months were: -0.08±0.64; 0.1±0.53; 0.2±0.48; 0.05±0.52; -0.29±0.47; 0.1±0.49 D, respectively. On day 1, uncorrected visual acuity (UCVA) increased to 0.78±0.17, rising to 0.94±0.11 by day 7, and remained stable throughout the follow-up. Mean keratometry values preoperatively were 44.32±1.3 D, and 40.89±1.65 D on day 1, with no statistically significant changes throughout the follow-up. Central corneal thickness decreased from 528.30±28.71 μm preoperatively to 459.32±28.92 μm on day 1 and 440.54±29.12 μm on day 7. Patient complaints of blurred vision on day 1 were associated with mild corneal edema due to residual riboflavin and energy load from UV treatment; these symptoms resolved by day 7. No regression of refractive results or keratectasia was observed throughout the follow-up period., Conclusion: SMILE Xtra can be used for myopia correction in cases with an increased risk of postoperative keratectasia in patients with thin corneas and/or borderline corneal topography readings.

Purpose: The study investigates the influence of changes in keratometric parameters after refractive surgery on the results of Maklakov tonometry., Material and Methods: The study examined a total of 61 people (121 eyes). The patients were divided into a control group with no history of surgery (16 people, 31 eyes), a LASIK group (13 people, 26 eyes), a femtosecond-assisted LASIK (FS-LASIK) group (16 people, 32 eyes), and a photorefractive keratectomy (PRK) group (16 people, 32 eyes). The patients underwent standard examination, keratometry (Km), Maklakov tonometry with a 10 g weight, and elastotonometry with 5, 7.5, and 15 g weights., Results: In the LASIK group, the indentation diameter with 5 and 7.5 g weights correlated with Km in the central and near-paracentral zone ( r =0.3-0.5). Tonometry with a 10 g weight did not correlate with anything. Tonometry with a 15 g weight inversely correlated with Km in the paracentral points (4 mm) of the strong meridian ( r = -0.5 ... -0.7). In the FS-LASIK group, a significant inverse correlation with Km was observed only for the indentation diameter with a 10 g weight in the paracentral (3-4 mm) zone ( r = -0.4 ... -0.5). In the PRK group, weak ( r <0.4) correlations were found between Km and the indentation diameter of the 7.5 and 10 g weights for the central zone (1-2 mm). No significant correlations were found for 5 and 15 g weights., In the control group, there were practically no correlations for 5 and 7.5 g weights. The indentation diameter of the 10 g weight evenly correlated with Km at all points ( r = -0.38 ... -0.60), the indentation of the 15 g weight correlated mainly with the curvature of the horizontal meridian ( r = -0.37 ... -0.49)., Conclusion: Tonometry readings with the 10 g weight are the most dependent on Km in different groups, and the readings with the 5 g weight are the least dependent. LASIK is characterized by the largest scatter of dependencies for weights of different masses, FS-LASIK - by the smallest. Tonometry readings with the 5 g weight correlated with Km only in the LASIK group, and this was the only direct correlation. Considering the inverse nature of most correlations, higher Km may be associated with an overestimation of tonometry results, and lower Km - with its underestimation.

Disturbances of refraction are one of the most urgent problems of pediatric ophthalmology. Late and incomplete correction of refractive errors leads to the development of amblyopia, disturbances of binocular vision, the appearance of strabismus. Such complications reduce the quality of life, drastically limit the choice of professional child. Pediatric Ophthalmology always face a choice: many drugs and technologies are not approved for use in pediatric patients, practitioners are forced to use their «off-label», but such situations require great care and strict medical indications. For example, refractive surgery has worked well in adults, but its use remains controversial in children for security reasons and unpredictable effects. Several authors have described the use of laser refractive surgery in children under the age of 18 years, but there are no results of a multicenter, controlled study evaluating the safety, efficacy, and especially long-term results. In all the studies, the calculation was performed on adult nomograms ablation, while not proved how they are accurate for children. Long-term results and data on the endothelial cell density, corneal curvature changes in catamnesis are presented no longer than two years. Despite the fact that currently there is insufficient information about the results of remote application keratorefractive laser surgery in children, and there are no indication system and contraindications, modern achievements in medicine should be used in pediatric patients, and our successful track record proves it clearly. Undoubtedly, the positive experience of the laser surgery use in a child with clouding of the cornea in the outcome of herpetic keratitis, which provided a positive result: high visual acuity, binocular vision and lack of infection relapses for 2 years, requires study, evidence multicenter studies, and possibly expansion of indications for refractive laser surgery.

Purpose. To evaluate an adaptation ability of posterior chamber phakic IOL (pIOL-3) to a lower diameter of sulcus ciliaris in eyes with high myopia.Material and methods. The pIOL-3 was implanted in 3 eyes of 2 patients with high myopia (spherical component: -22.5D), where the sulcus ciliaris diameter was lower than «pIOL-3» length to 0,5mm. The uncorrected visual acuity (UCVA) did not exceed 0.01, the best corrected visual acuity (BCVA) – 0.4. The followup was 1 year.Results. There were no complications intra- and postoperatively in all cases. The UCVA improvement up to 0.1 was noted already first hours after pIOL-3 implantation. The BCVA was limited by available alterations of macular area and did not exceed 0.4. The average loss of posterior epithelial cells did not exceed 2%. Any impact of performed surgical intervention on intraocular pressure was not revealed. The ultrasound biomicroscopy showed a good stable central pIOL-3 localization in the posterior chamber of the myopic eye without any excessive vaulting toward the anterior chamber within the entire follow-up.Conclusion. Constructive features of the pIOL-3 allow to avoid an excessive vaulting in cases of its implantation when the diameter of sulcus ciliaris is lower than the pIOL length. The pIOL-3 implantation in case of high myopia provides an achievement of maximum visual acuity already first hours after surgery.

Purpose. To develop a diagnostic and treatment algorithm of kerato-refractive surgery (KRS) choice after the optical reconstructive surgery with the implantation of iris-lens diaphragm and to evaluate the results of induced ametropy correction.Material and methods. In the follow-up 58 eyes (58 patients) with a residual ametropy and stable visual functions after reconstructive surgery with the implantation of iris-lens diaphragm were examined before and after keratorefractive operations. The PRK operation was performed in case of a corneal thickness less than 480µm and in presence of local thinning, the FemtoLASIK procedure – in case of a 480-500 micron pachymetry. The personalized laser ablation was carried out according to the corneal topography in the detection of irregular astigmatism.Results. Patients operated using the personalized ablation algorithm, after keratorefractive operations had a significant decreased SRI regularity index (р

Aim. To assess preliminary clinical functional outcomes of phakic intraocular lens pIOL-3 implantation in high myopia.Patients and methods. pIOL-3 was implanted in 6 patients (10 eyes) aged 27‑63 with high myopia and no concomitant pathologies. Follow-up period varied from 1 to 12 months. IOL is made of hydrophilic material Contamac CI26 with water content of 26% and refraction index of 1.46. pIOL design (holes in the haptic portions) provides its matching to ciliary sulcus size (0.5 mmless than linear size of the sulcus). Preoperative and postoperative examination included visual acuity measurement, biomicroscopy, ophthalmoscopy, visual field test, tonometry, endothelial microscopy, and ultrasound biomicroscopy. Simplicity of surgical technique, adaptability of haptics, and postoperative course were evaluated.Results. Early postoperative period was uncomplicated. Uncorrected (UCVA) and best-corrected visual acuity (BCVA) improved in the first hours after the surgery. No visual acuity worsening (as compared with preoperative BCVA) was observed. Surgical procedure did not affected IOP even despite the absence of basal iridotomy. Maximum endothelial cell loss was less than 5%. No IOL forward «vaulting» was observed.Conclusions. pIOL implantation in high myopia patients is safe and provides maximum visual acuity in the first postoperative hours. Owing to its design this IOL can be implanted into ciliary sulcus (which size is0.5 mmless than IOL diameter) without forward «vaulting».

The review presents possibilities of dry eye prophylaxis and treatment caused blepharitis and blepharoconjunctivitis after refrac- tive surgery. Among modern prophylactic approaches therapeutic eyelids hygiene is most promising for the everyday clinical practice.

The aim of this study was to evaluate corneal biomechanical properties in myopic patients after ReLEx SMILE and FemtoLASIK surgeries using the Corvis ST analyzer., Material and Methods: The SMILE group comprised 23 patients (46 eyes) with spherical refraction -3.8±1.8 diopters (D), the FemtoLASIK group included 18 patients (36 eyes) with spherical refraction -3.5±1.3 D. Analysis of the biomechanical properties of the cornea was carried out using the CORVIS ST device (Oculus, Germany) before and seven days after corneal refractive surgery., Results: In the SMILE group, with intraoperative decrease in corneal thickness of 91.43±19.43 µm, a significant increase in the following parameters was observed: deformation coefficient (DA ratio; p =0.0001), peak distance (PD; p =0.02) and inverse concave radius (ICR; p =0.003); a decrease in the stiffness parameter at first applanation (SP-A1; p =0.0001), Corvis biomechanical index (CBI; p =0.0001), intraocular pressure (IOP; p =0.001). In the FemtoLASIK group, with intraoperative decrease in corneal thickness of 75.33±32.3 µm, we observed a significant increase in DA ratio ( p =0.0002), PD ( p =0.04), ICR ( p =0.0002), a decrease in SP-A1 ( p <0.0001), IOP values ( p =0.0003). In comparison with the FemtoLASIK group, the deformation amplitude DA changed significantly less in the SMILE group ( p =0.04). In the FemtoLASIK group, in comparison with the SMILE group, the DA ratio ( p =0.0009) and SP-A1 ( p =0.0003) significantly increased. Intraoperative corneal thickness change correlates with ICR both in SMILE ( R =0.52) and in FemtoLASIK ( R =0.65)., Conclusion: Corneal biomechanical properties determined with CORVIS ST in eyes with mild to moderate myopia change to a lesser extent after ReLEx SMILE compared to FemtoLASIK.

Purpose: To study features of anatomical and morphometric parameters of the structures of anterior eye segment in young patients with moderate and high hyperopia in order to identify the signs of an increased risk of developing primary angle-closure glaucoma (PACG) and its acute attack., Material and Methods: The study included 160 eyes (80 patients) with axial length (AL) of less than 23 mm. Patients with moderate or high hyperopia were divided into two groups according to their age ranges (the 1 st - 27 patients (54 eyes) under 40 years old; the 2 nd - 27 patients (54 eyes) of 41-50 years old, the comparison group - 26 patients (52 eyes) of 42-50 years old with the initial stage of PACG. AL of the eyes, anterior chamber (AC) depth in the central zone, lens thickness (LT) in the optical zone were measured using IOL Master 700 («Carl Zeiss Meditec AG», Germany). AC volume and peripheral AC depth were measured using rotating Scheimpflug camera Pentacam («Oculus», Germany)., Results: While the average values of AL in patients of the 1 st and 2 nd groups were comparable, a statistically significant decrease in AC depth and a significant increase in LT were revealed in the 2 nd group. There was a statistically significant increase in LT, a decrease in peripheral AC depth and AC volume in the comparison group relative to the 2 nd group. In the 1 st group: in 2 eyes of one 38-year-old patient the maximum proximity of all 3 indices to the median values of the group of patients with PACG was found; in 4 eyes of two other patients (35 and 38 years old), a combination of small AC volume with increased LT or small AC volume with small AC on the periphery was noted., Conclusion: Significant differences in terms of LT, peripheral AC depth and AC volume were found between age-comparable (41-50 years old) healthy individuals with short eyes and patients with initial PACG. In 11% of the eyes of healthy patients with hyperopia aged 21 to 40 years, there was a combination of two or three of the studied morphometric signs, which may indicate the risk of developing PACG.

Posterior chamber phakic intraocular lens (PIOL) implantation is a widely accepted and performed refractive surgery for correction of moderate and high myopia used when corneal laser ablation procedures are not suitable. This paper analyzes literature data to reveal the advantages and limitations of the technology.

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. The article reviews literature devoted to the problem of changes of corneal biomechanical properties after refractive surgeries.

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.