A multi-center, cross-sectional study on the burden of infectious keratitis in China

Infectious Keratitis After Keratoplasty in the United States: Analysis of a National Medicare Claims Data Set

PURPOSE

The aim of this study was to assess the incidence, trends, and risk factors of infectious keratitis (IK) and subsequent repeat keratoplasty after penetrating keratoplasty (PK) and endothelial keratoplasty (EK).

METHODS

Using a retrospective cohort study design, IK cases within 6 months of keratoplasty were identified using billing codes among 100% Medicare beneficiaries aged 65 years and older who underwent either PK or EK between 2011 and 2020. Multivariable logistic regression models were used to evaluate factors associated with postkeratoplasty IK.

RESULTS

We identified 115,588 keratoplasties, of which 20.0% (n = 23,144) were PK and 80.0% (n = 92,444) were EK. IK developed within 6 months with a rate of 3.32% (n = 769) post-PK and 0.72% (n = 666) post-EK. Overall rates of IK decreased from 16.05 to 9.61 per 1000 keratoplasties between 2011 and 2020 ( P < 0.001). The median interval between keratoplasty and diagnosis of IK was 73 days (interquartile range: 29-114 days) for PK and 74 days (interquartile range: 38-116 days) for EK. After IK, 22.9% (n = 176) and 23.8% (n = 159) eyes underwent repeat keratoplasty within 1 year for PK and EK, respectively. The occurrence of IK after PK was associated with age 85 years and older [odds ratio (OR): 1.38; 95% confidence interval (CI): 1.13-1.68] relative to patients aged 65 to 74 years. The occurrence of IK after EK was also associated with age 85 years and older (OR: 1.44; 95% CI: 1.14-1.82) relative to patients aged 65 to 74 years.

CONCLUSIONS

IK was 4 times more common after PK than EK and the complication was associated with older age. Our findings may help corneal surgeons in counseling patients at higher risk and guiding their postoperative care.

Assessment of Direct Costs of Admission Due to Presumed Microbial Keratitis in a Tertiary Referral Hospital in Thailand: A 7-Year Retrospective Study

Objective

To evaluate the direct healthcare cost of admission and examine the effects of cost drivers of treating presumed microbial keratitis (MK) at a tertiary referral hospital.

Design

Retrospective study.

Methods

A total of 741 patients who presented with MK were included. All information regarding costs was collected, and demographic data were employed for risk factor analysis.

Results

The total cost of treating MK over a 7-year period at Rajavithi Hospital was US$14,514,625.04, while the median cost was US$10,840.17 per patient (Q1-3, US$5866.56-24,172.28). The medical professional services were the highest cost category in terms of both total cost of treatment over 7 years and median cost per patient, accounting for US$6,474,718.43 and US$5235.20 (Q1-3, US$2582.79-10,474.24) respectively. In 2020, the total cost of treatment declined, corresponding with fewer hospitalized patients; however, the median cost per patient was the highest of all years, amounting to US$15,089.90 (Q1-3, US$8064.17-29102.50), while the median cost per patient from 2014 to 2019 was US$9969.96 (Q1-3, US$5177.98-21,942.68). Statistical significance was found in the median cost per patient in 2020 compared to the median cost per patient in 2014-2019 (p-value 0.019). Risk factors associated with the more expensive cost of treatment were longer length of stay (LOS); age more than 60 years old; readmission; diabetes mellitus (DM); hypertension; and heart disease.

Conclusion

There were several key factors impacting the direct healthcare costs of severe MK treatment. Medical professional services emerged as the most substantial cost category, while longer hospital stays, older age groups, readmission cases, and comorbidities such as diabetes mellitus, hypertension, and heart disease were all linked to elevated treatment expenses. There were no statistically significant differences in the direct medical expenses during hospitalization associated with treating severe MK, whether the culture results were positive or negative, or regardless of the type of cultured organism utilized.

Characterization of Polymicrobial and Antibiotic-Resistant Infectious Keratitis in a County Hospital Setting

Purpose

Infectious keratitis is a serious cause of visual impairment, particularly in low-income communities. This study examines the associations between social risk factors and polymicrobial keratitis, multidrug resistance, pathogen spectrum, and outcomes at a county hospital.

Methods

We performed a retrospective study of Zuckerberg San Francisco General Hospital patients treated for infectious keratitis from 2010-2021. Multivariable regression was performed to analyze the relationships between social, medical, and psychiatric risk factors with polymicrobial growth, multidrug resistance, and clinical outcomes.

Results

Of 174 patients with infectious keratitis, 44 (25%) had polymicrobial growth. Six patients (14%) with polymicrobial growth had multidrug-resistant organisms. Homeless patients were more likely to present with polymicrobial infection (OR 3.4, p = 0.023), and polymicrobial infections were associated with multidrug-resistant organisms (p = 0.018). Smoking, drug use, HIV positivity, prior corneal pathology, and contact lens use were not associated with an increased risk of polymicrobial infection. Eleven patients (6.3%) were started on topical antibiotics prior to presentation; of these, none developed polymicrobial infections or multidrug-resistant organisms. Polymicrobial infections increased the likelihood to initiation of fortified antibiotics (OR 2.9, p = 0.011) but did not impact ulcer size, final visual acuity, time to resolution, or likelihood of emergent procedures.

Conclusions

Homelessness correlates with an increased risk of polymicrobial keratitis and subsequent multidrug resistance, supporting initiation of broad antibiotic coverage in this population. Prior topical antibiotics did not increase risk of polymicrobial infection. Polymicrobial infection did not significantly worsen clinical outcomes.

Bacterial Keratitis: Clinical Features, Causative Organisms, and Outcome During a 13-year Study Period

PURPOSE

This study aimed to review clinical features, causative organisms, complications, and outcome of bacterial keratitis cases at a tertiary eye hospital.

METHODS

A retrospective study was conducted on clinically diagnosed bacterial keratitis cases from 2007 to 2019. Poor outcome was flagged if any of the following was identified: final visual acuity (VA) worse than 20/200, decrease in VA (1 line or worse compared with presenting VA), corneal perforation, endophthalmitis, failed graft, or cases requiring enucleation or evisceration.

RESULTS

The study included 263 cases of bacterial keratitis with 169 cases (64.3%) of culture-positive bacterial keratitis. Gram-positive bacteria were found to be the causative organism in 106 cases (62.8%). The most common types were coagulase-negative staphylococci (23.1%) and Pseudomonas (23.1%). Culture-positive bacterial keratitis was associated with the development of anterior chamber reaction (≥1+) on multivariate analysis [adjusted odds ratio (OR): 3.03, confidence interval (CI): 1.23-7.45, P = 0.016]. The complications that occurred in the current cohort included visually significant scar (64.7%), perforation (10.8%), cataract (8.8%), nonhealing epithelial defects (8.0%), corneal neovascularization (4.9%), endophthalmitis (4.6%), and hypotony (1.5%). On multivariate analysis, diabetes mellitus (adjusted OR: 3.51, CI: 1.59-7.76, P = 0.002), poor presenting best-corrected VA (adjusted OR: 3.95, CI 1.96-7.96, P < 0.001), and positive cultures (adjusted OR: 2.36, CI: 1.11-5.00, P = 0.025) were associated with poor outcome.

CONCLUSIONS

Culture-negative keratitis had less severe infection and better outcomes when compared to culture-positive bacterial keratitis. Factors associated with poor outcome included diabetes, poor presenting VA, and positive cultures.

Construction of Graphene Quantum Dot-based Dissolving Microneedle Patches for the Treatment of Bacterial Keratitis

Bacterial keratitis (BK) is an ophthalmic infection caused by bacteria and poses a risk of blindness. Numerous drugs have been used to treat BK, the majority suffered from limited effect owing to their backward antimicrobial and delivery efficacy. Herein, we evaluated the antibacterial effect of a cationic carbon-based nanomaterial, i.e., imidazole-modified graphene quantum dots (IMZ-GQDs), which exhibits disinfection rates of >90% against three typical Gram-positive strains within 3 h owing to the loss of membrane integrity and decline in membrane potential. For ocular application, we further developed IMZ-GQDs-loaded dissolving microneedle patches (IMZ-GQDs MNs) via a typical two-step micromolding method. IMZ-GQDs MNs showed sufficient dissolution and penetration for intrastromal delivery in vitro and successfully overcome the rabbit corneal epithelial layer in vivo. The excellent biocompatibility of IMZ-GQDs MNs was demonstrated both in cell and animal models, and they exhibited low cytotoxicity, low invasiveness and low ocular irritation. The topical application of IMZ-GQDs MNs has the benefits of both high antibacterial activity and effective drug delivery, thereby leading to the resolution of Staphylococcus aureus-induced BK in rabbits in 7 days. Therefore, IMZ-GQDs MNs is a promising approach for BK treatment, which is safe and efficient.

TFOS lifestyle: Impact of societal challenges on the ocular surface

Societal factors associated with ocular surface diseases were mapped using a framework to characterize the relationship between the individual, their health and environment. The impact of the COVID-19 pandemic and mitigating factors on ocular surface diseases were considered in a systematic review. Age and sex effects were generally well-characterized for inflammatory, infectious, autoimmune and trauma-related conditions. Sex and gender, through biological, socio-economic, and cultural factors impact the prevalence and severity of disease, access to, and use of, care. Genetic factors, race, smoking and co-morbidities are generally well characterized, with interdependencies with geographical, employment and socioeconomic factors. Living and working conditions include employment, education, water and sanitation, poverty and socioeconomic class. Employment type and hobbies are associated with eye trauma and burns. Regional, global socio-economic, cultural and environmental conditions, include remoteness, geography, seasonality, availability of and access to services. Violence associated with war, acid attacks and domestic violence are associated with traumatic injuries. The impacts of conflict, pandemic and climate are exacerbated by decreased food security, access to health services and workers. Digital technology can impact diseases through physical and mental health effects and access to health information and services. The COVID-19 pandemic and related mitigating strategies are mostly associated with an increased risk of developing new or worsening existing ocular surface diseases. Societal factors impact the type and severity of ocular surface diseases, although there is considerable interdependence between factors. The overlay of the digital environment, natural disasters, conflict and the pandemic have modified access to services in some regions.

The epidemiology of infectious keratitis

Infectious keratitis is a rare but potentially severe sight-threatening disease, associated with considerable societal burden, cost and morbidity. This review summarises the most recent evidence for the incidence, risk factors and impact of disease, all of which vary widely according to region, access to health care, socioeconomic and environmental factors, predisposing conditions and causative organisms. The frequency and societal impact of infectious keratitis are significantly higher in low-income countries. In non-viral infectious keratitis, bacterial causes predominate in most regions. Fungi, particularly linked with agricultural trauma, are more frequently associated with infectious keratitis in low-income regions, particularly in India and certain African countries. The disease impact is compounded by poverty and limited access to services and treatment. Early diagnosis, access to appropriate treatment, prophylaxis in ocular trauma, availability of eye protection, awareness of risk factors may be associated with reduced disease severity and vision loss. Evidence for the incidence and burden of disease is lacking in certain regions and well-designed epidemiological studies to identify independent risk factors for the disease and those associated with more severe outcomes may better identify causation and guide resource allocation and preventative strategies.

Population-based study on the prevalence, clinical characteristics and vision-related quality of life in patients with corneal opacity resulting from infectious keratitis: results from the Corneal Opacity Rural Epidemiological study

AIM

To estimate prevalence and characterise clinical features and vision-related quality of life (VR-QoL) of corneal opacities (COs) resulting from infectious keratitis in a rural North Indian population.

METHODS

The Corneal Opacity Rural Epidemiological study was a cross-sectional study conducted in 25 randomly selected clusters of rural Gurgaon, Haryana, India to determine prevalence of corneal disease across all age groups. During house-to-house visits, sociodemographic details, presence, type and clinical characteristics of corneal disease, laterality and resultant visual impairment (VI) was noted. Subgroup analysis of data was performed to understand the prevalence, clinical characteristics, VR-QoL in patients with CO due to infectious keratitis. VR-QoL scores were compared with healthy controls.

RESULTS

Overall, 65 of 12 113 participants had evidence of infectious keratitis-related CO with a mean age of 63.3 (±14.7 SD) years. Prevalence of infectious keratitis-related CO, including both bilateral (12/65) and unilateral (53/65) cases was 0.54% (95% CI 0.41 to 0.66) seen in a total of 77 eyes of 65 participants. Mean visual acuity was 1.18±0.80 with 30/77 (38.9%) eyes having a presenting visual acuity <3/60. Most of the CO due to infectious keratitis was <3 mm in size (61.03%; 47/77), nebular (42.85%; 33/77) and central (49.35%; 38/77) in location. These participants had significantly higher VR-QoL scores and hence poorer VR-QoL across all three domains of vision function (scores of 28 vs 22, 7.5 vs 5 and 15.5 vs 9, respectively; p<0.0001) when compared with healthy controls.

CONCLUSION

The data from this study give an insight into the burden and clinical characteristics of COs resulting from infectious keratitis. VR-QoL is significantly impaired in patients with CO resulting from infectious keratitis, both in bilateral and unilateral cases.

Antimicrobial resistance in topical treatments for microbial keratitis: protocol for a systematic review and meta-analysis

INTRODUCTION

There is evidence for increased resistance against the antimicrobials used to treat keratitis. This review aims to provide global and regional prevalence estimates of antimicrobial resistance in corneal isolates and the range of minimum inhibitory concentrations (MIC) with their associated resistance breakpoints.

METHODS AND ANALYSIS

We report this protocol following Preferred Reporting Items for Systematic Review and Meta-Analyses Protocols guidelines. We will conduct an electronic bibliographic search in MEDLINE, EMBASE, Web of Science and the Cochrane Library. Eligible studies will report in any language data for the resistance or MIC for antimicrobials against bacterial, fungal or amoebic organisms isolated from suspected microbial keratitis. Studies that only report on viral keratitis will not be included. There will be no time restrictions on the date of publication. Screening for eligible studies, assessment of risk of bias and data extraction will be conducted by two reviewers independently, using predefined inclusion criteria and prepiloted data extraction forms. We will resolve disagreements between the reviewers by discussion and, if required, a third (senior) reviewer will arbitrate. We will assess the risk of bias using a tool validated in prevalence studies. The certainty of the evidence will be assessed using the Grades of Recommendation, Assessment, Development and Evaluation approach. Pooled proportion estimates will be calculated using a random-effects model. Heterogeneity will be assessed using the I2 statistic. We will explore differences between Global Burden of Disease regions and temporal trends.

ETHICS APPROVAL AND DISSEMINATION

Ethics approval is not required as this is a protocol for a systematic review of published data. The findings of this review will be published in an open-access, peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42023331126.

Analysis of the application effect of continuous care for patients with viral keratitis

BACKGROUND

In recent years, the incidence of viral keratitis has been on the rise.

OBJECTIVE

This study explored the application effect of continuous care for patients with viral keratitis.

METHODS

A total of 148 patients with viral keratitis admitted to the ophthalmology department of the authors' hospital from January 2019 to December 2020 were selected and divided into the observation group and the control group via the random number table method, with 74 cases in each group. Continuous care was conducted following routine discharge guidance for patients in the observation group, while routine discharge guidance only was provided for the control group. The patients in both groups were continuously observed for one year. The medication compliance, return visit rate, recurrence rate, nursing satisfaction, and quality of life between the two groups were compared and analyzed after one year.

RESULTS

The medication compliance was higher in the observation than in the control group and the difference was statistically significant (P< 0.05). The rate of return visits at 1 week, 1 month, 3 months, 6 months, and 1 year in the observation group were higher than those in the control group and the differences were statistically significant (P< 0.05). The difference in the recurrence rate between the two groups at 1 week was not statistically significant (P> 0.05), while the recurrence rate at 1, 3, and 6 months, and 1 year in the observation group were higher than those in the control group, and the difference was statistically significant (P< 0.05). The total score of the quality of life in the observation group was higher than in the control group and the difference was statistically significant (P< 0.05).

CONCLUSION

Continuous care had a good application effect on patients with viral keratitis, which could potentially effectively improve medication compliance and the rate of return visits, reduce recurrence rate, and improve patient satisfaction and their quality of life. Accordingly, the results of this study present high clinical value.

Potential new fluoroquinolone treatments for suspected bacterial keratitis

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.

Host Defense Peptides at the Ocular Surface: Roles in Health and Major Diseases, and Therapeutic Potentials

Sight is arguably the most important sense in human. Being constantly exposed to the environmental stress, irritants and pathogens, the ocular surface – a specialized functional and anatomical unit composed of tear film, conjunctival and corneal epithelium, lacrimal glands, meibomian glands, and nasolacrimal drainage apparatus – serves as a crucial front-line defense of the eye. Host defense peptides (HDPs), also known as antimicrobial peptides, are evolutionarily conserved molecular components of innate immunity that are found in all classes of life. Since the first discovery of lysozyme in 1922, a wide range of HDPs have been identified at the ocular surface. In addition to their antimicrobial activity, HDPs are increasingly recognized for their wide array of biological functions, including anti-biofilm, immunomodulation, wound healing, and anti-cancer properties. In this review, we provide an updated review on: (1) spectrum and expression of HDPs at the ocular surface; (2) participation of HDPs in ocular surface diseases/conditions such as infectious keratitis, conjunctivitis, dry eye disease, keratoconus, allergic eye disease, rosacea keratitis, and post-ocular surgery; (3) HDPs that are currently in the development pipeline for treatment of ocular diseases and infections; and (4) future potential of HDP-based clinical pharmacotherapy for ocular diseases.

Spectrum of bacterial keratitis in North India: A retrospective analysis of six years at a tertiary care eye center

Purpose

To analyze the pattern of bacterial pathogens causing infective keratitis and their resistance to the recommended antibiotics over six years.

Methods

It was a retrospective study of 9,357 cases of bacterial keratitis from January 2015 to December 2020, at a tertiary care ophthalmic center. A total of 9,547 corneal specimens were obtained from the study subjects. Demographic details of the patients, pathogenic bacteria isolated, and their antimicrobial susceptibility were noted and analyzed.

Results

Bacterial pathogens were identified in 23.52% of the specimens. The most common isolates were coagulase-negative Staphylococci (60.75%), followed by Pseudomonas aeruginosa (14.23%), Staphylococcus aureus (13.92%), gram negative bacilli of the family Enterobacterales (8.64%), Streptococcus spp. (1.72%), Acinetobacter spp. (0.13%), and other non-fermenting gram-negative bacilli (0.57%). In Staphylococci, 55-80% of isolates were resistant to erythromycin, and 40-70% to fluoroquinolones, while no resistance was observed against vancomycin. 40-60% of isolates of P. aeruginosa were resistant to cephalosporins, 40-55% to fluoroquinolones, and 30-60% to aminoglycosides. Also, 40-80% of isolates of Enterobacterales were resistant to cephalosporins, and 50-60% to fluoroquinolones. Most gram-negative isolates were susceptible to carbapenems and polymyxin B.

Conclusion

To the best of our knowledge, our study is the largest compilation of microbiological profile of bacterial keratitis from North India. It highlights the current trend of the bacterial pathogens that cause infectious keratitis. Staphylococci and Pseudomonas were found to be the most common pathogens. Increased resistance was seen against some of the commonly prescribed empirical antibiotics. Such evidence is useful for restructuring the empirical prescription practices from time to time.

Safety, efficacy and delivery of multiple nucleoside analogs via drug encapsulated carbon (DECON) based sustained drug release platform

Acyclovir and similar nucleoside analogs form an essential frontline treatment for various herpesvirus infections of the eye. However, these drugs have low ocular retention when delivered topically and need to be administered several times every day. We have previously demonstrated that acyclovir loaded into activated carbon can be used to significantly decrease dosage frequency in a murine model of ocular infection. In this study, we demonstrate that other nucleoside analogs such as ganciclovir, penciclovir and famciclovir have excellent loading and release profile similar to acyclovir. Similarly we also demonstrate that nucleoside analog loaded carbons termed DECON are effective at very low concentrations in treating active viral infection of human corneal epithelial cells. In this study, using a variety of techniques to evaluate corneal dryness, nerve sensitivity, intraocular pressure, corneal thickness, and somatic inflammation, we report that DECON is well tolerated after administration three times daily over the course of four weeks.

Epidemiology, Microbiology, and Genetics of Contact Lens-Related and Non-Contact Lens-Related Infectious Keratitis

ABSTRACT

Infectious keratitis is a rare but severe condition associated with a range of ocular and systemic predisposing conditions, including ocular trauma, prior surgery, surface disease, and contact lens (CL) wear. This review explores the epidemiology of infectious keratitis, specifically the differences in disease incidence and risk factors, causative organism profile and virulence characteristics and host microbiome, genetics, gene expression, proteomics, and metabolomic characteristics in CL-related and non-CL-related diseases. Differences exist in the epidemiology, demographics, causative organisms, and their virulence characteristics in CL-related and non-CL-related diseases, and there is less evidence to support differences between these groups of individuals in the ocular surface microbiome, genetics, and pathways of disease. Genetic variations, however, in the host immune profile are implicated in both the onset and severity of infectious keratitis in CL and non-CL wearers. As technologies in metabolomics, proteomics, and genomics improved to be better able to process small-volume samples from the ocular surface, there will be improved understanding of the interplay between the CL, ocular surface, host immune profile, and the microbial environment. This may result in a more personalized approach in the management of disease to reduce disease severity.

A Systematic Review of Multi-decade Antibiotic Resistance Data for Ocular Bacterial Pathogens in the United States

INTRODUCTION

Since 2009, the Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) surveillance study has been assessing in vitro antibiotic resistance for bacterial isolates sourced from ocular infections in the US. The main goal of this systematic review was to compare in vitro resistance data for ocular pathogens from published US studies with the most recently published data from the ARMOR study (2009-2018) and, where possible, to evaluate trends in bacterial resistance over time over all studies.

METHODS

A literature search was conducted using MEDLINE®, BIOSIS Previews®, and EMBASE^® databases (1/1/1995-6/30/2021). Data were extracted from relevant studies and antibiotic susceptibility rates for common ocular pathogens (Staphylococcus aureus, coagulase-negative staphylococci [CoNS], Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae), longitudinal changes in susceptibility, and multidrug resistance (MDR) were compared descriptively.

RESULTS

Thirty-two relevant studies were identified. High in vitro resistance was found among S. aureus and CoNS to fluoroquinolones, macrolides, and methicillin/oxacillin across studies, with high rates of MDR noted, specifically among methicillin-resistant staphylococci. Data from studies pre-dating or overlapping the early years of ARMOR reflected increasing rates of S. aureus resistance to fluoroquinolones, macrolides, methicillin/oxacillin, and aminoglycosides, while the ARMOR data suggested slight decreases in resistance to these classes between 2009 and 2018. Overall, methicillin-resistant S. aureus (MRSA) prevalence peaked from 2005 to 2015 with a possible decreasing trend in more recent years.

DISCUSSION AND CONCLUSIONS

Data from local and regional US datasets were generally consistent with data from the national ARMOR surveillance study. Continued surveillance of ocular bacterial pathogens is needed to track trends such as methicillin resistance and MDR prevalence and any new emerging antibiotic resistance phenotypes. Susceptibility data from ARMOR can inform initial choice of therapy, especially in practice areas where local antibiograms are unavailable.

Targeting NECTIN-1 Based on CRISPR/Cas9 System Attenuated the Herpes Simplex Virus Infection in Human Corneal Epithelial Cells In Vitro

PURPOSE

Viral keratitis caused by herpes simplex virus 1 (HSV-1) is a lifelong recurring disease and an unignored cause of blindness worldwide. Current antiviral therapy cannot eliminate the transcriptionally silent HSV-1 in latently infected patients. With the explosive applications of the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated nuclease (Cas) 9 gene-editing system in recent years, we aim to develop a CRISPR/Cas9 system targeting down the major HSV receptor, NECTIN-1 on human corneal epithelial cells (HCECs), to provide a novel strategy for herpes simplex keratitis (HSK) treatment.

METHODS

The selected single guide RNAs (sgRNAs) targeting human nectin cell adhesion molecule 1 (NECTIN-1), together with Cas-9, were assembled into lentivirus. HCECs were infected with Lenti-Cas9-gRNAs to establish NECTIN-1 knockdown cells. Following HSV-green fluorescent protein (GFP) infection, cell survival and virus infection were determined by fluorescence microscopy and flow cytometry. Relative HSV DNA amount was also compared through quantitative reverse transcriptase-polymerase chain reaction.

RESULTS

Lentivirus packaged with the CRISPR/Cas9 system and the two selected sgRNAs both successfully edited down the protein levels of NECTIN-1 of HCECs. After HSV-GFP infection, the infection rate of HCECs in knockdown groups dramatically decreased, especially in the NECTIN-1 knockdown group 1. In addition, the relative HSV DNA amount of both knockdown groups was only 30% when compared with the control group.

CONCLUSIONS

We successfully knocked down the NECTIN-1 expression in vitro by the CRISPR/Cas9 system, which alleviated the HSV infection in HCECs.

TRANSLATIONAL RELEVANCE

This study offered a promising target for the cure of HSK.

Bacterial keratitis: identifying the areas of clinical uncertainty

Bacterial keratitis is a common corneal infection that is treated with topical antimicrobials. By the time of presentation there may already be severe visual loss from corneal ulceration and opacity, which may persist despite treatment. There are significant differences in the associated risk factors and the bacterial isolates between high income and low- or middle-income countries, so that general management guidelines may not be appropriate. Although the diagnosis of bacterial keratitis may seem intuitive there are multiple uncertainties about the criteria that are used, which impacts the interpretation of investigations and recruitment to clinical studies. Importantly, the concept that bacterial keratitis can only be confirmed by culture ignores the approximately 50% of cases clinically consistent with bacterial keratitis in which investigations are negative. The aetiology of these culture-negative cases is unknown. Currently, the estimation of bacterial susceptibility to antimicrobials is based on data from systemic administration and achievable serum or tissue concentrations, rather than relevant corneal concentrations and biological activity in the cornea. The provision to the clinician of minimum inhibitory concentrations of the antimicrobials for the isolated bacteria would be an important step forward. An increase in the prevalence of antimicrobial resistance is a concern, but the effect this has on disease outcomes is yet unclear. Virulence factors are not routinely assessed although they may affect the pathogenicity of bacteria within species and affect outcomes. New technologies have been developed to detect and kill bacteria, and their application to bacterial keratitis is discussed. In this review we present the multiple areas of clinical uncertainty that hamper research and the clinical management of bacterial keratitis, and we address some of the assumptions and dogma that have become established in the literature.

Corneal Blindness in Asia: A Systematic Review and Meta-Analysis to Identify Challenges and Opportunities

PURPOSE

To describe the causes and prevalence of moderate-to-severe visual impairment (MSVI) and blindness from corneal diseases, as well as corneal transplantation across Asia.

METHODS

A meta-analysis of the published literature to identify population-based surveys conducted from 2008 to 2019 in 22 Asian countries regarding the prevalence and causes of MSVI and blindness from corneal disease, and a review of national corneal transplant data and eye bank statistics.

RESULTS

A total of 5307 records were screened to identify 57 reports that were used to estimate a prevalence of MSVI and blindness caused by corneal diseases in Asia of 0.38% (95% confidence interval, 0.29%-0.48%). The most frequent corneal diseases were infectious keratitis, trauma, and pseudophakic bullous keratopathy. As expected, these represented the most common indications for corneal transplantation, although the percentages in each country differed based on the level of economic development, with pseudophakic bullous keratopathy being the most common indication in countries with higher gross national income per capita. Despite this, endothelial keratoplasty is not the most commonly performed form of corneal transplantation in any Asian country and represents only a small percentage of keratoplasty procedures performed in most countries.

CONCLUSIONS

The prevalence of MSVI and blindness from corneal disease in Asia is approximately 0.4%, with a nearly 20-fold difference in the national prevalence across the region. The indications for keratoplasty, reflective of the causes of corneal dysfunction, also vary, more so according to the gross national income than to geographic location, and only a few Asian countries have rates of corneal transplantation above international means.

Risk-Based Estimate of Human Fungal Disease Burden, China

We conducted a systematic literature review to obtain risk population–based fungal disease incidence or prevalence data from China. Data were categorized by risk factors and extrapolated by using most recent demographic figures. A total of 71,316,101 cases (5.0% of the population) were attributed to 12 risk factors and 17 fungal diseases. Excluding recurrent Candida vaginitis (4,057/100,000 women) and onychomycosis (2,600/100,000 persons), aspergillosis (317/100,000 persons) was the most common problem; prevalence exceeded that in most other countries. Cryptococcal meningitis, an opportunistic infection, occurs in immunocompetent persons almost twice as often as AIDS. The pattern of fungal infections also varies geographically; Talaromyces marneffei is distributed mainly in the Pearl River Basin, and the Yangtze River bears the greatest histoplasmosis burden. New host populations, new endemic patterns, and high fungal burdens in China, which caused a huge impact on public health, underscore the urgent need for building diagnostic and therapeutic capacity.

Infectious keratitis: an update on epidemiology, causative microorganisms, risk factors, and antimicrobial resistance

Corneal opacity is the 5th leading cause of blindness and visual impairment globally, affecting ~6 million of the world population. In addition, it is responsible for 1.5-2.0 million new cases of monocular blindness per year, highlighting an ongoing uncurbed burden on human health. Among all aetiologies such as infection, trauma, inflammation, degeneration and nutritional deficiency, infectious keratitis (IK) represents the leading cause of corneal blindness in both developed and developing countries, with an estimated incidence ranging from 2.5 to 799 per 100,000 population-year. IK can be caused by a wide range of microorganisms, including bacteria, fungi, virus, parasites and polymicrobial infection. Subject to the geographical and temporal variations, bacteria and fungi have been shown to be the most common causative microorganisms for corneal infection. Although viral and Acanthamoeba keratitis are less common, they represent important causes for corneal blindness in the developed countries. Contact lens wear, trauma, ocular surface diseases, lid diseases, and post-ocular surgery have been shown to be the major risk factors for IK. Broad-spectrum topical antimicrobial treatment is the current mainstay of treatment for IK, though its effectiveness is being challenged by the emergence of antimicrobial resistance, including multidrug resistance, in some parts of the world. In this review, we aim to provide an updated review on IK, encompassing the epidemiology, causative microorganisms, major risk factors and the impact of antimicrobial resistance.

Procedures, Visits, and Procedure Costs in the Management of Microbial Keratitis

PURPOSE

To investigate the burden of procedures, visits, and procedure costs in the management of microbial keratitis (MK).

METHODS

Medical records of patients from an academic hospital outpatient facility between December 2013 and May 2018 were retrospectively reviewed. Patients were included if they were older than the age of 18 years, recruited for study of likely MK, and not concurrently undergoing treatment for other acute eye conditions. For procedural costs, Medicare data for billing were obtained using the Center for Medicare and Medicaid Services Physician Fee Lookup tool.

RESULTS

A total of 68 patients were included for analysis. Patients were on average 51.3 years (SD = 19.5), 55.9% women (n = 38), and 89.7% White (n = 61). Per person, the average number of procedures was 2.9 (SD = 4.2). The average number of visits was 13.9 (SD = 9.2) over an average of 26.9 weeks (SD = 24.3). Age (P < 0.0001), positive Gram stain (P = 0.03), and mixed Gram stain (P = 0.002) were positively associated with the number of procedures. Age (P = 0.0003), fungal keratitis (P = 0.02), and mixed Gram stain (P = 0.01) were positively associated with the number of visits. Race was inversely associated with the number of procedures (P = 0.045) and visits (0.03). Patients with bacterial keratitis were more likely to have amniotic membrane grafts (P = 0.01) and tarsorrhaphies (P = 0.03) than fungal patients. Across all procedures performed for the management of MK, the mean cost per patient was $1788.7 (SD = $3324.62).

CONCLUSIONS

Patients incur many procedural costs and attend many visits during the management of MK. These findings emphasize the importance of patient-provider communication for frequent follow-up care and the potential need to perform procedures for disease management.

Medical History, Clinical Features, Treatment Outcome and Its Predictors Among Infectious Keratitis Patients in Jimma University Medical Center, Southwest Ethiopia: Prospective Observational Study

BACKGROUND

Infectious keratitis is a major global cause of visual impairment and irreversible blindness among the corneal diseases. Its diagnosis and management remain getting challenge. The clinical and visual outcome remains poor in developing countries. The aim of this study was to determine treatment outcome and its predictors among patients with infectious keratitis.

METHODS

Prospective observational study was conducted among adult patients diagnosed with infectious keratitis at the Ophthalmology Department in Jimma University Medical Center from April 1 to September 30, 2019. The primary outcome indicator was response of the ulcer to empirical treatment. Ulcers that did not heal and required surgery had a poor outcome. Variables with a p-value of <0.25 were entered into a multivariate logistic regression model to determine the independent predictors of poor treatment outcome and variables with a p-value of <0.05 were considered statistically significant.

RESULTS

The research involved 131 adult patients. Eighty-seven (66.4%) were males. The mean age was 39.38 (±18.9) years. Eighty-three (63.4%) patients had poor treatment outcome. Mean length of hospital stay was 17.38 (±12.563) days. Poor visual outcome was observed among 71 (54.2%) participants. Evisceration was done for seven (5.3%) patients. Independent predictors of poor treatment outcome include perforation at admission (AOR=6.1, 95%CI: 1.5-25.1), presence of comorbidity (AOR=7.7, 95%CI: 2.16-27.3), poor adherence (AOR=5.3, 95%CI: 1.8-25.9), traditional medicine use (AOR=6.7, 95%CI: 1.8-25.4), ulcer depth >1/3 (AOR=7.6, 95%CI: 2.48-48.23) and farm workers (AOR=3.59, 95%CI: 1.09-11.77). Major complications occurred after admissions were perforation (14.5%), followed by endophthalmitis (7.63%) and corneal opacity (6.87%).

CONCLUSION AND RECOMMENDATION

Our study found high poor treatment outcomes and high poor visual outcomes. Presence of comorbidity, perforation at admission, traditional medicine use, working on a farm, poor adherence, and ulcer depth were the predictors of poor treatment outcome. This high poor outcome requires a nationwide interventional study and urgent intervention that may reach rural communities.

Treatment of Severe Acute Bacterial Keratitis in Rabbits Using Continuous Topical Ocular Instillation with Norvancomycin

Purpose

Efficacy of norvancomycin (NVCM) through continuous topical ocular instillation drug delivery (CTOIDD) system for treating severe acute bacterial keratitis infection with Staphylococcus aureus was investigated.

Methods

Rabbits with bacterial keratitis were treated using CTOIDD with NVCM (n=13), topical NVCM eye drops (n=11), and CTOIDD with saline (n=8). Clinical signs of keratitis in all groups were assessed consecutively for a week. Bacterial quantification of excised corneas was counted on the fourth and eighth days. Histopathologic examinations were performed to assess inflammatory cell infiltration on the eighth day.

Results

All signs of bacterial keratitis were alleviated in CTOIDD with NVCM according to criteria, and the CTOIDD-NVCM group had significantly less inflammation than CTOIDD-saline (p<0.05), and eye drop-NVCM (p<0.05). Two eyes in the eye drop-NVCM group, four eyes in the CTOIDD-saline group had corneal perforation (CP), while none of the rabbits showed CP in the CTOIDD-NVCM group. Bacterial counts were significantly less in the CTOIDD with NVCM group in comparison to the eye drop-NVCM (p<0.05), and CTOIDD-saline (p<0.05) groups. Severe inflammation and marked inflammatory cell infiltration were found in histopathologic examinations in the CTOIDD-saline and eye drop-NVCM groups, while significantly less inflammation was documented in the CTOIDD-NVCM (p<0.05) group.

Conclusion

CTOIDD with NVCM effectively reduced the severity and treated acute bacterial S. aureus keratitis infection in a rabbit model. The presented approach of CTOIDD with NVCM appears to be a promising therapeutic approach for severe acute bacterial keratitis.

Clinical Characteristics and Outcomes of Short-term Repeat Corneal Transplantation

PURPOSE

To explore the primary indications, direct causes and graft survival of short-term repeat keratoplasty.

METHODS

An analytical cross-sectional study.

RESULTS

The primary indications for keratoplasty were infectious keratitis (67.9%) and immune keratopathy (12.8%). The direct causes of graft failure were infectious ulcer (43.6%) and recurrence (30.8%). Pre-operative hypopyon (P = 0.017, HR = 1.757) and use of decellularized porcine corneas as grafts (P = 0.005, HR = 2.690) were independent risk factors for graft failure. The Kaplan-Meier analysis revealed that the 1-year survival rate of 88 repeat grafts was 85.2%, and the 5-year survival rate was 79.2%. The survival rates of the repeat grafts were significantly higher than those of the first grafts (P < 0.001).

CONCLUSION

Infectious keratitis is the most common indication of short-term graft failure and is often failed by infectious ulcer and keratitis recurrence. While the decellularized porcine cornea is a promising application in developing countries, certain difficulties, such as graft melting, remain unresolved.

Pathobiology and treatment of viral keratitis

Keratitis is one of the most prevalent ocular diseases manifested by partial or total loss of vision. Amongst infectious (viz., microbes including bacteria, fungi, amebae, and viruses) and non-infectious (viz., eye trauma, chemical exposure, and ultraviolet exposure, contact lens) risk factors, viral keratitis has been demonstrated as one of the leading causes of corneal opacity. While many viruses have been shown to cause keratitis (such as rhabdoviruses, coxsackieviruses, etc.), herpesviruses are the predominant etiologic agent of viral keratitis. This chapter will summarize current knowledge on the prevalence, diagnosis, and pathobiology of viral keratitis. Virus-mediated immunomodulation of host innate and adaptive immune components is critical for viral persistence, and dysfunctional immune responses may cause destruction of ocular tissues leading to keratitis. Immunosuppressed or immunocompromised individuals may display recurring disease with pronounced severity. Early diagnosis of viral keratitis is beneficial for disease management and response to treatment. Finally, we have discussed current and emerging therapies to treat viral keratitis.

Deep learning for identifying corneal diseases from ocular surface slit-lamp photographs

To demonstrate the identification of corneal diseases using a novel deep learning algorithm. A novel hierarchical deep learning network, which is composed of a family of multi-task multi-label learning classifiers representing different levels of eye diseases derived from a predefined hierarchical eye disease taxonomy was designed. Next, we proposed a multi-level eye disease-guided loss function to learn the fine-grained variability of eye diseases features. The proposed algorithm was trained end-to-end directly using 5,325 ocular surface images from a retrospective dataset. Finally, the algorithm's performance was tested against 10 ophthalmologists in a prospective clinic-based dataset with 510 outpatients newly enrolled with diseases of infectious keratitis, non-infectious keratitis, corneal dystrophy or degeneration, and corneal neoplasm. The area under the ROC curve of the algorithm for each corneal disease type was over 0.910 and in general it had sensitivity and specificity similar to or better than the average values of all ophthalmologists. Confusion matrices revealed similarities in misclassification between human experts and the algorithm. In addition, our algorithm outperformed over all four previous reported methods in identified corneal diseases. The proposed algorithm may be useful for computer-assisted corneal disease diagnosis.

Survey report on keratoplasty in China: A 5-year review from 2014 to 2018

To provide the general information on corneal transplantation (CT) in China, China Cornea Society designed a questionnaire on CT from 2014 to 2018 and entrusted it to 31 committee members for implementation of the survey nationwide. This article presents the results of the survey and compares the indicators used in the survey and those in the annual statistical report released by the Eye Bank Association of America (EBAA). The number of corneal transplantations completed by the 64 hospitals from 2014 to 2018 was respectively 5377, 6394, 7595, 8270 and 8980, totally 36,616 (22,959 male and 13,657 female). The five largest hospitals by the number of corneal transplantations completed 15,994 surgeries in total, accounting for 43.68% of all the surgeries performed in the 64 hospitals. The most common indication for corneal transplantations was corneal leukoma (7683, 20.98%), followed by bacterial keratitis (4209, 11.49%), corneal dystrophies (4189, 11.44%), keratoconus (3578, 9.77%) and corneal perforation (2839, 7.75%). The main surgical techniques were penetrating keratoplasty (PK) (19,896, 54.34%), anterior lamellar keratoplasty (ALK) (13,869, 37.88%). The proportion of PK decreased from 57.97% in 2014 to 52.88% in 2018 while the proportion of ALK increased from 36.04% in 2014 to 37.92% in 2018. The geographical distribution of keratoplasties performed in China is unbalanced. PK and ALK were the main techniques of CT and corneal leukoma, bacterial keratitis and corneal dystrophies were the main indications for CT in China.

Efficacy of a Novel Ophthalmic Antimicrobial Drug Combination Toward a Large Panel of Staphylococcus aureus Clinical Ocular Isolates From Around the World

PURPOSE

Staphylococcus aureus is a leading cause of keratitis requiring urgent antimicrobial treatment. However, rising antibiotic resistance has rendered current ophthalmic antibiotics increasingly ineffective. First, a diverse, ocular S. aureus strain set was evaluated for resistance to 6 commonly used ophthalmic antibiotics. Next, a recently discovered antimicrobial drug combination containing polymyxin B/trimethoprim (PT) + rifampin that displayed impressive efficacy toward S. aureus in both in vitro and in vivo studies was evaluated as a potential novel keratitis therapeutic through testing this combination's efficacy against the clinical strain set.

METHODS

A total of 163 S. aureus isolates were collected either commercially or from the Flaum Eye Institute, University of Rochester. The minimum inhibitory concentrations of moxifloxacin, levofloxacin, vancomycin, erythromycin, tobramycin, rifampin, and PT were determined for the entire strain set to establish the incidence of resistance to current treatment options among a contemporary clinical isolate set and compared with the performance of PT + rifampin.

RESULTS

Among all 163 isolates tested, high rates of antibiotic resistance were found toward erythromycin (69% resistance), moxifloxacin (33%), levofloxacin (40%), and tobramycin (17%). Conversely, the entire strain set, including multidrug resistant isolates, was sensitive to PT + rifampin, demonstrating the potency of this combination.

CONCLUSIONS

We established that antibiotic resistance is pervasive among clinical S. aureus isolates, underscoring the concern for the effectiveness of current ophthalmic antibiotics. The drug combination of PT + rifampin, however, eradicated 100% of isolates tested, demonstrating the ability to overcome existing circulating resistance factors, and as such, might represent a promising therapeutic for S. aureus keratitis.

Multi-modal Anterior Eye Imager Combining Ultra-High Resolution OCT and Microvascular Imaging for Structural and Functional Evaluation of the Human Eye

To establish complementary information for the diagnosis and evaluation of ocular surface diseases, we developed a multi-modal, non-invasive optical imaging platform by combining ultra-high resolution optical coherence tomography (UHR-OCT) with a microvascular imaging system based on slit-lamp biomicroscopy. Our customized UHR-OCT module achieves an axial resolution of ≈2.9 μm in corneal tissue with a broadband light source and an A-line acquisition rate of 24 kHz with a line array CCD camera. The microvascular imaging module has a lateral resolution of 3.5 μm under maximum magnification of ≈187.5× with an imaging rate of 60 frames/s, which is sufficient to image the conjunctival vessel network and record the movement trajectory of clusters of red blood cells. By combining the imaging optical paths of different modules, our customized multi-modal anterior eye imaging platform is capable of performing real-time cross-sectional UHR-OCT imaging of the anterior eye, conjunctival vessel network imaging, high-resolution conjunctival blood flow videography, fluorescein staining and traditional slit-lamp imaging on a single device. With self-developed software, a conjunctival vessel network image and blood flow videography were further analyzed to acquire quantitative morphological and hemodynamics parameters, including vessel fractal dimensions, blood flow velocity and vessel diameters. The ability of our multi-modal anterior eye imager to provide both structural and functional information for ophthalmic clinical applications was demonstrated on a healthy human subject and a keratitis patient.

Evaluation of Toluidine Blue-Mediated Photodynamic Therapy for Experimental Bacterial Keratitis in Rabbits

Objective

The objective of this study was to evaluate the effect of toluidine blue-mediated photodynamic therapy on experimental bacterial keratitis in rabbits.

Methods

Bacterial keratitis was induced in rabbits by the injection of 200 μl Staphylococcus aureus (S. aureus) solution into the anterior stroma of the right cornea. Rabbits were randomly divided into four groups: toluidine blue O and red light (TBOR), levofloxacin eye drops (LEV), the combination of TBOR and LEV (TBOR + LEV), and a control group. Clinical manifestations, histopathology, and transmission electron microscopy were analyzed at various time points.

Results

Conjunctival injection and surface area of the corneal ulcer in the TBOR group and the TBOR + LEV group showed significant improvement from baseline after 7 days of treatment. Compared to baseline, the depth of corneal infiltration was decreased at day 14 in the TBOR and TBOR + LEV groups. Microscopic analysis of the TBOR and TBOR + LEV groups showed that the structure of each layer was intact, and there were no inflammatory cells in the corneal stroma. Additionally, IL-1β and TNF-α were highly expressed in the LEV and control groups but were lower in the TBOR and TBOR + LEV groups. Under transmission electron microscopy, the corneas in the TBOR and TBOR + LEV groups were intact, whereas in the LEV and control groups, double-walled structures corresponding to S.aureus were found in the superficial stromal layer.

Conclusions

TBOR demonstrated in vivo antibacterial efficacy against S.aureus.

Translational Relevance

This study found in vivo antibacterial efficacy of toluidine blue-mediated photodynamic therapy on rabbit experimental bacterial keratitis, thus providing an additional new option for clinical treatment of bacterial keratitis.

In Vitro Effect of Toluidine Blue Antimicrobial Photodynamic Chemotherapy on Staphylococcus epidermidis and Staphylococcus aureus Isolated from Ocular Surface Infection

Purpose

We evaluate the antimicrobial effect of toluidine blue O (TBO)-mediated photodynamic antimicrobial chemotherapy (PACT) on Staphylococcus epidermidis and Staphylococcus aureus isolated from ocular surface infection.

Methods

We selected 24 strains of bacteria for this study. The antimicrobial effect of different TBO concentrations, light irradiation, and duration were evaluated. After determining the optimal PACT parameters, four experimental groups were included: Group 1, TBO alone (T+L−); Group 2, light-emitting diode (LED) irradiation alone (T−L+); Group 3, TBO–LED irradiation combination (T+L+); and Group 4, no treatment group (T−L−). The antibacterial effect of PACT was evaluated with the colony survival fraction (SF) methods.

Results

The antibacterial effect of PACT on S. epidermidis and S. aureus was dose-dependent to light irradiation and TBO concentration. The optimal PACT parameters were a TBO concentration of 60 μM, light irradiation of 5.27 mW/cm²_, and an irradiation duration of 30 minutes. In group 1, 60 μM TBO without irradiation did not show any antibacterial effect on S. epidermidis (1.48E7 ± 1.5E6 colony-forming units [CFU]/mL) or S. aureus (1.45E7 ± 9E5 CFU/mL). In group 2, irradiation alone with 5.27 mW/cm² did not modify bacterial growth (S. epidermidis, 1.49E7 ± 1.43E6; S. aureus, 1.5E7 ± 1.2E6). In group 3, after treatment, bacteria density dropped to 4000 ± 1000 and 3E5 ± 1E5 CFU/mL in S. epidermidis and S. aureus groups, respectively (P < 0.001, P = 0.030). In group 4, there was uniform bacterial growth (S. epidermidis, 1.51E7 ± 1.5E6; S. aureus, 1.48E7 ± 1.5E6) before and after treatment.

Conclusions

TBO-mediated PACT had an antibacterial efficacy in vitro on S. epidermidis and S. aureus isolated from ocular surface infection.

Translational Relevance

As TBO-mediated PACT has a strong antibacterial effect to S. epidermidis and S. aureus in vitro, this approach may assist in the treatment of ocular surface infectious diseases.

Incidence of recurrent fungal keratitis after primary keratoplasty and visual outcome and prognosis after intervention for the recurrence

There are no standardized protocols or guidelines for the treatment of recurrent fungal keratitis after therapeutic keratoplasty. This study aimed to investigate the incidence of recurrent fungal keratitis after the primary keratoplasty and the visual outcome and prognosis after intervention for the recurrence.This was a retrospective study. Patients with recurrent fungal keratitis after lamellar keratoplasty (LK) or penetrating keratoplasty (PK) were treated with different antifungal regimens at Shandong Eye Hospital and Qingdao Eye Hospital between Januray 2004 and December 2015. The operative techniques included PK, focal excision, tectonic keratoplasty with a patch graft, lensectomy and vitrectomy, and combined operation. Patients were followed at 1, 2, and 3 months, and then every 6 months after surgery for 2 years. Best corrected visual acuity was assessed and recurrence was recorded. Good prognosis was defined as the presence of visual acuity.Fungal keratitis recurred in 112 of 1448 patients (112/1448, 7.7%) treated initially with PK or LK. The good prognosis rates for different sites of recurrent fungal keratitis were: overall, 93 of 112 (83.0%); recipient bed, 64 of 69 (92.8%); anterior chamber, 14 of 14 (100%); posterior segment, 10 of 16 (62.5%); and atypical, 5 of 13 (38.5%). There was no significant difference in the timing of recurrence between the good and poor prognosis groups (P = .518). Recurrence rates were similar between patients with PK (8.6%) and those with LK (6.0%; P > .05), but the good prognosis rate in patients with post-LK recurrence (96.8%) was higher than that in patients with post-PK recurrence (77.8%, P = .017).Individualized treatment according to recurrent sites of fungal keratitis can achieve a good prognosis in most patients.

The persistent dilemma of microbial keratitis: Global burden, diagnosis, and antimicrobial resistance

Microbial keratitis is a potentially blinding condition that must be treated emergently to preserve vision. Although long recognized as a significant cause of corneal blindness, our understanding of its true global scale, associated burden of disease, and etiological patterns remains somewhat limited. Current epidemiological data suggest that microbial keratitis may be epidemic in parts of the world-particularly within South, South-East, and East Asia-and may exceed 2 million cases per year worldwide. Etiological patterns vary between economically developed and developing countries, with bacterial predominance in the former and fungal predominance in the latter. The key to effective management lies in timely diagnosis; however, the current gold standard of stain and culture remains time consuming and often yields no clinically useful results. For this reason, there are attempts to develop highly sensitive and accurate molecular diagnostic tools to provide rapid diagnosis, inform treatment decision making, and minimize the threat of antimicrobial resistance. We provide an overview of these key areas and of avenues for further research toward the goal of more effectively addressing the problem of microbial keratitis on both an individual and public health level.

Biological Staining and Culturing in Infectious Keratitis: Controversy in Clinical Utility

Infectious keratitis causes significant, financial burden and is only increasing in frequency with contact lens use. Despite this, no retrospective studies, prospective studies, or clinical trials have evaluated the diagnostic validity of clinical guidelines in cases of infectious keratitis. Currently, standard of care recommends that corneal samples be obtained for staining and culturing in select patients showing evidence of corneal ulceration. Ideally, diagnostic information from corneal sampling is thought to help guide therapeutic interventions, prevent disease progression, reduce antibiotic resistance, and decrease overall expenditures for the management and treatment of infectious keratitis. However, current staining and culturing methods are limited by poor sensitivity in non-bacterial cases (i.e. fungal, viral) and lengthy turnaround times, and these methods do not frequently change clinical decision making. Newer fluoroquinolones and broad-spectrum antibiotics resolve the vast majority of cases of infectious keratitis, rendering cultures less essential for management. We studied the clinical utility of obtaining corneal samples for culturing and staining and the need for future research to establish superior diagnostic guidelines for their use in infectious keratitis.

Gray Matter Volume Changes in Patients With Acute Eye Pain: A Voxel-Based Morphometry Study

PURPOSE

The present study was attempted to compare the differences in gray matter volume (GMV) between the acute eye pain (EP) patients and the healthy controls (HCs) using voxel-based morphometry (VBM), and to explore the relationship with clinical features and behavioral performance.

METHODS

A total of 24 patients (17 males, 7 females) with acute EP and 24 (17 males, 7 females) age-, sex-, and education-matched HCs were recruited from the Ophthalmology Department of the First Affiliated Hospital of Nanchang University. Functional magnetic resonance imaging (fMRI) scans were conducted in all subjects. We analyzed the original three-dimensional (3D) T1 brain images by VBM and compared the GMV values with the HCs. The acute EP patients can be distinguished from the HCs by receiver operating characteristic (ROC) curve.

RESULTS

Compared with HCs, the acute EP patients had significantly lower GMV values in the brain regions of the left cerebellum posterior lobe, the left limbic lobe, the right insula, the left insula, the left thalamus, the left caudate, and the right cuneus. In addition, the WMV values of the whole brain in acute EP patients decreased slightly.

CONCLUSIONS

These results demonstrated that the acute EP patients showed an abnormal reduction in GMV in some brain regions, which might provide valuable information for further exploration of underlying neural mechanisms. These abnormal brain regions may reflect the functional disorders of acute EP patients in somatosensory, motor, cognitive functions, and so on.

TRANSLATIONAL RELEVANCE

The VBM study provides a diagnostic method for identifying the cause of acute EP, additionally, a novel direction was presented for further exploration of underlying neural mechanisms of acute EP.

Epithelial defects after penetrating keratoplasty in infectious keratitis: An analysis of characteristics and risk factors

To investigate the clinical characteristics, treatment, risk factors of occurrence and graft transparency of corneal epithelial defects after penetrating keratoplasty in patients with infectious keratitis. 594 patients (594 eyes) with infectious keratitis treated by penetrating keratoplasty at Shandong Eye Institute were reviewed retrospectively between January 2008 and January 2018. We investigated the demographic data, diameter and sources of graft, onset time, location, scope, time of healing and treatment of epithelial defects, as well as other postoperative complications and graft clarity. 114 of the 594 grafts (19.2%) that developed epithelial defects were included in the epithelial defects group, while the other 480 patients were classified in the non-defect group. The mean age of patients with epithelial defects was statistically greater than that of patients without epithelial defects (P = 0.006). The epithelial defects group accounted for a larger proportion of male patients (P<0.001). The proportion of patients with a graft diameter >9mm in the epithelial defect group (29.8%) was more than that in the non-defects group (16.3%) (P = 0.001). The incidence of epithelial defects significantly differed among the pathogenic causes of infectious keratitis (P = 0.002). The incidence of graft infection (21.1%, 9.2%, respectively, P<0.001) and graft dysfunction (7.9%, 2.5%, respectively, P = 0.012) in the epithelial defect group was higher than in the non-defects group. Multivariate logistic regression revealed that male sex (P = 0.001), age ≥ 60 years (P = 0.024), graft diameter >9mm (P = 0.001), bacterial (P = 0.039) and herpes simplex keratitis (P = 0.008), rheumatism (P = 0.031) and cancer treated with chemo- or radiotherapy (P = 0.032) were independent risk factors for epithelial defects. Graft clarity after epithelial defects were significantly differed between fungal and viral infections (P<0.001). We found that being an elderly male patient, a graft diameter >9 mm, bacterial and viral keratitis and systemic diseases (including rheumatism and cancer treated with chemo- or radiotherapy) were independent risk factors for postoperative epithelial defects.

The Asia Cornea Society Infectious Keratitis Study: A Prospective Multicenter Study of Infectious Keratitis in Asia

PURPOSE

To survey the demographics, risk factors, microbiology, and outcomes for infectious keratitis in Asia.

DESIGN

Prospective, nonrandomized clinical study.

METHODS

Thirteen study centers and 30 sub-centers recruited consecutive subjects over 12-18 months, and performed standardized data collection. A microbiological protocol standardized the processing and reporting of all isolates. Treatment of the infectious keratitis was decided by the managing ophthalmologist. Subjects were observed for up to 6 months. Main outcome measures were final visual acuity and the need for surgery during infection.

RESULTS

A total of 6626 eyes of 6563 subjects were studied. The majority of subjects were male (n = 3992). Trauma (n = 2279, 34.7%) and contact lens wear (n = 704, 10.7%) were the commonest risk factors. Overall, bacterial keratitis was diagnosed in 2521 eyes (38.0%) and fungal keratitis in 2166 eyes (32.7%). Of the 2831 microorganisms isolated, the most common were Fusarium species (n = 518, 18.3%), Pseudomonas aeruginosa (n = 302, 10.7%), and Aspergillus flavus (n = 236, 8.3%). Cornea transplantation was performed in 628 eyes to manage ongoing infection, but 289 grafts (46%) had failed by the end of the study. Moderate visual impairment (Snellen vision less than 20/60) was documented in 3478 eyes (53.6%).

CONCLUSION

Demographic and risk factors for infection vary by country, but infections occur predominantly in male subjects and are frequently related to trauma. Overall, a similar percentage of bacterial and fungal infections were diagnosed in this study. Visual recovery after infectious keratitis is guarded, and corneal transplantation for active infection is associated with a high failure rate.

A comparative study of risk factors for corneal infection in diabetic and non-diabetic patients

AIM

To compare the clinical characteristics of infectious keratopathy in type 2 diabetes mellitus (T2DM) and non-diabetes mellitus (NDM) and to investigate risk factors for infectious keratopathy in T2DM patients.

METHODS

Totally 230 patients with T2DM and 168 with NDM diagnosed as infectious keratopathy were hospitalized at Qingdao Eye Hospital from 2001 to 2015. Data including sex, age, occupation, season, smoking and alcohol consumption habits, duration between onset and treatments, duration of hospitalization were collected. Initially identified indicators were analyzed with a multivariate logistic regression. Glycosylated hemoglobin A1c (HbA1c) in patients with T2DM was analyzed. The infectious keratopathies in the two groups were categorized and compared.

RESULTS

The diabetic group consisted of 146 (63.5%) males and 84 (36.5%) females. The NDM group consisted of 111 (66.1%) males and 57 (33.9%) females. There was no signigicantly difference in sex distribution between the two groups (P>0.05). There were significant differences in age, occupation of patients, season of the onset of diseases, duration between onset and treatment, and durations of hospitalization between the two groups (P<0.05). In most of the patients in the diabetic group, the duration between onset and treatment was ≤3mo, and most was ≥3mo in the NDM group. Multivariate logistic regression analysis revealed that age and season were related to the development of corneal infection in the T2DM group (OR=1.709, 1.706). In the T2DM group, HbA1c was 9.09%±2.12%. There were statistically significant differences in the incidences of bacterial keratitis and herpes simplex keratitis in the two groups (P<0.05), but no significant statistical difference was found between fungal keratitis and amoebic keratitis (P>0.05).

CONCLUSION

Advanced age and the summer and winter seasons are identified as risk factors for infectious keratopathy in T2DM patients, and T2DM patients are more prone to bacterial keratitis.

Multiple deprivation, vision loss, and ophthalmic disease in adults: global perspectives

The association between socioeconomic position and morbidity and mortality has long been recognized. We evaluate the evidence for an association between multiple aspects of deprivation and ocular health in a global context. This is a systematic review of studies that evaluated deprivation in the adult population in the context of the major acquired causes of visual loss such as cataract, diabetic eye disease, glaucoma, age-related macular degeneration, and ocular trauma. The search strategy identified relevant studies reported between 1946 and August 2016, with randomized control trials, case-control, cohort, and cross-sectional study designs being selected for inclusion. The studies identified in this review from across the world demonstrate the extent to which the common themes such as low educational attainment and low income may be associated with increased incidence of various sight-threatening conditions and may adversely affect access to specialist assessment and delivery of treatment. Health inequality may always persist, but an increased recognition of the importance of the various impacts of deprivation may empower policy makers to target limited resources to the most vulnerable groups in order to deliver the greatest benefit.

Effect of Ultraviolet Light Irradiation Combined with Riboflavin on Different Bacterial Pathogens from Ocular Surface Infection

In order to study Staphylococcus epidermis and Staphylococcus aureus in vitro viability after the exposure to ultraviolet (UV) light and riboflavin, twelve strains of Staphylococcus epidermis and twelve strains of Staphylococcus aureus were isolated from patients with bacterial keratitis. The growth situation of Staphylococcus epidermidis and Staphylococcus aureus under different experimental conditions was qualitatively observed. The number of colonies surviving bacteria was counted under different UV light power and different exposure time. The experiment showed that there was no inhibition effect on the growth of bacteria using riboflavin alone. In UV alone group and UV-riboflavin group, inhibition effect on the bacteria growth was found. The UV-riboflavin combination had better inhibition effect on bacteria than UV irradiation alone. The amount of bacteria in the UV-riboflavin group was decreased by 99.1%~99.5% and 54.8%~64.6% in the UV alone group, when the UV light power was 10.052 mW/cm² and the irradiation time was 30 min. Moreover, with the increase of the UV power or irradiation time, the survival rates of bacteria were rapidly reduced. Compared with Staphylococcus aureus, Staphylococcus epidermis was more easily to be killed under the action of UV light combined with riboflavin.

Comprehensive evaluation of decellularized porcine corneal after clinical transplantation

Corneal disease is the second most common blinding disease in the world. The shortage of cornea donors has become the greatest challenge in curing corneal disease. Decellularized porcine corneas have the potential to be clinically applied as a substitute for human cornea in lamellar keratoplasty. Porcine corneas will help relieve the cornea donor shortage. To comprehensively evaluate the characteristics of the grafts and the effect of the decellularized porcine cornea on the host cornea after clinical transplantation, we assessed the microstructure of the transplanted decellularized porcine corneal tissues. Through the analysis of the microstructure of the tissues by H&E staining, TEM and immunofluorescence of anti-human vimentin, anti-pig vimentin,IL-1, IL-2, IL-3, IL-6, IL-8, INF-γ, and TNF-α immunofluorescence staining, we found that despite the slight rejection that occurred, the porcine cornea has good biocompatibility and can provide a scaffold for cell growth. Genetic analysis using Solexa sequencing of the samples showed that decellularized porcine corneas cannot affect genes in patients' corneas. Decellularized porcine corneas are effective biological materials for use in corneal transplantation.

Association between socio-economic status and dental caries in elderly people in Sichuan Province, China: a cross-sectional study

OBJECTIVES

As a vulnerable group, the elders' oral health gained less attention, particularly the relationship between socioeconomic status (SES) and dental caries. This study aimed to assess the associations and to explore the effects of confounders on the associations in elderly people.

DESIGN

Cross-sectional study.

SETTINGS

3 neighbourhood committees and 3 village committees in Sichuan Province, China.

PARTICIPANTS

744 people (362 men and 382 women) aged 65-74 years were included.

OUTCOME MEASURES

Oral health outcomes included the decayed, missing and filled teeth (DMFT) index and its components. SES was assigned by educational level, household income and type of household. The bivariate association between the participants' characteristics and DMFT was analysed using non-parametric tests. Four logistic regression models were used to analyse the associations between SES and dental caries by regulating confounders.

RESULTS

Poor oral health was observed in these participants. Bivariate analysis showed a significant association between SES and DMFT (p﹤0.05). Only adjusting gender, high educational level (adjusted (AOR)=0.34, 95% CI 0.17 to 0.66), high household income (AOR=0.47, 95% CI 0.41 to 0.77) were protective factors against dental caries, and living in agricultural families (AOR=1.86, 95% CI 1.32 to 2.63) was risk factor (p﹤0.05). After adjusting other confounders, SES was partly related to the dental caries. Moreover, an interaction existed among SES indicators.

CONCLUSIONS

SES is associated with dental caries, and older people with low SES have poor oral health. The associations were explained partly by diet, behaviour and awareness. Our results provide effective evidence in targeted policy-making and intervention measures and implicate that pertinence measures, economic assistance and medical insurance funds should be provided to older people of low SES. Furthermore, a follow-up design should attempt to confirm the causal relationship between SES and dental caries and evaluate the effect of intervention.

Clinical evaluation of deep anterior lamellar keratoplasty using glycerol-cryopreserved corneal tissues for refractory herpetic stromal keratitis: An observational study

The study aimed to evaluate the therapeutic effects of deep anterior lamellar keratoplasty (DALK) using glycerol-cryopreserved corneal tissues (GCCTs) in patients with refractive herpes simplex keratitis (HSK). This article was a retrospective, noncomparative, and interventional case series. Patients with HSK underwent DALK using GCCTs at Shanghai Tongji Hospital from 2012 to 2015. The best spectacle corrected visual acuity, recurrent inflammation, graft status, postoperative central graft thickness, and pre/postoperative complications were detected. The follow-up ranged from 24.4 ± 5.6 months (range: 16-38 months). Overall, the best spectacle corrected visual acuity was increased from HM/10 cm to 0.15 before surgery to 0.41 ± 0.14 (range: 0.1-0.8; P < 0.05) at 12 months postoperatively. Intraoperative microperforation occurred in 4 eyes (14.81%), and rejection episodes were encountered in 3 of 27 eyes (11.1%), and all of the eyes reversed. HSK recurred in 2 eyes (7.41%), 1 eye with repeated recurring HSK, and eventually led to perpetual corneal opacity and the patient refused a retransplantation. The mean entire corneal thickness was 0.519 ± 0.018 mm (range: 0.5-0.56 mm) and the mean graft thickness was 0.405 ± 0.033 mm (range: 0.35-0.47 mm) in the final follow-up. The DALK using GCCTs was proven to be an effective and safe therapy in treating refractory HSK.