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.

Exploration of the ocular surface infection by SARS-CoV-2 and implications for corneal donation: An ex vivo study.

BACKGROUND: The risk of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) transmission through corneal graft is an ongoing debate and leads to strict restrictions in corneas procurement, leading to a major decrease in eye banking activity. The aims of this study are to specifically assess the capacity of human cornea to be infected by SARS-CoV-2 and promote its replication ex vivo, and to evaluate the real-life risk of corneal contamination by detecting SARS-CoV-2 RNA in corneas retrieved in donors diagnosed with Coronavirus Disease 2019 (COVID-19) and nonaffected donors. METHODS AND FINDINGS: To assess the capacity of human cornea to be infected by SARS-CoV-2, the expression pattern of SARS-CoV-2 receptor angiotensin-converting enzyme 2 (ACE-2) and activators TMPRSS2 and Cathepsins B and L in ocular surface tissues from nonaffected donors was explored by immunohistochemistry (n = 10 corneas, 78 ± 11 years, 40% female) and qPCR (n = 5 corneas, 80 ± 12 years, 40% female). Additionally, 5 freshly excised corneas (80 ± 12 years, 40% female) were infected ex vivo with highly concentrated SARS-CoV-2 solution (106 median tissue culture infectious dose (TCID50)/mL). Viral RNA was extracted from tissues and culture media and quantified by reverse transcription quantitative PCR (RT-qPCR) (viral RNA copies) 30 minutes (H0) and 24 hours (H24) after infection. To assess the risk of corneal contamination by SARS-CoV-2, viral RNA was tested by RT-qPCR (Ct value) in both corneas and organ culture media from 14 donors diagnosed with COVID-19 (74 ± 10 years, 29% female) and 26 healthy donors (79 ± 13 years, 57% female), and in organ culture media only from 133 consecutive nonaffected donors from 2 eye banks (73 ± 13 years, 29% female). The expression of receptor and activators was variable among samples at both protein and mRNA level. Based on immunohistochemistry findings, ACE-2 was localized mainly in the most superficial epithelial cells of peripheral cornea, limbus, and conjunctiva, whereas TMPRSS2 was mostly expressed in all layers of bulbar conjunctiva. A significant increase in total and positive strands of IP4 RNA sequence (RdRp viral gene) was observed from 30 minutes to 24 hours postinfection in central cornea (1.1 × 108 [95% CI: 6.4 × 107 to 2.4 × 108] to 3.0 × 109 [1.4 × 109 to 5.3 × 109], p = 0.0039 and 2.2 × 107 [1.4 × 107 to 3.6 × 107] to 5.1 × 107 [2.9 × 107 to 7.5 × 107], p = 0.0117, respectively) and in corneoscleral rim (4.5 × 109 [2.7 × 109 to 9.6 × 109] to 3.9 × 1010 [2.6 × 1010 to 4.4 × 1010], p = 0.0039 and 3.1 × 108 [1.2 × 108 to 5.3 × 108] to 7.8 × 108 [3.9 × 108 to 9.9 × 108], p = 0.0391, respectively). Viral RNA copies in ex vivo corneas were highly variable from one donor to another. Finally, viral RNA was detected in 3 out of 28 corneas (11%) from donors diagnosed with COVID-19. All samples from the 159 nonaffected donors were negative for SARS-CoV-2 RNA. The main limitation of this study relates to the limited sample size, due to limited access to donors diagnosed with COVID-19 and concomitant decrease in the procurement corneas from nonaffected donors. CONCLUSIONS: In this study, we observed the expression of SARS-CoV-2 receptors and activators at the human ocular surface and a variable increase in viral RNA copies 24 hours after experimental infection of freshly excised human corneas. We also found viral RNA only in a very limited percentage of donors with positive nasopharyngeal PCR. The low rate of positivity in donors diagnosed with COVID-19 calls into question the utility of donor selection algorithms. TRIAL REGISTRATION: Agence de la Biomédecine, PFS-20-011 https://www.agence-biomedecine.fr/.

Corneal Involvement in HIV-infected Individuals.

Corneal involvement in HIV-infected individuals may be broadly classified into two categories, namely, infectious and noninfectious with the vast majority of manifestations occurring in the former. In this article, we shall focus on these two categories and strive to highlight those presentations that should alert the clinician to suspect underlying HIV infection. Infectious group mainly consists of Herpitic group of viral infections. Bacterial causes may be due to Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeroginosa, alpha hemolytic Streptococcus, Micrococcus and Bacillus. Fungalf keratitis in HIV-infected individuals depends on the geographic locations from which patient comes. Microsporidia and Acanthamoeba are common Protozoal causes. Non-infective inflammatory causes include peripheral ulcerative keratitis, keratoconjunctivitis sicca, and squamous cell carcinoma of the conjunctiva. Severity which is abnormally severe or very minimally reactive makes the clinician suspect of immunosuppression.

Late Corneal Stromal Deposits After COVID-19.

ABSTRACT: We present 2 cases of striking stromal corneal infiltrates months after COVID-19 infection. While we cannot prove that these infiltrates are caused by or directly related to COVID-19, we did not find any other plausible cause that could explain these ophthalmic signs. In these cases, the ongoing process was detected in relatively early stages due to scheduled visits with patients and responded positively to prednisolone acetate 1% ophthalmic suspension. However, we do not know the response to treatment in more advanced cases.

Bilateral Acute Anterior Uveitis and Corneal Punctate Epitheliopathy in Children Diagnosed with Multisystem Inflammatory Syndrome Secondary to COVID-19.

Purpose: To report bilateral anterior uveitis and corneal punctate epitheliopathy in children with multisystem inflammatory syndrome (MIS-C) secondary to coronavirus disease (COVID-19).Participants and methods: Five patients who were positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies and diagnosed with MIS-C were evaluated. Ophthalmologic examinations were performed in order to reveal ocular findings in MIS-C disease.Results: Slit lamp examinations showed bilateral non-granulomatous acute anterior uveitis in all patients and severe corneal punctuate epitheliopathy in three of the patients. These ocular findings mostly disappeared with treatment in about one week.Conclusion: Bilateral non-granulomatous acute anterior uveitis and dry eye can be detected in patients diagnosed with MIS-C secondary to COVID-19. Even if generally, COVID-19 is not a life threatening disease in children by itself, inflammatory ocular manifestations can be detected in MIS-C secondary to COVID-19.

Adenovirus and the Cornea: More Than Meets the Eye.

Human adenoviruses cause disease at multiple mucosal sites, including the respiratory, gastrointestinal, and genitourinary tracts, and are common agents of conjunctivitis. One site of infection that has received sparse attention is the cornea, a transparent tissue and the window of the eye. While most adenovirus infections are self-limited, corneal inflammation (keratitis) due to adenovirus can persist or recur for months to years after infection, leading to reduced vision, discomfort, and light sensitivity. Topical corticosteroids effectively suppress late adenovirus keratitis but are associated with vision-threatening side effects. In this short review, we summarize current knowledge on infection of the cornea by adenoviruses, including corneal epithelial cell receptors and determinants of corneal tropism. We briefly discuss mechanisms of stromal keratitis due to adenovirus infection, and review an emerging therapy to mitigate adenovirus corneal infections based on evolving knowledge of corneal epithelial receptor usage.

Acute graft rejection in a COVID-19 patient: Co-incidence or causal association?

A 32-year-old man with a clear and compact graft following a penetrating keratoplasty 6 years back, developed an episode of acute graft rejection, coinciding with the COVID-19 disease. Subsequent to the infection with the novel coronavirus, he developed symptoms of acute graft rejection concurrent with the development of respiratory distress and peak systemic symptoms. This was the phase of cytokine storm as evidenced by the raised inflammatory markers in his blood tests. Such a case of acute corneal graft rejection coinciding with SARS-CoV-2 infection has been reported only once in the literature and this unique association needs to be researched further.

Absence of Severe Acute Respiratory Syndrome-Coronavirus-2 RNA in Human Corneal Tissues.

PURPOSE: To examine corneal tissue for severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) positivity regarding implications for tissue procurement, processing, corneal transplantation, and ocular surgery on healthy patients. We performed quantitative reverse transcription-polymerase chain reaction qRT-PCR-testing for SARS-CoV-2 RNA on corneal stroma and endothelium, bulbar conjunctiva, conjunctival fluid swabs, anterior chamber fluid, and corneal epithelium of coronavirus disease 2019 (COVID-19) postmortem donors. METHODS: Included in this study were 10 bulbi of 5 COVID-19 patients who died because of respiratory insufficiency. Informed consent and institutional review board approval was obtained before this study (241/2020BO2). SARS-CoV-2 was detected by using a pharyngeal swab and bronchoalveolar lavage. Tissue procurement and tissue preparation were performed with personal protective equipment (PPE) and the necessary protective measures. qRT-PCR-testing was performed for each of the abovementioned tissues and intraocular fluids. RESULTS: The qRT-PCRs yielded no viral RNA in the following ocular tissues and intraocular fluid: corneal stroma and endothelium, bulbar-limbal conjunctiva, conjunctival fluid swabs, anterior chamber fluid, and corneal epithelium. CONCLUSIONS: In this study, no SARS-CoV-2-RNA was detected in conjunctiva, anterior chamber fluid, and corneal tissues (endothelium, stroma, and epithelium) of COVID-19 donors. This implicates that the risk for SARS-CoV-2 infection using corneal or conjunctival tissue is very low. However, further studies on a higher number of COVID-19 patients are necessary to confirm these results. This might be of high importance for donor tissue procurement, processing, and corneal transplantation.

Drug-encapsulated carbon (DECON): A novel platform for enhanced drug delivery.

Current drug-delivery systems are designed primarily for parenteral applications and are either lipid or polymer drug conjugates. In our quest to inhibit herpes simplex virus infection via the compounds found in commonly used cosmetic products, we found that activated carbon particles inhibit infection and, in addition, substantially improve topical delivery and, hence, the efficacy of a common antiviral drug, acyclovir (ACV). Our in vitro studies demonstrate that highly porous carbon structures trapped virions, blocked infection and substantially improved efficacy when ACV was loaded onto them. Also, using murine models of corneal and genital herpes infections, we show that the topical use of drug-encapsulated carbon (DECON) reduced dosing frequency, shortened treatment duration, and exhibited higher therapeutic efficacy than currently approved topical or systemic antivirals alone. DECON is a nontoxic, cost-effective and nonimmunogenic alternative to current topical drug-delivery systems that is uniquely triggered for drug release by virus trapping.

Bilateral herpes simplex keratitis: lactation a trigger for recurrence!

A young lactating woman presenting to us with simultaneous bilateral corneal lesions was clinically diagnosed to have herpes simplex keratitis, which was confirmed by herpes simplex virus (HSV) PCR. The patient was administered topical and systemic acyclovir therapy and therapeutic penetrating keratoplasty was done in right eye. She was advised to continue breast feeding under strict hygienic conditions. Diagnosis and management of HSV keratitis in a lactating patient can be particularly challenging for both clinician and patient and adoption of a multidisciplinary approach is necessary to ensure safety of mother and child. At 3 months follow-up, the baby was clinically healthy, there were no side effects of acyclovir therapy in the mother or the baby and the patient showed no evidence of recurrence in either eye.

Long-term outcomes of penetrating keratoplasty for corneal complications of herpes zoster ophthalmicus.

BACKGROUND/AIM: To review the long-term outcomes of penetrating keratoplasty (PKP) for corneal complications of herpes zoster ophthalmicus (HZO). METHODS: We reviewed the medical records of 53 eyes of 53 patients who underwent PKP due to corneal complications of HZO at the Kellogg Eye Center. RESULTS: The mean age of patients at the time of PKP was 68.0±16.4 years, with a follow-up of 4.0±3.8 years and quiescent period of 6.5±5.3 years from active HZO to PKP. Preoperatively, 25 (47.2%) eyes were completely anaesthetic, while 16 (30.2%) had deep corneal neovascularisation in four quadrants. Comorbid ocular disease, including cataract, glaucoma and macular disease, was present in 25 (47.2%) eyes. Twenty patients (37.8%) received acyclovir for the entire postoperative period. There were no recurrences of zoster keratitis in any eye. The most common complications were difficulty healing the ocular surface (12/53, 22.6%) and glaucoma (14/53, 26.4%). Thirty per cent of the eyes required one or more additional postoperative procedures, most commonly tarsorrhaphy (10/53, 18.9%) and amniotic membrane graft (6/53, 11.3%). At 1, 2-4 and ≥5 years, 94%, 82% and 70% grafts remained clear, respectively. Visual acuity improved at 1 year postoperatively (p<0.0001), but this improvement was not sustained. There was no significant benefit of long-term acyclovir on visual acuity (p=0.2132) or graft survival (p=0.241). CONCLUSIONS: Even in eyes with significant preoperative risk factors, PKP for the corneal complications of HZO can achieve favourable tectonic and visual results. Although most grafts remained clear, long-term visual potential may be limited by comorbid ocular diseases. Prophylactic postoperative oral acyclovir did not improve outcomes.

Human Herpesvirus-6 corneal Endotheliitis after intravitreal injection of Ranibizumab.

BACKGROUND: To report the first case of human herpesvirus-6 (HHV-6) corneal endotheliitis that developed after intravitreal ranibizumab injections. CASE PRESENTATION: A 63-year-old man with a medical history of diabetes and systemic steroid treatment for bullous pemphigoid had been receiving intravitreal injections of ranibizumab in the left eye for 2 years according to a Pro Re Nata treatment regimen for macular edema associated with branch retinal vein occlusion. Twenty days after the last injection, the patient presented with pain and decreased visual acuity in his left eye. His best corrected visual acuity in the left eye was 2/200, and intraocular pressure was 45 mmHg with edema of the central stromal cornea, mild conjunctival injection, intermediate keratic precipitates, and mild anterior chamber reaction. HHV-6 DNA was detected in the aqueous humor using multiplex strip polymerase chain reaction, and it was identified as variant A, HHV-6A. A diagnosis of HHV-6A-associated corneal endotheliitis was made. Oral valganciclovir and topical ganciclovir therapy was initiated with good resolution of all symptoms and signs. CONCLUSIONS: HHV-6A can be a possible complication of intravitreal ranibizumab therapy. To the best of our knowledge, this is the first reported case of HHV-6A corneal endotheliitis following intravitreal ranibizumab injection.

Cytomegalovirus Corneal Endotheliitis After Descemet Membrane Endothelial Keratoplasty.

PURPOSE: To describe 4 cases of cytomegalovirus (CMV) corneal endotheliitis occurring after Descemet membrane endothelial keratoplasty (DMEK). METHODS: This is a retrospective, interventional case series. Case records of 4 patients (one eye each) diagnosed with CMV corneal endotheliitis after DMEK were reviewed retrospectively. Presenting clinical features, treatment, and outcomes were examined. RESULTS: Patients' age ranged from 68 to 77 years. Three patients underwent DMEK for failed corneal grafts and 1 for pseudophakic bullous keratopathy. Time from DMEK to presentation ranged from 5 to 15 weeks. Presenting features included corneal edema, pigmented keratic precipitates, mild anterior chamber inflammation, and raised intraocular pressure. Two cases were initially misdiagnosed as graft rejection and treated with corticosteroids. Both worsened, and delayed diagnoses of CMV corneal endotheliitis were made. The two other cases were diagnosed correctly at initial presentation. All cases were confirmed by anterior chamber paracentesis and polymerase chain reaction testing for CMV. All cases were treated initially with topical ganciclovir gel and oral valganciclovir. Three cases showed clinical resolution. Final corrected visual acuity ranged from 20/25 to 20/40. One case failed to respond to topical ganciclovir gel, oral valganciclovir, and intravenous ganciclovir and foscarnet. This patient declined further systemic treatment and was maintained on topical ganciclovir only but subsequently showed spontaneous resolution 3 months later. CONCLUSION: CMV corneal endotheliitis may occur after DMEK and can closely mimic graft rejection. Polymerase chain reaction testing of aqueous humor is advised for suspect cases. A high index of suspicion is important for prompt diagnosis and initiation of appropriate antiviral treatment.

Pathological processes activated by herpes simplex virus-1 (HSV-1) infection in the cornea.

Herpes simplex virus type-1 (HSV-1) is a ubiquitous pathogen that infects a large majority of the human population worldwide. It is also a leading cause of infection-related blindness in the developed world. HSV-1 infection of the cornea begins with viral entry into resident cells via a multistep process that involves interaction of viral glycoproteins and host cell surface receptors. Once inside, HSV-1 infection induces a chronic immune-inflammatory response resulting in corneal scarring, thinning and neovascularization. This leads to development of various ocular diseases such as herpes stromal keratitis, resulting in visual impairment and eventual blindness. HSV-1 can also invade the central nervous system and lead to encephalitis, a relatively common cause of sporadic fetal encephalitis worldwide. In this review, we discuss the pathological processes activated by corneal HSV-1 infection and existing antiviral therapies as well as novel therapeutic options currently under development.

Effect of storage time and temperature on the detection of Pseudomonas aeruginosa, Acanthamoeba and Herpes Simplex Virus from corneal impression membranes.

The effect of storage time and temperature on the recovery of pathogen DNA from polytetrafluorethylene (PTFE) was investigated. PTFE impression membranes were inoculated with Pseudomonas aeruginosa, Herpes Simplex Virus-1 (HSV-1) or Acanthamoeba and stored at -70 °C, -20 °C, +4 °C or +35 °C. PCR was performed on days 0, 1, 2, 3, 7 and months 1, 3 and 10 post-inoculation. We found no reduction in the DNA recovery of any of the studied microorganisms for the first 3 days of storage up to +35 °C. For HSV-1 and P. aeruginosa, storage for 3 months at +35 °C was associated with a significant reduction in DNA recovery (P<0.001), but not at +4 °C, -20 °C or -70 °C for 1 month for P. aeruginosa and for 10 months for HSV-1. Acanthamoeba DNA recovery was not affected by any storage parameters (P=0.203). These results will inform the investigation of microbial keratitis where access to microbiological testing is not readily available.

Topical ganciclovir treatment post-Descemet's stripping automated endothelial keratoplasty for patients with bullous keratopathy induced by cytomegalovirus.

BACKGROUND/AIMS: To investigate the efficacy of topical ganciclovir (GCV) for preventing disease recurrence and improving the surgical outcome post-Descemet's stripping automated endothelial keratoplasty (DSAEK) in patients with cytomegalovirus (CMV) endotheliitis. METHODS: This prospective, non-comparative case series study involved six eyes of six patients with endothelial decompensation due to CMV endotheliitis who underwent DSAEK, followed by a continuous, four to six times daily, topical administration of 0.5% GCV. Patient demographics, clinical history, and preoperative and postoperative examination (including any recurrence of CMV endotheliitis post-DSAEK), best corrected visual acuity (BCVA), intraocular pressure (IOP), graft survival rate and endothelial cell density (ECD) were examined. RESULTS: No recurrence of CMV endotheliitis was detected post-DSAEK. The mean follow-up period was 40 months (range, 12-60 months). The mean preoperative BCVA was 1.52±0.68 LogMAR (range, 0.52-2.40 LogMAR), yet it had significantly improved to 0.15±0.16 LogMAR (range: -0.08 to 0.30 LogMAR) by 1 year postoperative (P<0.01). In all patients, IOP was well controlled (10-20 mm Hg) postsurgery. The mean preoperative donor ECD was 2692±177 cells/mm2, and the mean postoperative ECD was 1974, 1771 and 1174 cells/mm2 for the ECD loss of 26%, 33% and 54% at 6, 12 and 36 months, respectively. No adverse effects were observed associated with the long-term topical administration of GCV. CONCLUSION: The continuous topical application of 0.5% GCV was found to be effective for preventing the recurrence of CMV endotheliitis, and it provided the optimal mid-term clinical outcomes post-DSAEK in patients with CMV endotheliitis. TRIAL REGISTRATION NUMBER: UMIN000026746.

Descemet Stripping Automated Endothelial Keratoplasty Outcomes in Patients With Cytomegalovirus Endotheliitis.

PURPOSE: There is currently limited information regarding the outcomes of endothelial keratoplasty in eyes with cytomegalovirus (CMV) endotheliitis. We report the results of Descemet stripping automated endothelial keratoplasty (DSAEK) for endothelial failure secondary to CMV. METHODS: This is a retrospective review of 4 eyes of 4 patients with CMV endotheliitis and DSAEK. CMV was confirmed in each case by a positive aqueous tap on qualitative polymerase chain reaction. The clinical characteristics of the patients and postoperative outcomes were studied. RESULTS: The mean age of the 4 patients was 69.6 ± 8.1 years. Two were ethnically Vietnamese, 1 Chinese, and 1 Lebanese. All were immunocompetent. Three eyes had presented with hypertensive uveitis and 1 with bullous keratopathy. Twelve DSAEKs were performed in total in the 4 eyes. Five grafts were performed without any perioperative treatment with oral valganciclovir. All subsequently failed after a mean of 8.0 ± 3.8 months. Seven grafts were managed with oral valganciclovir; 2 of these grafts failed after 18 and 37 months, and 1 graft had primary graft failure. Four grafts are currently surviving, despite an episode of CMV reactivation in 2 grafts. CONCLUSIONS: In cases of unexplained corneal decompensation or early graft failure after uncomplicated DSAEK, a diagnosis of CMV infection must be considered. Subsequent management of DSAEK in such cases remains challenging. The postoperative course can be complicated by CMV reactivation, which may masquerade either as graft rejection or graft failure. Long-term treatment with oral valganciclovir or topical ganciclovir may be required to decrease graft failure rates.

IL-6 Contributes to Corneal Nerve Degeneration after Herpes Simplex Virus Type I Infection.

Herpes simplex virus type 1 (HSV-1) is a leading cause of neurotrophic keratitis characterized by decreased corneal sensation because of damage to the corneal sensory fibers. We and others have reported regression of corneal nerves during acute HSV-1 infection. To determine whether denervation is caused directly by the virus or indirectly by the elicited immune response, mice were infected with HSV-1 and topically treated with dexamethasone (DEX) or control eye drops. Corneal sensitivity was measured using a Cochet-Bonnet esthesiometer and nerve network structure via immunohistochemistry. Corneas were assessed for viral content by plaque assay, leukocyte influx by flow cytometry, and content of chemokines and inflammatory cytokines by suspension array. DEX significantly preserved corneal nerve structure and sensitivity on infection. DEX reduced myeloid and T-cell populations in the cornea and did not affect viral contents at 4 and 8 days post infection. The elevated protein contents of chemokines and inflammatory cytokines on infection were greatly suppressed by DEX. Subconjunctival delivery of neutralizing antibody against IL-6 to infected mice resulted in partial preservation of corneal nerve structure and sensitivity. Our study supports a role for the immune response, but not local virus replication in the development of HSV-1-induced neurotrophic keratitis. IL-6 is one of the factors produced by the elicited inflammatory response to HSV-1 infection contributing to nerve regression.