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

Quality assurance in corneal transplants: Donor cornea assessment and oversight

The cornea is the most frequently transplanted human tissue, and corneal transplantation represents the most successful allogeneic transplant worldwide. In order to obtain good surgical outcome and visual rehabilitation and to ensure the safety of the recipient, accurate screening of donors and donor tissues is necessary throughout the process. This mitigates the risks of transmission to the recipient, including infectious diseases and environmental contaminants, and ensures high optical and functional quality of the tissues. The process can be divided into 3 stages: (1) donor evaluation and selection before tissue harvest performed by the retrieval team, (2) tissue analysis during the storage phase conducted by the eye bank technicians after the retrieval, and, (3) tissue quality checks undertaken by the surgeons in the operating room before transplantation. Although process improvements over the years have greatly enhanced safety, quality, and outcome of the corneal transplants, a lack of standardization between centers during certain phases of the process still remains, and may impact on the quality and number of transplanted corneas. Here we detail the donor screening process for the retrieval teams, eye bank operators. and ophthalmic surgeons and examine the limitations associated with each of these stages.

Long-Term Corneal Endothelial Parameters of COVID-19 Patients With Ocular Surface Symptoms

PURPOSE

This study aimed to investigate the long-term effects of COVID-19 on corneal endothelial cell morphology in patients with ocular symptoms to assess possible corneal involvement in patients who recovered.

METHODS

The COVID-19 group included patients diagnosed and treated at Istanbul University Cerrahpasa Medical Faculty with confirmed SARS-CoV-2 infection and ocular irritation symptoms. The control group was comprised of age- and sex-matched individuals. The controls had no ocular pathologies. Noncontact specular microscopy (Konan Cell Check SL, Hyogo, Japan) was performed using the center method after 156 ± 16 days of COVID-19 diagnosis. Parameters such as endothelial cell density (ECD), hexagonality (HEX), coefficient of variation, and central corneal thickness were analyzed.

RESULTS

Specular microscopy results of 54 COVID-19 patients with ocular irritation symptoms and 72 controls were evaluated. Ocular symptoms in COVID-19 patients included conjunctival hyperemia, foreign body sensation, tearing, ocular secretion, and chemosis. Mean (±SD) ECD was 2770 ± 31 (cells/mm2) in the COVID-19 group and 2897 ± 26 in the control group, and mean (±SD) HEX was 46.52 ± 6.38 in the COVID-19 group and 58.22 ± 13.94 in the control group. COVID-19 patients exhibited significantly lower endothelial ECD and HEX levels than controls (P = 0.003 and P < 0.001, respectively). Coefficient of variation and central corneal thickness analyses did not reach statistical significance.

CONCLUSIONS

COVID-19 can cause long-term alterations in the corneal endothelial cells, leading to decreased ECD and HEX. Future research should focus on the long-term implications of COVID-19 on the corneal health and visual outcomes.

Histopathology and SARS-CoV-2 Cellular Localization in Eye Tissues of COVID-19 Autopsies

Ophthalmic manifestations and tissue tropism of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been reported in association with coronavirus disease 2019 (COVID-19), but the pathology and cellular localization of SARS-CoV-2 are not well characterized. The objective of this study was to evaluate macroscopic and microscopic changes and investigate cellular localization of SARS-CoV-2 across ocular tissues at autopsy. Ocular tissues were obtained from 25 patients with COVID-19 at autopsy. SARS-CoV-2 nucleocapsid gene RNA was previously quantified by droplet digital PCR from one eye. Herein, contralateral eyes from 21 patients were fixed in formalin and subject to histopathologic examination. Sections of the droplet digital PCR-positive eyes from four other patients were evaluated by in situ hybridization to determine the cellular localization of SARS-CoV-2 spike gene RNA. Histopathologic abnormalities, including cytoid bodies, vascular changes, and retinal edema, with minimal or no inflammation in ocular tissues were observed in all 21 cases evaluated. In situ hybridization localized SARS-CoV-2 RNA to neuronal cells of the retinal inner and outer layers, ganglion cells, corneal epithelia, scleral fibroblasts, and oligodendrocytes of the optic nerve. In conclusion, a range of common histopathologic alterations were identified within ocular tissue, and SARS-CoV-2 RNA was localized to multiple cell types. Further studies will be required to determine whether the alterations observed were caused by SARS-CoV-2 infection, the host immune response, and/or preexisting comorbidities.

Virological and cytological changes in tears and conjunctiva of patients with COVID-19

Purpose

To analyze the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in tears/conjunctival epithelium and assess the cytomorphological changes in the conjunctival epithelium of coronavirus disease 2019 (COVID-19) patients.

Methods

In this pilot study, patients with moderate to severe COVID-19 were recruited from the COVID ward/intensive care unit of the institute. Tears and conjunctival swabs were collected from COVID-19 patients and sent to the virology laboratory for reverse transcription polymerase chain reaction (RT-PCR) testing. Conjunctival swabs were used to prepare smears, which underwent cytological evaluation and immunocytochemistry for SARS-CoV-2 nucleocapsid protein.

Results

Forty-two patients were included. The mean age of participants was 48.61 (range: 5-75) years. Seven (16.6%) patients tested positive for SARS-CoV-2 ribonucleic acid in tears samples, four (9.5%) of which were positive on conjunctival swab by RT-PCR in the first test. Cytomorphological changes were observed significantly more in smears from patients with positive RT-PCR on tear samples, including bi-/multi-nucleation (p = 0.01), chromatin clearing (p = 0.02), and intra-nuclear inclusions (p < 0.001). One case (3.2%) showed immunopositivity for SARS-CoV-2; this patient had severe disease and the lowest Ct values for tear and conjunctival samples among all positive cases.

Conclusion

Conjunctival smears from patients with COVID-19 revealed cytomorphological alterations, even in the absence of clinically significant ocular infection. However, viral proteins were demonstrated within epithelial cells only rarely, suggesting that although the conjunctival epithelium may serve as a portal for entry, viral replication is possibly rare or short-lived.

Eye banking and keratoplasty trend analysis during the COVID-19 pandemic: A South Indian observational study

Purpose

To analyze the impact on eye donation and corneal transplantation during the COVID-19 pandemic in a tertiary eye hospital in south India.

Methods

A retrospective analysis of the donor and recipient records during the study period from January 2020 to May 2021 was conducted and tabulated in Microsoft Excel 2013. Demographic details of the donor, utility rate, cause of death, culture characteristics, storage methods, wet lab usage, and the surgical donor outcomes were evaluated. Additionally, the postoperative workup of the recipients, diagnosis, graft infection and rejection episodes, development of COVID-19 postoperatively, and outcome in terms of visual acuity at one, three, and six months were also noted.

Results

A total of 466 eyes from 249 donors were received during the study period. The mean age of the donor population was 62.43 years (20.9). The corneal transplantation utility rate was 36.4% (n = 170). Fifty-one percent of the total transplant surgeries were for therapeutic purposes. This was followed by penetrating optical keratoplasty (34%), Descemet's stripping endothelial keratoplasty (9%), and patch grafts (3%). Seventeen (10%) graft rejection episodes were noted and nine (53%) had complete resolution after medical treatment.

Conclusion

Proper preventive measures are key to carrying out safe and efficient eye banking activities even during a deadly pandemic, as COVID-19 transmission via transplantation is rare.

Absence of detectable SARS-CoV-2 replication in ex vivo cultured cornea and cornea-derived epithelial cells

PURPOSE

To study the possibility of SARS-CoV-2 to infect human corneal cells and tissues under standard corneal culture conditions using explants of COVID-19 donors and primary cornea-derived epithelial cells.

METHODS

Cornea isolated from deceased COVID-19 donors was cultured for 4 weeks, and SARS-CoV-2 replication was monitored by qRT-PCR. Furthermore, primary corneal epithelial cells from healthy donors were cultured ex vivo and infected with SARS-CoV-2 and human cytomegalovirus (HCMV) as a control. Infection status was assessed by western blotting and reporter gene expression using green fluorescent protein-expressing viral strains. ACE2 and TMPRSS2 receptor expression levels in cornea and epithelial cells were assessed by qRT-PCR.

RESULTS

We did not detect SARS-CoV-2 replication in 10 corneas isolated from deceased COVID-19 patients and cultured for 4 weeks, indicating absence of infection under natural conditions. Furthermore, high-titer SARS-CoV-2 infection of ex vivo cultured cornea-derived epithelial cells did not result in productive virus replication. In contrast, the same cells were highly permissive for HCMV. This phenotype could potentially be explained by low ACE2 and TMPRSS2 transcriptional activity in cornea and cornea-derived epithelial cells.

CONCLUSIONS

Our data suggest that cornea and limbal epithelial cells are refractory to productive SARS-CoV-2 infection. This could be due to the absence of robust receptor expression levels necessary for viral entry. This study adds further evidence to support the very low possibility of transmission of SARS-CoV-2 from an infected corneal transplant donor to a recipient in corneal organ cultures.

COVID-19 and Eye Banking: Ongoing Impacts of the Pandemic

PURPOSE

The purpose of this study was to assess the impact of ongoing waves of the COVID-19 pandemic and resulting guidelines on the corneal donor pool with resumption of clinical operations.

METHODS

A retrospective analysis of donors deemed eligible for corneal transplantation at an eye bank from July 1, 2020, through December 31, 2021. Donors ineligible due to meeting Eye Bank Association of America (EBAA) COVID-19 guidelines or a positive postmortem COVID-19 testing were examined. The correlation between COVID-19 rule outs and state COVID positivity was calculated. The number of scheduled surgeries, suitable corneas, imports, and international exports was compared with a pre-COVID period. Postmortem testing was reduced for the final 5 months of the study, and numbers were compared before and after the policy change.

RESULTS

2.85% of referrals to the eye bank were ruled out because of EBAA guidelines. 3.2% of postmortem tests were positive or indeterminate resulting in an ineligible tissue donor (0.42% of referrals). Over the 18-month period, there was a 4.30% shortage of suitable corneas compared with transplantation procedures. There was a significant correlation between postmortem testing and state COVID-19 positivity (r = 0.37, P <0.01), but not with EBAA guidelines (r = 0.19, P = 0.07). When postmortem testing was reduced, significantly more corneas were exported internationally.

CONCLUSIONS

Although corneal transplant procedures were back to normal levels, there was a shortage of suitable corneal tissue. The discontinuation of postmortem testing was associated with a significant increase in international exports of corneal donor tissue.

Presence of SARS-CoV-2 RNA in human corneal tissues donated in Italy during the COVID-19 pandemic

Objective

To analyse corneal tissues from asymptomatic donors with a postmortem nasopharyngeal swab tested positive for the presence of SARS-CoV-2 RNA, and therefore, understand the role that corneal transplantation may have in viral transmission.

Methods and analysis

Between March 2020 and October 2021, 101 corneas (out of 8154 collected in Italy) from 51 donors (out of a total of 4155 Italian donors) positive for SARS-CoV-2 after postmortem nasopharyngeal swab tests were analysed for the presence of SARS-CoV-2 RNA through real-time RT-PCR. When available, the corneal tissue storage media were also assessed. Corneas and/or storage media with confirmed presence of SARS-CoV-2 RNA were further investigated by isolating SARS-CoV-2 virions, which were used to infect VeroE6 target cells.

Results

Only N=4 corneas and/or storage media out of 101 showed presence of SARS-CoV-2 RNA. No VeroE6 cell infection was detected with viral isolates, thus suggesting no presence of SARS-CoV-2 virions in corneal specimens and storage media.

Conclusions

The presence of SARS-CoV-2 in cornea specimens would seem to be more likely due to prolonged detection of RNA rather than to active viral replication, with very low risk of infectivity and transmission through keratoplasty.

COVID-19 and the eye: alternative facts The 2022 Bowman Club, David L. Easty lecture

In addition to catastrophic loss of life, and dramatic and unwanted alterations to the daily lives of those left behind, the COVID-19 pandemic has fostered the publication and dissemination of an unprecedented quantity of peer-reviewed medical and scientific publications on a single subject. In particular, the ophthalmic literature is now replete with clinical and laboratory studies on putative eye involvement by SARS-CoV-2, the aetiologic agent of COVID-19. In this review, we critically appraise the published literature on COVID-19, and suggest that the quality of scientific peer review and editorial decision-making also suffered during the COVID-19 pandemic.

The Impact of the COVID-19 Pandemic on Corneal Transplantation in Brazil

PURPOSE

The purpose of this study was to evaluate the impact of the coronavirus disease 2019 pandemic on corneal transplantation (CT) in Brazil.

METHODS

Data from patients who underwent CT at the Hospital Oftalmológico de Sorocaba (HOS), Brazil, were analyzed. National and state numbers of keratoplasties, patients added to the CT waiting list, and total patients on the waiting list were also obtained. Baseline prepandemic (from January 1, 2019, to March 31, 2020) data were compared with 2 time frames of the coronavirus disease 2019 pandemic: elective CT suspension period (between April 1, 2020, and September 31, 2020) and after elective CT resumption (between October 1, 2020, and April 30, 2021).

RESULTS

Despite elective CT resumption after the moratorium, the monthly CT rates did not return to baseline at HOS (-14.7%, P = 0.007), São Paulo state (-19.1%, P = 0.001), or Brazil (-30.1%, P < 0.001). The waiting list increased significantly regionally (P < 0.001) and nationally (P < 0.001). Among optical keratoplasties performed at HOS after resuming elective CTs, the proportion of endothelial keratoplasties declined from 38.2% to 30.0% (P < 0.001), whereas penetrating keratoplasties increased from 33.2% to 39.5% (P < 0.001) when comparing with prepandemic data.

CONCLUSIONS

Keratoplasty numbers dropped significantly locally, regionally, and nationally. Hence, the CT waiting lists had a progressive increase, with significant long-term implications. An estimated increment on monthly CT rates of approximately 34% in São Paulo state, and 91% in Brazil, is required for the CT waiting list to get back to prepandemic numbers over the next 2 years.

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/.

Clinical Utility of COVID-19 Real Time-Polymerase Chain Reaction Testing of Ocular Tissues of Non-COVID-19 Cornea Donors Deemed Suitable for Corneal Retrieval and Transplantation

PURPOSE

The purpose of this study was to evaluate the prevalence of SARS-CoV-2 in human postmortem ocular tissues of asymptomatic donors and its implications on our eye banking protocols.

METHODS

The expression of SARS-CoV-2 RNA was assessed by reverse transcription-polymerase chain reaction in corneal rims and conjunctival tissues from 100 donors who were found suitable for transplantation as per the donor screening guidelines of the Global Alliance of Eye Bank Associations. The donor's clinical history and cause of death were assessed for secondary analysis.

RESULTS

Of 200 ocular tissues (100 corneal and 100 conjunctival) from the same 1 eye of 100 surgical-intended donors, between September 2020 and April 2021, the overall positivity rate for SARS-CoV-2 was ∼1% (2/200). Both the ocular samples that tested positive were conjunctival biopsies (2/100, 2%), whereas corneal samples were negative (0/100, 0%) in both donors. The causes of donor death were trauma in 51 donors, suicide in 33, cardiac arrest in 7, electric shock in 5, metabolic cause in 2, malignancy in 1, and snake bite in 1. None of the donors had a medical history suggestive of COVID infection or possible contact. None of the recipients from the donors were reported to have any systemic adverse event after keratoplasty until the follow-up of 6 weeks.

CONCLUSIONS

The overall prevalence of SARS-CoV-2 was 1% (2% for conjunctival and 0% for corneal samples, P value = 0.5) in the donors who were found suitable for cornea recovery and transplantation. The findings of exceptionally low positive rates in our samples validate the criticality of history-based donor screening and do not support the necessity of postmortem PCR testing as a criterion for procurement and subsequent use for corneal transplantation.

Changes in Anterior Chamber Parameters Measured by Pentacam in Coronavirus Disease 2019 Infection: A Longitudinal Study

Purpose

To evaluate changes in anterior segment parameters measured by imaging in coronavirus disease 2019 (COVID-19) infection.

Methods

This longitudinal observational study included patients who recovered from COVID-19. All subjects exhibited a confirmed diagnosis of COVID-19 with a positive result of nasopharyngeal reverse transcription-polymerase chain reaction evaluation. Corneal Pentacam (Oculus, Dutenhofen, Germany) imaging was performed at least two weeks after recovery from systemic COVID-19. Measurements were repeated one and three months later.

Results

A total of 20 patients, 11 (55%) of whom were females, with a mean age of 35.5 ± 7.1 years (age range: 25–51 years) recovered from nonhospitalized COVID-19 infection, were enrolled in this study. An increase in the keratometry mean front, keratometry mean back, cornea volume, and anterior chamber depth was observed in the longitudinal evaluation; however, they showed no statistical significance. The anterior chamber volume was statistically increased at three-month follow-up, compared to baseline (baseline: 177.8 ± 36.68 mm³; three months: 182.25 ± 39.58 mm³, P=0.048).

Conclusion

COVID-19 infection may affect the cornea and anterior segment.

RT-PCR Testing of Organ Culture Medium for Corneal Storage Fails to Detect SARS-CoV-2 Infection Due to Lack of Viral Replication

Concerns of possible transmission of SARS-CoV-2 from donors to patients by corneal transplantation have caused a decline in corneal transplantations. Graft culture media are routinely tested for infectious risks, but it is unclear whether this constitutes a viable means to avoid transmitting SARS-CoV-2 via keratoplasty. We found that SARS-CoV-2 RNA was not present in the medium after seven days of organ culture of corneas from donors (n = 4), who were SARS-CoV-2-positive upon tissue procurement. These medium samples showed no presence of viral RNA. To pursue this question under controlled conditions and further exclude the possibility of productive infection in corneal grafts, we inoculated corneoscleral discs from healthy donors (n = 8) with infectious SARS-CoV-2 and performed PCR testing of the culture medium at various time points. After seven days of culture, we also tested for SARS-CoV-2 RNA within the inoculated corneal tissue. The medium from tissue samples inoculated with SARS-CoV-2 showed no increase in viral RNA, which may indicate lack of viral replication in these corneal grafts. SARS-CoV-2-RNA was, however, detected on or in corneal tissue seven days after inoculation. Our data suggest that corneal grafts may not be permissive for replication of SARS-CoV-2 and demonstrates that PCR testing of culture media cannot safely exclude that tissue has been exposed to SARS-CoV-2. It also demonstrates the difficulty to differentiate between virus adherence and virus replication by PCR testing in SARS-CoV-2 exposed tissue.

[Anterior eye segment damage in coronavirus infection (COVID-19)]

Conjunctivitis may appear as the first symptom of the coronavirus infection (COVID-19). In isolated cases, the lesion of the conjunctiva evokes a systemic infectious process. Currently, the conjunctiva is not considered as an area of long-term reproduction of coronavirus, and its damage is caused by hyperproduction of pro-inflammatory cytokines (especially IL-6); development of iridocyclitis and keratoconjunctivitis is also possible. Most often, local corticosteroids are used to treat these processes, although their use requires caution due to the risk of activating secondary infection (herpetic bacterial, fungal), which often develops as a result of immunodeficiency caused both by COVID-19 and the massive corticosteroid and antibiotic therapy employed when the course of the disease is severe. The severe condition of patients, the lung ventilation, and the prone position all contribute to corneal erosions, exposure keratopathy, pseudomonas aeruginosa keratitis and angle-closure glaucoma attacks. The risk of transmission of coronavirus infection during keratoplasty is estimated as minimal.

Detection of SARS-CoV-2-RNA in post-mortem samples of human eyes

Purpose

To detect SARS-CoV-2 RNA in post-mortem human eyes. Ocular symptoms are common in patients with COVID-19. In some cases, they can occur before the onset of respiratory and other symptoms. Accordingly, SARS-CoV-2 RNA has been detected in conjunctival samples and tear film of patients suffering from COVID-19. However, the detection and clinical relevance of intravitreal SARS-CoV-2 RNA still remain unclear due to so far contradictory reports in the literature.

Methods

In our study 20 patients with confirmed diagnosis of COVID-19 were evaluated post-mortem to assess the conjunctival and intraocular presence of SARS-CoV-2 RNA using sterile pulmonary and conjunctival swabs as well as intravitreal biopsies (IVB) via needle puncture. SARS-CoV-2 PCR and whole genome sequencing from the samples of the deceased patients were performed. Medical history and comorbidities of all subjects were recorded and analyzed for correlations with viral data.

Results

SARS-CoV-2 RNA was detected in 10 conjunctival (50%) and 6 vitreal (30%) samples. SARS-CoV-2 whole genome sequencing showed the distribution of cases largely reflecting the frequency of circulating lineages in the Munich area at the time of examination with no preponderance of specific variants. Especially there was no association between the presence of SARS-CoV-2 RNA in IVBs and infection with the variant of concern (VOC) alpha. Viral load in bronchial samples correlated positively with load in conjunctiva but not the vitreous.

Conclusion

SARS-CoV-2 RNA can be detected post mortem in conjunctival tissues and IVBs. This is relevant to the planning of ophthalmologic surgical procedures in COVID-19 patients, such as pars plana vitrectomy or corneal transplantation. Furthermore, not only during surgery but also in an outpatient setting it is important to emphasize the need for personal protection in order to avoid infection and spreading of SARS-CoV-2. Prospective studies are needed, especially to determine the clinical relevance of conjunctival and intravitreal SARS-CoV-2 detection concerning intraocular affection in active COVID-19 state and in post-COVID syndrome.

COVID-19 positivity rate in corneal tissue donors - A cause for concern!

Purpose

To determine the postmortem positivity for COVID-19 among voluntary eye donors who had been certified to have died of non-COVID-19 causes.

Methods

All donors who donated their corneas (from March 2021 onward) were assessed for COVID-19 positivity tested by nasopharyngeal swab reverse transcription-polymerase chain reaction (RT-PCR) test. Relevant screening history was taken prior to collection. Strict precautions were taken during the retrieval as per the guidelines issued by the National Program for Control of Blindness and Visual Impairment and the Eye Bank Association of India, and the tissues were handled as per standard operating protocol.

Results

85 eye calls were attended during this period, of which 56 were home-based and 29 were from a hospital setting. Samples from 12 of the former group of donors were found to be positive for COVID-19 (14%).

Conclusion

This study highlights the possibility of postmortem RT-PCR positivity in voluntary corneal tissue donors without a prior history of symptoms, signs, or diagnosis of illness suggestive of COVID-19. It is recommended that postmortem testing of donors should be done by RT-PCR for retrievals made during the pandemic.

Post-Mortem RT-PCR Assay for SARS-CoV-2 RNA in COVID-19 Patients' Corneal Epithelium, Conjunctival and Nasopharyngeal Swabs

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease has been described to possibly be associated with ocular surface disturbances. However, whether the virus could invade ocular tissues still remains elusive. In the present study, we tried to investigate the post-mortem presence of SARS-CoV-2 RNA in corneal epithelium gathered by patients with an ante-mortem confirmed diagnosis of Coronavirus disease-19 (COVID-19). Cadavers with an ante-mortem confirmed diagnosis of moderate to severe COVID-19 were examined. Clinical and demographic features were retrieved from hospital patients’ notes. For each cadaver, corneal scrapings, conjunctival swabs (CS) and nasopharyngeal swabs (NPS) were collected to perform real-time reverse transcriptase polymerase chain reaction ((RT)-PCR) for SARS-CoV-2. Fourteen consecutive cadavers with an ante-mortem confirmed diagnosis of moderate to severe COVID-19 were examined. The last NPS performed ante-mortem confirmed SARS-CoV-2 infection in 12/14 (85.7%) patients. The mean death-to-swab time (DtS) was 3.15 ± 0.5 (2.10–5.1) h. The post-mortem NPS and CS found positive for SARS-CoV-2 RNA were 9/14 (64.3%) and 3/28 (10.7%), respectively. None of the corneal epithelium scrapes tested positive to RT-PCR for SARS-CoV-2 RNA. These data promote the SARS-CoV-2 as not able to contaminate the post-mortem corneal epithelium, while it can persist in different other structures of the ocular surface (i.e., the conjunctiva). It is reasonable to assume that such a contamination can occur ante-mortem too.

Role of Reverse Transcriptase Polymerase Chain Reaction in Cornea Donors During the COVID-19 Pandemic

PURPOSE

The purpose of this study was to report the analysis of reverse transcriptase polymerase chain reaction (RT-PCR) of nasopharyngeal (NP) samples of cornea donors dying because of causes unrelated to severe acute respiratory coronavirus (SARS-CoV-2).

METHODS

A retrospective analysis of all cornea donors dying from causes other than SARS-CoV-2 between August 2020 and December 2020 was performed. Informed consent was obtained from the next of kin of the deceased for RT-PCR testing from NP swabs. Rapid antigen testing from all the deceased was performed before in situ cornea excision. In addition, NP samples in viral transport media for RT-PCR were also collected for SARS-CoV-2 analysis. Corneas were released from the eye bank only after a negative RT-PCR report.

RESULT

One hundred eighteen corneas from 59 donors were obtained by the eye bank. Eleven donors (18.64%) were positive for SARS-CoV-2 on RT-PCR testing. Six of these 11 donors had a Ct value of E gene less than 25.

CONCLUSIONS

NP samples of cornea donors dying due to causes other than coronavirus disease-19 were positive for SARS-CoV-2 on RT-PCR. This implicates that donors could be having asymptomatic/undetected coronavirus disease infection. We recommend adding the routine testing of NP samples of all cornea donors in the eye banking protocol in this ongoing SARS-CoV-2 pandemic.

Evidence of SARS-CoV-2 Infection in Cells, Tissues, and Organs and the Risk of Transmission Through Transplantation

The emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus responsible for the coronavirus disease 2019 (COVID-19) pandemic has raised concerns for programs overseeing donation and transplantation of cells, tissues, and organs (CTO) that this virus might be transmissible by transfusion or transplantation. Transplant recipients are considered particularly vulnerable to pathogens because of immunosuppression, and SARS-CoV-2 is likely to generate complications if contracted. Several signs and symptoms observed in COVID-19 positive patients reflect damage to multiple organs and tissues, raising the possibility of extrapulmonary SARS-CoV-2 infections and risk of transmission. At the beginning of the pandemic, a consensus has emerged not to consider COVID-19 positive patients as potential living or deceased donors, resulting in a global decrease in transplantation procedures. Medical decision-making at the time of organ allocation must consider safely alongside the survival advantages offered by transplantation. To address the risk of transmission by transplantation, this review summarizes the published cases of transplantation of cells or organs from donors infected with SARS-CoV-2 until January 2021 and assesses the current state of knowledge for the detection of this virus in different biologic specimens, cells, tissues, and organs. Evidence collected to date raises the possibility of SARS-CoV-2 infection and replication in some CTO, which makes it impossible to exclude transmission through transplantation. However, most studies focused on evaluating transmission under laboratory conditions with inconsistent findings, rendering the comparison of results difficult. Improved standardization of donors and CTO screening practices, along with a systematic follow-up of transplant recipients could facilitate the assessment of SARS-CoV-2 transmission risk by transplantation.

Updated safety precautions and guidance on eye banking procedures during the coronavirus disease 2019 pandemic

PURPOSE OF REVIEW

severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly infectious coronavirus causing the COVID-19 pandemic. Although airborne spread through infectious respiratory droplets is the primary source of transmission, recent literature has suggested the ocular surface may be able to harbor viral particles. Here, we aim to discuss how SARS-CoV-2 affects the ocular surface and updated guidance on how SARS-CoV-2 transmission should be considered in the setting of eye banking and corneal transplantation procedures.

RECENT FINDINGS

SARS-CoV-2 RNA can be found on the ocular surface, which may suggest the eye as a site of viral replication. However, there is poor correlation between PCR positivity on the ocular surface and ocular symptoms. To date, although viral particles can be found on the ocular surface, use of standard antiseptic procedures during corneal tissue procurement appears to sufficiently reduce viral load. In addition, preprocedure testing may further decrease the chances of transplanting an infected cornea without significantly impacting the overall accessibility to corneal tissue by decreasing the donor pool.

SUMMARY

Corneal transplantation remains a well tolerated and highly successful procedure with no evidence of viral transmission with transplantation. Although the ocular surface has the required receptors to allow for viral replication, there is no clear evidence that the eye is a site for primary viral infection.

Risk of SARS-CoV-2 virus transmission from donor corneal tissue: A review

Since the outbreak of respiratory coronavirus disease (COVID-19) caused by the coronavirus SARS-CoV-2, there is an ongoing discussion about whether the virus could be transmitted through corneal transplantation from donor to recipient. The purpose of this review was to summarize the current knowledge in the scientific community to provide aid in risk evaluation for potential virus transfer by corneal transplants. Literature was searched in PubMed.gov for relevant articles on coronavirus in conjunction with cornea processing, cornea transplantation and eye banking. Further, guidelines of health authorities and eye banking associations were reviewed. Studies have shown that SARS-CoV-2 RNA can be detected in ocular swabs and/or fluid of patients with COVID-19. However, the risk of SARS-CoV-2 virus transmission through these ocular tissues or fluid of patients is judged differently. To date, per literature and official guidelines, no evidence of viable virus in ocular tissue and no cases of transmission of SARS-CoV-2 via tissue preparations have been reported.

Severe acute respiratory Syndrome-Coronavirus-2: Can it be detected in the retina?

Background/Objectives

The systemic organ involvement of SARS-CoV-2 needs to be thoroughly investigated including the possibility of an ocular reservoir in humans. To examine retinal tissues and vitreous for histopathology and SARS-CoV-2 presence with regard to possible effects on the human retina and/ or vitreous. We performed histopathological analyses and quantitative (q)RT-PCR-testing for SARS-CoV-2 RNA on retinal tissues and vitreous of COVID-19 postmortem donors.

Subjects/Methods

Included in this study were 10 eyes of 5 deceased COVID-19 patients. The diagnosis of SARS-CoV-2 infection was confirmed via pharyngeal swabs and broncho-alveolar fluids. The highest level of personal protective equipment (PPE) and measures was employed during fluid-tissue procurement and preparation. Histopathological examinations and qRT-PCR-testing were carried out for all retinal tissues and vitreous fluids.

Results

The histopathological examinations revealed no signs of morphologically identifiable retinal inflammation or vessel occlusions based on hematoxylin and eosin stains. By qRT-PCRs, we detected no significant level of viral RNA in human retina and vitreous.

Conclusions

In this study, no significant level of SARS-CoV-2-RNA was detected in the human retinal and vitreous fluid samples of deceased COVID-19 patients. Histopathological examinations confirmed no morphological sign of damage to retinal vasculature or tissues. Further studies are needed to confirm or refute the results.

The Transmission of SARS-CoV-2 Infection on the Ocular Surface and Prevention Strategies

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a global health problem. Although the respiratory system is the main impaired organ, conjunctivitis is one of its common findings. However, it is not yet understood if SARS-CoV-2 can infect the eye and if the ocular surface can be a potential route of SARS-CoV-2 transmissions. Our review focuses on the viral entry mechanisms to give a better understanding of the interaction between SARS-CoV-2 and the eye. We highlighted findings that give evidence for multiple potential receptors of SARS-CoV-2 on the ocular surface. Additionally, we focused on data concerning the detection of viral RNA and its spike protein in the various ocular tissues from patients. However, the expression level seemed to be relatively low compared to the respiratory tissues as a result of a unique environment surrounding the ocular surface and the innate immune response of SARS-CoV-2. Nevertheless, our review suggests the ocular surface as a potential route for SARS-CoV-2 transmission, and as a result of this study we strongly recommend the protection of the eyes for ophthalmologists and patients at risk.

Ocular Manifestations of Patients with Coronavirus Disease 2019: A Comprehensive Review

Apart from conjunctival involvement which is the most well-known ocular manifestation of coronavirus infectious disease 2019 (COVID-19), there are multiple reports of the involvement of other ocular structures by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We comprehensively reviewed PubMed, Scopus, Embase, and Google Scholar for available evidence regarding COVID-19 various ocular manifestations, with special focus on less known and unusual ocular findings. We then categorized the findings based on the parts of the eye which was involved. In anterior sections of the eye, the involvement of the eyelid (tarsadenitis), conjunctiva and cornea (follicular conjunctivitis, pseudomembranous conjunctivitis, and keratoconjunctivitis), episclera (nodular episcleritis), uvea (anterior uveitis) were reported. Also, third, fourth, and sixth nerve palsy, retinal vasculitis, retinal optical coherence tomography (OCT) changes (hyper-reflective lesions and increased retinal nerve fiber layer thickness [RNFLT]), optic neuritis, papillophlebitis, Miller Fisher syndrome, posterior reversible leukoencephalopathy (PRES), ophthalmic artery and central retinal artery occlusion, and polyneuritis cranialis were reported in different studies. Postmortem evaluation of COVID-19 patients detected no viral RNA in different anterior and posterior segments of the eyes. However, another study revealed a 21.4% positivity of the retinal biopsies of dead patients. The results of this study can help ophthalmologists to be vigilant when they see these findings in a suspected case of COVID-19. In addition, wearing face masks and protective goggles or eye shields are recommended, especially in high risk contacts.

Detection of SARS-CoV-2 RNA in the corneal epithelium of a patient after recovery from COVID-19

Purpose

To report a case of a patient presenting with unilateral keratouveitis associated with ocular hypertension six weeks after being discharged from the hospital for COVID-19. Ocular specimens were obtained for testing.

Observations

A 69-year-old African American woman developed poor vision while hospitalized for COVID-19 in April but did not seek ophthalmic care until end of May. She had an edematous cornea, stromal keratitis, and highly elevated intraocular pressure by June. After lack of response to oral valacyclovir, aqueous fluid and swabs of her conjunctiva and limbal epithelium with corneal epithelium anterior to the limbus were sent for real-time polymerase chain reaction (PCR) for herpes simplex virus, herpes zoster virus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Epithelium from the cornea and limbus was positive for SARS-CoV-2 by PCR; specimens from the other two ocular sites were negative. All specimens were negative for herpes simplex virus and varicella zoster virus. The patient refused further treatment despite intraocular pressure above 50 mm Hg at last follow-up.

Conclusions and Importance

Although SARS-CoV-2 and severe acute respiratory syndrome coronavirus (SARS-CoV) have been detected by PCR in the conjunctiva and tears of patients with acute respiratory infection, presence in corneal tissue has not been described. In addition, no one has studied whether ocular tissues in convalesced patients can harbor viral RNA. Here we describe unilateral keratouveitis in a convalesced patient whose corneal epithelium/limbal tissue was positive for SARS-CoV-2 by PCR. Further investigation is required to determine whether active viral replication or viral remnants account for this result.

Retrospective study of COVID-19 seroprevalence among tissue donors at the onset of the outbreak before implementation of strict lockdown measures in France

Background The COVID-19 pandemic has altered organ and tissue donations as well as transplantation practices. SARS-CoV-2 serological tests could help in the selection of donors. We assessed COVID-19 seroprevalence in a population of tissue donors, at the onset of the outbreak in France, before systematic screening of donors for SARS-CoV-2 RNA. Methods 235 tissue donors at the Lille Tissue Bank between November 1, 2019 and March 16, 2020 were included. Archived serum samples were tested for SARS-CoV-2 antibodies using two FDA-approved kits. Results Most donors were at higher risks for severe COVID-19 illness including age over 65 years (142/235) and/or presence of co-morbidities (141/235). According to the COVID-19 risk assessment of transmission, 183 out of 235 tissue donors presented with a low risk level and 52 donors with an intermediate risk level of donor derived infection. Four out of the 235 (1.7%) tested specimens were positive for anti-SARS-CoV-2 antibodies: 2 donors with anti-N protein IgG and 2 other donors with anti-S protein total Ig. None of them had both type of antibodies. Conclusion Regarding the seroprevalence among tissue donors, we concluded that the transmission probability to recipient via tissue products was very low at the beginning of the outbreak.

One threat, different answers: the impact of COVID-19 pandemic on cornea donation and donor selection across Europe

OBJECTIVES

To assess to which extent the COVID-19 pandemic affected corneal transplantation by virtue of donor selection algorithms in different European countries.

DESIGN

Survey.

SETTING

110 eye banks in 26 European countries.

PARTICIPANTS

64 eye banks covering 95% of European corneal transplantation activity.

INTERVENTIONS

A questionnaire listing the number of corneas procured and distributed from February to May 2018-2020 was circulated to eye banks.

MAIN OUTCOME MEASURES

The primary outcome was the number of corneal procurements. Additional outcomes were national algorithms for donor selection, classified according to their stringency (donors with COVID-19 history, suspected for COVID-19, asymptomatic, PCR testing) and the pandemic severity in each country. We calculated Spearman's correlation coefficient to determine, two by two, the relationship between the 3-month decline in eye banking activity (procurement), the stringency of donor selection algorithm and the grading of pandemic severity (cases and deaths). A partial correlation was run to determine the relationship between decline and stringency while controlling for pandemic severity.

RESULTS

Procurements decreased by 38%, 68% and 41%, respectively, in March, April and May 2020 compared with the mean of the previous 2 years, while grafts decreased, respectively, by 28%, 68% and 56% corresponding to 3866 untreated patients in 3 months. Significant disparities between countries and the decrease in activity correlated with stringency in donor selection independent of pandemic severity.

CONCLUSIONS

Our data demonstrate significant differences between countries regarding donor screening algorithms based on precautionary principles and, consequently, a decrease in the donor pool, already constrained by a long list of contraindications. Fundamental studies are needed to determine the risk of SARS-CoV-2 transmission by corneal transplantation and guide evidence-based recommendations for donor selection to justify their substantial medical and economic impact.