Conjunctival conveyance of SARS-CoV-2 in asymptomatic and non-severe symptomatic COVID-19 patients.

INTRODUCTION: The prevalence of ocular conveyance of SARS-CoV-2 has been well described for severe/hospitalized cases, but scarcely reported in asymptomatic and non-severe patients, who are unaware that they are carriers. MATERIAL & METHODS: This prospective cross-sectional study quantitatively evaluated SARS-CoV-2 shedding on the ocular surface (OS). Conjunctival testing was suggested to all hospital personnel being screened by nasopharyngeal (NP) SARS-CoV-2 reverse transcription polymerase chain reaction (RT-PCR). Disease symptoms were evaluated using a standardized questionnaire and telephone follow-up 6±3 months later for disease evolution (recovery with/without severe disease). RESULTS: Four hundred and eighty seven patients were included. From 46 NP SARS-CoV-2-positive subjects (cycle threshold [CT]=24.2±7.1), 13% tested positive at the OS (CT=36.4±2.8). Most SARS-CoV-2-positive subjects were symptomatic (n=40, 87%), while 6 were asymptomatic (being tested as contact cases). Systemic symptoms were not significantly different in OS-positive vs OS-negative subjects, although headache tended to be more frequent in OS-positives (83% vs 54%, P=0.06). None of the OS-positive subjects reported ocular symptoms and none developed severe disease requiring hospitalization or oxygen therapy. CONCLUSION: SARS-CoV-2 shedding at the OS may occur in asymptomatic and non-severe COVID-19 individuals (including those absent of ocular symptoms). However, the high RT-PCR CT values attained may indicate a low risk of transmissibility via this route.

Omega-3 fatty acids supplements for dry eye - Are they effective or ineffective?

Purpose: To evaluate effectiveness of omega-3 fatty acid supplements in relieving dry eye symptoms and signs in symptomatic visual display terminal users (VDT). Methods: A randomized controlled study was done; eyes of 470 VDT users were randomized to receive four capsules twice daily for 6 months (O3FAgroup), each containing 180 mg of eicosapentaenoic acid and 120 mg docosahexaenoic acid. The O3FA group was compared with another group (n = 480) who received four capsules of a placebo (olive oil) twice daily. Patients were evaluated at baseline, 1, 3, and 6 months, respectively. The primary outcome was improvement in omega-3 index (a measure of EPA and DHA ratio in RBC membrane). Secondary outcomes were improvement dry eye symptoms, Nelson grade on conjunctival impression cytology, Schirmer test values, tear film breakup time (TBUT), and tear film osmolarity. Means of groups (pre-treatment, 1, 3, and 6-months) were compared with repeated measure analysis of variance. Results: At baseline, 81% patients had low omega-3 index. In the O3FA group, a significant increase in omega-3 index, improvement in symptoms, reduction in tear film osmolarity, and increase in Schirmer, TBUT, and goblet cell density was observed. These changes were not significant in the placebo group. Improvement in test parameters was significantly (P < 0.001) better in patients with low omega3 index (<4%) subgroup. Conclusion: Dietary omega-3 fatty acids are effective for dry eye in VDT users; omega-3 index appears to be the predictor to identify potential dry eye patients who are likely to benefit from oral omega-3 dietary intervention.

Relations between the ocular surface and SARS-CoV-2 / Relações entre superfície ocular e SARS-CoV-2

ABSTRACT Introduction: The SARS-CoV-2 pandemic has been a major challenge for the international scientific community. Since its inception, studies aiming to describe pathophysiological aspects and clinical manifestations of the disease have been conducted, raising hypotheses and confirming possible associations. One aspect of this scientific medical production is the role of the ocular surface as a means of transmission and clinical presentation of viral syndrome. Objectives: To analyze the role of the ocular surface in transmission, pathophysiology, and clinical manifestations of SARS-CoV-2, by means of a systematic review. Methods: The search was carried out in three databases: Cochrane, PubMed Central Journals and MEDLINE, using the following descriptors: "COVID-19, ophthalmology". The filters last five years and studies on humans resulted in 32 studies; in that 12 were excluded for not meeting the purpose of the study. Results: There are still few published studies on the relation between SARS-CoV-2 and the ocular route. Most studies showed an association between the presence of nonspecific ocular manifestations and infection by the new coronavirus, with limitations in the number of patients analyzed and the methodology adopted. Hypotheses about the pathophysiological role are largely anchored in the association of SARS-CoV and the ocular surface evaluated in the past. Comments: The results found are still not sufficient to confirm the role of the ocular surface in the pathophysiology of the disease. Most of these preliminary studies are of considerable importance in raising hypotheses based on the medical analysis of the patients studied. However, larger studies with standardized methodology for diagnostic protocol and laboratory analysis of the individuals assessed are required.

RESUMO Introdução: A pandemia da SARS-CoV-2 tem sido um grande desafio para a comunidade científica internacional. Desde seu surgimento, estudos com a intenção de descrever os aspectos fisiopatológicos e as manifestações clínicas da doença vêm sendo conduzidos, levantando hipóteses e confirmando possíveis associações. Um dos temas dessa produção médica científica é o papel da superfície ocular como meio de transmissão e apresentação clínica da síndrome viral. Objetivo: Analisar o papel da superfície ocular na transmissão, na fisiopatologia e nas manifestações clínicas de SARS-CoV-2, através de uma revisão sistemática. Realizou-se a busca em três bancos de dados Cochrane Database, PubMed® e MEDLINE®, utilizando os descritores "COVID-19 e ophthalmology". Foram definidos como filtros o artigo ter sido publicado nos últimos 5 anos e estudo realizado em humanos, tendo sido encontrados 32 artigos. Destes, foram excluídos 12 por não corresponderem ao objetivo do estudo. Resultados: Ainda são poucos os estudos publicados sobre a relação entre o coronavírus 2 da síndrome respiratória aguda grave (SARS-CoV-2) e a via ocular. A maioria dos estudos mostrou associação entre a presença de manifestações oculares inespecíficas e a infecção pelo novo coronavírus, com limitações no número de pacientes analisados e na metodologia adotada. Hipóteses sobre o papel fisiopatológico se ancoram, em grande parte, na associação estudada entre o SARS-CoV-2 e a superfície ocular no passado. Comentários: Os resultados encontrados ainda não são suficientes para confirmar o papel da superfície ocular na fisiopatologia da doença. Grande parte desses estudos preliminares têm importância considerável ao levantar hipóteses baseadas na análise clínica dos pacientes estudados. No entanto, são necessários estudos maiores e com metodologia padronizada para protocolo diagnóstico e análise laboratorial dos indivíduos avaliados.

Superior ophthalmic vein and cavernous sinus thrombosis associated with COVID-19: a case report / Trombose de veia oftálmica superior e seio cavernoso associada à COVID-19: relato de caso

ABSTRACT Cavernous sinus and superior ophthalmic vein thrombosis is a rare clinical condition, and little described in the literature. The clinical presentation is nonspecific and highly variable, and symptoms may include red eye, ophthalmoplegia, coma, and death. The main etiology results from infection of the paranasal sinuses. The final diagnosis must be made through imaging tests such as magnetic resonance imaging. We describe a case of cavernous sinus and superior ophthalmic vein thrombosis after COVID-19 infection in a 64-year-old patient with persistent ocular hyperemia and pain on eye movement. Ophthalmological examination showed preserved visual acuity, conjunctival hyperemia, dilation of episcleral vessels and retinal vascular tortuosity in the right eye. Magnetic resonance imaging confirmed the diagnosis. The association with the COVID-19 was raised, excluding other infectious causes. Enoxaparin and Warfarin were started with significant improvement in the ocular clinical presentation and maintenance of initial visual acuity after 12 months of follow-up.

RESUMO A trombose de seio cavernoso e veia oftálmica superior é uma condição clínica rara e pouco descrita na literatura. A apresentação clínica é inespecífica e altamente variável. Os sintomas podem incluir olho vermelho, oftalmoplegia, coma e morte. A etiologia principal resulta da infecção dos seios paranasais. O diagnóstico final deve ser efetuado por meio de exames de imagem, como ressonância magnética. Descrevemos um caso de trombose de seio cavernoso e veia oftálmica superior após COVID-19 em paciente de 64 anos e com quadro de hiperemia ocular persistente e dor à movimentação ocular. Ao exame oftalmológico, observou-se acuidade visual preservada, hiperemia conjuntival, dilatação de vasos episclerais e tortuosidade vascular retiniana em olho direito. A ressonância confirmou o diagnóstico. A associação com a COVID-19 foi levantada, excluindo-se demais causas infecciosas. Prescrevemos enoxaparina e varfarina, com melhora do quadro clínico ocular e manutenção da acuidade visual inicial após 12 meses de acompanhamento.

[Ocular manifestations in patients with COVID-19]. / Okuläre Manifestationen bei COVID-19-Patienten.

BACKGROUND: There are only few reports on ocular symptoms and manifestations in association with coronavirus disease 2019 (COVID-19). OBJECTIVE: The aim of this study is to describe ocular manifestations in the anterior and posterior segments of the eye and to analyze viral prevalence in tears of patients with COVID-19. METHODS: Hospitalized COVID-19 patients treated from 16 April 2020 to 7 January 2021 at this hospital were screened for ocular manifestations in the anterior and posterior segments. Conjunctival swabs were analyzed for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA. RESULTS: A total of 37 patients were enrolled in this study. In the anterior segment we found chemosis of the conjunctiva (5), hyposphagma (2) and conjunctivitis (1). In 11 patients vascular alterations and potentially disease-specific manifestations of the fundus were found in one or both eyes: retinal hemorrhages (5), cotton wool spots (5) and tortuosity (5). One patient demonstrated branch artery occlusion, one had branch retinal vein occlusion and two patients had positive conjunctival swab results in one or both eyes. CONCLUSION: Our findings of the anterior segment are commonly known, although not specific for COVID-19. Various vascular fundus abnormalities were found in the study; however, it is unclear whether these were correlated to systemic comorbidities or whether they were caused or exacerbated by COVID-19. This study suggests that the risk of viral transmission via tears is low.

Evaluation of the Long-Term Clinical Results of 3 Patients Implanted with the Argus II Retinal Prosthesis.

This study presents the long-term clinical results of Argus II retinal prosthesis implantation in eyes with light perception and projection in 3 patients with end-stage retinitis pigmentosa. No conjunctival erosion, hypotony, or implant displacement was observed during postoperative follow-up. The electrical threshold values were lower in the macular region and higher close to the tack fixation region and peripherally. Optical coherence tomography scans showed fibrosis and retinoschisis formation at the retina-implant interface in two cases. This was attributed to mechanical and electrical effects on the tissue due to the active daily use of the system and the electrodes' proximity to the retina. The patients were able to integrate the system into their daily lives and perform activities that they could not do before. Studies on retinal prostheses for the rehabilitation of hereditary retinal diseases are ongoing, so both social and clinical observations and experiences related to the implant are valuable.

Key Genes of Immunity Associated with Pterygium and Primary Sjögren's Syndrome.

Pterygium and primary Sjögren's Syndrome (pSS) share many similarities in clinical symptoms and ocular pathophysiological changes, but their etiology is unclear. To identify the potential genes and pathways related to immunity, two published datasets, GSE2513 containing pterygium information and GSE176510 containing pSS information, were selected from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) of pterygium or pSS patients compared with healthy control conjunctiva, and the common DEGs between them were analyzed. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were conducted for common DEGs. The protein-protein interaction (PPI) network was constructed using the STRING database to find the hub genes, which were verified in clinical samples. There were 14 co-upregulated DEGs. The GO and KEGG analyses showed that these common DEGs were enriched in pathways correlated with virus infection, antigen processing and presentation, nuclear factor-kappa B (NF-κB) and Th17 cell differentiation. The hub genes (IL1R1, ICAM1, IRAK1, S100A9, and S100A8) were selected by PPI construction. In the era of the COVID-19 epidemic, the relationship between virus infection, vaccination, and the incidence of pSS and pterygium growth deserves more attention.

In vitro infection of human ocular tissues by SARS-CoV-2 lineage A isolates.

BACKGROUND: The purpose of this study was: [1] to evaluate the infectivity of two SARS-CoV-2 lineage A variants on human ocular tissues in vitro, and [2] to evaluate the stability of SARS-CoV-2 lineage A variants in corneal preservation medium. METHODS: Primary cultures of donor corneal, conjunctival, and limbal epithelium were inoculated with two lineage A, GISAID clade S isolates of SARS-CoV-2 (Hong Kong/VM20001061/2020, USA-WA1/2020), to evaluate the susceptibility of the ocular tissue to infection. Flat-mounted Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK) grafts were inoculated with SARS-CoV-2 to evaluate the susceptibility of the endothelium to infection. All inoculated samples were immunostained for SARS-CoV-2 nucleocapsid (N)-protein expression to confirm positive infection. SARS-CoV-2 Hong Kong was then inoculated into cornea preservation media (Life4°C, Numedis, Inc.). Inoculated media was stored at 4oC for 14 days and assayed over time for changes in infectious viral titers. RESULTS: Corneal, conjunctival, and limbal epithelial cells all demonstrated susceptibility to infection by SARS-CoV-2 lineage A variants. Conjunctiva demonstrated the highest infection rate (78% of samples infected [14/18]); however, infection rates did not differ statistically between cell types and viral isolates. After inoculation, 40% (4/10) of DSAEK grafts had active infection in the endothelium. SARS-CoV-2 lineage A demonstrated < 1 log decline in viral titers out to 14 days in corneal preservation media. CONCLUSIONS: SARS-CoV-2 lineage A variants can infect corneal, limbal, and conjunctival epithelium, as well as corneal endothelium. There was no statistical difference in infectivity between different lineage A variants. SARS-CoV-2 lineage A can survive and remain infectious in corneal preservation media out to 14 days in cold storage.

Eye Infection with SARS-CoV-2 as a Route to Systemic Immunization?

Infectious diseases of the conjunctiva and cornea usually leave behind both broad local and systemic immunity. Case reports of SARS-CoV-2-positive conjunctivitis with subsequent systemic immunity suggest a new route of immunization preventing the primary infection of the airways. MATERIAL AND METHODS: A total of 24 Syrian field hamsters were treated. In systematic animal experiments, we infected the eyes of n = 8 animals (group 1) and the airways of another n = 8 animals (group 2) with SARS-CoV-2 (Wuhan type); n = 8 hamsters served as controls (group 3). The weight development of the animals was recorded. After two weeks of observation of disease symptoms, all animals were re-exposed to SARS-CoV-2 in the respiratory tract (challenge) to determine whether immunity to the virus had been achieved. RESULTS: The epi-ocularly infected animals (group 1) showed no clinically visible disease during the ocular infection phase. At most, there was a slightly reduced weight gain compared to the control group (group 3), while the respiratory infected animals (group 2) all lost weight, became lethargic, and slowly recovered after two weeks. After the challenge, none of the animals in groups 1 and 2 became ill again. The animals in the negative control (group 3) all became ill. Cytotoxic antibodies were detectable in the blood of the infected groups before and after challenge, with higher titers in the epi-ocularly infected animals. CONCLUSION: By epi-ocular infection with SARS-CoV-2, the development of systemic immunity with formation of cytotoxic antibodies without severe general disease could be observed in the experimental animals, which did not induce any more disease upon a second infection in the respiratory tract. Therefore, it can be concluded that a purely epi-ocular infection with SARS-CoV2 only induces a weak disease pattern followed by systemic immunity.

Increased proinflammatory cytokines in tears correspond with conjunctival SARS-CoV-2 positivity in symptomatic COVID-19 patients.

Tear fluid cytokine levels may serve as biomarkers of innate immune system response against SARS-CoV-2 infection. Therefore, our aim was to analyze panel of selected inflammatory cytokines in tears of COVID-19 patients in relation to presence of SARS-CoV-2 viral load in conjunctival secretions. In this study concentrations of TNF-α, IL-1b, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12 p70, GM-CSF, and IFN-γ were determined by a magnetic bead assay in tear film collected from 232 symptomatic COVID-19 patients. SARS-CoV-2 ocular infection was confirmed based on positive conjunctival swab-based RT-PCR testing. Viral RNA in conjunctival sac was detected in 21 patients (9%). No relation between presence and the duration of ophthalmic symptoms and SARS-CoV-2 infection detected in conjunctival secretions was found. The tear film concentrations of IFN-γ, TNF-α, IL-5, IL-8 and GM-CSF were found to be significantly greater among patients with positive conjunctival swab results as compared to the group negative for SARS-CoV-2 in conjunctival sac. Our current data depict a group of inflammatory mediators in human tears, which may play a significant role in ocular pathology of SARS-CoV-2 conjunctival infection.

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.

The COVID-19 Pandemic from an Ophthalmologist's Perspective.

The current coronavirus disease 2019 (COVID-19) pandemic is rapidly spreading around the world. The first doctor to report this new disease was an ophthalmologist: this exemplifies the role of ophthalmologists in an infectious disease pandemic. Here we review how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) affects the eye and discuss implications for ophthalmologists.

Detection of COVID-19 in tears of ICU-admitted patients with SARS-CoV-2 infection.

PURPOSE: Upon the outbreak of 2019, novel coronavirus (COVID-19) pandemic confirmed the cases surpassed 20 million. Despite a few reports identified the association of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with ocular manifestations, it may assess the ocular symptoms of patients with the COVID-19 by ophthalmologists facilitate the diagnosis and prevent transmission. METHODS: A total of 60 patients with the COVID-19 admitted to Baghiatallah hospital from March 2020 to May 2020 were retrospectively reviewed and analyzed for the ocular manifestations, blood tests, and reverse transcriptase-polymerase chain reaction (RT-PCR) for SARS-CoV-2 using nasopharyngeal and conjunctival swabs. RESULTS: Among 60 included patients with clinically confirmed COVID-19, the median age 58.36 years (IQR: 30-88 years), 27 (45%) were male. Furthermore, 29 (48%) and 5 (8%) patients yielded positive for SARS-CoV-2 on RT-PCR from nasopharyngeal swabs and conjunctival specimens, respectively. Among 60 patients, 10 (16%) and 3 (5%), respectively, had the ocular manifestations and positive results for SARS-CoV-2 on RT-PCR from conjunctival and nasopharyngeal swabs. CONCLUSION: Although the positive rate of tear RT-PCR rate is not noticeable as nasopharyngeal swabs yet, COVID-19 transmission through the eyes is biologically plausible.

[Anterior eye segment damage in coronavirus infection (COVID-19)]. / Porazhenie perednego segmenta glaza pri koronavirusnoi infektsii (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.

Characterization of SARS-CoV-2 Entry Factors' Expression in Corneal and Limbal Tissues of Adult Human Donors Aged from 58 to 85.

Purpose: Recent studies have shown the presence of SARS-CoV-2 entry factors on the ocular surface, identifying the eye as an additional entry route for the virus. Moreover, the coexpression of angiotensin-converting enzyme 2 (ACE2) with other SARS-CoV-2 entry factors [transmembrane protease serine 2 (TMPRSS2), transmembrane protease serine 4 (TMPRSS4), and dipeptidyl peptidase-4 (DPP4)] facilitates the virus infection. Methods: Here, we performed a study over 10 adult corneal and limbal tissues from human donors, both male and female between 58 and 85 years of age. Some of the main virus entry factors were analyzed and their expression was quantified and correlated with the age and sex of the donors through western blot. The receptors' localization was investigated through immunofluorescence. Results: Immunofluorescence confirmed the localization of ACE2 and TMPRSS2 on the ocular surface and showed, for the first time, the localization of TMPRSS4 and DPP4 in limbal and corneal epithelial superficial cells. The quantitative analysis showed that the expression of SARS-CoV-2 entry factors on corneal and limbal cells is likely to be modulated in an age-dependent manner, in agreement with the increased susceptibility to COVID-19 in the elderly. Moreover, we found a relationship between the expression of TMPRSS proteases with the activation state of limbal cells in 80-year-old donors. Conclusion: This study provides information on the expression of SARS-CoV-2 entry factors on the ocular surface of 10 adult human donors and is a first observation of a possible age-dependent modulation on corneal and limbal tissues. Our data pave the way to further investigate the susceptibility to the infection through the ocular surface in the elderly.

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.

Detection of SARS-CoV-2 RNA in a conjunctival swab sample in real-time-polymerase chain reaction positive COVID-19 patients and its association with comorbidity and severity at a designated COVID-19 hospital in Central India.

PURPOSE: To evaluate the presence of SARS-CoV-2 RNA in the conjunctival swab sample of positive confirmed COVID-19 patients and to find out its association with comorbidity and severity of COVID-19 disease. METHODS: We conducted an observational cross-sectional study at a dedicated tertiary COVID-19 hospital in central India for a period of 8 weeks from February 2021to March 2021. We included patients who tested positive for SARS-CoV-2 RNA through nasopharyngeal swab and were above 18 years of age. Swab samples have been collected within 48 h of admission. Conjunctival swab was taken from the lower fornix of both eyes and sent to microbiology laboratory for real-time- polymerase chain reaction (RT-PCR). RESULTS: Out of 150 patients, conjunctival swab RT-PCR was positive in five patients (3.33%). Two patients had conjunctival manifestations in the form of conjunctivitis but conjunctival swab RT-PCR was negative in those patients. Among the RT-PCR positive patients, two (40%) were from mild, one (20%) was from moderate, and two (40%) were from severe category. No association could be established between conjunctival swab RT-PCR positivity and severity of the disease or associated comorbidity. CONCLUSION: Our study provides evidence that SARS-CoV-2 RNA could be detected in conjunctival secretions, and though the risk is relatively low, the eye may act as source of transmission. Extra caution should be taken by healthcare workers, and use of proper precautions like face shields and goggles should be encouraged.

Hydroxychloroquine treatment on SARS-CoV-2 receptor ACE2, TMPRSS2 and NRP1 expression in human primary pterygium and conjunctival cells.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the pathogen for coronavirus disease 2019 (COVID-19) pandemic. Its infection depends on the binding of spike protein to the host cell receptor angiotensin-converting enzyme 2 (ACE2), type II transmembrane serine protease (TMPRSS2) and neuropilin-1 (NRP1). Hydroxychloroquine has been applied as one of the COVID-19 treatment strategies. Here we aimed to evaluate hydroxychloroquine treatment on SARS-CoV-2 receptor expression in human primary pterygium and conjunctival cells and its potential influences. Expression of ACE2, TMPRSS2 and NRP1 proteins were found in the epithelial layer of both primary pterygium and conjunctiva tissues as well as in their isolated fibroblasts. High concentration of hydroxychloroquine treatment significantly reduced the viability of both primary pterygium and conjunctival cells. ACE2 protein expression was significantly decreased in both pterygium and conjunctival cells after hydroxychloroquine treatment. Hydroxychloroquine also reduced NRP1 protein expression in conjunctival cells. In contrast, TMPRSS2 protein expression showed slightly increased in conjunctival cells. Notably, ROS production and SOD2 expression was significantly elevated in both pterygium and conjunctival cells after hydroxychloroquine treatment. In summary, this study revealed the reduction of ACE2 and NRP1 expression by hydroxychloroquine in human primary pterygium and conjunctival fibroblasts; yet with the increase in TMPRSS2 expression and oxidative stress and decrease in cell viability. Implementation of hydroxychloroquine for COVID-19 treatment should be carefully considered with its potential side effects and in combination with TMPRSS2 inhibitor.