Eyes on coronavirus

Dry eye disease caused by viral infection: Past, present and future

Following viral infection, the innate immune system senses viral products, such as viral nucleic acids, to activate innate defence pathways, leading to inflammation and apoptosis, control of cell proliferation, and consequently, threat to the whole body. The ocular surface is exposed to the external environment and extremely vulnerable to viral infection. Several studies have revealed that viral infection can induce inflammation of the ocular surface and reduce tear secretion of the lacrimal gland (LG), consequently triggering ocular morphological and functional changes and resulting in dry eye disease (DED). Understanding the mechanisms of DED caused by viral infection and its potential therapeutic strategies are crucial for clinical interventional advances in DED. This review summarizes the roles of viral infection in the pathogenesis of DED, applicable diagnostic and therapeutic strategies, and potential regions of future studies.

Retinal Changes in Patients With Covid-19 and Different Expressiveness of Metabolic Changes

AIMS

To study the relationship between the severity of COVID-induced metabolic changes and the structure and frequency of retinal changes, according to funduscopy data in patients with different clinical courses of COVID-19.

MATERIALS AND METHODS

117 patients with COVID-19 were examined. While examining patients, severity of the course of COVID-19, the expressiveness of changes in the metabolic status were determined; fundus image registration was performed with portable fundus cameras Pictor Plus Fundus Camera and VistaView (Volk Optical).

RESULTS

As a result of the research, retinal changes were found in 49 (41.9 %) patients with COVID-19. In 8 (16.3 %) cases, clinically significant (vitreous hemorrhage, prethrombosis of the central retinal vein or branches of the central retinal vein, thrombosis of the central retinal vein or branches of the central retinal vein) COVID-induced retinal and ophthalmological changes were observed, which caused a decrease in visual acuity. In 41 (83.7 %) cases, clinically insignificant changes (cotton wool spots, narrowed retinal vessels, intraretinal and petechial hemorrhages, tortuosity and dilatation of retinal venules) COVID-induced retinal changes were observed. Clinically significant retinal changes occur in patients with a statistically significantly higher level of D-dimer and a greater percentage of lung parenchyma lesion than in the group of patients with clinically insignificant retinal changes (p < 0.05).

CONCLUSIONS

The structure of retinal changes in patients with COVID-19 correlates with the severity of the clinical course of the disease and changes in the metabolic status of patients. Metabolic changes are correlated with retinal changes and can be predictive for preventing general vascular complications in COVID-19.

Long-term effects of SARS-CoV-2 infection on human brain and memory

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants have caused several waves of outbreaks. From the ancestral strain to Omicron variant, SARS-CoV-2 has evolved with the high transmissibility and increased immune escape against vaccines. Because of the multiple basic amino acids in the S1-S2 junction of spike protein, the widespread distribution of angiotensin-converting enzyme 2 (ACE2) receptor in human body and the high transmissibility, SARS-CoV-2 can infect multiple organs and has led to over 0.7 billion infectious cases. Studies showed that SARS-CoV-2 infection can cause more than 10% patients with the Long-COVID syndrome, including pathological changes in brains. This review mainly provides the molecular foundations for understanding the mechanism of SARS-CoV-2 invading human brain and the molecular basis of SARS-CoV-2 infection interfering with human brain and memory, which are associated with the immune dysfunction, syncytia-induced cell death, the persistence of SARS-CoV-2 infection, microclots and biopsychosocial aspects. We also discuss the strategies for reducing the Long-COVID syndrome. Further studies and analysis of shared researches will allow for further clarity regarding the long-term health consequences.

Choroidal and Retinal Vascular Findings in Patients with COVID-19 Complicated with Pneumonia: Widefield Imaging

Purpose: The purpose of this study was to analyze choroidal and retinal vascular alterations of both the macula and midperiphery areas in patients hospitalized for COVID-19 infection complicated with pneumonia within 30 days from discharge. Methods: A total of 46 eyes of 23 subjects with a history of symptomatic COVID-19 infection and recent hospitalization for pneumonia were enrolled in this observational study. Patients had not been previously vaccinated against COVID-19. A group of patients homogenous for age and sex was enrolled as controls. Microvascular retinal and choroidal features of the enrolled patients were studied with widefield optical coherence tomography angiography (OCT-A). Perfusion parameters in terms of the vessel density (VD) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) and the choroidal vascularity index (CVI) on enhanced depth imaging (EDI) mode OCT scans were analyzed. Results: Our cohort of patients showed a trend of reduction in VD, significantly in the SCP VD of the superior and inferior midperiphery sectors, whereas the CVI did not show significant differences between the cases and controls. Moreover, a positive correlation between CVI and vessel density in the deep capillary plexus in the macular area (VD-DCP-MAC) was found. Conclusion: The systemic disease due to COVID-19 can also involve the retina and choroid with multiple mechanisms: ischemic and inflammatory. Our study showed changes in perfusion occurring in the eyes of patients with a recent hospitalization for COVID-19 complicated with pneumonia and without any possible ocular effect due to the vaccines. There is still the need to better comprise how long COVID-19 actually affects vascular changes in the eye.

Investigation of changes in retinal vascular parameters and choroidal vascular index values during the early recovery period of COVID-19: The COVID-OCTA study

BACKGROUND

COVID-19 effects microvasculature in many tissues. This study investigated whether the choroidal structure is also affected.

METHODS

This cross-sectional study included 80 patients with COVID-19 and the same number of age- and gender-matched healthy individuals. All participants' right eye measurements were examined. Optical coherence tomography angiography (OCTA) was used for imaging. Otherwise, two independent researchers used the Choroidal vascular index (CVI) for choroidal parameters calculation.

RESULTS

Superior and deep flow values were lower in the COVID-19 group than in the control group, and vascular density (VD) values were lower in all regions in this group. Except for the superior mean VD, there was no statistically significant difference (p = 0.003). However, the COVID-19 group had significantly lower subfoveal choroidal thickness (SFChT) measurements than the control group (p = 0.001). In addition, no significant difference was observed between the groups in evaluating mean CVI values (p>0.05).

CONCLUSION

Noninvasive diagnostic tools such as OCTA and EDI-OCT can be used to monitor early changes in diseases affecting microvessels, such as from COVID-19.

COVID-19-associated retinovasculitis in the late stage of HIV infection: a clinical case

A clinical case of retinovasculitis with coronavirus infection COVID-19 involving a female patient in the late stage of HIV infection is reported. The patient had no antiretroviral therapy. Clinical features of eye changes, their severity and dynamics influenced by the ophthalmic therapy were revealed. A relationship between the course of COVID-19 and the state of immunodeficiency causes by HIV was found. As a result of the long disease duration and the complications, the patient died.

Update on overview of ocular manifestations of COVID-19

The coronavirus disease 2019 (COVID-19) has become the most critical health crisis at present, and research is continued about the exact pathophysiology, presentations, and complications of this pandemic. It influences several organs, and many studies have addressed the organs, the involvement of which during the COVID-19 results in patients' death. One of the important organs that can be involved during COVID-19, which is also a transmission route of the disease, is the eye. According to the evidence, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can have ocular manifestations and complications. According to the literature, conjunctivitis is the most common presentation, which can develop at any stage of COVID-19 (during and even after the disease), and the major pathophysiology of the eye involvement during the disease is attributed to the direct effect of the virus on the eyes, tissue damage caused by inflammation, underlying diseases, and the adverse effect of the medications prescribed. There are also reports of life-threatening complications, such as rhino-orbital cerebral mucormycosis, which require urgent treatment and are associated with a great mortality rate. Ocular manifestations may also be the presentation of a life-threatening event, such as stroke; therefore, it is necessary to pay great attention to the ocular manifestations during COVID-19. In this review, after about 2 years of the pandemic started, we present a narrative review on ocular manifestations during COVID-19, categorized into three main categories; ophthalmic, orbital, and neuro-ophthalmological manifestations with a detailed description of the presenting symptoms, risk factor, diagnostic, and therapeutic strategies suggested for each.

Association of COVID-19 Infection With Wearing Glasses in a High-Prevalence Area in Denmark and Sweden

Importance

Observational studies have indicated that glasses might protect against contracting COVID-19 through reduced airborne and contact transmission.

Objective

To investigate the association between wearing one's own glasses with contracting COVID-19 when adjusting for relevant confounders.

Design, Setting, and Participants

This cohort study was conducted during the first wave of the COVID-19 pandemic (June to August 2020) in Denmark and Sweden, where personal protective equipment was not recommended for the general population at the time. Employees at Falck, an international rescue corps with different job functions (ambulance, health care, office, and field staff, firefighters, and roadside assistance) participated in the study.

Exposures

The main exposure was wearing glasses (also including contact lenses and reading glasses), which was assessed in a questionnaire. Persons wearing glasses were compared with those who did not wear glasses (ie, nonusers). To adjust for potential confounders, information on age, sex, job function, and number of workday contacts were included.

Main Outcomes and Measures

The outcome was COVID-19 infection before (positive polymerase chain reaction test) or during the study period (biweekly voluntary tests with a rapid test). The investigated hypothesis was formulated after collecting the data.

Results

A total of 1279 employees in Denmark and 841 in Sweden were included (839 [39.6%] female and 1281 [60.4%] male; 20.5% were aged <40 years; 57.0%, 40-60 years, and 22.5%, >60 years). Of these, 829 individuals (64.8%) in Denmark and 619 (73.6%) in Sweden wore glasses. Wearing glasses was inversely associated with COVID-19 infection in the Swedish cohort (odds ratio [OR], 0.61 [95% CI, 0.37-0.99]; P = .047; seroprevalence, 9.3%) but not in the Danish cohort (OR, 1.14 [95% CI, 0.53-2.45]; P = .73; seroprevalence, 2.4%). Adjusting for age, sex, job function, and number of workday contacts in Sweden, wearing glasses no longer was associated with COVID-19 infection (OR, 0.64 [95% CI, 0.37-1.11]; P = .11). When stratifying by job function, a large difference was observed among office staff (OR, 0.20 [95% CI, 0.06-0.70]; P = .01) but not ambulance staff (OR, 0.83 [95% CI, 0.41-1.67]; P = .60) nor health care staff (OR, 0.89 [95% CI, 0.35-2.30]; P = .81).

Conclusions and Relevance

While wearing one's glasses was inversely associated with COVID-19 in Sweden in an unadjusted analysis, an association no longer was identified when adjusting for confounders. These results provide inconclusive findings regarding whether wearing one's own glasses is associated with a decreased risk of COVID-19 infections.

Danshensu alleviates pseudo-typed SARS-CoV-2 induced mouse acute lung inflammation

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can induce acute inflammatory response like acute lung inflammation (ALI) or acute respiratory distress syndrome, leading to severe progression and mortality. Therapeutics for treatment of SARS-CoV-2-triggered respiratory inflammation are urgent to be discovered. Our previous study shows that Salvianolic acid C potently inhibits SARS-CoV-2 infection. In this study, we investigated the antiviral effects of a Salvia miltiorrhiza compound, Danshensu, in vitro and in vivo, including the mechanism of S protein-mediated virus attachment and entry into target cells. In authentic and pseudo-typed virus assays in vitro, Danshensu displayed a potent antiviral activity against SARS-CoV-2 with EC₅₀ of 0.97 μM, and potently inhibited the entry of SARS-CoV-2 S protein-pseudo-typed virus (SARS-CoV-2 S) into ACE2-overexpressed HEK-293T cells (IC₅₀ = 0.31 μM) and Vero-E6 cell (IC₅₀ = 4.97 μM). Mice received SARS-CoV-2 S via trachea to induce ALI, while the VSV-G treated mice served as controls. The mice were administered Danshensu (25, 50, 100 mg/kg, i.v., once) or Danshensu (25, 50, 100 mg·kg^-1·d^-1, oral administration, for 7 days) before SARS-CoV-2 S infection. We showed that SARS-CoV-2 S infection induced severe inflammatory cell infiltration, severely damaged lung tissue structure, highly expressed levels of inflammatory cytokines, and activated TLR4 and hyperphosphorylation of the NF-κB p65; the high expression of angiotensinogen (AGT) and low expression of ACE2 at the mRNA level in the lung tissue were also observed. Both oral and intravenous pretreatment with Danshensu dose-dependently alleviated the pathological alterations in mice infected with SARS-CoV-2 S. This study not only establishes a mouse model of pseudo-typed SARS-CoV-2 (SARS-CoV-2 S) induced ALI, but also demonstrates that Danshensu is a potential treatment for COVID-19 patients to inhibit the lung inflammatory response.

Posterior ocular structural and vascular alterations in severe COVID-19 patients

Purpose

This study aimed to evaluate posterior ocular structural and vascular changes in severe coronavirus disease 2019 (COVID-19) patients.

Methods

This was an observational, prospective, and controlled study including 106 eyes of 53 severe COVID-19 patients, compared to after recovery and 106 eyes of 53 age- and gender-matched healthy controls. All subjects were previously healthy adults and were assessed using spectral domain optical coherence tomography (SD-OCT) and ImageJ software. Subfoveal over a 1500-μm span and macular over a 6000-μm span cross-sectional areas of the vascular, stromal, and total choroid were measured.

Results

Of the 53 included patients, 28 (52.8%) were male, and 25 (47.2%) were female, with a mean age of 50.2 ± 7.4 years. In the active period of the disease, compared to after recovery and healthy controls, the outer plexiform layer thickness showed a significant increase (p = 0.004), and mean choroidal thickness was significantly higher (p < 0.0001); however, choroidal vascularity was significantly lower (p < 0.0001). The stromal area to vascular area (S/V) ratio of the choroid was significantly increased (p < 0.0001). All quadrants of the peripapillary retinal nerve fiber layer (RNFL) thicknesses were significantly increased (for all, p < 0.05). The reflectivity of OCT echo of the choroid and peripapillary RNFL was significantly higher (p = 0.023, p < 0.0001, respectively).

Conclusion

This study detected significant posterior ocular structural and vascular alterations in patients with severe COVID-19 infections. These findings may be associated with direct host-virus interaction or linked to an autoimmune process, vasculopathy, or viral-mediated inflammation.

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.

Value of anal swabs for SARS-COV-2 detection: a literature review

Facing the unprecedented global public health crisis caused by coronavirus disease 2019 (COVID-19), nucleic acid tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are the gold standard for diagnosing COVID-19. The asymptomatic carriers were not suspected of playing a significant role in the ongoing pandemic, and universal nucleic acid screening in close contacts of confirmed cases and asymptomatic carriers has been carried out in many medium- and high-risk areas for the spread of the virus. Recently, anal swabs for key population screening have been shown to not only reduce missed diagnoses but also facilitate the traceability of infectious sources. As a specimen for the detection of viruses, the goal of this paper is to briefly review the transmission route of SARS-CoV-2 and the necessity of using anal swabs for SARS-CoV-2 screening to minimize transmission and a threat to other people with COVID-19.

Renal involvement in COVID-19: focus on kidney transplant sector

INTRODUCTION

Kidney transplant recipients and patients on the waiting list for kidney transplant who acquire SARS-CoV-2 infection are at serious risk of developing severe COVID-19, with an increased risk of mortality for the their immunosuppressive state; other risk factors for mortality have been identified in some comorbidities such as obesity, diabetes, asthma and chronic lung disease.

MATERIALS AND METHODS

The COVID-19 pandemic has led to a sharp reduction in kidney transplants in most countries, mainly due to the concern of patients on the waiting list for their potential increased susceptibility to acquire SARS-CoV-2 infection in healthcare facilities and for the difficulties of transplant centers to ensure full activity as hospitals have had to focus most of their attention on COVID-19 patients. Indeed, while the infection curve continued its exponential rise, there was a vertical decline in kidney donation/transplant activity.

CONCLUSION

This review article focuses on the damage induced by SARS-CoV-2 infection on kidney and on the adverse effect of this pandemic on the entire kidney transplant sector.