Risk Factors For Microbial Keratitis Research Articles

Epidemiology of Microbial Keratitis at a Tertiary Care Hospital in Southern Thailand.

This study aimed to ascertain the microbial profiles and predisposing risk factors for microbial keratitis and to analyze the trend of mixed microbial infection cases over 8 years. In this retrospective analysis, we reviewed the electronic medical records of inpatients diagnosed with microbial keratitis between January 2012 and December 2019. Data on demographics, risk factors, and causative pathogens were analyzed. Multivariate logistic regression models were utilized to identify risk factors associated with pathogens. This study included 640 eyes of 638 patients. Trauma was the most common predisposing risk factor (57.2%), followed by a combination of factors (14.4%). Among diagnostic test results, bacteria, fungi, and mixed pathogens were identified in 46.72%, 46.56%, and 21.41% of cases, respectively. Positive culture results were obtained in 324 eyes (53.6%), with Pseudomonas aeruginosa (25.1%) and Fusarium spp. (17.4%) being the most prevalent pathogens. In the multivariate logistic regression model, contact lens use, presence of diabetes mellitus, and HIV infection were statistically significant risk factors for Pseudomonas aeruginosa infection (p = 0.001, p = 0.046, and p = 0.04, respectively). Trauma was associated with Fusarium spp. infection (p = 0.001). An increase in the percentage of mixed microbial infection cases was observed when comparing the periods of 2016-2019 with 2012-2015 (p = 0.023). Bacteria and fungi are equally common causes of microbial keratitis, with Pseudomonas aeruginosa and Fusarium spp. being the predominant pathogens causing bacterial and fungal infections. Trauma is the primary predisposing risk factor for microbial keratitis. There was a notable increase in mixed infection cases over the study period.

Prevalence of Bacterial Keratitis in Contact Lens Wearing Female Medical Students in Sana'a, Yemen

Bacterial keratitis is bacterial infection of the cornea of eye and it is the fifth leading cause of blindness. Contact lens wearing is the most critical risk factor for microbial keratitis in developed countries and developing countries.In Yemen, females wear contact lens mainly for cosmetic purposes and there are no reliable statistics documenting the prevalence of Bacterial keratitis among contact lens wear especially among females. Amis: To find the prevalence of Bacterial keratitis and associated risk factors among female medical students at the National University who wear Contact Lenses in Sana'a city, Yemen. Methods: A cross-sectional structured questionnaire survey of 50 elements conducted to evaluate the behavioral and socio-demographic data.Corneal specimens were collected and cultured to isolate bacteria that cause keratitis. Results: the results revealed that, the prevalence rate of bacterial keratitis among participants was 72%. Staphylococcus aurous and coagulase negative staphylococci were the most common agents of bacterial keratitis.There were statistically significant differences between bacterial keratitis and age, extended wear contact lens wear, sharing contact lens with others, cleaning of contact lens and use eye drops. Conclusion: The major risk factors for bacterial keratitis include prolonged wear of contact lenses, sharing of lenses with others and poor hygiene practices when handling contact lenses. Female students aged 38–42 are the most at-risk group. Bacterial keratitis is preventable diseases.

Epidemiological profile of microbial keratitis in Alexandria-Egypt a 5 years retrospective study

ObjectiveTo evaluate the epidemiologic profile of microbial keratitis in Alexandria- Egypt, with special emphasis on risk factors, visual outcome and microbiological results.MethodsThis retrospective study reviewed files of patients treated for microbial keratitis during a period of 5 years at Alexandria Ophthalmology Hospital Cornea Clinic, Alexandria- Egypt, between February 2017 and June 2022. The patients were evaluated for the risk factors e.g., trauma, eyelid disorders, co-morbidities, and contact lens use. They were also evaluated for their clinical picture, the identified microorganisms, visual outcomes, and complications. Non-microbial keratitis and incomplete files were excluded from the study.ResultsA total of 284 patients were diagnosed as microbial keratitis in our study. Viral keratitis was the most common cause of microbial keratitis (n = 118 (41.55%)), followed by bacterial keratitis (n = 77 (27.11%)), mixed keratitis (n = 51 (17.96%)), acanthamoeba keratitis (n = 22 (7.75%)) and the least cause was fungal keratitis (n = 16 (5.63%)). Trauma was the most common risk factor for microbial keratitis (29.2%). Fungal keratitis had a statistically significant association with trauma (p < 0.001), while the use of contact lenses had a statistically significant association with Acanthamoeba keratitis (p < 0.001). The percentage of culture-positive results in our study was 76.8%. Gram-positive bacteria were the most frequently isolated bacterial isolate (n = 25 (36.2%)), while filamentous fungi were the most frequently isolated fungi (n = 13(18.8%)). After treatment, there was a significant increase in the mean visual acuity among all groups; it was significantly higher in Acanthamoeba keratitis group with a mean difference of 0.262 ± 0.161 (p = 0.003).ConclusionViral keratitis followed by bacterial keratitis were the most frequent etiologic agents causing microbial keratitis found in our study. Although trauma was the most frequent risk factor for microbial keratitis, contact lens wear was found an important preventable risk factor for microbial keratitis in young patients. Performing culture properly whenever indicated before starting antimicrobial treatment increased the cultures’ positive results.

Mikrobakterielle Keratitis: Wie sicher ist Orthokerato- logie heute?

Purpose. The purpose of this review is to summarize and clinically evaluate microbial keratitis (MK) in accelerated orthokeratology (OK). Material and Methods. Based on a PubMed and EMBASE search, a systematic literature review of previous and current studies and theories on the pathogenesis of contact lens associated MK was performed. In chronological order, the results were described and analyzed. Results. Risk factors of MK are inadequate contact lens care, use of tap water, non-adherence to hygiene procedures and wearing contact lenses despite pre-existing ocular irritation. The statistical absolute incidence MK is 7.7 MK cases per 100,000 patient-years for all contact lens (CL) wearers and 13.9 per 100,000 patient-years for young CL wearers. The most significant germ is Pseudomonas aeruginosa followed by Acanthamoeba. The predominant age group is 15.4 years old on average, and the predominant ethnic group is persons of Asian descent. Most MK cases are diagnosed in the first 19 months – most users are not contact lens novices. The cor- neal epithelium is the most significant tissue for OK success and most significant for infection protection. Conclusion. Contact lens practitioners have a high respon- sibility for safety in OK. MK in OK is highly preventable if risk factors and general hygiene are observed. Regular check-ups at short intervals, adherence to agreed procedures, discipline, education/training and communication are important tools to minimize the risk of MK in OK. Keywords Orthokeratology, contact lenses, microbacterial keratitis, risk factors

Microbial keratitis in Sydney, Australia: risk factors, patient outcomes, and seasonal variation.

To provide recent data on patient demographics, clinical profile and outcomes of patients with microbial keratitis over a 5-year period at the Sydney Eye Hospital, and to identify seasonal variations of the main causative organisms. A retrospective study of patients with a clinical diagnosis of microbial keratitis and corneal scrape performed between 1 January 2012 and 31 December 2016. Clinical information was gathered from medical records and pathology data. One thousand fifty-two eyes from 979 patients with a mean age of 54.7 ± 21.5years (range 18-100years) were included. The majority of cases were bacterial (65%) followed by polymicrobial (2.4%), fungi (2.3%), and culture-negative (31%). Common risk factors for microbial keratitis were contact lens wear (63%) and previous topical steroid use (24%). Factors significantly associated with poor patient outcomes in the multivariate model were age, visual acuity, and epithelial defect size (p< 0.05). Patients with fungal or polymicrobial keratitis presented with worse clinical features at initial and final presentation (p< 0.05). There was a significant variation in the occurrence of Pseudomonas aeruginosa (p= 0.018) and fungal keratitis (predominately made up of Candida and Fusarium species) (p= 0.056) in the hottest seasons. Poorer outcomes are more likely to be seen in older patients and those presenting with poor visual acuity and large epithelial defects at the initial presentation.

Mussel-Inspired Durable Antimicrobial Contact Lenses: The Role of Covalent and Noncovalent Attachment of Antimicrobials.

Contact lens is a major risk factor for microbial keratitis among contact lens wearers. Chemical strategies that can prevent microbial adhesion and biofilm formation are required to improve a wearer's hygiene and safety. Taking advantage of the material-independent properties of a polydopamine (pDA) coating, we investigated the role of covalent/noncovalent interactions of the antimicrobials and pDA in conferring long-term antimicrobial activities. The developed antimicrobial contact lenses not only retain their antibacterial efficiency against different bacterial strains for 2 weeks but also inhibit microbial adhesion and biofilm formation on the lens surfaces. The designed antimicrobial coatings were found to be safe for ocular cell lines. Moreover, the antimicrobial coatings did not affect the functional and surface properties of coated contact lenses. This methodology can be used to protect the contact lenses from microbial contamination for prolonged periods and has the potential to be extended for designing antimicrobial coatings for other medical devices as well.

Microbial keratitis and clinical outcomes following penetrating and endothelial keratoplasty.

The goal of this study was to review the incidence, risk factors and outcomes of microbial keratitis after penetrating keratoplasty (PK) and endothelial keratoplasty (EK). The electronic medical records at Wills Eye Hospital were queried for cases of microbial keratitis following PK or EK performed between 1 May 2007 and 1 September 2018. Charts were reviewed to obtain demographic data, transplant characteristics, details of microbial keratitis, graft survival and clinical outcomes. During the study period, 2098 transplants were performed in 1601 patients. Of these, 1267 (60.4%) were PKs and 831 (39.6%) were EKs. We identified 86 (4.1%) cases of subsequent microbial keratitis. The incidence of microbial keratitis after PK was significantly higher than after EK (5.9% versus 1.3%; p=0.005). Furthermore, the rate of infection was higher after repeat transplants (either PK or EK) compared to initial keratoplasties (5.5% versus 3.4%; p=0.02). Twenty-six (32.1%) grafts remained clear at most recent follow-up after microbial keratitis, and the proportion of clear grafts was higher after EK than PK (66.7% versus 27.8%; p=0.03). Rates of microbial keratitis were significantly higher after PK compared to EK, and repeat transplantation was a risk factor for microbial keratitis. To the best of our knowledge, there is no prior study in the literature evaluating microbial keratitis rates after PK and EK and comparing outcomes.

Risk Factors of Microbial Keratitis in Uganda: A Case Control Study

ABSTRACTPurpose: Microbial keratitis (MK), is a frequent cause of sight loss worldwide, particularly in low and middle-income countries. This study aimed to investigate the risk factors of MK in Uganda.Methods: Using a nested case control, we recruited healthy community controls for patients presenting with MK at the two main eye units in Southern Uganda between December 2016 and March 2018. Controls were individually matched for age, gender and village of the cases on a 1:1 ratio. We collected information on demographics, occupation, HIV and Diabetes Mellitus status. In STATA version 14.1, multivariable conditional logistic regression was used to generate odds ratios for risk factors of MK and a likelihood ratio test used to assess statistical significance of associations.Results: Two hundred and fifteen case-control pairs were enrolled. The HIV positive patients among the cases was 9% versus 1% among the controls, p = .0003. Diabetes 7% among the cases versus 1.4% among the controls, p = .012. Eye trauma was 29% versus 0% among the cases and controls. In the multivariable model adjusted for age, sex and village, HIV (OR 83.5, 95%CI 2.01–3456, p = .020), Diabetes (OR 9.38, 95% CI 1.48–59.3, p = .017) and a farming occupation (OR 2.60, 95%CI 1.21–5.57, p = .014) were associated with MK. Compared to a low socio-economic status, a middle status was less likely to be associated with MK (OR 0.29, 95%CI 0.09–0.89, p < .0001).Conclusion: MK was associated with HIV, Diabetes, being poor and farming as the main occupation. More studies are needed to explore how these factors predispose to MK.

Bandage contact lens and topical steroids are risk factors for the development of microbial keratitis after epithelium-off CXL

ObjectiveTo investigate the role of bandage contact lenses (BCL) and topical steroids as risk factors for the development of microbial keratitis after epithelium-off corneal collagen cross-linking (CXL).Methods and AnalysisPatients undergoing...

Corneal biopsy for diagnosis of recalcitrant microbial keratitis.

To document the findings of corneal biopsies for progressive microbial keratitis in a large tertiary referral institution. A retrospective medical records review of all patients who underwent at least one corneal biopsy for the diagnosis of microbial keratitis at Sydney Eye Hospital, Australia between January 1, 2010 and December 31, 2016 was performed. Thirty-eight patients (18 men and 20 women) underwent a corneal biopsy for progressive microbial keratitis unresponsive to broad-spectrum topical antimicrobials. Risk factors for microbial keratitis included contact lens wear in 8 (21%), recent intraocular surgery in 5 cases (13%), recent agricultural trauma in 3 cases (8%), exposure keratopathy due to Graves' orbitopathy in 1 case (3%), and profound systemic immunosuppression due to chemotherapy for leukaemia in 1 case (3%). The remaining 20 patients had no identifiable risk factors. Fifteen patients (39%) had a positive biopsy result, which identified bacteria in 6 cases and Mycobacteria in 1 case, both by culture of the biopsy specimen. Three cases of fungus were identified on culture of biopsy specimen, two of which were also confirmed on histopathology and an additional case was identified from histopathology alone. A single case of Acanthamoeba was diagnosed by culture and histopathology, and an additional 3 cases were diagnosed on histopathology alone. A corneal biopsy yielded new organisms in 73% (11/15) cases where the culture results of biopsy specimens were positive. Corneal biopsy is an important tool in the diagnosis of progressive keratitis, often identifying causal organisms not found on corneal scraping alone.

Orthokeratology for myopia control: an optometrist’s view

Orthokeratology (OK) is a clinical technique that uses reverse geometry design rigid contact lenses to reshape the corneal profile and modify its refractive power during overnight lens wear in order to correct refractive error temporarily. OK achieves its reshaping effect through thinning of the central corneal epithelium. This raises concerns about the safety of this modality particularly in terms of microbial keratitis (MK). Since the mid 2000’s, with our increasing understanding of modifiable risk factors for MK in OK the prevalence of MK appears to have reduced significantly. It is now clear that the relative risk of MK in overnight OK is equivalent to other modalities of contact lens wear, provided that safe practice is followed in terms of lens fitting, wear and care. Although OK was originally used predominantly for correction of low to moderate myopic refractive error, its use for myopia control have become more common in recent years. This follows on from published clinical trials demonstrating an average of approximately 45% reduction in axial eye elongation when overnight OK is used in progressive myopic children. But there is significant individual variability in efficacy, and one of the current challenges for OK in myopia control is to identify those children who will benefit most from this particular intervention. Modifying OK lens parameters to customise corneal reshaping for enhanced myopia control efficacy also remains a significant challenge for the future of this modality.

Risk factors and causative organisms in microbial keratitis in daily disposable contact lens wear.

PurposeThis study investigated independent risk factors and causative organisms in microbial keratitis in daily disposable contact lens (CL)-wearers.MethodsA multisite prospective case-control study was undertaken. Cases were daily disposable CL-wearers attending Moorfields Eye Hospital with microbial keratitis and those reported through a one-year surveillance study in Australia and in New Zealand. A population-based telephone survey identified daily disposable CL-wearing controls. Subjects completed a questionnaire describing CL-wear history, hygiene and demographics. The sample used for risk factor analysis was weighted in proportion to the CL-wearing population at each location. Corneal scrape results were accessed. Independent risk factors were determined using multiple binary logistic regression. Causative organisms in different CL-wear modalities were compared using a chi-squared test.Results963 daily disposable CL-wearers were identified, from which 67 cases and 374 controls were sampled. Independent risk factors were; wearing CLs every day compared with less frequent use (OR 10.4x; 95% CI 2.9–56.4), any overnight wear (OR 1.8x; 95% CI 1.6–2.1), less frequent hand washing (OR 1.8x; 95% CI 1.6–2.0), and smoking (OR 1.3x; 95% CI 1.1–1.6). Certain daily disposable CLs (OR 0.2x; 95% CI 0.1–0.2) had protective effects. Environmental organisms were less frequently recovered with daily disposable CLs (20%), compared with other modalities (36%; p<0.02).ConclusionOvernight wear, increased exposure in daily wear, smoking and poor hand hygiene are significant risk factors for microbial keratitis with daily disposable CLs. Risk varied with daily disposable CL type. The profile of causative organisms is consistent with less severe disease.

Emerging trends in contact lens-related infections.

This article reviews the literature on past and recent trends in contact lens-related microbial keratitis from bacterial, fungal, and Acanthamoeba infections. Contact lens wear is the most important risk factor for microbial keratitis. Despite increased use of daily disposable contact lens wear, the incidence of bacterial ulcers related to contact lens wear remains high. Overnight contact lens wear is the leading risk factor in contact lens-related bacterial infections. There may be a trend towards increasing antibiotic resistance of Gram-positive bacteria to fourth-generation fluoroquinolones. The incidence of Acanthamoeba and fungal infections, despite resolution of two outbreaks involving multipurpose solutions, are also on the rise. Contact lens-related microbial keratitis is rising and may be associated with more severe, vision threatening, infections.

Bacterial Keratitis Risk Factors, Pathogens and Antibiotic Susceptibilities: A 5- Year Review of Cases at Dubai hospital, Dubai

Objective: Microbial keratitis is a sight threatening infection of the cornea. Its incidence has been increased in the past few years, with the contact lens wear as the major risk factor. In the past few years other risk factors have also come up in light. We thus aimed to present a 5-year study comprising of 37 patients with microbial keratitis who yielded only positive culture; other cases with negative cultures were excluded. Methods: Local microbiology database and retrospective audit of patients (who had a corneal scraping for culture over a 5-year period) medical records were used in this study. Results: We found that in our study also contact lens wear is the major risk factor for microbial keratitis. Pseudomonas aeruginosa was the most widely recognized causative organism isolated, present in 37% of the patient’s cultures. We found an association between risk factors for keratitis and variables collectively using multivariate analysis (p value<0.001), and an association of age with the risk factor for keratitis on performing separate ANOVA for each variable (p value<0.001). Conclusion: This study will help the clinical management of patients with keratitis and will raise awareness of sufficient lens care and disinfection practices.

Resistant Microbial Keratitis in South Nile Delta, Egypt: Influence of Regional Risk Factors

Purpose: This study was conducted in an attempt to identify the regional, geographic, climatic, socioeconomic, and other risk factors for microbial keratitis in south Nile Delta, Egypt. Methods: This is a prospective cross-sectional study that was carried out on 340 eyes of 340 patients with microbial keratitis attending at the outpatient clinic of Ophthalmology Department of Menoufia University Hospital during a period of three years between March 2010 and March 2013. Results: Epidemiological factors, lines of management, and follow-up results were recorded and statistically analyzed and there were regional variations in the prevalence, risk factors, and outcome in resistant corneal ulcers. Conclusion: Higher incidence of affections and complications has appeared in farmers, rural area residents, and illiterates which are considered the main predisposing factors for ulcer resistance. According to culture results, bacterial organisms (especially Staphylococcus aureus) were the main cause of resistant corneal ulcers.

Microbial Keratitis Profile at a University Hospital in Hong Kong.

Purpose. To evaluate the recent trends in demographics, risk factors, and microbiological profiles of microbial keratitis at a university hospital in Hong Kong. Design. Retrospective review. Methods. The medical records of 51 patients admitted to the Prince of Wales Hospital for microbial keratitis from January 2010 to June 2012 were reviewed. Demographics, risk factors, clinical features, microbiological results, and treatment were recorded. Data was analyzed and compared to our historical sampled data collected 11 years ago. Results. The mean age of patients was 41.6 ± 20.3 years. Contact lens use was the major risk factor (45%), followed by injury (12%). The culture positive rate was 59%, of which 37% were Gram-positive organisms and 53% were Gram-negative organisms. Pseudomonas aeruginosa (50%) and coagulase-negative Staphylococcus (13%) were the most commonly isolated pathogens. No resistance to fluoroquinolones was identified. Conclusions. Our study showed that contact lens wear remained the major risk factor for microbial keratitis in Hong Kong and Pseudomonas aeruginosa remained the commonest bacterium isolated. This is comparable to our historical data and other studies conducted in East Asia.

Corneal cross-linking in microbial keratitis to prevent à chaud keratoplasty: a retrospective case series

Corneal cross-linking (CXL) with riboflavin is being used more frequently for the treatment of therapy-resistant microbial keratitis, since increasing drug resistance and specific pathogens, e.g. contact lens-associated Acanthamoeba, make this therapy appear as an attractive option to avoid a keratoplasty à chaud. This retrospective case series of 11 consecutive patients (4 women, 7 men, aged 24-82 years) who received standardised antimicrobial CXL for therapy-resistant keratitis to avoid a keratoplasty à chaud, included 4 cases with detection of bacterial pathogens, one case with proven fungal infection and 6 cases without pathogen detection. Analysed data comprised ophthalmic medical history, general risk factors for microbial keratitis, treatment before and after CXL. The characterisation of the corneal ulcer included photometric measurements of the infiltrates with a median of 16.2 mm² and four unmeasurable cases due to extended, not circumscribed lesions. Within the follow-up period (mean 134 ± standard deviation 82 days), a penetrating keratoplasty was successfully avoided in 6 patients (55 %). After CXL 9 patients (82 %) received additionally amniotic membrane transplantation. After CXL treatment, topical antibiotic therapy was continued for a mean 27 ± 13 days postoperatively. Steroids were applied in 91 % of the patients. The cornea cleared at least to some extent in 9 patients (82 %). Patients with neurotrophic keratopathy or potentially compromised immune system showed no increased failure rate. These results suggest that antimicrobial CXL might be a useful option in patients with therapy-resistant corneal ulcer in order to avoid a perforating keratoplasty à chaud. For a comprehensive scientific assessment of this therapy, however, further, ideally prospective randomised interventional studies with large sample sizes are needed.

Pediatric Microbial Keratitis in Taiwan: Clinical and Microbiological Profiles, 1998–2002 Versus 2008–2012

To identify the change in clinical and microbiological profiles of pediatric microbial keratitis in Taiwan between 1998-2002 and 2008-2012. Retrospective, observational study. setting: Chang Gung Memorial Hospital, a referral center in Taiwan. patient population: We retrospectively reviewed the medical records of 68 eyes of 67 children aged 16 years or younger who were diagnosed with microbial keratitis and treated at our hospital between July 2008 and December 2012. main outcomes and measures: Predisposing factors, isolated organisms, antibiotic susceptibility, and clinical outcomes. The findings were compared with the results of our previous study conducted between July 1998 and December 2002. As in 1998-2002, the leading risk factor for microbial keratitis during 2008-2012 was contact lens use, and the infection rate significantly increased from 40.7% to 52.9% (P= .024), which was mainly attributable to the recent increase in the rate of orthokeratology-related keratitis from 9.9% to 19.1% (P= .011). Pseudomonas aeruginosa remained the most commonly isolated organism (30.6%), but the number of isolated coagulase-negative Staphylococcus cases increased significantly in the 2008-2012 cases (P= .04). Antibiotic susceptibility of organisms did not change significantly between the 2 study periods. By using multiple linear stepwise regression analysis, we found that gram-negative bacterial infection played a crucial role in poor visual outcome. Contact lens-related microbial keratitis increased in Taiwanese children over time, especially because of the use of overnight orthokeratology. Clinicians must understand the infection background and pay further attention to contact lens use in pediatric patients.

Microbial Keratitis after Boston Type I Keratoprosthesis Implantation: Incidence, Organisms, Risk Factors, and Outcomes

To identify the incidence of and risk factors for microbial keratitis after implantation of the Boston type I keratoprosthesis (Massachusetts Eye and Ear Infirmary, Boston, MA). Retrospective, single-surgeon consecutive case series. A total of 105 patients (125 keratoprosthesis procedures in 110 eyes) who underwent Boston type I keratoprosthesis implantation at the Jules Stein Eye Institute between May 1, 2004, and April 1, 2012. Data regarding ocular history, relevant intraoperative data, postoperative management, and outcomes were collected for each procedure. Risk factor analyses were performed using the Fisher exact test, log-rank test, and hazard ratio (HR). Incidence of microbial keratitis, organisms responsible, risk factors, and outcomes. During the period under review, 20 presumed infectious infiltrates were diagnosed in 15 eyes (13.6%) of 15 patients (14.3%), for a rate of 0.073 infections per eye-year. The rate of culture-positive bacterial keratitis was 0.022 infections per eye-year, and the rate of culture-positive fungal keratitis was 0.015 infections per eye-year. Topical vancomycin use, topical steroid use, and contact lens wear did not increase the incidence of infectious keratitis, but prolonged vancomycin use was associated with an increased risk for fungal keratitis and infectious keratitis overall. Persistent corneal epithelial defect formation also was associated with an increased incidence of fungal keratitis and infectious keratitis overall. There were no cases of endophthalmitis resulting from infectious keratitis. Infectious keratitis develops in 13.6% of eyes after keratoprosthesis implantation, with a similar rate of culture-positive bacterial and fungal keratitis. The observed rate of microbial keratitis suggests the need for additional topical antimicrobial prophylaxis after keratoprosthesis implantation in eyes at higher risk, such as those with persistent corneal epithelial defect formation or prolonged vancomycin use.

Impact of Lens Case Hygiene Guidelines on Contact Lens Case Contamination

Lens case contamination is a risk factor for microbial keratitis. The effectiveness of manufacturers' lens case cleaning guidelines in limiting microbial contamination has not been evaluated in vivo. This study compared the effectiveness of manufacturers' guidelines and an alternative cleaning regimen. A randomized cross-over clinical trial with two phases (n = 40) was performed. Participants used the lens types of their choice in conjunction with the provided multipurpose solution (containing polyhexamethylene biguanide) for daily wear. In the manufacturers' guideline phase, cases were rinsed with multipurpose solution and air dried. In the alternative regimen phase, cases were rubbed, rinsed with solution, tissue wiped, and air-dried face down. The duration of each phase was 1 month. Lens cases were collected at the end of each phase for microbiological investigation. The levels of microbial contamination were compared, and compliance to both regimens was assessed. The case contamination rate was 82% (32/39) in the manufacturers' guideline group, compared with 72% (28/39) in the alternative regimen group. There were significantly fewer (p = 0.004) colony forming units (CFU) of bacteria from cases used by following the alternative regimen (CFU range of 0 to 10, and median of 12 CFU per well) compared with that of the manufacturer's guidelines (CFU range of 0 to 10, and median of 28 CFU per well). The compliance level between both guidelines was not significantly different (p > 0.05). The alternative guidelines are more effective in eliminating microbial contamination from lens cases than that of the current manufacturer's guideline. Simply incorporating rubbing and tissue-wiping steps in daily case hygiene reduces viable organism contamination.