Report of the Eye Bank Association of America medical advisory board subcommittee on fungal infection after corneal transplantation

Trends in infectious adverse events after elective optical keratoplasty (PK, EK, and ALK) - Ten years' analysis from an eye bank

PURPOSE

To report the clinical profile and donor characteristics of post-optical keratoplasty adverse events notified at an eye bank.

METHODS

Between January 2013 and December 2022, 37,041 donor corneas were utilized for keratoplasty, of which 16,531 were used for penetrating keratoplasty (PK), 12,171 for endothelial keratoplasty (EK), and 1356 for anterior lamellar keratoplasty (ALK). EK included 10,956 Descemet stripping automated endothelial keratoplasty (DSAEK) and 1215 Descemet membrane endothelial keratoplasty (DMEK). The adverse events reported within the first 6 weeks of optical keratoplasty were analyzed for donor-related parameters.

RESULTS

A total of 41 (0.11%) recipients had post-keratoplasty infections. Of these, 33 occurred after EK (29 after DSAEK, and four after DMEK), two after ALK, and six after PK. The clinical presentation was keratitis alone in 16 eyes and associated with endophthalmitis in 25 eyes. The organisms isolated were gram-negative bacteria in 26 eyes, fungus in eight eyes, gram-positive bacteria in four eyes, mixed infection in five eyes, and microbiology inconclusive in seven eyes. The majority (78%) of the gram-negative infections were due to multidrug-resistant organisms. Most (88%) donor corneas were harvested from hospital premises. The most common cause of donor mortality was trauma. The median duration of presentation from surgery was 4.46 (range: 1-30) days. The death to preservation time was 4.18 (1.5-7.65) hours. The death to utilization time was 3 (2-4.7) days.

CONCLUSION

The overall risk of infectious adverse events after keratoplasty was 0.11%, ranging from 0.08% to 0.36%. Most (80.4%) of the adverse events occurred after EK. The majority (78.9%) of the adverse events were of bacterial etiology, of which gram-negative infections (68.4%) were the most common. The trends and microbiological spectrum of organisms associated with infections should be thoroughly documented in eye banks to gain insights and formulate guidelines on the management of adverse events.

Clinical Features, Risk Factors, and Management of Candida Keratitis

BACKGROUND/AIMS

To determine the clinical features, predisposing factors, and management of infectious keratitis caused by Candida spp.

METHODS

Retrospective chart review.

RESULTS

The medical records of 52 patients (54 eyes) with Candida keratitis were available for statistical analysis. Thinning of the corneal stroma was identified in 34 eyes (63.0%), and corneal perforation occurred in 16 eyes (29.6%). Corneal thinning and perforation were more common in Candida albicans compared with non-albicans (P-val < .001, P = .09, respectively). The most common predisposing factors for Candida keratitis were topical steroid use (21 patients, 40.4%), previous corneal transplantation (17 patients, 32.7%), and preexisting ocular surface disease (15 patients, 28.8%). Fourteen eyes (25.9%) required cyanoacrylate glue application and 10 eyes (18.5%) underwent therapeutic penetrating keratoplasty (TPK).

CONCLUSION

Local immunosuppression and ocular surface disease play an important role in Candida keratitis. C. albicans appears to be more invasive compared with non-albicans spp.

A Comprehensive Review of Donor Corneal Preservation Strategies

ABSTRACT

Successful corneal transplantation relies on the viability of the corneal endothelium. Although various preservation systems have been developed in the field of eye banking, long-term storage of the corneal endothelium poses challenges and is costly. Optisol-GS in the past has been the most commonly used solution for intermediate-term corneal storage in the United States. However, disruptions in the availability of Optisol-GS, caused by rising costs and supply shortages, have necessitated alternative methods of corneal preservation. Previously described preservation methods include hypothermia (2-8°C) for short-term storage (7-14 days), organ culture (28-37°C) for intermediate storage (4-7 weeks), and cryopreservation for longer-term storage. In this review, we examine standard practice and alternative methods for corneal storage.

Investigating the Influence of Temperature and Supplementation Timing on Antifungal Efficacy in Storage Medium for Corneal Transplantation

INTRODUCTION

Although antifungal supplementation reduces the fungal load in the corneal storage medium, consensus is lacking on the influence of dosing and temperature. The study aims to evaluate the impact of eye bank warming protocol and timing of antifungal supplements on efficacy in Optisol-GS and tissue.

METHODS

Corneoscleral rims contaminated with Candida albicans (C. albicans) were incubated in Optisol-GS, either without antifungal agents or with the addition of amphotericin B or voriconazole at various concentrations (2 ×, 5 ×, 10 ×, and 20 × MIC), at different time points, and under various preservation temperatures (2-8 °C versus 2 h-room temperature exposure). Antifungal efficacy was evaluated by counting viable yeast colonies cultured from Optisol-GS samples. Tissue sterility was determined through direct tissue culture and histological examination of the contaminated rims after a 14-day incubation period.

RESULTS

Room temperature exposure did not increase colony growth at the same multiple MIC of antifungal agents. Although antifungal addition reduced C. albicans growth in a concentration-dependent manner, yeast growth was still observed in all Optisol-GS samples with a single supplementation after a 14-day incubation. Only groups with additional antifungal supplementation on either day 2 or day 6 showed a 99% or greater reduction of C. albicans growth in Optisol-GS samples and yielded negative results in direct tissue culture.

CONCLUSIONS

The eye bank warming protocol did not compromise antifungal efficacy. To sustain the required concentration and effectively reduce C. albicans growth in Optisol-GS and contaminated tissue, additional antifungal supplementation on either day 2 or day 6 was necessary during a 2-week preservation period.

Post-Keratoplasty Microbial Keratitis in the Era of Lamellar Transplants-A Comprehensive Review

Microbial keratitis in a post-transplant cornea should be considered a distinct entity from microbial keratitis in a non-transplant cornea. Firstly, the use of immunosuppressive treatments and sutures in corneal transplants changes the etiology of keratitis. Secondly, corneal transplant has an impact on corneal biomechanics and structure, which facilitates the spread of infection. Finally, the emergence of lamellar transplants has introduced a new form of keratitis known as interface keratitis. Given these factors, there is a clear need to update our understanding of and management strategies for microbial keratitis following corneal transplantation, especially in the era of lamellar transplants. To address this, a comprehensive review is provided, covering the incidence, risk factors, causes, and timing of microbial keratitis, as well as both clinical and surgical management approaches for its treatment in cases of penetrating and lamellar corneal transplants.

Correlation Between the Cost and Safety of Corneal Graft Types

Background Corneal diseases are the fourth most common cause of blindness worldwide. In the majority of these diseases, vision reduction is reversible and can be restored to a large extent by replacing the cornea through specific surgery and, in particular, transplantation. In Greece, due to a lack of organized eye banks as well as donors, the grafts intended for corneal transplantation usually come from eye banks abroad. This study focuses on the dynamics of cost versus value in the decision-making process for the procurement of corneal grafts, ultimately investigating the safety that the procured grafts provide to patients. Methodology A total of 267 patients with severe vision problems who underwent 301 corneal and amniotic membrane transplants from years 2020 to 2023 at the Transplant Unit of the Athens General Hospital "Georgios Gennimatas" were included in this study. All patients who were deemed appropriate to undergo corneal transplant operations, the diagnosis that led to the specific surgery, and other relevant data were recorded and evaluated. Results There was no significant difference in the ratio between males and females (51.3% male and 48.7% female). The mean age of the patients was 66.5 years (SD = 13.7 years). Graft problems were faced by 13.9% of the patients, with the amniotic membrane by 1.5% (in the total number of surgical operations) and both eyes by 4.5% of patients. The majority of the patients had undergone only one surgery (88.8%). Reoperation was needed in 14% of the cases, and 7.6% of the cases were surgeries that occurred due to graft rejection or non-functioning grafts from surgeries performed at another hospital or clinic. In the majority of surgeries (60.8%), a Descemet's stripping automated endothelial keratoplasty graft was used. The mean cost was 3,167 euro (SD = 960.3 euro). Furthermore, in 35.8% of the surgeries, the graft was preserved with amphotericin. Conclusions The present study draws useful conclusions about the effectiveness of surgical interventions through the correlation of cost and safety of the grafts that are approved and finally used in corneal transplants, as well as the submission of proposals to improve the procedures and lead to patient benefits.

Incidence and management of early postoperative complications in lamellar corneal transplantation

PURPOSE

To provide a comprehensive review of the incidence, risk factors, and management of early complications after deep anterior lamellar keratoplasty (DALK), Descemet stripping automated keratoplasty (DSAEK), and Descemet membrane endothelial keratoplasty (DMEK).

METHODS

A literature review of complications, that can occur from the time of the transplant up to 1 month after the transplant procedure, was conducted. Case reports and case series were included in the review.

RESULTS

Complications in the earliest postoperative days following anterior and posterior lamellar keratoplasty have shown to affect graft survival. These complications include, but are not limited to, double anterior chamber, sclerokeratitis endothelial graft detachment, acute glaucoma, fluid misdirection syndrome, donor-transmitted and recurrent infection, and Uretts-Zavalia syndrome.

CONCLUSION

It is essential for surgeons and clinicians to not only be aware of these complications but also know how to manage them to minimize their impact on long-term transplant survival and visual outcomes.

Clinical and in vivo confocal microscopy characteristics of Candida keratitis following keratoplasty

BACKGROUND

We present six patients who developed Candida keratitis postoperatively. The clinical features, diagnostic testing including in vivo confocal microscopy, and outcomes are presented.

METHODS

Six patients who developed Candida keratitis following penetrating and endothelial keratoplasty, were referred to Tianjin Medical University Eye Hospital between 2018 to 2021.The diagnosis was established following cultures of either corneal scraping or biopsy. In vivo confocal microscopy examination was also performed to confirm the diagnosis and characterize the morphology, distribution and the depth of Candida spp. All patients were treated with topical voriconazole (VCZ) 1% and natamycin (NTM) 5%. Patients with mid/deep stromal keratitis or interface infection were treated additionally with intrastromal or interface VCZ irrigation (0.05 mg/0.1mL).

RESULTS

The cultures of corneal scrapings (4 cases) or biopsies (2 cases) were all positive for Candida spp. In vivo confocal microscopy examination was positive for fungal elements in five of the six patients. The infection resolved in five of the six patients. The patients' final uncorrected visual acuity (UCVA) ranged from hand movements (HM) to 20/80.

CONCLUSION

In vivo confocal microscopy is a useful non-invasive clinical technique for confirming the diagnosis of Candida keratitis. Intrastromal and interface irrigated VCZ injections are effective treatment options.

Anti-fungal efficacy of combination of amphotericin B with colistin and gentamicin in McCarey-Kaufman corneal preservation medium

Purpose

To curtail the potential of donor corneal tissue disseminating fungi to the recipient's eye, we evaluated the addition of amphotericin B to McCarey-Kaufman (M-K)-corneal storage medium supplemented with colistin.

Methods

Amphotericin B was examined for its ability to inhibit the growth of Candida albicans and Aspergillus flavus using a microbroth dilution test and checkerboard assay in combination with only gentamicin and a combination of colistin, gentamicin, and amphotericin B. The safety on epithelium and endothelium was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.

Results

The minimal inhibitory concentration of gentamicin was found to be >256 μg/ml against both C. albicans and A. flavus, whereas that of amphotericin B was found to be in a range of 0.25-0.5 and 1-2 μg/ml for C. albicans and A. flavus, respectively. According to the checkerboard assay, 80% (4/5) of C. albicans isolates and 100% (5/5) of A. flavus isolates responded synergistically to the combination of amphotericin B and gentamicin, but only 20% (1/5) of C. albicans isolates showed an additive effect. None of the tested isolates displayed antagonism. The combined effect of the three drugs also did not display any antagonistic effect. Additionally, the MTT assay reveals no toxic effect of the antimicrobials used on corneal epithelial and endothelial cells.

Conclusion

In vitro experiments demonstrate that amphotericin B is not toxic to either epithelium or endothelium and is a promising additive to the M-K medium supplemented with colistin.

Fungal Infection After Descemet Membrane Endothelial Keratoplasty: Incidence and Outcomes

PURPOSE

The aim of the study was to describe the incidence, presentation, management, and outcomes of fungal infection after Descemet membrane endothelial keratoplasty (DMEK).

METHODS

Retrospective case series of culture-proven fungal infections after DMEK reported in the literature, directly by surgeons, and to the Eye Bank Association of America from January 1, 2011, to December 31, 2020.

RESULTS

The domestic incidence of fungal infections, fungal keratitis, and fungal endophthalmitis after DMEK from 2011 to 2020 was 3.5, 1.3, and 2.2 per 10,000 cases, respectively, with no significant increasing trend. Thirty-four cases were identified, 14 (41.2%) published and 20 (58.8%) unpublished. Donor tissue fungal cultures were performed in 20 of the 34 (58.8%) cases and were positive in 19 of the 20 (95.0%), all but one Candida species. Recipient fungal cultures were performed in 29 of the 34 (85.3%) cases and were positive in 26 of the 29 (89.7%), all but one Candida species. Infection presented a mean of 33 ± 38 days (median 23, range 2-200, outlier 949) after transplantation: 25 (73.5%) with endophthalmitis and 9 (26.5%) with keratitis. Topical, intrastromal, intracameral, intravitreal, or systemic antifungal therapy was used in all 27 eyes with treatment data. Surgical intervention (DMEK explantation or partial removal, repeat endothelial keratoplasty, penetrating keratoplasty, and/or pars plana vitrectomy) was required in 21 of the 27 (77.8%) eyes. The corrected distance visual acuity at the last follow-up was ≥20/40 in 13 of the 27 (48.1%) eyes and counting fingers or worse in 6 of the 27 (22.2%) eyes.

CONCLUSIONS

Fungal infection is a rare but serious complication of DMEK that results in counting fingers or worse corrected distance visual acuity in nearly a quarter of eyes.

Prospective In Vitro Comparison of Kerasave and Optisol-GS Corneal Storage Solutions

PURPOSE

The aim of this study was to compare the performance of Kerasave and Optisol-GS for hypothermic corneal storage for 14 days.

METHODS

This study was a prospective laboratory investigation. Mate corneas were recovered into Kerasave or Optisol-GS (27 pairs) and stored at 2°C to 8°C for 14 days. Corneas were evaluated by trained eye bank technicians, and study parameters were compared between the initial and final evaluations. Endothelial cell density (ECD), hexagonality (HEX), and coefficient of variation (CV) were evaluated by specular microscopy, and central corneal thickness (CCT) was examined by optical coherence tomography after 1, 3, 7, and 14 days of storage. Corneal transparency was scored using slit lamp examination at days 1 and 14.

RESULTS

Average ECD, HEX, and CV for the Kerasave (2653 ± 303 cells/mm 2 , 57 ± 4%, and 36 ± 3%) and Optisol-GS (2623 ± 306 cells/mm 2 , 57 ± 5%, and 36 ± 4%) groups were not significantly different at day 1. There was also no difference at any other study time points (all P > 0.05). ECD did not significantly change from day 1 to day 14 in either group ( P > 0.05), but a statistically significant change in HEX and CV was observed between day 1 and day 14 in both groups ( P < 0.01). Average CCT measured at day 1 for corneas stored in Kerasave was 622 ± 49 μm and those stored in Optisol-GS was 580 ± 35 μm ( P < 0.01). The difference in CCT measurements was not significantly different at day 14 (Kerasave: 674 ± 46 μm vs. Optisol-GS: 647 ± 58 μm, P > 0.05). Corneal transparency was not significantly different between the 2 groups at day 1 or day 14.

CONCLUSIONS

The corneal quality and clinically relevant parameters including ECD, endothelial morphometry, and corneal transparency were not different in corneas stored in Kerasave or Optisol-GS for 14 days. The initial difference in CCT between the 2 groups decreased at day 14. These results demonstrated that Kerasave corneal storage solution preserves the corneal endothelium similarly to Optisol-GS.

Donor related corneal graft infection: a review of literature and preventive strategies

PURPOSE

Donor-related infections are a serious threat to patient safety after corneal transplantation. We provide a concise review of literature from the last decade on donor-related graft infections, sources of contamination and means to reduce the contamination of donor tissue and preservation media.

METHODS

We reviewed 50 papers from year 2005 to 2021 related to donor-related graft infections. We included 14 studies related to the risk factors associated with post-keratoplasty infection and preventive methods.

RESULTS

Incidence of post-keratoplasty infections has been reported to be approximately 0.2%-0.77% for endophthalmitis and 6.5%-10.5% for microbial keratitis. We analyzed six important studies regarding the risk factors related to donor contamination. It was observed that younger donor age, increased death to retrieval time, warming cycles and increased eye bank processing time and positive corneo-scleral rim cultures were important risk factors for donor-related infections post keratoplasty. Eye banks have adapted newer protocols over the time period for prevention of donor-related contamination. Recommended preventive strategies were published in about eight important studies over the past decade. In addition to meticulous donor screening, rapid warming cycles, double contact with povidone iodine during retrieval and addition of antifungals like amphotericin B, Voriconazole and cycloheximide have been suggested over the last decade although their use is still in debate with regard to the efficacy, toxicity and cost-effectiveness.

CONCLUSION

The last decade has witnessed a relative rise of fungal infections and multidrug resistant bacterial infections post-keratoplasty. Eye bank prepared corneas for lamellar surgeries are at increased risk for donor contamination due to increased exposure to the higher temperatures during their processing. Addition of antifungals and broad spectrum antibiotics to the hypothermic preservation media needs to be considered in the new era of increasing trends of lamellar keratoplasty.

Keratoplasty Registries: Lessons Learned

ABSTRACT

Clinical registries have been developed for decades in the field of ophthalmology, and they are especially well-suited to the study of keratoplasty practices. A comprehensive donor/recipient registry system can provide insight into donor, recipient, and surgical factors associated with immediate and long-term outcomes and adverse reactions. Furthermore, linkage with demographic databases can elucidate relationships with social determinants of health and potentially shape public policy. The vast sample size and multicenter nature of registries enable researchers to conduct sophisticated multivariate or multilayered analyses. In this review, we aim to emphasize the importance of registry data for keratoplasty practice and 1) summarize the structure of current keratoplasty registries; 2) examine the features and scientific contributions of the registries from Australia, the United Kingdom, Singapore, the Netherlands, Sweden, Eye Bank Association of America, and European Cornea and Cell Transplant registries; 3) compare registry-based studies with large single-site clinical studies; 4) compare registry-based studies with randomized control studies; and 5) make recommendations for future development of keratoplasty registries. Keratoplasty registries have increased our knowledge of corneal transplant practices and their outcomes. Future keratoplasty registry-based studies may be further strengthened by record linkage, data sharing, and international collaboration.

Repeat lamellar keratoplasty treatment for positive rim lamellar keratoplasty

A case describes repeat lamellar keratoplasty (LKP) as a treatment for positive rim of Candida glabrata LKP. As have postulated in the literature, having positive rim is a substantial risk factor for a developing fungal keratitis. Different management approaches of fungal keratitis over a corneal graft have used. Herein, we provide a description of the clinical findings, management approach and used surgical technique with review of the literature.

Gram stain and addition of amphotericin B to improve the microbial safety of human donor corneas

To determine the effectiveness of two methods to improve the microbial safety of human corneas preserved in organ culture. We compared the number of positive preservation solutions of corneas in organ culture in which the initial short-term hypothermic corneal maintenance solution was supplemented with amphotericin B 2.5 µg/mL and the historical data of microbial test results (2015-2019). In addition, we appraised the efficacy of Gram stain to detect bacterial or fungal contamination in the organ culture solutions of corneas from at-risk donors compared to the culture tests of corneas from not-at-risk donors. Statistical analysis was performed using STATA and statistical significance set at p < 0.05. The number of positive culture tests after preservation was 15 (0.5%) in 2020 compared to a mean of 37 (1.2%) in the period 2015-2019 (p < 0.01), with 10 (1.0%) positive samples in the cohort of 998 corneas from at-risk donors and 5 (0.2%) in the 2046 corneas from not-at-risk donors (p < 0.01). All corneas from at-risk donors tested positive at Gram stain and the results were available 1-3 days before those of the conventional culture tests. Amphotericin B supplementation in the short-term maintenance solution markedly reduced the number of positive microbial tests after organ culture and the early detection of contaminants, including slow-growing microorganisms, by Gram stain before the standard culture results. This meant fewer corneas being discarded and a greater likelihood of preventing post-graft infections.

Effect of Increasing Povidone-Iodine Exposure on Corneal Epithelium and Impact on Donor Rim Cultures

PURPOSE

The purpose of this study was to assess the effect of a second povidone-iodine (PVP-I) application at the time of donor tissue recovery on overall tissue quality and to analyze the rate of positive fungal and bacterial rim cultures before and after implementing increased PVP-I exposure.

METHODS

The left cornea was recovered after a single application of PVP-I, while the right cornea was recovered after double PVP-I application in research-consented donors. The epithelial cell death rate was estimated using viability assay in corneal whole mounts under 10× objective (n = 5). Clinical characteristics of epithelium, stroma, and endothelium; positive rim culture rate; and incidences of infectious postoperative adverse reactions were compared for a period of 14 months before and after implementation of increased PVP-I protocol.

RESULTS

The average epithelial cell death rate was unaltered between single and double PVP-I exposure groups. We observed a modest 10% increase in the number of tissues with mild edema after implementation of increased PVP-I exposure. Nonetheless, the percentage of tissues with moderate or severe edema was unaltered. The average positive rim culture rate decreased from 1.17% to 0.88% (P = 0.075) after implementation of the double PVP-I soak procedure. There has been only one report of infectious postoperative adverse reactions since this procedure change. By contrast, there were 5 reports for a period of 14 months before implementation of this protocol.

CONCLUSIONS

These results indicate that new donor preparation methods with an additional 5 minutes of PVP-I exposure do not affect tissue quality, reduce positive rim cultures, and lead to lower incidence of postoperative infection.

The impact of amphotericin B-fortified preservation media on donor rim cultures and posttransplant infection

Purpose

To determine the impact of amphotericin B supplementation to donor cornea preservation solutions on the rates of positive donor rim fungal cultures and postkeratoplasty fungal infections.

Methods

This was a retrospective analysis of cases undergoing corneal transplantations at a single tertiary referral center from 2016 to 2021. Patients undergoing corneal transplantations with and without amphotericin B supplementation to the storage media were reviewed for donor rim culture results and postoperative infection. The primary outcome measures were positive donor rim fungal culture results and postkeratoplasty fungal infection.

Results

A total of 1238 corneal transplants were analyzed. Of these, 849 were stored in preservation solution without amphotericin B, while 389 had amphotericin B included. There was a lower incidence of positive donor rim fungal cultures in cases with amphotericin B supplementation (1.8%) compared to the cases without amphotericin B (2.9%), although this difference was not statistically significant (P = 0.24). Of the 389 cases with amphotericin B supplementation, one (0.25%) went on to develop clinically significant infection, while three of 849 (0.35%) cases without amphotericin B developed infection. The sample size was too small to determine the effect of amphotericin B on the incidence of postkeratoplasty fungal infection.

Conclusion

The addition of amphotericin B to donor cornea preservation solution resulted in a downward trend of positive donor rim fungal cultures and postkeratoplasty fungal infections, although these differences did not reach statistical significance. Further studies with larger sample sizes are necessary to appropriately determine the impact of amphotericin B supplementation in the storage solution on positive donor rims and postkeratoplasty fungal infections.

Fungal Infectious Interface Keratitis Presenting 2 Years After Descemet Membrane Endothelial Keratoplasty

PURPOSE

The purpose of this study was to describe infectious interface keratitis after Descemet membrane endothelial keratoplasty (DMEK) more than 2 years after surgery.

METHODS

A case study.

RESULTS

In this study, we report a case of fungal infectious interface keratitis occurring 2 years after uncomplicated Descemet membrane endothelial keratoplasty. The donor corneal rim culture at the time of surgery grew a single colony of Candida albicans/dubliniensis , but the patient was not treated with antifungals at that time. At the onset of clinical infection, more than 2 years postoperatively, the patient was treated with systemic antifungals and adjuvant intrastromal amphotericin-B injection. The patient subsequently required penetrating keratoplasty with ultimately well-preserved visual acuity.

CONCLUSIONS

Fungal infectious interface keratitis (IIK) is a rare complication associated with lamellar keratoplasty. Although most common in the early postoperative period, this complication can occur several years after successful transplantation. Management may require a combination of systemic and stromal antifungal therapy. However, some patients may eventually require penetrating keratoplasty for definitive treatment.

Toxicity of Amphotericin B in Rabbit Corneal Epithelial Cells Stored in Optisol™-GS: Corneal Epithelial Cell Morphology and Migration

PURPOSE

To evaluate the toxicity of Amphotericin B (AmB) in Optisol™-GS Corneal Storage Media (Bausch & Lomb) on corneal epithelial cell (CEC) morphology and migration ability.

METHODS

Sclerocorneal strips were removed from male Japanese white rabbits, and then stored at 4 °C in Optisol™-GS containing 0 µg/ml of AmB (control group) and 2.5, 5, 25, and 50 µg/ml of AmB (AmB groups; four eyes per group). After 7 days of storage, CEC morphology was evaluated by hematoxylin-eosin staining, immunohistochemical staining (ZO-1), and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Moreover, to evaluate CEC migration ability, three corneal blocks (6-8 × 3 mm each) from one preserved cornea were cultured for 24 h, and the area of CEC migration (2 mm at the central region) onto the stromal surface was then measured.

RESULTS

At 5, 25, and 50 µg/ml of AmB, deformation and vacuolation of CECs were observed in all preserved corneas. ZO-1 expression was significantly reduced in corneas preserved at AmB concentrations of 25 and 50 µg/ml. TUNEL Labeling Index was significantly increased at AmB concentrations of ≥5 µg/ml. CEC migration was inhibited in a dose-dependent manner at AmB concentrations of 25 and 50 µg/ml compared to the control group.

CONCLUSIONS

The addition of AmB to Optisol™-GS can be toxic to CECs and inhibit their migration at a concentration of ≥5 µg/ml. AmB at a concentration of 2.5 µg/ml can be considered safe for the preservation of donor corneal tissue used in corneal epithelial transplantation surgery.

Update on diagnosis and management of refractory corneal infections

Infectious keratitis is a medical emergency resulting in significant visual morbidity. Indiscriminate use of antimicrobials leading to the emergence of resistant or refractory microorganisms has further worsened the prognosis. Coexisting ocular surface diseases, delay in diagnosis due to inadequate microbiological sample, a slow-growing/virulent organism, or systemic immunosuppressive state all contribute to the refractory response of the ulcer. With improved understanding of these varied ocular and systemic factors contributing to the refractory nature of the microbes, role of biofilm formation and recent research on improving the bioavailability of drugs along with the development of alternative therapies have helped provide the required multidimensional approach to effectively diagnose and manage cases of refractory corneal ulcers and prevent corneal perforations or further dissemination of disease. In this review, we explore the current literature and future directions of the diagnosis and treatment of refractory keratitis.

Keratitis following descemet's stripping endothelial keratoplasty (DSEK): Clinical features and outcome in early vs late presentation

OBJECTIVE

To compare the clinical presentation, risk factors, causative organisms, and final outcome of early- and late- onset microbial keratitis following Descemet's Stripping Endothelial Keratoplasty (DSEK).

MATERIALS AND METHODS

In a retrospective, comparative, case series, twenty-three (10 early-onset keratitis, 13 late-onset keratitis) cases were included for analysis from a single centre tertiary eye care setup. Data about demography, indication, clinical features, and outcome were collected for both the groups. Comparison of clinical presentation, risk factors, microbiology and final outcome were carried out.

RESULTS

The most common indication was failed graft. While all patients with late-onset keratitis presented with ulcerative keratitis, 60% of early-onset keratitis presented with ulcerative keratitis. Four patients in the early-onset group had interface keratitis. Associated endophthalmitis was more in the early-onset compared to the late-onset group. Early-onset interface keratitis cases are mostly associated with donor-related infection. Gram-positive bacteria were the most common organisms isolated from both early- and late- onset infection. Major surgical procedures in both early- and late- onset keratitis included lenticule removal (n = 4) and therapeutic penetrating keratoplasty (n = 5).

CONCLUSIONS

Failed graft is a major risk factor in post-DSEK keratitis. Interface keratitis and endophthalmitis are commonly observed in early-onset keratitis. A majority of the patients need surgical intervention.

Overview of Short-Term and Intermediate-Term Corneal Storage Solution: Comparison of Clinical Outcomes and Need For Future Research

ABSTRACT

Corneal donor tissue preservation techniques have incrementally improved since the introduction of McCarey-Kaufman storage solution from short-term storage to intermediate duration of storage with the advent of organ culture and Optisol GS storage solutions. Improved understanding of the corneal endothelial cell physiology has helped in designing newer storage solutions, such as the Life 4C and Cornea Cold. The incorporation of antibiotics, ATP precursors, minerals, and vitamins has improved the viability of tissues. In addition, these modifications to the newer storage solutions have increased the endothelial longevity and metabolic activity. Despite these advances, the duration of tissue storage has largely been restricted to 2 weeks in Optisol GS and 4 weeks in organ culture. The role and cost-effectiveness of antifungal supplementation and the need for improved epithelial preservation are additional areas that need to be explored. This review intends to summarize the efficacy and viability of donor corneas in different tissue storage solution and compare clinical outcomes while providing an insight into the challenges in developing newer methods of corneal preservation.

Analysis in Results of Microbiologic Exam Related to Donor Corneas

Purpose: This study analyzed the microorganisms identified in donor corneas and their clinical significance.Methods: The medical records of 94 patients (114 eyes) who underwent keratoplasty and microbiological tests of the donor corneas from October 2008 to December 2020 at our hospital were reviewed retrospectively. During keratoplasty, we conducted microbiological tests of the corneoscleral rim of the donor cornea and preserving solution Optisol™-GS (Bausch & Lomb, Rochester, NY, USA), and examined the antibiotic susceptibility of bacterial isolates from the cultures.Results: Some isolates of domestic donor corneas revealed bacteria, but none of the imported corneas did. Gram-negative bacilli were detected from the corneoscleral rim in three eyes (2.6%): two cases of Acinetobacter baumannii/haemolyticus and one case of Pseudomonas aeruginosa. In one case (0.9%), Acinetobacter baumannii/haemolyticus was identified from preserving solution, with no bacteria found in the corneoscleral rim. Antibiotic susceptibility tests showed multi-drug resistance, except to colistin. In all cases where bacteria were detected, there was no keratitis or endophthalmitis after corneal transplantation.Conclusions: Although rare, bacteria can be identified from donor corneas or the preserving solution used in corneal transplantation. Therefore, caution is needed in all processes dealing with donor corneas. Empirical antibiotics that have sufficient antimicrobial activity to suppress multi-drug resistant bacteria should be selected in corneal transplantation.

Endophthalmitis secondary to donor to host infection in posterior lamellar keratoplasties: A systematic review

Donor to host transmission of infectious agents is a well-recognized entity, more commonly related to Endothelial Keratoplasty (EK) than to Penetrating Keratoplasty (PK), that involves complications ranging from interface keratitis to endophthalmitis. A systematic review of the literature was conducted to identify the published articles until December 2020 reporting cases of endophthalmitis secondary to corneal graft contamination in posterior lamellar keratoplasties (DSAEK and DMEK) along with donor characteristics, microbiological profile, treatment and outcomes. Each identified article was assessed to meet donor to host infection criteria, defined as a post-procedural infection in which the same microbiological agent was identified in both the donor corneoscleral rim or preservation medium and receptor ocular tissue. From 23 research articles, eight reports of endophthalmitis in nine patients following DSAEK or DMEK secondary to donor to host infection fulfilled the inclusion criteria. The majority were male and the median age was 72.0 (45.0-81.0) years old. Indications of surgery were primarily pseudophakic bullous keratopathy and Fuchs dystrophy. A fungal pathogen was identified in eight of nine patients. All the cases underwent surgical management with lenticule removal or endothelial plaque aspiration. The final corrected distance visual acuity (CDVA) in all cases was 20/200 or better. Endophthalmitis after an EK procedure is a rare complication whose outcome depends on the aggressive and precocious treatment. Identification of early signs of interface keratitis and lenticule removal seems mandatory in patients undergoing DSAEK or DMEK to prevent further involvement of the globe.

Current Perspectives on Corneal Transplantation

Disease of the cornea is the third leading cause of blindness worldwide. Corneal graft surgery is one of the most successful forms of solid organ transplantations in humans, with ever-increasing developments in surgical technique. To date, approximately 4504 corneal transplants are performed in the United Kingdom each year. While full thickness transplantation was the most commonly performed keratoplasty over the last few decades, selective lamellar transplantation of the diseased layers of the cornea has been universally adopted. This comprehensive review aims to provide an updated synthesis on different types of corneal transplantations, their treatment outcomes, and the associated complications of each procedure in both adult and paediatric population. In addition, we also present an up-to-date summary of the emerging therapeutic approaches that have the potential to reduce the demand for donor-dependent keratoplasty.

Killing efficacy of a new hypothermic corneal storage medium against the micro-organisms frequently found in human donor cornea intended for transplantation

Objective

To study the in vitro killing efficacy of Kerasave (AL.CHI.MI.A Srl), a medium provided with amphotericin B tablet for hypothermic storage of human donor corneas, against relevant contaminants associated with postkeratoplasty infections.

Methods and Analysis

The antimicrobial activity of Kerasave was determined after 0, 3 and 14 days of incubation at 2°C-8°C, inoculating Kerasave and the control medium with 10⁵-10⁶ colony forming units (CFU) of Candida albicans (CA), Fusarium solani (FS), Aspergillus brasiliensis (AB), Staphylococcus aureus (SA), Enterococcus faecalis (EF), Bacillus subtilis spizizenii (BS), Pseudomonas aeruginosa (PA), Enterobacter cloacae (EC) and Klebsiella pneumoniae (KP). Log₁₀ reductions at different time intervals were determined by assessing the number of viable CFU using the serial dilution plating technique.

Results

After 3 days, Kerasave induced the highest log₁₀ decrease in the concentrations of KP, PA, CA and EC (5.37, 4.15, 2.97 and 2.67, respectively; all p<0.001). The log₁₀ decreases of SA and EF were 2.27 and 2.11, respectively (all p<0.001). The lowest log₁₀ decrease was observed in BS, AB and FS concentrations (0.25, 0.30 and 0.67, respectively; p<0.001 for BS and AB and p=0.004 for FS). After 14 days, the microbial count of CA, FS, SA, EF, PA and EC further decreased (p=0.006 for FS; p<0.001 for the others).

Conclusion

Kerasave effectively reduced or kept unchanged the microbial concentration of almost all tested strains after 3 days. Thus, this novel medium represents a valuable tool to control the microbial contamination of human donor corneas during hypothermic storage for up to 14 days before transplantation.

Candida keratitis and endopthalmitis after corneal transplantation; two case reports, a novel regimen and literature overview of therapeutic options

PURPOSE

To evaluate treatment options for candida keratitis and endopthalmitis after corneal transplantation.

METHODS

Case reports and literature review.

RESULTS

Two patients with keratitis due to Candida glabrata/parapsilosis after corneal transplantation were successfully treated with a combination of topical voriconazole, intracameral voriconazole and amphotericin B, and systemic treatment with flucytosine.

CONCLUSIONS

Natamycine and voriconazole topically are preferred therapeutic options for the treatment of fungal keratitis. Systemic flucytosine is a useful alternative additive, particularly for countries where natamycine is not registered as a pharmaceutical agent.

Distribution, Prevalence, and Causative Agents of Fungal Keratitis: A Systematic Review and Meta-Analysis (1990 to 2020)

Objectives

This study aims to provide an overview of the prevalence, distribution, and causative agents of fungal keratitis.

Methods

All the articles with data on the prevalence of fungal keratitis among various patient groups from January 1, 1990 to May 27, 2020 were retrieved through a systematic search in PubMed, Scopus, Web of Science, and Google Scholar. Data were extracted, and the pooled estimated prevalence of fungal keratitis, yeast/mold infection, the spectrum and frequency of various causative agents, and the pooled estimated prevalence of mixed infections were calculated in general and in various countries (wherever possible) using meta-analysis.

Results

From 11,235 articles retrieved in the primary search step, 169 met the inclusion criteria. The 169 eligible articles were divided into six groups and analyzed separately. The pooled prevalence of fungal keratitis was variable with values ranging from 0.05% among postkeratoplasty patients to 43.01% among patients with a clinical suspicion of fungal keratitis. There was also a country-dependent variation in the prevalence (Paraguay: 50.1% (95% CI, 35.11, 65.00); Ireland: 1.1% (95% CI, 0.03, 6.04)). Except for postkeratoplasty cases (yeast: 51.80%), in all patient groups, molds were more common than yeasts. Although more than 50 distinct species of fungi have been found to cause fungal keratitis, Fusarium species followed by Aspergillus species were the most common causes of the disease. In general, 9.29% (95% CI, 6.52, 12.38) of fungal keratitis cases were mixed with bacterial agents.

Conclusion

The prevalence of fungal keratitis can vary dramatically depending on the patient groups and geographical origin; however, the dominant causative agents are generally similar.

Fungal keratitis: Mechanisms of infection and management strategies

Fungal corneal ulcers are an uncommon, yet challenging, cause of vision loss. In the United States, geographic location appears to dictate not only the incidence of fungal ulcers, but also the fungal genera most encountered. These patterns of infection can be linked to environmental factors and individual characteristics of fungal organisms. Successful management of fungal ulcers is dependent on an early diagnosis. New diagnostic modalities like confocal microscopy and polymerase chain reaction are being increasingly used to detect and identify infectious organisms. Several novel therapies, including crosslinking and light therapy, are currently being tested as alternatives to conventional antifungal medications. We explore the biology of Candida, Fusarium, and Aspergillus, the three most common genera of fungi causing corneal ulcers in the United States and discuss current treatment regimens for the management of fungal keratitis.

Corneal Donation: Current Guidelines and Future Direction

PURPOSE

This review aims to outline current practices and guidelines of corneal donation and eye banking, describes the implications of COVID-19 and emerging diseases on the corneal donor pool, and discusses future trends to improve and increase the efficiency of the processes involved in corneal donation and eye banking.

SUMMARY

Corneal screening, preservation, corneal storage, and prevention of systemic disease transmission from donor to recipient have been crucial in shaping the policies of the FDA and eye banks across the world. Eye banks globally have developed varying guidelines and criteria for evaluating the viability of donor corneas. Variables such as the age of the donor, medical history, and potential disease transmission are important screening parameters. While known infectious diseases may be transmissible through the cornea, emerging infectious diseases that are not well studied may be more transmissible than other infections. In particular, coronavirus has impacted corneal transplantation as SARS-CoV-2 expression has been detected in corneal tissue and conjunctiva. In recent years, partial-thickness corneal transplantations have been introduced. Lamellar grafts and other corneal layers are now utilized for transplantation of the specific areas that are damaged.

The Role of Corneal Donor Rim Fungal Cultures: Pro Side

ABSTRACT

Fungal infection after corneal transplantation is a rare but potentially devastating complication. It is of paramount concern for transplant surgeons and the eye banking community. The value of universal corneal rim cultures for keratoplasty remains controversial. In 2016, The Eye Bank Association for America reported an increasing trend in the incidence of post keratoplasty fungal infections and a higher incidence of post keratoplasty [penetrating keratoplasty and endothelial keratoplasty (EK)] fungal endophthalmitis cases. This increasing trend in rate over time from previous Eye Bank Association for America reports was disproportionately associated with EK and Candida species. Additionally, several studies confirmed a high correlation between positive corneoscleral donor rim fungal cultures and postoperative infections, and a higher risk to the mate eye of a cornea that had the positive fungal corneal rim culture and developed an infection. Positive fungal donor rim cultures-especially in the setting of interface keratitis after EK surgery-can raise the index of suspicion for a fungal cause and may help direct therapy, especially in the early stages, where the symptoms and signs of spread may not be obvious and obtaining direct cultures is inherently difficult without surgical intervention.

Antifungal Efficacy and Safety of Cycloheximide as a Supplement in Optisol-GS

PURPOSE

The incidence of fungal infection after corneal transplant has increased significantly in recent years, especially Candida spp. This study aimed to evaluate the efficacy and safety of the addition of cycloheximide in Optisol-GS media in decreasing the growth of Candida spp. strains.

METHODS

This in vitro laboratory efficacy study measured fungal colony growth in 24 vials of Optisol-GS that were divided into 6 groups of 4 vials each, as follows: (1) MIC/2 cycloheximide, (2) MIC cycloheximide, (3) MICx5 cycloheximide, (4) MICx10 cycloheximide, from MIC values obtained for each strain, (5) unsupplemented optisol-GS as a positive control (added inoculum), and (6) unsupplemented optisol-GS as a negative control (no inoculum). In each group was added Candida albicans, C. glabrata and C. parapsilosis, except in the negative control. The evaluated variables were fungal colony growth from the Optisol-GS vials, corneal endothelial cell density and endothelial cell viability at different concentrations of cycloheximide.

RESULTS

In the efficacy study, all strains showed a reduction in fungal cell growth from the second day at all evaluated concentrations of optisol-GS supplemented with cycloheximide, even at subinhibitory concentrations (MIC/2). For C. glabrata, the colony count was reduced to 99%. No evidence of corneal endothelial toxicity was found at any concentration, in the safety study, compared with the paired control.

CONCLUSION

The addition of cycloheximide to optisol-GS decreased the fungal growth, demonstrating fungicide action against C. glabrata and fungistatic action against C. albicans and C. parapsilosis. This drug did not demonstrate toxicity to the corneal endothelium at different concentrations.

Early postoperative infection following lamellar keratoplasty: a review

With the growing popularity of lamellar keratoplasty for selective replacement of diseased corneal tissue, it is important to understand the risk of developing an infection after the procedure. Although lesser than that postpenetrating keratoplasty, the reports on post lamellar keratoplasty infectious keratitis are not negligible. Trends of acute infections arising within 2 months of surgery are a subject of interest. Most of these infections are reported post Descemet's stripping endothelial keratoplasty with a preponderance of Candida species. A donor to host transmission of infection is not uncommon. Among the Candida cases, about 80% seem to occur due to a donor to host transmission. Infections presenting as or progressing to endophthalmitis lead to a poor visual outcome. Strict aseptic measures and protocols during corneal tissue harvesting, tissue processing, tissue storage and surgery are essential to prevent occurrence of these infections. After the infection has occurred, determining the aetiology and drug susceptibility through microbiological testing is vital. This helps to guide treatment protocols and hence determines final outcome of these cases. Most cases require some form of surgical management for resolution of infection, most often a graft removal and therapeutic keratoplasty. Secondary surgical interventions are performed to restore graft clarity and achieve a good final visual outcome.

Incidence of Fungal Infection in Positive Donor Rim Cultures after Corneal Transplantation

PURPOSE

To determine the clinical outcomes of corneal transplant patients that had positive rim cultures for fungi.

METHODS

Retrospective study.

RESULTS

Of 1276 rim cultures obtained between 2009 and 2019, 16 were positive for fungus (incidence of 1.25%). Clinical data were available for 12 patients. Candida and Cladosporium species were the most common organisms. Recipient ages ranged from 51 to 86 (median age 69 years; 9 males, 7 females). The most common surgery was Endothelial Keratoplasty (n = 8). There were no instances of fungal keratitis or endophthalmitis. Three patients were treated with prophylactic antimycotics. One patient developed bacterial keratitis. One patient had a varicella zoster virus reactivation without corneal involvement.

CONCLUSIONS

This study adds to the growing data on the low rate of fungal keratitis and endophthalmitis after a corneal transplant, even in the case of positive rim cultures. This study also suggests that positive rim cultures do not advance the risk of postoperative fungal infection in the recipient.

Endophthalmitis After Descemet Stripping Endothelial Keratoplasty: Microbiological Yield and Visual Outcomes

PURPOSE

To describe the clinical presentation, management, and visual outcomes of 6 eyes with endophthalmitis after Descemet stripping endothelial keratoplasty (DSEK).

DESIGN

Retrospective case series.

METHODS

Setting: Tertiary, academic eye center. StudyPopulation: Individuals developing endophthalmitis after DSEK at the Duke Eye Center from January 1, 2009, to January 1, 2018, with at least 6 months of follow-up. ObservationProcedure: Retrospective chart review. OutcomeMeasures: Diagnostic procedures, microbiological yield, and visual outcomes.

RESULTS

Six eyes of 6 patients were identified. Mean time from surgery to presentation was 51 days (range, 4-137 days). Dense vitreous opacities were present in all cases. Five of 6 cases (83%) had culture-proven infectious endophthalmitis (2 Candida glabrata, 2 coagulase-negative Staphylococcus, 1 Streptococcus pneumoniae). Aqueous tap yielded positive culture in 2 of 2 cases with adequate sample (100%); needle vitreous tap yielded positive culture in 0 of 3 cases. One eye underwent vitrectomy on presentation, and 3 eyes (50%) underwent subsequent vitrectomy for persistent endophthalmitis after a mean of 37 days. Mean pre-endophthalmitis visual acuity (VA) was 20/64; mean VA at 6 months was 20/2069 (average 15 ETDRS lines lost). VA at 6 months was light perception or no light perception in 3 of 6 cases (50%). One eye underwent enucleation at 6 months, and 1 eye became phthisical 1 year after endophthalmitis.

CONCLUSIONS

DSEK-related endophthalmitis may lead to severe vision loss, even with prompt and appropriate treatment. Aqueous tap had a higher culture yield than needle vitreous tap in our series.

Incidence and outcome of transplantation of fungal-culture-positive donor corneoscleral tissue in optical keratoplasty

PURPOSE

This study aims to determine the incidence of fungal-culture-positive corneoscleral donor rim in patients undergoing keratoplasty and evaluate clinical outcomes of eyes that received these contaminated donor tissues.

METHODS

Patients who had optical keratoplasty between 2006 and 2016 and were found to have fungal-culture-positive donor rim were included. Microbiological and eye bank records were reviewed to determine the incidence of positive fungal rim cultures. Data were collected on visual and clinical outcomes. The main outcome measures were fungal-culture-positive donor rim and development of fungal keratitis or endophthalmitis post keratoplasty. Long-term clinical outcome and associated complications were the secondary outcome measures.

RESULTS

Out of 9620 cases of corneal transplants, 145 (1.5%) had fungal-culture-positive donor rim. Candida was the most common organism, cultured in 127 (87.6%) cases. There were no cases of postoperative fungal keratitis or endophthalmitis. Median follow-up was 4.8 years (interquartile range 3.8-7.2 years). Only eight cases (5.5%) received prophylactic antifungal treatment. There were 34 (23.4%) cases of rejection, 13 (8.9%) developed glaucoma, and 7 (4.8%) developed late bacterial keratitis. At last follow-up, best corrected visual acuity was 20/60 or better in 88 cases (60.7%) and 115 eyes (79.3%) had a clear graft.

CONCLUSION

The incidence of fungal-culture-positive donor rim is extremely low. The risk of developing fungal keratitis or endophthalmitis in patients who received contaminated donor tissue was almost negligible. Further studies are warranted to prove whether prophylaxis or adding amphotericin B in Optisol-GS confers any added benefit.

Infectious keratitis after lamellar keratoplasty

Infectious keratitis after lamellar keratoplasty is a potentially devastating complication that may severely limit the visual and anatomical outcomes. The deep-seated location of the infiltrates, sequestration of the pathogenic microorganisms and limited penetration of the currently available antimicrobial agents often results in delayed diagnosis that may jeopardize the management in these cases. Fungal keratitis is more common as compared with bacterial or viral keratitis and classically presents as white interface infiltrates that may not be associated with significant inflammation. Confocal microscopy may help to establish a rapid diagnosis in such cases, and anterior segment optical coherence tomography may be used to determine the extent of infection and monitor its progression. Conservative measures such as topical antimicrobials and interface irrigation with antimicrobial agents may be done. Surgical intervention in the form of partial excision/removal of the graft in endothelial keratoplasty or a full-thickness keratoplasty is often required for the effective management of deep-seated infections. Timely diagnosis and intervention may result in complete resolution of infection in both anterior lamellar and endothelial keratoplasty. Infections after anterior lamellar keratoplasty have a fair prognosis, and a clear graft with functional visual acuity may be achieved in most cases. By contrast, infections after endothelial keratoplasty have a guarded prognosis, and the presence of concomitant endophthalmitis may further complicate the graft survival and visual outcomes.

A new storage medium containing amphotericin B versus Optisol-GS for preservation of human donor corneas

BACKGROUND/AIM

We compared the quality of human donor corneas stored in a cold storage medium containing 2.5 μg/ml of amphotericin B (Kerasave, AL.CHI.MI.A. S.R.L., Ponte San Nicolò, Italy) and Optisol-GS (Bausch & Lomb Inc., Bridgewater, NJ, USA) for 14 days.

METHODS

Sixteen pairs of human donor corneas were collected in Eusol-C (AL.CHI.MI.A. S.R.L., Ponte San Nicolò, Italy). Next, all tissues underwent the first evaluation that included the assessments of central corneal thickness (CCT), endothelial cell density (ECD) measured using both trypan blue staining and specular microscopy, endothelial cell (EC) mortality and morphology, and corneal transparency within 24 hours from recovery (Day 1). Afterwards, one cornea of each pair was transferred into Kerasave or Optisol-GS. ECD and CCT were also assessed at Day 7, and all the metrics were evaluated again at the end of the storage period (Day 14).

RESULTS

At all tested time points, no differences were found in the qualitative (corneal transparency, EC morphology) and quantitative metrics (ECD, CCT, EC mortality) between the Kerasave and the Optisol-GS storage groups. At Day 14, the corneas stored in Kerasave and Optisol-GS showed ECD of 2312±98 and 2335±128 cells/mm² (p=0.886), CCT of 717±17 and 697±19 μm (p=0.454) and central EC mortality of 0.54%±0.40% and 0.14%±0.14% (p=0.719), respectively.

CONCLUSIONS

The new amphotericin B-containing medium Kerasave was comparable to Optisol-GS in terms of preservation of corneal characteristics at 2-8°C for 14 days.

Acute endophthalmitis after penetrating and endothelial keratoplasty at a tertiary eye care center over a 13-year period

PURPOSE

To evaluate the clinico-microbiological profile, donor cornea risk factors, and outcomes of postkeratoplasty endophthalmitis at a tertiary care center.

METHODS

Retrospective analysis of charts of 28 consecutive patients (28 eyes) of acute endophthalmitis following either an endothelial keratoplasty (EK) or an optical penetrating keratoplasty (PK) surgery, performed between 2006 and 2018 (13-year period). Positive microbiology, identification and classification of predisposing factors, surveillance of utilized paired donors, treatment outcomes, and differences in the rate and severity of the event between optical penetrating and endothelial keratoplasty.

RESULTS

The estimated incidence of endophthalmitis was 0.23% in the entire cohort; it was 0.34% and 0.15%, after EK and PK, respectively (P = 0.049). The median time of endophthalmitis was 4.5 days postsurgery. Donor-related endophthalmitis was recognized in 7/28 (25%) eyes. Culture positivity was 68% (n = 19 of 28). Bacteria was isolated in 84% (n = 16 of 19) instances; Gram-negative bacilli were more common (87.5%; 14 of 16), and Pseudomonas species (50%; 7 of 14) was the most common Gram-negative bacterium. Majority (>75%) of the Gram-negative bacteria were resistant to all fluoroquinolones, aminoglycosides, 3rd generation cephalosporins, and meropenam; 1/3rd were resistant to imipenem; and 90% were sensitive to colistin. Treatment included intraocular antibiotic injections (96.4%), vitrectomy (42.9%), and therapeutic keratoplasty (50%). In 85.7% (24 of 28), globe was salvaged. The final vision was 20/200 or better in 39.1% (9 of 23) eyes.

CONCLUSION

EK carried a higher risk of endophthalmitis than PK in this cohort. Bacterial infection was more common in this series, with Gram negative bacilli being the commonest organisms. Multidrug resistance was common (~75%) in Gram negative isolates.

Excisional penetrating keratoplasty for fungal interface keratitis after endothelial keratoplasty: surgical timing and visual outcome

PURPOSE

In this paper, we describe two cases of fungal interface infectious keratitis (IIK) developed after endothelial keratoplasty (EK) who underwent delayed therapeutic penetrating keratoplasty (TPK) with a poor visual outcome. Furthermore, we conducted a review of the literature and analyzed the visual outcomes of TPK in relation to the time from IIK diagnosis.

METHODS

We searched the literature for fungal IIK cases occurred after EK and treated by TPK. We identified 17 cases of fungal IIK, mostly caused by Candida spp. (88%).

RESULTS

Infection was diagnosed at a median time of 21 (range 1-90 days) days after EK. The median lag time between infection diagnosis and TPK was 30 (range 7-393) days. The median distance corrected visual acuity (DCVA) measured 4-12 months after surgery was 20/40 (range 20/200-20/20). When TPK was performed within one month from diagnosis, the final median DCVA was 20/30 (range 20/100-20/20), with 83% of patients achieving ≥ 20/40 vision. When TPK was carried out later, the final median DCVA was 20/50 (range 20/200-20/22) with 44% of patients achieving ≥ 20/40 vision. One patient in the early surgery and four patients in the late surgery group showed postoperative DCVA ≤ 20/100 despite clear grafts.

CONCLUSION

TPK with removal of the sequestered infection is advocated as a safe and effective measure to treat a post-EK infection. Early surgery allows a reduced exposure time to infection and therefore may result in better visual outcomes and lower risk of complications caused by prolonged inflammation.

Microorganism detection and contamination rate of donor eyes in Japan

PURPOSE

To evaluate the microorganism detection and contamination rate of donor eyes.

STUDY DESIGN

Retrospective study.

METHODS

In this retrospective study, we reviewed all donor cornea data collected from Kyoto Prefectural University of Medicine (KPUM) Eye Bank, Kyoto, Japan from April 2015 to June 2018, including microbiologic data obtained from conjunctival swabs and preservation medium and findings of postoperative infection from the medical records.

RESULTS

During the study period, 77 eyes from 44 deceased individuals (mean age at time of death: 75 ± 17.3 years [range, 30-102 years]) were donated to the KPUM Eye Bank after being harvested using standard safety precautions and disinfection procedures. In 49 of the 77 eyes (63.6%), the conjunctival-swab culture revealed microorganisms, with the 3 most commonly detected being methicillin-resistant Staphylococcus epidermidis (MRSE), methicillin-sensitive S aureus (MSSA), and methicillin-resistant S aureus (MRSA). The data revealed positive microorganism detection in only 4 (5.2%) of the 77 donor-cornea storage-medium cultures. Positive microorganism detection was found in all the age groups, with no statistical difference between the groups (P > .05). In the eyes enucleated ≥ 2.5 h postmortem, a higher positive microorganism detection occurred (P = .03). During the postoperative follow-up period, there was no record of corneal infection.

CONCLUSIONS

The preenucleation conjunctival-swab-culture findings revealed that the rate of positive microorganism detection was similar for advanced-age and younger-age donors and that a shorter elapsed time from donor death to postmortem enucleation resulted in less donor-microorganism contamination.

Corneal graft failure: an update

Corneal graft surgery is one of the most successful forms of human solid-tissue transplantation, and nowadays, there is a worldwide expansion of the surgical volume of corneal grafts. This surgery is continuously evolving, with new surgical techniques and postoperative treatments that have considerably increased the chance of survival for the grafts. Despite the high rate of success, corneal transplantation is still complicated by a relevant risk of graft failure. This study investigates the causes that lead to the failure of the different corneal graft surgical techniques and provides an updated synthesis on this topic. A comprehensive review of the main pathological pathways that determine the failure of corneal grafts is provided, analysing the main risk factors and disclosing the survival rates of the principal form of corneal grafts. Our results revealed that penetrating keratoplasty has higher failure rates than lamellar keratoplasty, with immunological rejection being the leading cause of graft failure, followed by late endothelial failure (LEF) and ocular surface disorders. Postoperative glaucoma and dehiscence of the surgical wound represent other important causes of failure. Endothelial keratoplasty showed the lowest rates of failure in the mid-term, with LEF, detachment of the graft and primary graft failure representing the most common pathological reasons for failure.

Intensive care unit time and prolonged enucleation to processing interval are associated with donor cornea contamination

PURPOSE

To determine donor cornea contamination rate and to determine factors associated with cornea contamination. To assess the effect of hospitalization, intensive care unit (ICU) time, and antibiotic use on corneal contamination rate. To determine the spectrum of the contaminating microorganisms.

METHODS

The contamination rate of 212 corneas, obtained by enucleation from April 2014 to January 2015 in a single eye bank, was assessed retrospectively according to age, sex, cause of death, systemic antibiotic use, hospitalization time, ICU time, mechanical ventilation (MV), death to enucleation interval (DEI), enucleation to processing interval (EPI), and corneal epithelial exposure grading. The relative risk (RR) and adjusted RR with a 95% confidence interval were calculated using IBM-SPSS 20.0.

RESULTS

The contamination rate was 35.6% (n = 75). On multivariate analysis, ICU stay of 4 days or longer and enucleation to processing interval (EPI) greater than 7.4 h (RR 1.58, CI 0.96-2.60, P = 0.06) were associated with donor cornea contamination. Corneal contamination risk was highest from 4 to 6 days at the ICU (RR 3.40, CI 1.54-7.51, P < 0.01) and decreased after 7 days (RR 2.22, CI 1.00-4.93, P = 0.05). Coagulase-negative Staphylococcus was the most common isolated bacteria (69.6%). The frequency of gentamicin-resistant bacteria was higher among patients who stayed 4 days or longer at the ICU.

CONCLUSION

Patients staying at the intensive care unit 4 days or longer showed increased risk of corneal contamination. This is an important result to consider further indication for cornea donation.

Efficacy of Amphotericin B in Corneal Preservation Media After Extended Frozen Storage

PURPOSE

To investigate the antimycotic activity of amphotericin B deoxycholate that has been previously frozen for 28 days before supplementation of Optisol-GS.

METHODS

Triplicate Optisol-GS samples were inoculated with 10 colony-forming units (CFU) of Candida albicans. Each set of triplicate cultures was supplemented with 2.5 μg/mL of amphotericin B that was either freshly resuspended and never frozen, frozen overnight at -20°C and thawed, or frozen at -20°C for 4 weeks and thawed. The cultures were stored at 4°C, with aliquots taken at 0, 6, 24, and 72 hours for quantification. The efficacy of each preparation of amphotericin B in reducing C. albicans growth was assessed at these time points.

RESULTS

Six hours after antifungal supplementation, there was a 1.33 log10 CFU reduction with freshly resuspended amphotericin B, compared with a 1.31 log10 reduction with amphotericin B that was frozen overnight (P = 0.20) and a 1.18 log10 reduction with amphotericin B that was frozen for 4 weeks (P = 0.05). After 72 hours, there was a 2.72 log10 CFU reduction with freshly resuspended amphotericin B, a 2.64 log10 CFU reduction with amphotericin B that was frozen overnight (P = 0.45), and a 2.18 log10 CFU reduction with amphotericin B that was frozen for 4 weeks (P = 0.05).

CONCLUSIONS

Previously frozen amphotericin B remains highly effective against C. albicans. Optisol-GS supplemented with 2.5 μg/mL amphotericin B that was frozen for 4 weeks at -20°C resulted in >90% CFU reduction by 6 hours and >99% reduction by 72 hours.

Bibliometric and visualized analysis of global research on fungal keratitis from 1959 to 2019

BACKGROUND

Fungal keratitis is one of the leading causes of ocular morbidity. The prognosis of fungal keratitis is poorer than many other forms of keratitis but the research of which relatively lags behind. We conducted a bibliometric and visualized analysis in order to characterize the overall status, general trends and current foci of keratomycosis research field.

METHODS

Literature database ranged from 1959 to 2019 was obtained from web of science core collection and analyzed by Citespace and VOSviewer software.

RESULTS

A total of 1906 papers of fungal keratitis were retrieved and derived a 27,917 references document set. The number of publications increased rapidly in past 30 years. Cornea was the journal published most papers of keratomycosis. The leading countries were United States of America (USA), India and Peoples Republic of China (PRC), from where came the most productive and most cited institutions and authors. Co-cited reference analysis revealed the most cited manuscripts were concerned about epidemiology or spectrum. Lens-associated Fusarium, amphotericin B, voriconazole, corneal cross-linking, predisposing factor are some of the high frequency topics in clustered co-cited reference analysis and co-occurrence keywords analysis. Burst detection analysis of keywords showed ocular drug delivery was the new research foci.

CONCLUSION

From this study, we received an overall view to the current status, trends and hot spots of fungal keratitis research field. Visualized bibliometric analysis is an efficient way for literature learning and useful for future researchers.

Performance of New Hypothermic Corneal Storage Media With an Antimycotic Tablet in Comparison to Traditional Hypothermic Media During Simulated Eye Bank Processing

PURPOSE

To compare the performance of Kerasave (AL.CHI.MI.A. S.R.L., Ponte San Nicolò, Italy) containing 2.5 μg/mL of amphotericin B and Optisol-GS (Bausch & Lomb, Bridgewater, NJ) cold corneal storage media on donor corneas during routine eye bank procedures.

METHODS

Forty-four paired donor corneas were preserved after swab sample collection and povidone-iodine decontamination. Right and left corneas were immersed in Kerasave and Optisol-GS, respectively, and stored at 4°C before the initial evaluation. Paired corneas were assigned to processing subgroups for penetrating keratoplasty (n = 20), Descemet stripping automated endothelial keratoplasty (n = 14), or Descemet membrane endothelial keratoplasty (n = 10). Endothelial cell density, central corneal thickness, slit-lamp examination, and endothelial cell damage were assessed at different intervals. Sterility testing was performed on media samples.

RESULTS

At the initial evaluation, after 25.6 ± 3.2 hours of storage, the mean central corneal thickness of all corneas in Kerasave (n = 22) was greater than those in Optisol-GS (n = 22) (571 ± 12 μm vs. 526 ± 10 μm, respectively; P = 0.006). All other metrics were comparable between Kerasave and Optisol-GS in processing subgroups at all time intervals. Corneal swabs were positive in 90% of corneas before decontamination with povidone-iodine. At the initial evaluation, fungal contamination was detected in 24% and 19% of Kerasave and Optisol-GS, respectively. At the final evaluation, no fungi was detected in Kerasave and 1 Optisol-GS sample was positive (P = 0.999).

CONCLUSIONS

Metrics of corneas stored in Kerasave and Optisol-GS were comparable. Kerasave might be considered an antifungal-possessing alternative to Optisol-GS.

Late-onset fungal interface keratitis following endothelial keratoplasty with positive donor fungal culture

Purpose

To describe late-onset fungal keratitis after Descemet's stripping endothelial keratoplasty (DSEK) with positive fungal culture of the donor corneal rim.

Observations

A case report of a patient undergoing DSEK is described whereby the donor corneal rim culture grew fungus. No infection was initially noted, but the patient developed fungal keratitis 1 year after the original DSEK procedure, despite prophylactic treatment at the time of the positive donor culture. The patient responded to antifungal therapy, but fungal keratitis recurred following completion of a 1-year course of antifungal treatment. The patient eventually underwent full thickness keratoplasty.

Conclusions and importance

A positive fungal culture of the donor rim tissue at the time of endothelial keratoplasty is a risk factor for fungal keratitis. Even with prophylactic antifungal treatment, fungal keratitis may eventually develop as late as 1 year after the initial endothelial keratoplasty procedure. Treatment may need to be aggressive, but keratitis may recur despite resolution with antifungal treatment.