Corneal Infection Research Articles

Five years of emergency keratoplasty at a tertiary eye hospital.

The aim of this study is to present the results of patients who underwent emergency keratoplasty for tectonic or therapeutic reasons. Medical records of 33 patients who underwent tectonic or therapeutic keratoplasty at Ege University Department of Ophthalmology between January 2019 and January 2024 were retrospectively evaluated. Demographic characteristics, ocular and systemic findings, indications of keratoplasty, size of grafts, need for re-keratoplasty, preoperative treatment modalities, need for additional surgical interventions, and prognosis of the patients were investigated. During this period, 450 penetrating keratoplasty (PK) surgeries were performed and 34 (7.55%) were emergency PK (34 eyes of 33 patients). The mean age of the patients was 65.30 ± 15.40 (40-91). Female to male ratio was 18/15. 17 (50.00%) emergency PKs were performed for tectonic and 17 (50.00%) were performed for therapeutic purposes. Mean follow up time was 24.85 ± 26.62 (2-120) months. A total of 20 (58.82%) eyes required additional surgery, 9 (26.47%) of which required re-keratoplasty with different indications during follow-up. Graft rejection or failure developed in 17 (50.00%) of the eyes in an average of 12.05 (1-45) months. Evisceration was needed in 2 (5.88%) eyes. Despite limited access to donor cornea and high complication rate, emergency keratoplasty is one of the most important options that retain ocular integrity in the treatment of corneal infections and non-traumatic corneal perforations unresponsive to conventional treatment.

Evaluation of Fungitell (1,3)-β-D-glucan assay in tear samples for rapid diagnosis of fungal keratitis.

Fungal keratitis (FK) is a serious suppurative and ulcerative corneal infection leading to blindness and vision loss. Rapid diagnosis of FK can contribute to prompt clinical management with early recovery. The study aimed to standardize the detection of (1,3)-β-D-glucan (BDG) and establish the diagnostic cut-off concentration in tears of suspected FK patients along with non-infected controls. This prospective multicentric study was conducted between the period of August 2022 and April 2024. Samples were collected from three tertiary eye-care facilities across India. All suspected FK patients were enrolled in the study. Prior to tear collection, the eye and eyelid were gently cleansed using sterile normal saline (NS) and lint-free tissue paper. Subsequently, 50 µL of sterile NS was instilled into the eye, followed by tear sample collection after 60 s using sterile fine microtips. Tear samples were collected from the contralateral eyes of the FK patients, and those from healthy volunteers served as controls. The concentration of BDG in tears in varying dilutions was quantitatively measured using the Fungitell Assay Kit (Associates of Cape Cod, East Falmouth, Massachusetts). A total of 53 tear samples were analyzed at 1:10 and 1:20 dilutions. The receiver operating curve revealed an area under the curve (AUC) of 0.919 for the 1:10 dilution, with a cut-off value of 123 pg/mL, yielding a sensitivity of 100% and specificity of 84.85%. The corresponding Youden Index was 0.798. At the 1:20 dilution, the AUC was 0.898 with a cut-off of 84 pg/mL, achieving a sensitivity of 70% and specificity of 96.88% with a Youden Index of 0.670. Given the higher specificity at the 1:20 dilution, it was further validated in 145 tear samples. The validation cohort demonstrated a sensitivity of 95.56%, specificity of 83%, positive predictive value (PPV) of 71.67%, negative predictive value (NPV) of 97.65%, and diagnostic odds ratio of 112.4. Notably, a significantly higher BDG concentration (P < 0.0001) was observed in infected tear samples compared to controls (270.6 ± 128.5 vs 37.31 ± 31.32). Detection of BDG in tear samples is a new, non-invasive, and rapid technique showing excellent performance and can be effectively implemented for diagnosing FK in laboratories.

A single-center study on the distribution and shifting trend of infectious keratitis pathogens from 2018 to 2022

Objective: To investigate the pathogen species, composition, and distribution characteristics of infectious keratitis pathogens in Shandong Province and its surrounding areas. Methods: In this cross-sectional study, patients with keratitis who underwent corneal sampling and microbiological culture at the Shandong Eye Hospital from January 1, 2018 to December 31, 2022 were included. Under topical anesthesia, the edge of the lesion was scraped by an experienced physician. The samples were inoculated on blood agar and Sabouraud dextrose agar plates, separately for bacterial and fungal culture and identification. If necessary, the samples were inoculated on a non-nutrient agar medium with Escherichia coli for Acanthamoeba culture. Bacterial isolates were identified using Vitek 2 compact or matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Fungal isolates were identified based on morphological characteristics or sent to a company for sequencing in cases of difficult identification. The epidemiological data of the patients, pathogen species and number (counting as 1 strain if the same strain was isolated from multiple corneal specimens of the same patient), culture positivity rate, and seasonal distribution were recorded. Differences in pathogen positivity rates among different seasons were analyzed using the chi-square test. Results: Among the 4, 024 patients with infectious keratitis during the study period, there were 2 510 males (62.3%) and 1 514 females (37.6%), aged from 46 days to 94 years. Positive microbial culture results were achieved in 2, 363 patients (58.7%), including 906 cases (38.3%) with bacterial positivity, 1 231 cases (52.1%) with fungal positivity, 28 cases (1.2%) with Acanthamoeba positivity, and 198 cases (8.4%) with mixed fungal and bacterial infections. A total of 2 561 strains were isolated, including 1 104 bacterial strains. The most common bacteria were coagulase-negative Staphylococcus spp. (623/1 104, 56.4%), followed by Streptococcus spp. (131/1 104, 11.9%) and Pseudomonas aeruginosa (68/1 104, 6.2%). The most common fungi were Fusarium spp. (634/1 429, 44.4%), followed by Aspergillus spp. (279/1 429, 19.5%) and Alternaria spp. (229/1 429, 16.0%). Bacterial keratitis was more common in summer and autumn, while fungal keratitis was more common in autumn and winter. Conclusions: Among infectious keratitis cases in Shandong Eye Hospital, Fusarium species were predominant fungal pathogens, while coagulase-negative Staphylococcus predominated in bacterial pathogens. Both fungal and bacterial corneal infections showed seasonal variations.

Case Report: An Integrated Approach To Treating Infected Corneal Laceration With Traumatic Endophthalmitis In Paediatric Age Group

This case report presents a case of infected corneal laceration with traumatic endophthalmitis in a pediatric patient. A boy in his middle childhood sustained an ocular injury with scissors, resulting in a full-thickness corneal laceration and infection. Despite the delay in seeking treatment, the patient underwent successful surgical interventions, including corneal scraping, pars plana lensectomy, vitrectomy, and secondary intraocular lens implantation (IOL). The infection was managed with targeted antibiotics, and Staphylococcus aureus was confirmed as the causative organism. Remarkably, these efforts led to a satisfactory improvement in the patient’s vision to 20/50. This case underscores the importance of early intervention and a multidisciplinary approach in the management of pediatric ocular trauma to optimize outcomes.

Is it really descemetocele? Morphology of extremely thin membrane that remained after severe corneal melting: a case report.

The aim of this study was to report transmission electron microscopic findings of a case with whole corneal descemetocele following infective corneal ulcer for the first time in literature. A 72-year-old male patient presented with infective corneal ulcer. After resolution of the infection, corneoscleral transplantation was performed. The excised very thin corneal membrane was processed for transmission electron microscopic examination. Transmission electron microscopic examination of the specimen revealed many layered structures that consisted of two different types of cells. The first type consisted of lighter staining polygonal cells, while the second consisted of elongated cells with relatively dense staining. All cells were connected with a large number of gap or adherens junctions with intercalation of the cell membranes of adjacent cells. A haphazard distribution of cytoplasmic microfilaments were also observed in all of the cell types. There was no evidence of the presence of endothelial cells throughout the specimen. There was also no evidence of Descemet membrane presence except for a small part adjacent to iris tissue that contained some melanosomes. Although we clinically diagnosed descemetocele, Descemet membrane was not present at the electron microscopic level, and thus, the expression "descemetocele" is inappropriate.

RTP4 Enhances Corneal HSV-1 Infection in Mice With Type 2 Diabetes Mellitus.

The purpose of this study was to investigate whether corneal lesions in mice with type 2 diabetes mellitus (T2D) infected with herpes simplex virus (HSV)-1 are more severe, and to elucidate the specific underlying mechanism. The corneas of control mice and T2D mice induced by a high-fat diet combined with streptozotocin were infected with the HSV-1 Mckrae strain to assess corneal infection, opacity, and HSV-1 replication. RNA sequencing of the corneal epithelium from wild-type and db/db mice (a genetic T2D mouse model) was conducted to identify the key gene affecting T2D infection. Immunofluorescence staining was performed on corneal sections from T2D mice and patients with T2D. The effect of small interfering RNA (siRNA) knockdown on corneal HSV-1 infection was evaluated in both in vitro and in vivo models. T2D mice exhibited a more severe infection phenotype following HSV-1 infection, characterized by augmented corneal opacity scores, elevated viral titers, and transcripts compared to control mice. Transcriptome analysis of corneal epithelium revealed a hyperactive viral response in T2D mice, highlighting the differentially expressed gene Rtp4 (encoding receptor transporter protein 4). Receptor transporter protein 4 (RTP4) expression was enhanced in the corneal epithelium of T2D mice and patients with T2D. Virus binding assays demonstrated that RTP4 facilitated HSV-1 binding to human corneal epithelial cells. Silencing RTP4 alleviated HSV-1 infection in both in vitro and in vivo T2D models. The findings indicate that elevated RTP4 exacerbates HSV-1 infection by enhancing its binding to corneal epithelial cells, whereas Rtp4 knockdown mitigated corneal lesions in T2D mice. This implies RTP4 as a potential target for intervention in diabetic HSV-1 infection.

Amniotic membrane graft (AMG) for persistent epithelial defects following infective corneal ulcers and keratitis - A systematic review.

Management of nonhealing corneal ulcers is challenging as it can lead to complications such as melting, descemetocele, and perforation, which can be prevented by amniotic membrane graft (AMG). The absence of any review (English language) on AMG for corneal ulcers prompted us to conduct this review. We looked for clinical trials (randomized and controlled) on the effect of AMG combined with other treatments, through various search engines utilizing the terms amniotic membrane and corneal ulcer. All patients who received AMG and/or conventional medication were included. Risk of bias tools derived from Cochrane collaboration were used to ascertain the standard and quality of the trials. Visual acuity and epithelial healing time were the main outcome measures studied. Three trials were finally selected for analysis. AMG was noted to be associated with better uncorrected visual acuity and reduction in neovascularization. There was no difference in best corrected visual acuity, epithelial healing time, and corneal opacity. There is evidence that the use of AMG is associated with improved uncorrected visual acuity as well as reduction in neovascularization of the cornea among patients with corneal ulcers, but there was no improvement in epithelial healing time or corneal opacity. Further multicenter randomized controlled trials are needed to elicit the beneficial effects of the intervention and augment the validity of this review.

S100A12 inhibits Streptococcus pneumoniae and aids in wound healing of corneal epithelial cells both in vitro and in vivo

Streptococcus pneumoniae, a leading cause of corneal infections worldwide, are extremely aggressive despite antibiotic sensitivity and exhibit increased resistance towards antibiotics. Antimicrobial peptides are often considered as potent alternatives against antibiotic resistance and here we have investigated the possible roles of S100A12, a host defense peptide, in wound healing and S. pneumoniae infection. S100A12 significantly inhibited growth of S. pneumoniae by disruption of membrane integrity along with increased generation of reactive oxygen species. Additionally, S100A12 accelerated cell migration and wound closure in human corneal epithelial cells and in a murine corneal wound model by activation of EGFR and MAPK signaling pathways.

A Comprehensive Review on Acanthamoeba Keratitis: An Overview of Epidemiology, Risk Factors, and Therapeutic Strategies.

Acanthamoeba keratitis (AK) is a rare but severe corneal infection caused by the free-living amoeba, Acanthamoeba, which is ubiquitously present in the environment. This condition predominantly affects contact lens wearers but can also occur in non-lens users, particularly those exposed to contaminated water or with compromised immune systems. AK is characterized by progressive corneal inflammation, epithelial defects, and ulceration, which can lead to significant visual impairment or blindness if not promptly diagnosed and treated. This review aims to provide a comprehensive overview of AK by synthesizing current knowledge on its epidemiology, risk factors, pathophysiology, clinical manifestations, diagnostic approaches, and therapeutic strategies. The review also highlights preventive measures and public health strategies to reduce the incidence of this debilitating condition. A detailed examination of existing literature was conducted, focusing on the global incidence of AK, demographic trends, and various risk factors such as contact lens use, environmental exposures, and immunity status. The review also delves into the pathophysiology of Acanthamoeba infection, the host immune response, and the challenges in distinguishing AK from other forms of infectious keratitis. Therapeutic strategies, including medical and surgical interventions, are analyzed, along with emerging treatments. The global incidence of AK has increased, particularly among contact lens users, due to poor hygiene practices and environmental exposures. Early diagnosis remains challenging, often leading to delayed treatment and poorer outcomes. Biguanides and diamidines are the mainstays of medical therapy, with surgical options considered in advanced cases. Emerging therapies, such as photodynamic therapy and antimicrobial peptides, show promise in enhancing treatment outcomes.AK poses a significant threat to ocular health due to its potential for severe visual impairment and the complexities associated with its diagnosis and treatment. Early recognition, appropriate management, and public health initiatives focused on prevention are crucial for improving patient outcomes. Ongoing research and a collaborative approach among healthcare providers are essential to advancing the understanding and management of AK.

The Role of Pseudomonas aeruginosa in the Pathogenesis of Corneal Ulcer, Its Associated Virulence Factors, and Suggested Novel Treatment Approaches.

Pseudomonas aeruginosa (P. aeruginosa), is a diverse Gram-negative pathogen commonly associated with a wide spectrum of infections. It is indicated to be the most prevalent causative agent in the development of bacterial keratitis linked with the use of contact lens. Corneal infections attributed to P. aeruginosa frequently have poor clinical outcomes necessitating lengthy and costly therapies. Therefore, this review looks at the aetiology of P. aeruginosa bacterial keratitis as well as the bacterial drivers of its virulence and the potential therapeutics on the horizon. A literature review with the articles used for the review searched for and retrieved from PubMed, Scopus, and Google Scholar (date last accessed 1 April 2024). The keywords used for the search criteria were "Pseudomonas and keratitis, biofilm and cornea as well as P. aeruginosa". P. aeruginosa is implicated in the pathogenesis of bacterial keratitis associated with contact lens usage. To reduce the potential seriousness of these infections, a variety of contact lens-cleaning options are available. However, continuous exposure to a range of antibiotics doses, from sub-inhibitory to inhibitory, has been shown to lead to the development of resistance to both antibiotics and disinfectant. Generally, there is a global public health concern regarding the rise of difficult-to-treat infections, particularly in the case of P. aeruginosa virulence in ocular infections. This study of the basic pathogenesis of a prevalent P. aeruginosa strain is therefore implicated in keratitis. To this effect, anti-virulence methods and phage therapy are being researched and developed in response to increasing antibiotic resistance. This review has shown P. aeruginosa to be a significant cause of bacterial keratitis, particularly among users of contact lens. It also revealed treatment options, their advantages, and their drawbacks, including prospective candidates.

Atypical mycobacterial keratitis: Clinical outcome in nonrefractive surgery cases.

To identify the predisposing factors, clinico-microbiological profiles, and treatment responses in patients with atypical mycobacterial keratitis. The study retrospectively analyzed patients who presented at a tertiary eyecare center in eastern India with atypical mycobacterial keratitis between 2008 and 2021. The diagnostic criteria included cases positive for acid-fast bacilli on Ziehl-Nielsen stain or culture. The antibiotic susceptibility pattern was observed, and treatment was initiated accordingly. Out of the 29 cases, ocular predisposing factors were present in 62.1% with an antecedent history of trauma, and vegetative matter was the most common risk factor. There was no predisposing association with systemic conditions in any case. A long lag time was observed between the onset of corneal infection and presentation in 79.3% of cases, with the average time being 43.7 days. Clinical signs mimicked fungal keratitis in most cases. Typical cracked windshield appearance was only observed in two cases. Two patients presented with clinical pictures like peripheral ulcerative keratitis. Topical amikacin was used as treatment in 28 cases. Based on disk diffusion assay, 28 (96.5%) isolates were sensitive to amikacin. Twelve (41.3%) were sensitive to vancomycin, six (20.6%) to gatifloxacin, six (20.6%) to ciprofloxacin, and four (13.7%) to moxifloxacin. Twelve participants showed good final visual acuity posttreatment, which improved to over two lines of Snellen's visual acuity chart (44.5%). Atypical mycobacteria keratitis may not present with classically described clinical features. The duration of presentation, clinical presentation, special microbiological stains, targeted therapy, and antibiotic susceptibility patterns are the key to successfully managing these intractable infections and obtaining favorable outcomes.

Utilization of multiplex polymerase chain reaction for simultaneous and rapid detection of viral infections from different ocular structures

The impact of viral keratitis (VK) on individuals and society is notable. Early diagnosis and treatment are crucial in managing viral keratitis effectively. Timely intervention with antiviral medications and supportive care can help mitigate the severity of the infection and improve visual outcomes. We examined the prevalence of varicella-zoster virus (VZV), herpes simplex virus type 1 (HSV-1), adenovirus (AdV) and herpes simplex virus type 2 (HSV-2) in patients suspected for ocular infections. Patients included in the study exhibited various clinical manifestations indicative of ocular pathology, such as infectious keratitis, corneal scar, endogenous endophthalmitis, panuveitis, endothelitis, stromal edema, and other relevant conditions. Four different types of tear fluid, corneal samples epithelium, aqueous humor and vitreous humor were taken. After genome extraction, multiplex real-time PCR was used for diagnosis of viruses. 48 (29.6%) out of the total of 162 (100%) eye specimen were positive. The dominant prevalence was VZV (12.3%) and HSV-1 (11.7%) followed by AdV (4.9%) and HSV-2 (0.6%). There were 4 (8.3%) coinfections within the samples (HSV-1 and VZV). Aqueous humor samples demonstrated superior virus detection ability and our only HSV-2 positive sample was from aqueous humor. The utilization of multiplex real-time PCR assays in differential diagnosis of VK holds promise for expeditious diagnoses while also preventing unwarranted antibiotic prescriptions. Moreover, the aqueous humor appears to be a more sensitive site for detecting viral keratitis.

Drug-impregnated contact lenses via supercritical carbon dioxide: A viable solution for the treatment of bacterial and fungal keratitis

Keratitis is a corneal infection caused by various bacteria and fungi. Eye drop treatment of keratitis involves significant challenges due to difficulties in administration, inefficiencies in therapeutic dosage, and frequency of drug applications. All these are troublesome and result in unsuccessful treatment, high cost, time loss, development of drug resistance by microorganisms, and a massive burden on human health and the healthcare system. Most of the antibacterial and antifungal medications are non-water-soluble and/or include toxic drug formulations. Here, the aim was to develop drug-loaded contact lenses with therapeutic dosage formulations and extended drug release capability as an alternative to eye drops, by employing supercritical carbon dioxide (ScCO2) as a drug impregnation solvent to overcome inefficient ophthalmic drug use. ScCO2, known as a green solvent, has very low viscosity which provides high mass transfer power and could enhance drug penetration into contact lenses much better with respect to drug loading using other solvents. Here, moxifloxacin (MOX) antibiotic and amphotericin B (AMB) antifungal medicines were separately loaded into commercially available silicone hydrogel contact lenses through 1) drug adsorption from the aqueous solutions and 2) impregnation techniques via ScCO2 and their efficacies were compared. Drug impregnation parameters, i.e., 8–25 MPa pressure, 310–320 K temperature, 2–16-hour impregnation times, and the presence of ethanol as polar co-solvent were investigated for the optimization of the ScCO2 drug impregnation process. The highest drug loading and long-term release kinetic from the contact lenses were obtained at 25 MPa and 313 K with 2.5 h impregnation time by using 1 % ethanol (by volume). Furthermore, antibacterial/antifungal activities of the MOX- and AMB-impregnated contact lenses were effective against in vitro Pseudomonas aeruginosa (ATCC 10145) bacteria and Fusarium solani (ATCC 36031) fungus for up to one week. Consequently, the ScCO2 method can be effectively used to impregnate commercial contact lenses with drugs, and these can then be safely used for the treatment of keratitis. This offers a sustainable delivery system at effective dosage formulations with complete bacterial/fungal inhibition and termination, making it viable for real animal/human applications.

Platelet-derived biomaterial controls aspergillus fumigatus keratitis by decreasing fungal burden: an in vivo study.

Fungal keratitis is a severe corneal infection characterized by suppurative and ulcerative lesions. Aspergillus fumigatus is a common cause of fungal keratitis. Antifungal drugs, such as natamycin, are currently the first-line treatment for fungal keratitis, but their ineffectiveness leads to blindness and perforation. Additionally, the development of fungal resistance makes treating fungal keratitis significantly more challenging. The present study used platelet-derived biomaterial (PDB) to manage A. fumigatus keratitis in the animal model. Freezing and thawing processes were used to prepare PDB, and then A. fumigatus keratitis was induced in the mice. Topical administration of PDB, natamycin, and plasma was performed; quantitative real-time PCR (qPCR) and histopathologic examination (HE) were used to assess the inhibitory effect of the mentioned compounds against fungal keratitis. The qPCR results showed that PDB significantly decreased the count of A. fumigatus compared to the control group (P-value ≤ 5). Natamycin also remarkably reduced the count of fungi in comparison to the untreated animal, but its inhibitory effect was not better than PDB (P-value > 5). The findings of HE also demonstrated that treatment with PDB and natamycin decreased the fungal loads in the corneal tissue. However, plasma did not show a significant inhibitory effect against A. fumigatus. PDB is intrinsically safe and free of any infections or allergic responses; additionally, this compound has a potential role in decreasing the burden of A. fumigatus and treating fungal keratitis. Therefore, scientists should consider PDB an applicable approach to managing fungal keratitis and an alternative to conventional antifungal agents.

An essential role for the Hv1 voltage-gated proton channel in Pseudomonas aeruginosa corneal infection.

Assembly of NADPH oxidase 2 (NOX2) proteins in neutrophils plays an essential role in controlling microbial infections by producing high levels of reactive oxygen species (ROS). In contrast, the role of the Hv1 voltage-gated proton channel that is required for sustained NOX2 activity is less well characterized. We examined the role of Hv1 in a murine model of blinding Pseudomonas aeruginosa corneal infection and found that in contrast to C57BL/6 mice, Hvcn1 -/- mice exhibit an impaired ability to kill bacteria and regulate disease severity. In vitro, we used a novel Hv1 Inhibitor Flexible (HIF) to block ROS production by human and murine neutrophils and found that HIF inhibits ROS production in a dose-dependent manner following stimulation with PMA or infection with P. aeruginosa. Collectively, these findings demonstrate an important role for Hv1 on controlling bacterial growth in a clinically relevant bacterial infection model.

Infectious keratitis in pediatric population aged less than two years: a tertiary eye institute experience

BackgroundInfectious keratitis is a serious ocular condition, which can lead to corneal scarring, vision loss, and even blindness. Pediatric infectious keratitis accounts for about 13% of all cases, although there is a lack of comprehensive data regarding keratitis in less than two years of age population group. This study was aimed to determine predisposing factors, clinical characteristics, microbial profile, and management of infectious keratitis in a population of children aged less than two years.Materials and methodsA retrospective study was carried out in a tertiary eye institute over a period of 18 years from July 2005 to December 2022. Collected data was analyzed for demographics, predisposing factors, clinical features, and treatment methods.ResultsFifty-seven cases of keratitis were identified. Age of the patients ranged from 1 to 24 months (Median: 6, interquartile range: 2–10). Thirty cases were male (52.6%). Predisposing factors were identified in 39 cases (68.4%): consisting of prior ocular trauma (n = 15), previous intraocular surgery (n = 11), ocular surface disease (n = 10), nasolacrimal duct obstruction (n = 4), prematurity (n = 3), developmental delay (n = 2), TORCH infection (n = 1), and contact lens (n = 1). Corneal thinning was observed in 29 eyes (50.9%), which progressed to perforation in 13 eyes (22.8%). Three patients developed endophthalmitis (95% CI, 1.5–13.4%). Most eyes had negative smear (60.4%) and culture (59.6%) results. Pseudomonas aeruginosa was the most common microorganism (11 of 21). Candida albicans was isolated in one case. In vitro susceptibility results showed good coverage of the combined ceftazidime and vancomycin regimen (100%). Surgical procedures were carried out in 35 eyes (61.4%) and 15 eyes required tectonic procedures (26.3%).ConclusionDespite good coverage of medical treatment over cultured isolates, surgical tectonic intervention was required in nearly a quarter of cases to resolve the corneal infection. This finding indicates the necessity of prompt patient referring, corneal sampling and initiation of the treatment.

Etiopathology, Epidemiology, Diagnosis, and Treatment of Fungal Keratitis.

Fungal keratitis (FK) is a severe ocular condition resulting from corneal infection that is prevalent in tropical countries, particularly in developing regions of Asia and Africa. Factors like corneal lens misuse, inappropriate steroid use, and diagnostic challenges have provoked the epidemic. FK causes significant vision impairment, scarring, and ocular deformities. Accurate pathological diagnosis is crucial for effective therapeutic intervention. Topical antifungal therapy with surface healing medications proves effective in preventing fungal-borne ulcers. Managing FK requires a comprehensive understanding of fungal pathogenesis, guiding formulation strategies and preventive measures to curb global ocular blindness. This review provides in-depth insights into FK, covering etiology, epidemiology, pathogenesis, therapeutic interventions, antifungal resistance, limitations, prevention, and future perspectives on ocular surface disease management.

Establishment of a corneal ulcer prognostic model based on machine learning

Corneal infection is a major public health concern worldwide and the most common cause of unilateral corneal blindness. Toxic effects of different microorganisms, such as bacteria and fungi, worsen keratitis leading to corneal perforation even with optimal drug treatment. The cornea forms the main refractive surface of the eye. Diseases affecting the cornea can cause severe visual impairment. Therefore, it is crucial to analyze the risk of corneal perforation and visual impairment in corneal ulcer patients for making early treatment strategies. The modeling of a fully automated prognostic model system was performed in two parts. In the first part, the dataset contained 4973 slit lamp images of corneal ulcer patients in three centers. A deep learning model was developed and tested for segmenting and classifying five lesions (corneal ulcer, corneal scar, hypopyon, corneal descementocele, and corneal neovascularization) in the eyes of corneal ulcer patients. Further, hierarchical quantification was carried out based on policy rules. In the second part, the dataset included clinical data (name, gender, age, best corrected visual acuity, and type of corneal ulcer) of 240 patients with corneal ulcers and respective 1010 slit lamp images under two light sources (natural light and cobalt blue light). The slit lamp images were then quantified hierarchically according to the policy rules developed in the first part of the modeling. Combining the above clinical data, the features were used to build the final prognostic model system for corneal ulcer perforation outcome and visual impairment using machine learning algorithms such as XGBoost, LightGBM. The ROC curve area (AUC value) evaluated the model’s performance. For segmentation of the five lesions, the accuracy rates of hypopyon, descemetocele, corneal ulcer under blue light, and corneal neovascularization were 96.86, 91.64, 90.51, and 93.97, respectively. For the corneal scar lesion classification, the accuracy rate of the final model was 69.76. The XGBoost model performed the best in predicting the 1-month prognosis of patients, with an AUC of 0.81 (95% CI 0.63–1.00) for ulcer perforation and an AUC of 0.77 (95% CI 0.63–0.91) for visual impairment. In predicting the 3-month prognosis of patients, the XGBoost model received the best AUC of 0.97 (95% CI 0.92–1.00) for ulcer perforation, while the LightGBM model achieved the best performance with an AUC of 0.98 (95% CI 0.94–1.00) for visual impairment.

Case Report : Navigating the uncommon: Medicopsis romeroi-induced corneal ulcer

Abstract* This report details a rare case of corneal infection caused by Medicopsis romeroi, highlighting clinical presentation, diagnostic methods, treatment, and outcome. An early adolescence male, after recent corneal tear repair, presented acute eye pain, redness, and decreased vision for 1 day. He underwent corneal tear repair elsewhere post vegetative matter-related swimming injury. Ophthalmic examination revealed a 2.5*3.3mm ulcer around sutures. Corneal scrapings enabled microscopy and culture. With lesion worsening, tissue adhesive (TA) and bandage contact lens (BCL) were applied. Fungal culture identified Medicopsis romeroi. Patient's history, clinical course, and treatment were documented. Microscopy unveiled fungal hyphae, later confirmed as Medicopsis romeroi. Treatment included topical/systemic antifungals. Post-TA + BCL, significant improvement followed, with re-epithelialization, scarring. This report underscores the importance of considering rare fungal pathogens like Medicopsis romeroi in cases of corneal ulcers, especially in individuals with unusual risk factors. Timely diagnosis through microscopy and fungal culture, coupled with tailored antifungal treatment led to successful management and favorable patient outcomes. This case also emphasizes the significance of vigilant clinical observation, precise laboratory analysis, and multidisciplinary collaboration between ophthalmologists and microbiologists in managing atypical ocular infections.

Pseudomonas aeruginosa impairs mitochondrial function and metabolism during infection of corneal epithelial cells.

Pseudomonas aeruginosa (PA) is a gram-negative opportunistic pathogen that can infect the cornea as a result of trauma or contact lens wear. In addition to their known energy producing role, mitochondria are important mediators of immune signaling and host defense. While certain pathogens have developed strategies to evade host defenses by modulating host mitochondrial dynamics and metabolism, the ability of PA to harness host cell mitochondria during corneal infection is unknown. Using a combination of biochemical and imaging techniques, we show that PA infection of corneal epithelial cells induced mitochondrial fission in a DRP1-dependent manner that preceded PINK1/Parkin and FUNDC1-mediated mitophagy. PA also impaired NADH-linked respiration through a reduction in complex 1. This corresponded to a decrease in metabolic pathways related to glycolysis and the TCA cycle. Metabolomics analysis further demonstrated an upregulation of the pentose phosphate pathway, arginine, purine, and pyrimidine metabolism in PA infected cells. These pathways may provide a key source of nucleotides, amino acids, and nitrogen for both the host cell and PA, in addition to antioxidant functions. Following treatment with gentamicin to kill all extracellular bacteria, metabolic flux analysis showed that corneal epithelial cells were able to restore mitochondrial function despite the continued presence of intracellular PA. Taken together, these data demonstrate that mitochondrial dysfunction and metabolic rewiring in host cells is triggered by extracellular PA, but once inside, PA requires healthy mitochondria to ensure host cell survival.