Covid-19 and its relation to the human eye: transmission, infection, and ocular manifestations.

BACKGROUND: The world is suffering from a new strain of the coronavirus family-Covid-19. This virus strain affected different organs in the human body with a wide range of mild symptoms and moderate signs to severe and deadly ones. Multiple organs can be infected, and one of these organs is the eye. The eye is a vital organ that consists of vascular tissues and is connected to the respiratory tract through the tears and the nasolacrimal duct. METHODS: Recent papers and research from PubMed, Researchgate, and Google Scholar were cited and thoroughly discussed. These papers were chosen based on their relevancy, reliability, publication year, published journal, and ease of accessibility to the paper itself. RESULTS: The theory concluded that the ocular surface might consider a pathway for the virus attack and infection causation through the tears and the angiotensin-converting enzyme 2 located in the eye. This article thoroughly reviewed the history, the existing aspects of Covid-19, the ocular system features, and the claims about the possible involvement of the eye in the virus transmission along with the eye infection. There was no consensus on the eye's involvement theory. CONCLUSION: The authors highlighted the extra work and research needed to be conducted to prove or deny these claims to provide a better understanding of the immune response of the eye to Covid-19 infection.

Stochastic Epidemic Model for COVID-19 Transmission under Intervention Strategies in China

In this paper, we discuss an EIQJR model with stochastic perturbation. First, a globally positive solution of the proposed model has been discussed. In addition, the global asymptotic stability and exponential mean-square stability of the disease-free equilibrium have been proven under suitable conditions for our model. This means that the disease will die over time. We investigate the asymptotic behavior around the endemic equilibrium of the deterministic model to show when the disease will prevail. Constructing a suitable Lyapunov functional method is crucial to our investigation. Parameter estimations and numerical simulations are performed to depict the transmission process of COVID-19 pandemic in China and to support analytical results.