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Objective Microbial keratitis (MK) is a significant cause of blindness in sub-Saharan Africa. We investigated the feasibility of using a novel corneal impression membrane (CIM) for obtaining and processing samples by culture, PCR and whole-genome sequencing (WGS) in patients presenting with suspected MK in Malawi.Methods and analysis Samples were collected from patients presenting with suspected MK using a 12 mm diameter polytetrafluoroethylene CIM disc. Samples were processed using culture and PCR for Acanthamoeba, herpes simplex virus type 1 (HSV-1) and the bacterial 16S rRNA gene. Minimum inhibitory concentrations of isolates to eight antimicrobials were measured using susceptibility strips. WGS was used to characterise Staphylococcus aureus isolates.Results 71 eyes of 71 patients were included. The overall CIM isolation rate was 81.7% (58 positive samples from 71 participants). 69 (81.2%) of isolates were Gram-positive cocci. Coagulase-negative Staphylococcus 31.8% and Streptococcus species 14.1% were the most isolated bacteria. Seven (9.9%) participants were positive for HSV-1. Fungi and Acanthamoeba were not detected. Moxifloxacin and chloramphenicol offered the best coverage for both Gram-positive and Gram-negative isolates when susceptibility was determined using known antimicrobial first quartile concentrations and European Committee on Antimicrobial Susceptibility Testing breakpoints, respectively. WGS identified known virulence genes associated with S. aureus keratitis.Conclusions In a resource-poor setting, a CIM can be used to safely sample the cornea in patients presenting with suspected MK, enabling identification of causative microorganisms by culture and PCR. Although the microbiological spectrum found was limited to the dry season, these preliminary results could be used to guide empirical treatment.

Abstract To provide a solution for average paraxial lens power (ApP) of a lens. Orthogonal and oblique sections through a lens of power $$F$$ F were reduced to a paraxial representation of lens power followed by integration. Visual acuity was measured using lenses of different powers (cylinders of − 1.0 and − 2.0D) and axes, mean spherical equivalent (MSE) of S + C/2, ApP and a toric correction, with the order of correction randomised. A digital screen at 6 m was used on which a Landolt C with crowding bars was displayed for 0.3 s before vanishing. The general equation for a symmetrical lens of refractive index (n), radius of curvature R, in medium of refractive index n1, through orthogonal ( $$\theta$$ θ ) and oblique meridians ( $$\gamma$$ γ ) as a function of the angle of incidence ( $$\alpha$$ α ) reduces for paraxial rays ( $$\alpha \sim 0$$ α ∼ 0 ) to $$F_{n,R} \left( {\alpha ,\theta ,\gamma } \right)\left. \right|_{\alpha \sim 0} = \frac{{n - n_{1} }}{R}\cos^{2} \theta \cos^{2} \gamma$$ F n , R α , θ , γ α ∼ 0 = n - n 1 R cos 2 θ cos 2 γ . The average of this function is $$F_{n,R} \left( {\alpha ,\theta ,\gamma } \right)\left. \right|_{\alpha \sim 0} = \frac{{n - n_{1} }}{4R} $$ F n , R α , θ , γ α ∼ 0 = n - n 1 4 R providing a solution of $$\frac{F}{4}$$ F 4 for ApP.For central (p = 0.04), but not peripheral (p = 0.17) viewing, correction with ApP was associated with better visual acuity than a MSE across all tested refractive errors (p = 0.04). These findings suggest that $$\frac{F}{4}$$ F 4 may be a more inclusive representation of the average paraxial power of a cylindrical lens than the MSE.

Ember accumulation on and around homes can lead to spot fires and home ignition. Post wildland fire assessments suggest that this mechanism is one of the leading causes of home destruction in wildland urban interface (WUI) fires. However, the process of ember deposition and accumulation on and around houses remains poorly understood. Herein, we develop a deep learning (DL) model to analyze data from a series of ember-related wind tunnel experiments for a range of wind conditions and roof slopes. The developed model is designed to identify building roof regions where embers will remain in contact with the rooftop. Our results show that the DL model is capable of accurately predicting the position and fraction of the roof on which embers remain in place as a function of the wind speed, wind direction, roof slope, and location on the windward and leeward faces of the rooftop. The DL model was augmented with explainable AI (XAI) measures to examine the extent of the influence of these parameters on the rooftop ember coverage and potential ignition.

Introduction The success of keratoplasty strongly depends on the health status of the transplanted endothelial cells. Donor corneal tissues are routinely screened for endothelial damage before shipment; however, surgical teams have currently no means of assessing the overall viability of corneal endothelium immediately prior to transplantation. The aim of this study is to validate a preoperative method of evaluating the endothelial health of donor corneal tissues, to assess the proportion of tissues deemed suitable for transplantation by the surgeons and to prospectively record the clinical outcomes of a cohort of patients undergoing keratoplasty in relation to preoperatively defined endothelial viability.Methods and analysis In this multicentre cohort study, consecutive patients undergoing keratoplasty (perforating keratoplasty, Descemet stripping automated endothelial keratoplasty (DSAEK), ultra-thin DSAEK (UT-DSAEK) or Descemet membrane endothelial keratoplasty) will be enrolled and followed-up for 1 year. Before transplantation, the endothelial viability of the donor corneal tissue will be evaluated preoperatively through trypan blue staining and custom image analysis to estimate the overall percentage of trypan blue-positive areas (TBPAs), a proxy of endothelial damage. Functional and structural outcomes at the end of the follow-up will be correlated with preoperatively assessed TBPA values.Ethics and dissemination The protocol will be reviewed by the ethical committees of participating centres, with the sponsor centre issuing the final definitive approval. The results will be disseminated on ClinicalTrials.gov, at national and international conferences, by partner patient groups and in open access, peer-reviewed journals.Trial registration number NCT05847387.

Abstract The skin serves as a crucial barrier against environmental insults and invading pathogens. However, traumatic injury or skin disorder can compromise this barrier function, leasing to bacterial colonization and infection of the wound with microorganisms such as Staphylococcus aureus, which are normally present on healthy skin. The secretion of bacterial proteases such as V8 protease from S. aureus can disturb the equilibrium between extracellular matrix degradation and deposition during wound healing resulting in loss of barrier integrity. We report the feasibility of a nitric oxide (NO) releasing poly‐ε‐lysine (pεK) hydrogel to prevent loss of barrier function caused by V8 proteases. The fabrication and characterization of the pεK hydrogel and NO releasing properties in biologically relevant media are reported. The NO‐releasing pεK hydrogel have demonstrated bactericidal activity against a clinical isolate of S. aureus in complex physiological media and concurrently reduce the catalytic activity of secreted V8 protease. Moreover, pεK hydrogels are cytocompatible with keratinocytes and dermal fibroblasts. In contrast, Penicillin G loaded pεK hydrogels showed excellent antimicrobial efficacy but did not affect V8 catalytic activity. This demonstrates that NO‐releasing pεK hydrogels hold potential as an effective treatment for infected wounds reducing the microbial burden and inactivating bacterial secreted proteases.

The ocular surface is composed of two phenotypically and functionally different epithelial cell types: corneal and the conjunctival epithelium. Upon injury or disease, ocular surface homeostasis is impaired resulting in migration of conjunctival epithelium on to the corneal surface. This can lead to incomplete transdifferentiation toward corneal epithelial-like cells in response to corneal basement membrane cues. We show that corneal extracellular matrix (ECM) proteins induce conjunctival epithelial cells to express corneal associated markers losing their conjunctival associated phenotype at both, mRNA and protein level. Corneal epithelial cells behave the same in the presence of conjunctival ECM proteins, expressing markers associated with conjunctival epithelium. This process of differentiation is accompanied by an intermediate step of cell de-differentiation as an up-regulation in the expression of epithelial stem cell markers is observed. In addition, analysis of ECM proteins by laminin screening assays showed that epithelial cell response is laminin-type dependent, and cells cultured on laminin-511 showed lower levels of lineage commitment. The phosphorylation and proteolysis levels of proteins mainly involved in cell growth and differentiation showed lower modifications in cells with lower lineage commitment. These observations showed that the ECM proteins may serve as tools to induce cell differentiation, which may have potential applications for the treatment of ocular surface injuries.

Topical fluoroquinolones (FQs) are an established treatment for suspected microbial keratitis. An increased FQ resistance in some classes of bacterial pathogens is a concern. Some recently developed FQs have an extended spectrum of activity, making them a suitable alternative for topical ophthalmic use. For example, the new generation FQs, avarofloxacin, delafloxacin, finafloxacin, lascufloxacin, nadifloxacin, levonadifloxacin, nemonoxacin and zabofloxacin have good activity against the common ophthalmic pathogens such as Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pneumoniae and several of the Enterobacteriaceae. However, because there are no published ophthalmic break-point concentrations, the susceptibility of an isolated micro-organism to a topical FQ is extrapolated from systemic break-point data and wild type susceptibility. The purpose of this review is to compare the pharmacokinetics and pharmacodynamics of the FQs licensed for topical ophthalmic use with the same parameters for new generation FQs. We performed a literature review of the FQs approved for topical treatment and the new generation FQs licensed to treat systemic infections. We then compared the minimum inhibitory concentrations (MIC) of bacterial isolates and the published concentrations that FQs achieved in the cornea and aqueous. We also considered the potential suitability of new generation FQs for topical use based on their medicinal properties. Notably, we found significant variation in the reported corneal and aqueous FQ concentrations so that reliance on the reported mean concentration may not be appropriate, and the first quartile concentration may be more clinically relevant. The provision of the MIC for the microorganism together with the achieved lower (first) quartile concentration of a FQ in the cornea could inform management decisions such as whether to continue with the prescribed antimicrobial, increase the frequency of application, use a combination of antimicrobials or change treatment.

Abstract Background Selective lamellar corneal transplantation (keratoplasty) has overtaken full thickness penetrating keratoplasty as the graft choice for endothelial failure. Even more recently eye bank prepared tissues are becoming increasing popular as a way to reduce the risks of tissue loss and stress during endothelial keratoplasty preparation in the surgical theatre. This study compares costs between surgeon and eye bank prepared tissues for Descemet’s stripping automated endothelial keratoplasty (DSAEK) and Descemet’s membrane endothelial keratoplasty (DMEK). Methods Retrospective study conducted at the Royal Liverpool University Hospital including endothelial keratoplasties with a minimum of 6 months follow-up time. Cost analysis included surgical expenses, tissue acquisition fees, cost of patient’s ward admission and out-patient expenses, including cost of re-bubbling procedures, costs of visits, anterior segment imaging and optometrist visits within the first 6 months follow-up. Results Ninety-eight eyes of 98 patients were included in the study of which 42 underwent DSAEK surgery and 56 DMEK surgery. Cost analysis of surgical expenses in the DSAEK group showed a significant difference between using surgeon prepared and eye bank prepared tissue (£3866 ± 296 and £4389 ± 360, respectively; p

Objective To determine whether patients who receive corneas from the same donor have similar risks of endothelial failure and rejection.Methods and Analysis Patients with Fuchs endothelial dystrophy (FED) and pseudophakic bullous keratopathy (PBK) who received their first corneal transplant between 1999 and 2016 were analysed. Patients receiving corneas from donors who donated both corneas for the same indication were defined as ‘paired’. Gray’s test was used to compare the cumulative incidence of endothelial failure and rejection within 5 years post-transplant for ‘paired’ and ‘unpaired’ groups. Cox regression models were fitted to determine whether there was an association between recorded donor characteristics (endothelial cell density (ECD), age and sex and endothelial graft failure and rejection.Results 10 838 patients were analysed of whom 1536 (14%) were paired. The unpaired group comprised 1837 (69%) recipients of single corneal donors and 7465 (69%) donors who donated both corneas for another indication. ECD was lower for unpaired single cornea donors (p0.16 for ECD, p>0.32 for donor age, p>0.14 for sex match and p>0.17 for the donor effect).Conclusion The absence of a significant difference in graft outcome for corneal transplants for FED and PBK between paired and unpaired donors may reflect a homogeneous donor pool in the UK.

Abstract Early relapse after platinum chemotherapy in epithelial ovarian cancer (EOC) portends poor survival. A‐priori identification of platinum resistance is therefore crucial to improve on standard first‐line carboplatin–paclitaxel treatment. The DNA repair pathway homologous recombination (HR) repairs platinum‐induced damage, and the HR recombinase RAD51 is overexpressed in cancer. We therefore designed a REMARK‐compliant study of pre‐treatment RAD51 expression in EOC, using fluorescent quantitative immunohistochemistry (qIHC) to overcome challenges in quantitation of protein expression in situ. In a discovery cohort (n = 284), RAD51‐High tumours had shorter progression‐free and overall survival compared to RAD51‐Low cases in univariate and multivariate analyses. The association of RAD51 with relapse/survival was validated in a carboplatin monotherapy SCOTROC4 clinical trial cohort (n = 264) and was predominantly noted in HR‐proficient cancers (Myriad HRDscore

Candida parapsilosis has been considered an emerging pathogen with increasing incidence reported in the literature. As a normal commensal of human skin, it is likely that Candida species could gain access to soft tissues of the hand and wrist by direct inoculation, resulting in an infectious tenosynovitis. With the increased prevalence of intravenous drug use (IVDU), users are at increasing risk for musculoskeletal infections including soft tissue abscesses, cellulitis, tenosynovitis, and septic arthritis. Chronic tenosynovitis, with rice body formation in particular, is a comparatively rare musculoskeletal infection. Knowledge of this entity, the related pathogens, imaging findings, and the treatment plan is important not only to the treating clinician, but also to radiologists as the physiological and anatomic consequences can be detrimental to patient recovery. Keywords: Candida Parapsilosis, Extensor tendon, Wrist, Intravenous drug use

The corneal endothelium is the posterior monolayer of cells that are responsible for maintaining overall transparency of the avascular corneal tissue via pump function. These cells are non-regenerative in vivo and therefore, approximately 40% of corneal transplants undertaken worldwide are a result of damage or dysfunction of endothelial cells. The number of available corneal donor tissues is limited worldwide, hence, cultivation of human corneal endothelial cells (hCECs) in vitro has been attempted in order to produce tissue engineered corneal endothelial grafts. Researchers have attempted to recreate the current gold standard treatment of replacing the endothelial layer with accompanying Descemet’s membrane or a small portion of stroma as support with tissue engineering strategies using various substrates of both biologically derived and synthetic origin. Here we review the potential biomaterials that are currently in development to support the transplantation of a cultured monolayer of hCECs.

Purpose: To investigate if shotgun-sequencing method could be useful in detailed diagnosis of herpes simplex virus (HSV) infection and compare it with the conventional diagnostic method. Observations: Using a sterile scraper, the infectious part of the ocular surface was scraped gently and placed on a glass slide for conventional diagnosis using PCR and histology and in RNA stabilizing reagent for shotgun sequencing respectively. Concentration of the DNA was determined using a sensitive fluorescence dye-based Qubit dsDNA HS Assay Kit. Shotgun-sequencing libraries were generated using the NEBNext DNA ultra II protocol. The samples were sequenced on the Illumina NextSeq 500 in high output mode with 2X150 bp paired-end sequencing. Taxonomic and functional profiles were generated.Conventional diagnostic method suspected herpetic keratitis. The results indicated presence of an amplified product of 92 bp positive HSV-DNA. Conventional diagnostic method detected the presence of Herpes Simplex Virus DNA (type 1). Shotgun sequencing confirmed the diagnosis of HSV along with the taxonomical profiling of the virus. These results were achieved using 1.9 ng/μL of DNA concentration (114 ng in 60 μL) of the total sample volume. Conclusions and importance: Shotgun sequencing is a hypothesis-free approach that identifies full taxonomic and functional profile of an organism. This technology is advantageous as it requires smaller sample size compared to conventional diagnostic methods.

Purpose: To report the management of an intraoperative complication during large (9.5 mm) ultra-thin Descemet Stripping Automated Endothelial Keratoplasty (UT-DSAEK) surgery in a patient with a large area of dysfunctional endothelium. Observations: A single case study of an 89 y/o male with a history of Fuchs corneal endothelial dystrophy is presented. The patient was listed for a large UT-DSAEK, but due to an intraoperative complication during graft preparation, an 8.00 mm Descemet membrane endothelial keratoplasty (DMEK) was prepared from the same graft using a standardized SCUBA technique and delivered. Early postoperative examination of the graft showed decentred, residual corneal oedema in the absence of DM detachment and a well-formed anterior chamber. The endothelial graft was found attached after 3 months and the corneal oedema was cleared. After 5 months, the patient's BSCVA was recorded at 6/6(20/20) in the left eye, but complained of mild discomfort. A circular ring of corneal oedema was observed around the graft and decentralization of the transplanted graft was observed. Endothelial cell density (ECD) of the central cornea at 5th month was 1506 cells/mm2 at a focal depth of 496 μm with some polymegathism. Conclusions: and importance: It is possible to prepare DMEK starting from a failed DSAEK graft. Thickness map on corneal tomography could be a useful tool after DMEK for checking graft centration, function, and corneal recovery indirectly. It is recommended to only maintain a small distance between the descemetorhexis area and the size of the endothelial graft. Keywords: Endothelial keratoplasty, DMEK

Purpose: To report two cases of spontaneous Descemet's membrane detachment (DMD) and dehiscence following penetrating keratoplasty (PK). Case Reports: Spontaneous DMD or Descemet's membrane (DM) dehiscence following PK is a rare occurrence. Here, we describe two cases of such an occurrence following PK arising from the graft–host interface. A possible causative relation between DMD/dehiscence and DM–stromal interface attachment is suggested. Conclusion: DMD and dehiscence after PK can be explained by the peripheral thinning of DM and possible changes to the recently characterized anchoring zone of interwoven collagen fibers and proteoglycans at the Descemet–stroma interface.

Purpose. To investigate if the peripheral corneal endothelium that is usually discarded after a corneal transplant could be used for endothelial cell culture. Methods. Donor corneas (n = 19) with a mean age of 72 years, male : female ratio of 15 : 4, and death-to-preservation time of 10 hours were assessed for endothelial cell density (ECD) and number of dead cells before isolation. Alizarin red staining (n = 3) was performed to check the morphology of cells in the center and periphery. Descemet’s membrane-endothelial complex was peeled from the center (8.25 mm) and the periphery (2.75 mm) and plated in two different wells of an 8-well chamber slide with media refreshed every alternate day. The confluence rate was monitored by microscopy. Live/dead analysis was performed (n = 3) at confluence. Tag-2A12 as a monoclonal antibody against peroxiredoxin-6 (Prdx-6) (n = 4), ZO-1 (zonula occludens-1) as a tight junction protein (n = 4), and Ki-67 as a proliferative cell marker (n = 4) were used to characterize the cells at confluence. Results. At confluence, 8.25% average increase in the number of cells was observed from the central zone compared with 16.5% from the peripheral zone. Proliferation rate, hexagonality, Ki-67 positivity, and the cell area did not significantly differ between the groups (p>0.05). All the proteins corresponding to the biomarkers tested were expressed in both the groups. Conclusions. Although there are significantly fewer amounts of peripheral cells available after graft preparation for keratoplasty, these cells can still be used for endothelial cell culture due to their proliferative capability. The peripheral cells that are discarded after graft preparation can thus be utilized to increase the donor endothelial cell pool for regenerative treatments.