Infectious keratitis in Vietnam: etiology, organisms, and management at Vietnam National Eye Hospital

AIM: To report the etiologies, risk factors, treatments, and outcomes of infectious keratitis (IK) at a major Vietnamese eye hospital. METHODS: This is a retrospective review of all cases of IK at Vietnam National Eye Hospital (VNEH) in Hanoi, Vietnam. Medical histories, demographics, clinical features, microbiological results, and treatment outcomes were reviewed. RESULTS: IK was diagnosed in 1974 eyes of 1952 patients, with ocular trauma being the greatest risk factor for IK (34.2%), frequently resulting from an agriculture-related injury (53.3%). The mean duration between symptom onset and presentation to VNEH was 19.3±14.4d, and 98.7% of patients had been treated with topical antibiotic and/or antifungal agents prior to evaluation at VNEH. Based on smear results of 1706 samples, the most common organisms identified were bacteria (n=1107, 64.9%) and fungi (n=1092, 64.0%), with identification of both bacteria and fungi in 614 (36.0%) eyes. Fifty-five of 374 bacterial cultures (14.7%) and 426 of 838 fungal cultures (50.8%) were positive, with the most commonly cultured pathogens being Pseudomonas aeruginosa, Streptococcus pneumonia, Fusarium spp., and Aspergillus spp. Corneal perforation and descemetocele developed in 391 (19.8%) and 93 (4.7%) eyes, respectively. Medical treatment was successful in resolving IK in 50.4% eyes, while 337 (17.1%) eyes underwent penetrating or anterior lamellar keratoplasty. Evisceration was performed in 7.1% of eyes, most commonly in the setting of fungal keratitis. CONCLUSION: Ocular trauma is a major risk factor for IK in Vietnam, which is diagnosed in almost 400 patients each year at VNEH. Given this, and as approximately one quarter of the eyes that develop IK require corneal transplantation or evisceration, greater emphasis should be placed on the development of prevention and treatment programs for IK in Vietnam.

Histomorphological view of the cornea investigated by laser confocal microscopy in keratoplasty

Introduction. Corneal transplantation is the most successful and commonly performed allotransplantation procedure as compared with other organs and tissues. Over 100,000 corneal transplantations are performed worldwide every year.Purpose. This study investigated whether in vivo confocal microscopy (IVCM) can aid in the diagnosis of a graft rejection reaction by detecting changes in cellular structures and density of immune cells after penetrating keratoplasty.Materials and methods. The study included thirty-four eyes of 34 patients who underwent penetrating keratoplasty (7 eyes with corneal graft rejection, 27 without rejection). The average age of patients is 51.1 ± 13.6 years (from 23 to 76 years). The follow-up period ranged from 12 to 36 months (24.5 ± 4.84 months). Follow-up was performed at 1, 3, 6, 12 months and annually after PKP. To study the morphology of the cornea all patients underwent IVCM to assess the basal epithelium, subbasal layer, stroma and endothelium. Immune cells were identified and evaluated for the shape, length of the processes and their density.Results. Patients with corneal graft rejection demonstrated significant accumulation of corneal dendritic-like immune cells compared to patients with non-rejected grafts. In addition, the cells acquired a more mature morphology (grade 2–3). The density of dendritic cells (DC) was 809.17 ± 342.19 (p < 0.001). A positive correlation was found between DC density and graft rejection (p < 0.001). As well the patients showed signs of endothelial failure with low endothelial cell density and pleomorphism, increased light scattering and hyperreflectivity of the stroma.Conclusions. In a complex of diagnostic measures, confocal microscopy may provide a valuable clinical adjunctive tool in diagnosis and management of early corneal graft rejection.

Isolation and Propagation of Human Corneal Stromal Keratocytes for Tissue Engineering and Cell Therapy

The human corneal stroma contains corneal stromal keratocytes (CSKs) that synthesize and deposit collagens and keratan sulfate proteoglycans into the stromal matrix to maintain the corneal structural integrity and transparency. In adult corneas, CSKs are quiescent and arrested in the G0 phase of the cell cycle. Following injury, some CSKs undergo apoptosis, whereas the surviving cells are activated to become stromal fibroblasts (SFs) and myofibroblasts (MyoFBs), as a natural mechanism of wound healing. The SFs and MyoFBs secrete abnormal extracellular matrix proteins, leading to corneal fibrosis and scar formation (corneal opacification). The issue is compounded by the fact that CSK transformation into SFs or MyoFBs is irreversible in vivo, which leads to chronic opacification. In this scenario, corneal transplantation is the only recourse. The application of cell therapy by replenishing CSKs, propagated in vitro, in the injured corneas has been demonstrated to be efficacious in resolving early-onset corneal opacification. However, expanding CSKs is challenging and has been the limiting factor for the application in corneal tissue engineering and cell therapy. The supplementation of serum in the culture medium promotes cell division but inevitably converts the CSKs into SFs. Similar to the in vivo conditions, the transformation is irreversible, even when the SF culture is switched to a serum-free medium. In the current article, we present a detailed protocol on the isolation and propagation of bona fide human CSKs and the morphological and genotypic differences from SFs.

Keratoplasty for keratoconus: advantages and disadvantages

Keratoconus is a progressive bilateral corneal ectasia, accompanied by loss of vision due to high irregular astigmatism, which is the leading indication for corneal transplantation. The review presents a variety of surgical corneal transplantation techniques for keratoconus available today and discussed their advantages and disadvantages.

Corneal Surgeries

This chapter includes corneal surgeries performed in the center such as corneal transplantation (PK, DALK, DSAEK, DMEK) with all possible complications: graft rejections, recurrence of previous diseases, reactivation of previous infection, and other rare complications. Photos of conjunctival limbal autotransplantation, Boston type 1 keratoprosthesis surgery, and corneal tattooing are included as well. Some interesting cases are discussed with management. Several possible complications after excimer laser procedures are also presented.

To Evaluate the Effectiveness of Plasmapheresis as a Method for the Graft Disease Prevention in Patients with Keratoplasty

Purpose: to evaluate the effectiveness of plasmapheresis as a method for preventing and treating the graft rejection reaction in corneal transplantation.Patients and methods. The study involved patients with surgical pathology of the cornea, who underwent a prophylactic course of plasmapheresis procedures and underwent penetrating keratoplasty (Main group); and patients with surgical pathology of the cornea who underwent penetrating keratoplasty, but did not undergo plasmapheresis (Comparison group), whose data were analyzed retrospectively. The control group consisted of conditionally healthy individuals of both genders. Subgroups of patients with high and low risk keratoplasty were also identified within the Main group and the Comparison group.Results. Patients with keratoplasty who received a course of therapeutic plasmapheresis in the perioperative period demonstrated a statistically significant increase in the number of cases of a decrease in the level of C-reactive protein and a statistically significant decrease in the median values of the mean stimulated cytochemical index and the mobilization coefficient. Depending on the risk group for keratoplasty, the patients showed different dynamics of the levels of the studied interleukins after the course of plasmapheresis and keratoplasty. In patients of the Comparison group who did not receive a course of plasmapheresis in the preoperative period, over a period of 1.3 years, 22 cases (24 %) developed graft disease, while patients of both subgroups of the Main group who received a course of therapeutic plasmapheresis in the preoperative period, didn’t demonstrate any cases of graft disease. In patients of the Comparison group (in total for two subgroups), the maximum number of cases of graft disease (n = 24) was observed in the first 500 days after surgery. At the same time, the patients of the Main group who underwent plasmapheresis had the best graft survival rates: during the observation period, there were no cases of graft disease (in both subgroups).Conclusion: the obtained data indicate the ability of plasmapheresis, performed in the perioperative period, to prevent the development of graft disease in patients with keratoplasty.

Detection of SARS-CoV-2-RNA in post-mortem samples of human eyes

Purpose To detect SARS-CoV-2 RNA in post-mortem human eyes. Ocular symptoms are common in patients with COVID-19. In some cases, they can occur before the onset of respiratory and other symptoms. Accordingly, SARS-CoV-2 RNA has been detected in conjunctival samples and tear film of patients suffering from COVID-19. However, the detection and clinical relevance of intravitreal SARS-CoV-2 RNA still remain unclear due to so far contradictory reports in the literature. Methods In our study 20 patients with confirmed diagnosis of COVID-19 were evaluated post-mortem to assess the conjunctival and intraocular presence of SARS-CoV-2 RNA using sterile pulmonary and conjunctival swabs as well as intravitreal biopsies (IVB) via needle puncture. SARS-CoV-2 PCR and whole genome sequencing from the samples of the deceased patients were performed. Medical history and comorbidities of all subjects were recorded and analyzed for correlations with viral data. Results SARS-CoV-2 RNA was detected in 10 conjunctival (50%) and 6 vitreal (30%) samples. SARS-CoV-2 whole genome sequencing showed the distribution of cases largely reflecting the frequency of circulating lineages in the Munich area at the time of examination with no preponderance of specific variants. Especially there was no association between the presence of SARS-CoV-2 RNA in IVBs and infection with the variant of concern (VOC) alpha. Viral load in bronchial samples correlated positively with load in conjunctiva but not the vitreous. Conclusion SARS-CoV-2 RNA can be detected post mortem in conjunctival tissues and IVBs. This is relevant to the planning of ophthalmologic surgical procedures in COVID-19 patients, such as pars plana vitrectomy or corneal transplantation. Furthermore, not only during surgery but also in an outpatient setting it is important to emphasize the need for personal protection in order to avoid infection and spreading of SARS-CoV-2. Prospective studies are needed, especially to determine the clinical relevance of conjunctival and intravitreal SARS-CoV-2 detection concerning intraocular affection in active COVID-19 state and in post-COVID syndrome.

Corneal graft survival analysis after penetrating keratoplasty in a retrospective cohort study

Purpose. To assess the results of penetrating keratoplasty and identify the risk factors for the graft disease (GD) development. Material and methods. Data of 582 patients after corneal transplantation performed in the period since 2011 to 2019 for keratoconus (41%), as well for corneal leucorrhoea and dystrophies (59%), aggravated by concomitant pathology, the so-called high-risk keratoplasty (HRK) were analyzed in a retrospective cohort study. We estimated the functional results and incidence of GD. The calculation of the t-criterion; cross-tabulation method; Kaplan–Meier survival analysis and multivariate analysis were applied. Results. As a result of penetrating keratoplasty, the BCVA (best corrected visual acuity) in patients with keratoconus increased by 20%; in patients with HRK – by 8%. In the general group the graft survival rate was 72%, while the 8-year successful graft engraftment in patients with keratoconus comprised 91%, with HRK – 60%. A significant relationship of the GD development with preoperative diagnosis and rekeratoplasty was determined. The risk of GD incidence was minimal in patients under 30 years of age and maximum in patients aged from 50 to 70 years. Survival rates for corneal transplants were better in men than in women. Conclusion. Penetrating keratoplasty in patients with keratoconus provides a good functional result with a minimal risk of GD development. With penetrating keratoplasty in high-risk patients, the effectiveness of surgical interventions is significantly lower (by ~30%). Key words: keratoconus, penetrating keratoplasty, corneal transplantation, survival analysis