Demographic pattern, predisposing factors and management of ulcerative keratitis: evaluation of one thousand unilateral cases at a tertiary care centre

Epidemiological and microbiological profiles of microbial keratitis in a tertiary eye center in Eastern India (Bihar)

Purpose

To determine the demography, risk factors, and causative organisms of microbial keratitis (MK) in Bihar, an eastern state of India.

Design

Retrospective study.

Methods

We reviewed the demographic, clinical, and microbiological data of 2303 patients with MK (non-viral) presenting between January 2019 and December 2022.

Results

This study revealed a predominance of males (65.0%) compared to females (34.9%), with a mean age of 48.4 ± 16.5 years. The majority of patients (63.1%) presented after 2 weeks from the onset of symptoms. The most common risk factor observed was corneal injury (58.1%), followed by ocular surface diseases (13.6%) and diabetes mellitus (13.3%). The majority of patients (73.16%) were involved in agriculture. Prior to presentation, almost all patients (92%) had received topical antibiotics. Unsupervised use of topical corticosteroids was observed in 29.2% of the patients for the median duration of 3 days (odds ratio, 0.17). At presentation, the median size of corneal ulcers was 5 mm, the best-corrected visual acuity was less than 20/400 in 51.4% of patients, and corneal perforation was in 14% of patients. The smear and culture positivity rate were 75.4% and 47.9%, respectively. The common causative organism was fungus (48.8%), followed by bacteria (17.4%). Aspergillus spp. and Staphylococcus spp. were the most commonly identified organisms; a quarter of the patients (24.5%) remained unidentified. All bacteria showed good sensitivity to vancomycin.

Conclusion

MK is a significant cause of ocular morbidity in Bihar. The knowledge of epidemiology, risk factors, and microbiological profiles of MK can provide a valuable approach to disease prevention, diagnosis, and management.

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.

Successful management of recalcitrant fungal keratitis with topical caspofungin

Objective

To report a case of recalcitrant fungal keratitis successfully managed with topical caspofungin acetate in North India.

Methods

Case report and literature review.

Results

An 18-year-old male patient presented with complaints of redness, watering, pain and diminution of vision in the right eye and was referred to our centre as a case of corneal ulcer. The patient was examined and found to have a near total epithelial defect, with corneal infiltrates approximately 8x8 mm. A provisional diagnosis of polymicrobial keratitis was made based on corneal scraping suggestive of S tap h ylococcus aureus and confocal scan revealing fungal hyphae. The patient failed to respond to topical voriconazole 1%, natamycin 5% and moxifloxacin hydrochloride 0.5% with oral voriconazole. In view of the poor response to these drugs, the patient was subsequently administered topical caspofungin 0.5% in place of natamycin and continued on topical and oral voriconazole, in addition to topical moxifloxacin and cycloplegics, which finally led to healing with minimal scarring. The patient attained a best corrected visual acuity (BCVA) of 6/12.

Conclusion

Topical caspofungin may be used as a useful and effective alternative in cases of recalcitrant fungal keratitis. It may result in healing with minimal scarring.

Mycobiomes of the Ocular Surface in Bacterial Keratitis Patients

Inflammation of the cornea is known as keratitis, and bacteria, fungi, protozoans, and viruses are the etiological agents of this disease. Delayed treatment of keratitis could result in loss of vision and, under certain severity conditions, the removal of an eye and its associated structures. In the current study, the ocular surface (conjunctiva and cornea) mycobiomes of individuals with bacterial keratitis were compared with the ocular mycobiome (conjunctiva) of healthy individuals, free of any ocular morbidity. Mycobiomes were generated through NGS approach using conjunctival swabs and corneal scrapings as the source of DNA from which ITS2 was amplified and sequenced, as a proxy to identify fungi. The results indicated significant changes in the alpha-diversity indices and in the abundance at the phylum and genera level. Hierarchical clustering using a heatmap showed that the mycobiomes were different. Furthermore, NMDS plots also differentiated the mycobiomes in the three cohorts, implying dysbiosis in the mycobiomes of the conjunctivae and corneal scrapings of bacterial keratitis individuals compared to control individuals. A preponderance of negative interactions in the hub genera in the conjunctival swabs of bacterial keratitis individuals compared to healthy controls further re-emphasized the differences in the mycobiomes. The dysbiotic changes at the genera level in conjunctivae and corneal scrapings of bacterial keratitis individuals are discussed with respect to their possible role in causing or exacerbating ocular surface inflammation. These results demonstrate dysbiosis in the ocular mycobiome in bacterial keratitis patients compared to healthy controls for the first time.

Epidemiology, clinical profile and treatment outcomes of bacterial and fungal keratitis

PURPOSE

The purpose of the study is to determine the microbiological etiology, epidemiological factors, and clinical profile and treatment outcomes of infective keratitis in Ophthalmology department, Minia University, Egypt.

METHODS

Prospective, nonrandomized, observational clinical series of cases, including 150 patients with mean age 30 (range 12 to 85 years), 90 patients (60%) were males and 60 (40%) were females, clinically diagnosed as infective corneal ulcer, attending the Ophthalmology Department-Faculty of Medicine. Minia University, Minia, Egypt. From December 2018 to December 2020. Detailed history taking and all clinical findings were collected. Corneal scrapings were obtained from patients and subjected to staining and culture for bacterial and fungal pathogens; Bacterial and fungal growth were identified by standard laboratory procedures.

RESULTS

Corneal trauma by a vegetative matter was the commonest risk factor associated with infective keratitis in 92 cases (61.3%). Smear and culture was positive in 83 cases (58.4%) of 142 corneal scrapings obtained, of which 60 cases were fungal (72.3%), 21 cases were bacterial (25.3%) and two cases were mixed bacterial and fungal (2.4%), Aspergillus species was the commonest fungal species isolated in fungal keratitis. One hundred forty-two cases (94.67%) healed completely with scar. Only six cases (4%) required evisceration due to aggressive presentation from the start and keratoplasty was performed for two cases (1.33%).

CONCLUSIONS

Fungal keratitis was the commonest type in cases attending to our department. Adequate diagnosis, management and follow-up helped in achieving high successful curative outcomes.

CLINICAL TRIAL NUMBER

Clinical Trials.gov ID: NCT04894630. Time of registration 1 December 2018.

Preventing corneal blindness caused by keratitis using artificial intelligence

Keratitis is the main cause of corneal blindness worldwide. Most vision loss caused by keratitis can be avoidable via early detection and treatment. The diagnosis of keratitis often requires skilled ophthalmologists. However, the world is short of ophthalmologists, especially in resource-limited settings, making the early diagnosis of keratitis challenging. Here, we develop a deep learning system for the automated classification of keratitis, other cornea abnormalities, and normal cornea based on 6,567 slit-lamp images. Our system exhibits remarkable performance in cornea images captured by the different types of digital slit lamp cameras and a smartphone with the super macro mode (all AUCs>0.96). The comparable sensitivity and specificity in keratitis detection are observed between the system and experienced cornea specialists. Our system has the potential to be applied to both digital slit lamp cameras and smartphones to promote the early diagnosis and treatment of keratitis, preventing the corneal blindness caused by keratitis.

Mycotic Keratitis-A Global Threat from the Filamentous Fungi

Mycotic or fungal keratitis (FK) is a sight-threatening disease, caused by infection of the cornea by filamentous fungi or yeasts. In tropical, low and middle-income countries, it accounts for the majority of cases of microbial keratitis (MK). Filamentous fungi, in particular Fusarium spp., the aspergilli and dematiaceous fungi, are responsible for the greatest burden of disease. The predominant risk factor for filamentous fungal keratitis is trauma, typically with organic, plant-based material. In developed countries, contact lens wear and related products are frequently implicated as risk factors, and have been linked to global outbreaks of Fusarium keratitis in the recent past. In 2020, the incidence of FK was estimated to be over 1 million cases per year, and there is significant geographical variation; accounting for less than 1% of cases of MK in some European countries to over 80% in parts of south and south-east Asia. The proportion of MK cases is inversely correlated to distance from the equator and there is emerging evidence that the incidence of FK may be increasing. Diagnosing FK is challenging; accurate diagnosis relies on reliable microscopy and culture, aided by adjunctive tools such as in vivo confocal microscopy or PCR. Unfortunately, these facilities are infrequently available in areas most in need. Current topical antifungals are not very effective; infections can progress despite prompt treatment. Antifungal drops are often unavailable. When available, natamycin is usually first-line treatment. However, infections may progress to perforation in ~25% of cases. Future work needs to be directed at addressing these challenges and unmet needs. This review discusses the epidemiology, clinical features, diagnosis, management and aetiology of FK.

Alterations in the conjunctival surface bacterial microbiome in bacterial keratitis patients

Microbial keratitis is an infectious disease of the eye, in which the cornea is inflamed. Under severe conditions, keratitis can lead to significant loss of vision and enucleation of the eye. Ocular trauma is the major risk factor causing keratitis and microorganisms viz., bacteria, fungi, viruses are the causative agents. The current study characterized the conjunctival bacterial microbiomes of healthy individuals and individuals with bacterial keratitis (BK) and assessed whether ocular microbiome dysbiosis is prevalent in BK patients. Ocular bacterial microbiomes were generated from the conjunctival swabs of healthy controls (HC-SW) and conjunctival swabs (BK-SW) and corneal scrapings (BK-CR) of BK patients using V3-V4 amplicon sequencing and data analysed using QIIME and R software. The Alpha diversity indices, diversity and abundance of different phyla and genera, heat map analysis, NMDS plots and inferred functional pathway analysis clearly discriminated the bacterial microbiomes of conjunctival swabs of healthy controls from that of BK patients. Preponderance of negative interactions in the hub genera were observed in BK-CR and BK-SW compared to HC-SW. In addition, a consistent increase in the abundance of pathogenic bacteria, as inferred from published literature, was observed in the conjunctiva of BK patients compared to HC and this may be related to causing or exacerbating ocular surface inflammation. This is the first study demonstrating dysbiosis in the ocular bacterial microbiome of conjunctiva of bacterial keratitis patients compared to the eye of healthy controls. The bacterial microbiome associated with the corneal scrapings of keratitis individuals is also described for the first time.

[Epidemiology and treatment of fungal keratitis]

Infectious keratitis in most cases is caused by bacterial, viral or fungal agents, but their structure is changing. Some researchers have noted a substantial increase in fungal corneal lesions in recent decades, but important local etiological therapy remains unavailable in developing countries. While bacterial keratitis and ophthalmoherpes are controlled by widely available local etiotropic therapy, treatment of keratomycosis in the Russian Federation is carried out with off-label medicine. Lack of skills and availability of diagnostic methods and official etiotropic therapy creates unequal conditions for ophthalmology specialists in the fight against ophthalmomycosis. In part, this causes a reduced level of «myco-caution», which leads to long-term ineffective treatment using antibacterial drops, lasting suffering of patients, and results in the loss of the eye functionally and - in some cases - anatomically. Therefore, the study of fungal keratitis remains relevant. The article provides an overview of research data on current epidemiology in different regions of the world, analyzes available antifungal drugs and the prospects for development of affordable and effective treatment of fungal keratitis.

The Spectrum of Microbial Keratitis: An Updated Review

Background:

In microbial keratitis, infection of the cornea can threaten vision through permanent corneal scarring and even perforation resulting in the loss of the eye. A literature review was conducted by Karsten, Watson and Foster (2012) to determine the spectrum of microbial keratitis. Since this publication, there have been over 2600 articles published investigating the causative pathogens of microbial keratitis.

Objective:

To determine the current spectrum of possible pathogens implicated in microbial keratitis relative to the 2012 study.

Methods:

An exhaustive literature review was conducted of all the peer-reviewed articles reporting on microbial pathogens implicated in keratitis. Databases including MEDLINE, EMBASE, Scopus and Web of Science were searched utilising their entire year limits (1950-2019).

Results:

Six-hundred and eighty-eight species representing 271 genera from 145 families were implicated in microbial keratitis. Fungal pathogens, though less frequent than bacteria, demonstrated the greatest diversity with 393 species from 169 genera that were found to cause microbial keratitis. There were 254 species of bacteria from 82 genera, 27 species of amoeba from 11 genera, and 14 species of virus from 9 genera, which were also identified as pathogens of microbial keratitis.

Conclusion:

The spectrum of pathogens implicated in microbial keratitis is extremely diverse. Bacteria were most commonly encountered and in comparison, to the review published in 2012, further 456 pathogens have been identified as causative pathogens of microbial keratitis. Therefore, the current review provides an important update on the potential spectrum of microbes, to assist clinicians in the diagnosis and treatment of microbial keratitis.

Outcomes of combined keratoplasty and pars plana vitrectomy for endophthalmitis with compromised corneal clarity

IMPORTANCE

Studies evaluating combined penetrating keratoplasty and pars plana vitrectomy for infectious aetiologies are limited.

BACKGROUND

To evaluate the outcomes of combined penetrating keratoplasty and pars plana vitrectomy in patients with endophthalmitis and poor corneal clarity.

DESIGN

Retrospective interventional case series conducted at a tertiary care eye hospital in North India.

PARTICIPANTS

Review of records of 43 eyes of 43 patients. Mean age of patients was 53.39 ± 12.94 years (26 males). Patients with age > 14 years with minimum follow-up of 6 months were included.

METHODS

Combined penetrating keratoplasty and pars plana vitrectomy was performed in all eyes.

MAIN OUTCOME MEASURES

We analysed the preoperative, intraoperative and microbiological characteristics of patients undergoing combined surgeries. Anatomic and functional success and failure were pre-defined.

RESULTS

Aetiology for corneal opacification was corneal ulcer in 30(69.7%) eyes, corneal graft infection in eight(18.6%) eyes, bullous keratopathy in four (9.3%) eyes and corneal scar in one eye. Postoperative visual acuity improved in 20(46.5%) eyes, did not change in 14 (32.5%) eyes and deteriorated in nine eyes (20.9%). Anatomical failure (uncontrolled infection leading to phthisis bulbi or evisceration) was seen in 15 (34.8%) eyes. Microbiological analysis revealed bacterial growth in 26, fungal in 14 and no growth in three eyes. Fungal infection had a poorer outcome (P = 0.03). Six out of 11 monoocular patients regained ambulatory vision.

CONCLUSIONS AND RELEVANCE

Combined penetrating keratoplasty and pars plana vitrectomy is a complex but globe salvaging procedure for poor prognosis eyes which otherwise may need evisceration. Fungal infection carries a poorer prognosis.

Seasonal Variation in the Presentation of Infectious Keratitis

INTRODUCTION

Infectious keratitis is a common ophthalmic disease with the potential for severe ocular morbidity. Multiple studies have described various risk factors for the development of infectious keratitis. The purpose of this study was to analyze the seasonal variation in the presentation of infectious keratitis, and also seasonal changes in its etiologies and risk factors.

METHODS

A retrospective chart review was performed on consecutive patients presenting to the emergency department at our tertiary care urban hospital center who were diagnosed with infectious keratitis from 2008 to 2013. A chi-square analysis was performed to determine whether a significant seasonal variation existed between the month, season, frequency of presentation of ulcers, and other risk factors.

RESULTS

A total of 155 patients-53 men and 102 women-with a mean age of 40 (range, 3-97; median, 36) diagnosed with infectious keratitis were included in the analysis. Sixty-nine (44.5%) ulcers presented in the summer, 19 (12.3%) in the fall, 34 (21.9%) in the winter, and 33 (21.3%) in the spring (P<0.0001). Seventeen (11%) patients experienced diabetes mellitus, 60 (39%) were contact lens wearers, 12 (8%) ulcers occurred in the setting of trauma, and 19 (12%) patients underwent previous ocular surgery. A total of 92 ulcers were cultured, of which 53.8% were positive in the summer, 42.9% in the fall, 55.0% in the winter, and 42.1% in the spring. A significant seasonal variation in the frequency of 1 organism, Pseudomonas aeruginosa, was identified (P=<0.0001); up to 47.6% of culture-positive ulcers in the summer were P. aeruginosa positive, whereas cultures in the remaining seasons were 0, 9.1% and 12.5% positive for this organism.

DISCUSSION

The summer months have a higher frequency of infectious keratitis and P. aeruginosa positivity in this study. Possible factors leading to this increased summer presentation include warmer temperatures, higher humidity, and greater ocular exposure to water. Clinicians should increase their vigilance and education to high-risk patients during these periods and potentially modify empiric treatment regimens.

Clinical and microbiological characteristics of corneal ulcers in a Thai referral center

Background: There are regional variations in causative organisms and epidemiologic patterns of corneal ulcers. It is essential to review periodically in terms of epidemiology and the microbial keratitis profiles that occur in a specific region in order to develop a comprehensive strategy for diagnosis and management of corneal ulcers.

Objective: To review the epidemiology, predisposing factors, microbiological characteristics and visual outcomes in corneal ulcers at a referral center in Thailand.

Methods: A retrospective review of patients with clinically diagnosed corneal ulcers presenting between January 2006 and December 2010 was performed.

Results: A total of 159 patients (159 eyes) were analyzed. Ninety-one cases (57.2%) were in men. The mean age of the patients was 43.0 ± 20.0 years. The most common predisposing factor was ocular trauma found in 72 eyes (45%). Culture was grown from 123 eyes and results were positive in 52%. The most frequent causative organisms were bacteria (72%), followed by fungus (28%). The most common bacteria was Pseudomonas aeruginosa (55%) and most common fungus was Fusarium species (33%). In a comparison between fungal and bacterial groups, the latter was more likely to be associated with contact lens wear (p = 0.05). The hospitalization time for the fungal group was significantly longer than for the bacterial group (p = 0.001). The posttreatment corrected visual acuity equal to or better than 20/200 was found significantly more commonly in the bacterial group than in the fungal group (p = 0.031). While therapeutic keratoplasty was significantly higher in the fungal group than in the bacterial group (p = 0.048).

Conclusion: Fungal keratitis was more severe than bacterial keratitis resulting in longer hospitalization time, poorer visual acuity, and with more chance to have therapeutic keratoplasty.

Expert Views on Innovative Future Uses for Contact Lenses

Over the past 10 to 15 years, the availability of new materials and technologies has resulted in revolutionary concepts for contact lenses being proposed that go well beyond correcting vision. These novel uses include their prescribing to deliver topical ocular and systemic drugs, assist with ocular surface disease management, and limit the progression of myopia and novel methods to display visual information. How likely are these concepts to become commercially available, how successful will they be, and what are the potential issues to consider for them to come to market? To answer these questions, a panel of four experts were invited to discuss the benefits and pitfalls of these technologies and what challenges lay ahead of these concepts before their availability. Their responses provide a fascinating insight for the clinician into the likelihood of such revolutionary contact lenses being available in a clinical setting.

Risk Factors and Microbiological Features of Patients Hospitalized for Microbial Keratitis: A 10-Year Study in a Referral Center in Taiwan

We conducted a retrospective, cross-sectional study to analyze predisposing factors, clinical features, and microbiological characteristics of patients with microbial keratitis hospitalized over 10 years.The medical records of 558 patients who were diagnosed with microbial keratitis and admitted to Chang Gung Memorial Hospital (CGMH), a referral center in Taiwan, from January 1, 2003 to December 31, 2012 were reviewed. Demographics, predisposing factors, isolated organisms, treatment, and hospital stay were recorded. Yearly trends were tested using a linear-by-linear association.Contact lens wear was the most common predisposing factor (31.4%), followed by ocular and systemic diseases (26.3%) and trauma (23.5%). Contact lens-related infectious keratitis increased year by year (P = 0.011). Pseudomonas aeruginosa was the most commonly isolated organism (28%), followed by fungi (17.6%) and coagulase-negative Staphylococcus (5.4%). Except for Serratia marcescens, the identified organisms did not change over 10 years. Most bacterial infections were controlled using antimicrobial treatment, but more than half of patients with fungal keratitis required surgical interventions. The mean hospital stay was 13.7 ± 11.5 days. Previous ocular surgery, large ulcer size, nontuberculous myycobacteris infection, and surgery during admission were related to prolonged hospital stay.In Taiwan, contact lens-related pseudomonal keratitis remained the most common cause of microbial keratitis in patients hospitalized from 2003 to 2012.

[Purulent corneal ulcers: etiology, pathogenesis, classification]

Advanced purulent corneal ulcer, as well as abscess, is a serious vision-threatening condition notable for its fulminant course and possible loss of the eye due to endophthalmitis. Its leading causes, pathogenesis, and classifications are described and analyzed in this paper.

Filamentous fungal infections of the cornea: a global overview of epidemiology and drug sensitivity

Fungal keratitis is a serious suppurative, usually ulcerative corneal infection which may result in blindness or reduced vision. Epidemiological studies indicate that the occurrence of fungal keratitis is higher in warm, humid regions with agricultural economy. The most frequent filamentous fungal genera among the causal agents are Fusarium, Aspergillus and Curvularia. A more successful therapy of fungal keratitis relies on precise identification of the pathogen to the species level using molecular tools. As the sequence analysis of the internal transcribed spacer (ITS) region of the ribosomal RNA gene cluster (rDNA) is not discriminative enough to reveal a species-level diagnosis for several filamentous fungal species highly relevant in keratitis infections, analysis of other loci is also required for an exact diagnosis. Molecular identifications may also reveal the involvement of fungal species which were not previously reported from corneal infections. The routinely applied chemotherapy of fungal keratitis is based on the topical and systemic administration of polyenes and azole compounds. Antifungal susceptibility testing of the causal agents is of special importance due to the emergence and spread of resistance. Testing the applicability of further available antifungals and screening for new, potential compounds for the therapy of fungal keratitis are of highlighted interest.

Clinical utility of caspofungin eye drops in fungal keratitis

Treatment of fungal keratitis remains challenging. To date, only the polyenes and azoles are commonly used topically in the management of fungal keratitis. Natamycin, a polyene, is the only antifungal eye drop that is commercially available; the remainder are prepared in-house and are used in an 'off-label' manner. Failure of medical treatment for fungal keratitis is common, hence there is a need for more effective topical antifungal therapy. To increase the antifungal eye drop armamentarium, it is important to investigate the utility of other classes of antifungal agents for topical use. Caspofungin, an echinocandin antifungal agent, could potentially be used to address the existing shortcomings. However, little is known about the usefulness of topically administered caspofungin. This review will briefly explore the incidence, epidemiology and antifungal treatment of fungal keratitis. It will focus primarily on evidence related to the efficacy, safety and practicality of using caspofungin eye drops in fungal keratitis.

Spectrum of fungal keratitis: clinicopathologic study of 44 cases

AIM

To determine the causative agents of fungal keratitis and study the predisposing factors over a period of ten years in a single tertiary care hospital.

METHODS

A retrospective analysis of fungal corneal ulcers was done from 2003-2012. Patients' clinical data were noted from the file records. Correlation of histopathological diagnosis was done with the report on fungal culture.

RESULTS

Mycotic keratitis was established in 44 cases by a positive fungal culture. Direct microscopic examination of potassium hydroxide (KOH) mounts revealed fungal elements in 39 cases while 40 cases showed fungus on Gram stained smears. Males (54.55%) were more commonly affected than the females (45.45%). The age ranged from 18 to 82 years. Most common age group to be involved was 41-60 years. Predisposing risk factors were seen in 34 (77.27%) cases. Most common findings on clinical examination were anterior chamber reaction and conjunctival injection seen in all the cases. Other common findings were stromal infiltration and hypopyon seen in 20 (45.45%) and 18 (40.91%) cases respectively. On histopathological examination the fungus was typed, as aspergillus in 34 cases while no definite typing was possible in 10 cases. The predominant isolate was aspergillus flavus (59.09%) followed by fusarium (15.91%). Mixed fungal and bacterial infection was seen in 3 (6.82%) cases.

CONCLUSION

Although culture is the gold standard for definitive diagnosis of fungal keratitis, direct microscopic examination of corneal scrapings or histomorphological evaluation of biopsies allow a rapid preliminary diagnosis. Early administration of antifungal treatment helps in preventing dreadful complications.

Profile of sight-threatening infectious keratitis: a prospective study

PURPOSE

To prospectively study patients presenting with sight-threatening corneal ulcers with a view to identify the predisposing factors, causative organisms, clinical signs and treatment outcomes.

METHODS

Prospectively, over 3-year period, all cases with serious infective keratitis presenting to Queens Medical Hospital in Nottingham, UK, were recruited. Detailed information on the aetiology, culture results, signs & symptoms, the treatment given and the patient's response was collected and statistically analysed.

RESULTS

One hundred and forty-three eyes of 129 patients were enrolled. Thirty-one patients were managed as out-patients, and 98 were treated as in-patients. The mean duration of admission was 9 ± 13 days but was significantly higher in older patients and in Acanthamoeba keratitis cases. The important risk factors were ocular surface disease (32%), contact lens wear (26%) and previous ocular surgery (20%). Old age, deep infiltration, steroid use and poor initial vision were risk factors for prolonged course of treatment in bacterial keratitis. Corneal scrapings were done in 89% of the cases, but positive results were obtained only in 41.7%. Staphylococcus aureus was the most common isolated bacteria (18.8%). Acanthamoeba and Pseudomonas aeruginosa were the second and third common causative organisms (16.6% and 15%, respectively). Overall, 8.3% needed corneal grafting, which survived in 83.3% and eradicated infection in 100%.

CONCLUSION

Microbial keratitis is an important cause of ocular morbidity. Previous ocular disease is an important predisposing factor. Old age, steroid use and poor presenting visual acuity are important prognostic indicators. Corneal grafting is an effective option for managing recalcitrant corneal infections.

Geographic and temporal risk factors for interruptions to soft contact lens wear in young wearers

OBJECTIVES

This was a secondary analysis of an existing dataset of soft contact lens wearers age 8-33 years, who received eye care outside of a clinical trial. The aim was to identify geographical and temporal factors associated with interruptions to contact lens wear.

METHODS

Data from six academic centers in North America captured 522 events in 3549 patients. Cases were analyzed overall and in subcategories of allergic, and serious and significant adverse events. General estimating equations were used to model the effect of geographic (Northwest, West, Central, Northeast, Southeast) and temporal (season, month, day of the week) factors, along with previously identified risk factors associated with interruptions in lens wear (patient age, contact lens material, overnight wear, lens care system, replacement schedule, and years of contact lens wear).

RESULTS

After controlling for established risk factors, both region and temporal factors disrupted the patients' ability to maintain contact lens wear. About 4% of all visits had complications that led to an interruption in wear. Allergic events were highest in the Central region. Serious and significant adverse events peaked in the Southeast during the Autumn and Winter months (September, October, December). Day of the week was not significant in any model.

CONCLUSIONS

This study provides evidence of seasonal and regional challenges to contact lens wear. As the use of soft contact lenses expands for both cosmetic and medical reasons, practitioners must examine ways to maintain continuous, safe, and healthy use of contact lenses across all patients.

Corneal collagen cross-linking (CXL) for the treatment of melting keratitis in cats and dogs: a pilot study

OBJECTIVE

UV-A/riboflavin cross-linking (CXL) of corneal collagen fibers is an established, highly promising therapy for corneal melting in physician-based ophthalmology. A prospective pilot study was conducted to demonstrate proof of principle of this novel method for the treatment of melting corneal ulcers in dogs and cats.

PROCEDURES

After obtaining owner consent, CXL was performed in three cats and three dogs with corneal melting, which either affected the entire corneal surface or was resistant to conventional antibiotic and anticollagenolytic therapy, and affected parts or all of the corneal surface. Medical therapy was continued in all patients. The available follow-up ranged from 2 to 22.5 months and involved slit-lamp examination, fluorescein staining, and photographic documentation during all rechecks.

RESULTS

Surgical stabilization of the cornea was not necessary in any case, because progression of corneal melting was arrested in all cases within 1-20 days of CXL treatment. Corneal re-epithelization occurred within 7-40 days in all eyes. At 40 days after CXL, all eyes presented a quiescent corneal state without signs of active inflammation and with beginning scar formation. The complications observed in three of the six animals included a corneal sequestrum, superficial corneal stromal pigmentation, and bullous keratopathy.

CONCLUSIONS

This study shows the feasibility of CXL to treat progressive corneal melting in veterinary patients. CXL may represent a cost-efficient and safe alternative therapy in the treatment for corneal melting in veterinary ophthalmology. More investigations comparing the effectivity and complication rate of CXL to those of standard medical treatment are necessary.

Photo-activated riboflavin therapy of refractory corneal ulcers

PURPOSE

To evaluate the therapeutic effect of photo-activated riboflavin (PAR) for treating refractory corneal ulcers.

METHODS

Seven eyes with infectious keratitis, presented with a gradually deteriorating, vision-threatening, corneal ulcer, despite intense antimicrobial therapy, were treated with PAR. The surgical procedure was deepithelialization of the affected corneas followed by UV-A riboflavin (B2) cross-linking. Local antimicrobial therapy was continued after the procedure.

RESULTS

In all cases, the progression of corneal melting was halted after PAR treatment. Emergency keratoplasty was not necessary in any of the 7 eyes presented. More importantly, all the ulcers were healed without significant vascularization.

CONCLUSION

PAR is a promising option for treating patients with therapy-refractory infectious keratitis to avoid emergency keratoplasty and should be considered as a potential adjuvant therapeutic tool in such eyes.

Changing referral patterns of infectious corneal ulcers to a tertiary care facility in south India - 7-year analysis

PURPOSE

To report changing trends in referral patterns of microbial keratitis evidenced by laboratory results of culture-positive cases from a tertiary eye-care hospital in south India.

METHODS

All patients presenting with microbial (nonviral) keratitis to the cornea services of Aravind Eye Hospital from 2003 to 2009 were identified from a computerized database. Microbiologic characteristics were recorded and annual distributions of causative organisms over the 7-year study period were compared.

RESULTS

Out of a total of 3059 cases of presumed microbial keratitis, 1756 had positive cultures (57.4%). Among the culture-positive cases, fungal pathogens were isolated from 1224 cases (70%), 488 (27.7%) showed bacterial growth, 18 (1.03%) grew acanthamoeba species and 26 (1.5%) demonstrated mixed bacterial and fungal growth. The percentage of fungal isolates in culture-positive cases increased gradually over the study period from 59% in 2004 to 78% in 2009. This increase in frequency of fungal keratitis was statistically significant (P = 0.023). A proportionally decreasing trend was seen in the number of bacterial isolates ranging from 31% in 2003-2005 to 22% in 2009 (P = 0.04).

CONCLUSIONS

An incremental increase was seen in the number of fungal keratitis cases referred to our institute during the study period. Bacterial keratitis showed a decline. This disconcerting trend may lead to an increase in the incidence of corneal blindness in the developing world and thus warrants further research.

Management and treatment of contact lens-related Pseudomonas keratitis

Pubmed and Medline were searched for articles referring to Pseudomonas keratitis between the years 2007 and 2012 to obtain an overview of the current state of this disease. Keyword searches used the terms "Pseudomonas" + "Keratitis" limit to "2007-2012", and ["Ulcerative" or "Microbial"] + "Keratitis" + "Contact lenses" limit to "2007-2012". These articles were then reviewed for information on the percentage of microbial keratitis cases associated with contact lens wear, the frequency of Pseudomonas sp. as a causative agent of microbial keratitis around the world, the most common therapies to treat Pseudomonas keratitis, and the sensitivity of isolates of Pseudomonas to commonly prescribed antibiotics. The percentage of microbial keratitis associated with contact lens wear ranged from 0% in a study from Nepal to 54.5% from Japan. These differences may be due in part to different frequencies of contact lens wear. The frequency of Pseudomonas sp. as a causative agent of keratitis ranged from 1% in Japan to over 50% in studies from India, Malaysia, and Thailand. The most commonly reported agents used to treat Pseudomonas keratitis were either aminoglycoside (usually gentamicin) fortified with a cephalosporin, or monotherapy with a fluoroquinolone (usually ciprofloxacin). In most geographical areas, most strains of Pseudomonas sp. (≥95%) were sensitive to ciprofloxacin, but reports from India, Nigeria, and Thailand reported sensitivity to this antibiotic and similar fluoroquinolones of between 76% and 90%.

Geographic variations in microbial keratitis: an analysis of the peer-reviewed literature

The epidemiology of microbial keratitis has been investigated in several studies by analysis of organisms cultured from corneal scrapes. However, a comparison of the frequency of different organisms causing keratitis in different parts of the world is lacking. The authors present a review incorporating an analysis of data from studies worldwide. The data provide a comparison of the frequency of culture-positive organisms found in different parts of the world. Associations between a country's gross national income and types of causative organism are explored. The highest proportion of bacterial corneal ulcers was reported in studies from North America, Australia, The Netherlands and Singapore. The highest proportion of staphylococcal ulcers was found in a study from Paraguay, while the highest proportion of pseudomonas ulcers was reported in a study from Bangkok. The highest proportions of fungal infections were found in studies from India and Nepal. The Spearman correlation coefficient demonstrated statistically significant correlations between gross national income and percentages of bacterial (0.85 (95% CI 0.68 to 0.91, p<0.0001)), fungal (-0.81 (95% CI -0.90 to -0.66, p<0.0001)) and streptococcal (-0.43 (95% CI -0.66 to -0.12, p=0.009)) isolates.

Etiologic diagnosis of corneal ulceration at a tertiary eye center in Kathmandu, Nepal

PURPOSE

To determine the etiologic diagnosis of infectious corneal ulcers at Tilganga Institute of Ophthalmology, a tertiary teaching hospital in Kathmandu Nepal, from 2006-2009.

METHODS

This study involved a review of all microbiology records at Tilganga Institute of Ophthalmology from August 2006 through July 2009. Microbiologic records from the corneal scrapings of all patients suspected of having infectious corneal ulcers were included.

RESULTS

Corneal scrapings were obtained from 468 patients. The average patient age was 52 years, and 55% of the affected cases were males. Microorganisms were grown from 185 of the corneal scrapings (40%). Pure bacterial cultures were obtained from 72 patients (39%), and pure fungal cultures were obtained from 113 patients (61%). Gram stain was 75% sensitive (95% confidence interval, 0.632-0.841) in identifying bacterial infection, whereas KOH prep was 80.5% sensitive (95% confidence interval, 0.718-0.871) in identifying fungal organisms. Of 72 bacterial isolates, 50 isolates (69%) were Streptococcus pneumoniae, the most common organism isolated in this study. Of 113 fungal isolates, 40 of isolates (35%) were identified as Aspergillus sp.

CONCLUSIONS

Fungal organisms (61%) are the most common cause of infectious keratitis in this patient population. Of all organisms, S. pneumoniae was the most common organism identified. Smear microscopy is reliable in rapidly determining the etiology of the corneal infection and can be used to help guide initial therapy in this setting.

Epidemiology and etiologic diagnosis of infectious keratitis in Uberlandia, Brazil

PURPOSE

To study risk factors, microbiological characteristics, and clinical course of nonviral infectious keratitis diagnosed in a referral service of ophthalmology.

METHODS

A total of 65 charts of patients with microbial keratitis were retrospectively reviewed at the Clinical Hospital of Federal University of Uberlandia, Brazil, from July 2001 through August 2004. All cases were submitted to microbiological tests and treated according to local protocol. Risk factors, clinical course, therapeutic keratoplasty, and visual outcomes were analyzed.

RESULTS

The mean age of patients was 45.9 years (2-83 years) and male to female ratio 2.6:1. Symptoms at presentation ranged from 1-3 days in 16 patients out of 65 (24.61%), 4-7 days in 19 cases (19/65; 29.23%), and more than 7 days in 27 patients (27/65; 41.53%). The major risk factor was trauma (28/65; 40%), predominantly by organic material. A total of 32 eyes out of 65 (49.23%) were culture positive. Fungi were the most common isolates (18/32; 56.25%), being headed by Fusarium sp. (11/65; 16.92%), and the most common bacteria was Streptococcus pneumoniae (7/65; 10.77%). Final visual acuity was equal to or better than 20/60 in 20 patients out of 65 (30.77%), between 20/60 and 20/400 in 7 patients (7/65; 10.77%), and worse than 20/400 in 35 patients out of 65 (53.85%). A total of 48 eyes out of 65 (73.84%) presented corneal scar, 12 eyes (12/65; 18.46%) needed therapeutic penetrating keratoplasty, and 2 eyes (2/65; 3.08%) were eviscerated.

CONCLUSIONS

The high incidence of fungal keratitis in the studied population shows their vulnerability to such infections, which may result in devastating visual outcomes.

Role of neutrophils, MyD88-mediated neutrophil recruitment, and complement in antibody-mediated defense against Pseudomonas aeruginosa keratitis

Purpose. Ulcerative keratitis due to Pseudomonas aeruginosa is a sight-threatening disease leading to loss of vision due to corneal inflammation. A human IgG1 monoclonal antibody (MAb F429) to the alginate capsule significantly reduces pathology and bacterial burdens in the cornea when applied topically starting 8 hours post-infection. The purpose of this study was to determine whether local polymorphonuclear neutrophils (PMN) recruitment and complement were important lipopolysaccharide co-factors in MAb F429-mediated reductions in P. aeruginosa tissue levels and corneal pathology. Methods. MyD88 knock-out mice unable to recruit PMN to tissues, mice depleted of PMNs, or mice depleted of complement component C3 were topically treated with MAb F429 starting 8 hours post-infection and evaluated for bacterial levels and corneal pathology 48 hours after infection with two P. aeruginosa isolates. Results. An inability to recruit PMN or systemic PMN depletion plus topical application of MAb F429 resulted in less pathology in the eye, but bacterial burdens were markedly increased in the cornea, brains, and spleens of these mice, indicative of systemic spread. Intraperitoneal injection of cobra venom factor (CVF) reduced C3 levels in the cornea approximately 40%, which did not change the beneficial effects of MAb F429. Both systemic injection and topical application of CVF reduced local C3 levels >60%, which eliminated MAb-mediated reductions in corneal pathology and bacterial levels. Conclusions. PMN recruitment and complement are both needed for maximal in vivo efficacy of MAb F429 in therapeutically treating P. aeruginosa keratitis, and attempts to reduce pathology by limiting PMN influx could have consequences leading to more extensive local and systemic infection.

Predisposing factors and etiologic diagnosis of ulcerative keratitis

PURPOSE

To determine the predisposing factors, demographic characteristics, and etiology of ulcerative keratitis in a referral center in Bangkok, Thailand.

METHODS

The medical records of admitted patients with positive-culture ulcerative keratitis were retrospectively reviewed for demographic data, predisposing factors, and microbial culture results. Predisposing factors were compared between bacterial and fungal keratitis.

RESULTS

From January 2001 to December 2004, there were 127 positive-culture ulcerative keratitis cases. The most frequent microbiological diagnosis was bacterial keratitis (76 eyes, 60%), followed by fungal (48 eyes, 38%) and Acanthamoeba keratitis (3 eyes, 2%). The most common organisms isolated were Pseudomonas spp. for bacteria and Fusarium spp. for fungus. Compared with bacterial keratitis, fungal keratitis was more likely to be associated with ocular trauma (odds ratio = 11.20; 95% confidence interval, 3.62-34.66) but less likely to be associated with contact lens wear (odds ratio = 0.02; 95% confidence interval, 0.01-0.08).

CONCLUSIONS

In our study, Pseudomonas and Fusarium species are the most common causes of bacterial and fungal keratitis, respectively. Fungal keratitis was more likely than bacterial keratitis to be associated with ocular trauma, whereas fungal keratitis was less likely to be associated with contact lens wear.