RESULTS OF CANALOPLASTY IN GLAUCOMA SURGERY. REVIEW OF LITERATURE

The article presents a review of literature on a micro-invasive surgical treatment of glaucoma based on the principle of recovery of natural pathways of aqueous humor outflow through the Schlemm’s canal. The surgical experience of this operation revealed a number of advantages versus the trabeculectomy, including, a more physiologic approach, a less quantity of intraand postoperative complications, a rapid rehabilitation of the patients

MATHEMATICAL RATIONALE FOR A NEW MODEL OF POLYMER SEGMENTS FOR CORNEAL INTRASTROMAL KERATOPLASTY

Purpose. To develop a new model of intrastromal corneal ring segment (ICSR) for the treatment of corneal ectasia of various genesis, based on mathematical modeling of the efficacy in the ICSR implantation and taking into consideration anatomical and topographic features of the cornea.Material and methods. Geometric patterns typical for the optical centered systems were used to calculate the corneal ICRS parameters taking into account factors affecting the changes in optical parameters of the cornea (the geometric parameters of the ICRS). The calculation of the optical effect of the ICSR implantation with settings parameters was carried out on the basis of the Barraquer geometric ratio formula. Various models of corneal segments were investigated in aspect of their influence on the curvature of anterior and posterior surfaces of cornea.Results. On the basis of the carried-out mathematical calculations the main tendencies in the determination of necessary geometric parameters of corneal segments were allocated, that will ensure an optimum distribution of biomechanical stresses in the cornea leading to an increase of the efficiency of the ICRS implantation and to a reduction of the likelihood of postoper ative complications.Conclusion. The disadvantages of pre-existing ICRS models and peculiarities of the structure of the corneal stroma were taken into account in the mathematical modeling of the new ICRS model that can be used in the intrastromal keratoplasty. New optimal geometric parameters of the ICRS design were mathematically calculated to provide an improvement of the functional characteristics of these implants and a refractive effect of ICRS implantation

Clinical outcomes of autologous cultured oral mucosal epithelium transplantation for treatment of limbal stem cell deficiency

The review presents an analysis of clinical trials results for autologous cultured oral mucosal epithelium transplantation (COMET) in patients with bilateral corneal limbal stem cell deficiency (LSCD) over the past 15 years. Detailed characteristics and evaluation are given for anatomical outcomes, visual acuity changes, and complication rates. The results obtained during the analysis confirm the consistency of the concept of corneal re-epithelization by means of COMET. COMET promoted persistent corneal re-epithelization in 81.5% of cases, and visual acuity improvement in 78.8% of patients with LSCD. COMET does not require systemic immunosuppression, and it is accompanied by much smaller numbers and significantly lower grades of complications compared with keratoprosthesis. About 15% of patients experienced developing superficial peripheral corneal neovascularization regressed spontaneously by 12 months of observation. Based on the COMET clinical trials results, the management of patients with bilateral LSCD is under optimization by reference to the pathogenesis of the underlying disease. Thus, autologous cultured oral mucosal epithelium transplantation seems promising for further studies and introduction into routine clinical practice

Impact on visual acuity in neovascular age related macular degeneration (Namd) in europe due to covid-19 pandemic lockdown

This is a retrospective, multicenter study of consecutive patients with nAMD scheduled for a visit and/or a treatment with an intravitreal injection (IVI) during the 3 months before lockdown in the Ophthalmology Departments of six centers of Europe.The study was conducted on 546 patients, of which 55.13% were females, almost 100% of the patients were White/Caucasian race, and 71.53% of the patients presented a type 1 macular neovascularization (NVM). A total of 62.82% of patients (343 patients) that were on scheduled clinic visits and/or intravitreal injection treatment during the 3 months before the quarantine did not attend either to visit or for treatment during the lockdown. The mean number of injections during the lockdown was significantly reduced. This was followed by a significant reduction in the mean best-corrected visual acuity (BCVA) between the 3 months before the lockdown (mean BCVA of 60.68 ± 19.77 letters) and 6 months after lockdown (mean BCVA of 56.98 ± 22.59 letters). Patients with better BCVA before the lockdown and the ones showing neovascular activity were more likely to attend their scheduled visits and/or IVI treatments. The COVID-19 pandemic and the lockdown have led to a decrease in the number of IVI treatments in patients with nAMD, evidencing a significant vision loss at 6 months

Early impact of COVID-19 outbreak on eye care: Insights from EUROCOVCAT group

The recent outbreak of coronavirus disease 2019 (COVID-19) has been declared a public health emergency worldwide. The scientific community has put in much effort and published studies that described COVID-19’s biology, transmission, clinical diagnosis, candidate therapeutics, and vaccines. However, to date, only a few data are available on the impact of COVID-19 pandemic on ophthalmological care in different health care systems, its future consequences in terms of disability, and access to sight-saving cures for many patients. To reduce human-to-human transmission of the virus and also ensure supply of infrastructures, human resources, and disposable medical devices to many regions, it is crucial to assess risks and postpone non-essential outpatient visits and elective surgical procedures, especially in older patients and those with comorbidities. This delay or suspension in essential eye procedures may cause significant and rapid vision impairment to irreversible blindness. Determining the risk-benefit profile of treating these ocular pathologies is a public health issue of supreme priority, even though many patients benefiting from therapeutic treatments are elderly, who are more vulnerable to COVID-19. If not reversible, this process could lead to a dramatic increase in disability and unsustainable social costs for many Governments

COVID-19 outbreak and increased risk of amblyopia and epidemic myopia: Insights from EUROCOVCAT group

The most common cause of vision impairment in children is amblyopia. It is defined as impaired visual acuity in one or both eyes that is present with no demonstrable abnormality of the visual pathway and is not immediately resolved by wearing glasses. After the World Health Organization (WHO) recognized COVID-19 as a global pandemic on March 11, 2020, widespread changes and restrictions to social and sanitary practices have presented significant issues in access to eye care during the COVID-19 pandemic. A reduction of more than 80% in pediatric eye care volume up to its total cessation has been observed in different departments. In this scenario, reduced or absent eyesight, due to delay in timely treatment of amblyopic conditions, could create major, long-lasting effects on all aspects of life, including daily personal activities, interacting with the community, school and work opportunities and the ability to access public services. Processes coming out of lockdown should be gradually easing restrictions giving priority to ophthalmology and eye care facilities so that amblyopia does not remain unattended and irreversible as in adults due to lack of timely treatments. If not reversible, this process could lead to a dramatic increase in disability and unsustainable social costs for many governments

Results of posterior lamellar femto-keratoplasty using two different lasers

Purpose. To evaluate the results of treatment of patients with pseudophakic bullous keratopathy (PBK) by the method of posterior lamellar femto-keratoplasty with ultrathin graft (FS-DSEK) harvested using two different lasers.Material and methods. The results of surgical treatment of 82 patients (82 eyes) underwent posterior lamellar femto-keratoplasty for PBK were analyzed. In the 1st group included 43 patients (43 eyes) with PBK underwent FS-DSEK using FS laser Femto-Visum (Optosystems, Russia). In the 2nd group included 39 patients (39 eyes) with PBK underwent FS-DSEK using LDV Z8 (Ziemer, Switzerland). Observation period was 1 year. Before and after surgery following indicators were evaluated: uncorrected visual acuity (UCVA), best spectacle corrected visual acuity (BSCVA), postoperative astigmatism, central corneal thickness (CCT), graft thickness, center-periphery (C:P) ratio, endothelial cell density (ECD), endothelial cell (EC) loss, optical density .Results. Transparent engraftment at 1-year observation period was observed in 88% of cases. In the 1st group UCVA=0.22±0.11, BSCVA=0.32±0.12, in the 2nd group UCVA=0.18±0.08, BSCVA=0.29±0.1 (p>0.05). The maximum BSCVA in both groups was 0.6. Postoperative astigmatism was comparative in 2nd groups – 1.43±1.1 and 1.38±1.0 D, respectively (p>0.05). In the 1st group, CCT=549±31, graft thickness in the central zone – 83±12, C:P ratio – 0.92±0.05; in the 2nd group CCT=546±28, graft thickness – 80±10, C:P ratio – 0.94±0.06 (p>0.05). In the 1st group ECD – 1326±282, EC loss – 55±6%; ECD in the 2nd – 850±230, EC loss – 70±7% (p<0.05). According to the results of densitometry, optical density of the posterior layers of the cornea and «donor–recipient» interface zone was higher in the 2nd group, both in the central and in the paracentral zones: in the 1st group in the posterior layers of the stroma – 16.4±1.2 (0–2 mm) and 15.8±1.0 (2–6 mm), in the interface zone – 14.5±0.9 (0–2) and 13.9±0.8 (2–6), in the 2nd group in the posterior layers – 18.3±1.3 (0–2 mm) and 17.9±1.1 (2–6 mm), and in the interface zone – 17.3±1.2 (0–2 mm) and 17.0±1.0 (2–6 mm, p<0.05).Conclusions. FS-DSEK showed high efficiency for treating patients with PBK. Functional results were comparative in 2nd groups. Statistical analysis showed highest safety of transplanted endothelium in the 1st group at 1-year observation period

LONG-TERM RESULTS OF DIFFERENT UV-CROSSLINKING TECHNIQUES IN PATIENTS WITH PROGRESSIVE KERATOCONUS

Purpose. To compare a clinical effectiveness of different UV-crosslinking techniques in patients with progressive keratoconus.Material and methods. Randomized prospective clinical trial included 130 eyes of 117 keratoconic patients. There were created 2 equal groups of 65 eyes. In the group I patients underwent a classical UV-crosslinking technique with a complete central corneal deepithelialization, in the group II a UV-crosslinking with dosed corneal epithelium scarification was performed using a new device. The postoperative follow-up period was 24 months. Preoperatively in the group I the uncorrected visual acuity (UCVA) was 0.21±0.11, the best corrected visual acuity (BCVA) was 0.49±0.14, the central corneal pachymetry (CCP) – 469.1±23/4μm, the mean keratometry (Kave) – 46.1±1.7D, in the group II: UCVA was 0.22±0.09, BCVA – 0.48±0.12, CCP – 475.2±28.5μm, Кave – 46.7±1.4D.Results. The mean postoperative pain score was 6.9±1.3, relief on the 3-rd ±1.2 day post-op. in the group I, and 2.8±1.1 relief on the 1-st±0.4 day post-op. in the group II. All patients had a 0.1 to 0.12 visual acuity loss 7 days after the surgery that was due to a mild corneal opacification. At 3 months after operation in both groups the UCVA and the BCVA were back to their preoperative values. In the group I the UCVA increased by 0.07±0.03 (р<0.05) 2 years after the treatment, the BCVA increased by 0.11±0.04 (р<0.05). At that time in the group II the similar values were obtained: 0.08±0.02 (р<0.05), 0.1±0.04 (р<0.05) respectively. The Kave index in both groups gradually decreased during first 12 months after operation and then stabilized. At the end of the follow up it was lower by 2.6±0.5D (р<0.05) in the group I and by 2.4±0.3D (р<0.05) in the group II. According to the anterior OCT, the depth of demarcation line was 327±11μm in the group I and 318±13μm in the group II. The demarcation line was absent in all cases 12 months after surgery. In the early postoperative period 3 months after operation the CCP gradually decreased. It reduced by 3.77±0.83% (р<0.05) in the group I and by 3.17±0.88% (р<0.05) in the group II. After that the CCP slowly increased during the entire follow-up, but 24 months later it was still lower by 2.36±0.57% (р<0.05) in the group I and by 1.68%±0.75 (р<0.05) in the group II. Confocal microscopy 1 month after surgery revealed typical changes of corneal structure at the depth up to 310±9μm (290 to 335) in the group I and 300±8μm (280 to 330) in the group II. A full reinnervation and the repopulation of the cornea with keratocytes was seen 6 months after operation. The only complication (delayed corneal epithelization) was in the group with classical UV-crosslinking technique.Conclusions. The trial revealed similar clinical outcomes after classical UV-crosslinking technique and UV-crosslinking with dosed corneal epithelium scarification, however in the latter case during the postoperative period the severity and duration of pain were significantly reduced

Rethinking elective cataract surgery diagnostics, assessments, and tools after the COVID-19 pandemic experience and beyond: Insights from the EUROCOVCAT group

The progressive deterioration of the visual function in patients on waiting lists for cataract surgery has a negative impact on their quality of life, especially in the elderly population. Patient waiting times for cataract surgeries in many healthcare settings have increased recently due to the prolonged stop or slowdown of elective cataract surgery as a result of coronavirus disease 19 (COVID-19). The aim of this review is to highlight the impact of such a “de-prioritization” of cataract surgery and to summarize some critical issues and useful hints on how to reorganize cataract pathways, with a special focus on perioperative diagnostic tools during the recovery phase and beyond. The experiences of a group of surgeons originating from nine different countries, named the European COVID-19 Cataract Group (EUROCOVCAT), have been combined with the literature and recommendations from scientific ophthalmic societies and healthcare institutions. Key considerations for elective cataract surgery should include the reduction of the number of unnecessary visits and examinations, adoption of precautionary measures, and implementation of telemedicine instruments. New strategies should be adopted to provide an adequate level of assistance and to guarantee safety conditions. Flexibility will be the watchword and regular updates would be necessary following scientific insights and the development of the pandemic

Impact on refractive surgery due to increasing use of personal protection equipment: Insights from EUROCOVCAT group

Since the World Health Organization declared COVID-19 to be a pandemic on 11th March 2020, changes to social and sanitary practices have included significant issues in access and management of eye care during the COVID-19 pandemic. Additionally, the fear of loss, coupled with social distancing, lockdown, economic instability, and uncertainty, have led to a significant psychosocial impact that will have to be addressed. In the current COVID-19 pandemic, personal protective equipment such as face masks or face coverings have become a daily necessity. While "mass masking" along with hand hygiene and social distancing became more widespread, new issues began to emerge - particularly in those who wore spectacles as a means of vision correction. As we began to see routine patients again after the first lockdown had been lifted, many patients visited our clinics for refractive surgery consultations with a primary motivating factor of wanting spectacle independence due to the fogging of their spectacles as a result of wearing a mask. In this article, we report on new emerging issues in eye care due to the widespread use of masks and on the new unmet need in the corneal and cataract refractive surgery fields