The Effect of Tear Film Quality on Protective Properties against SARS-CoV-2 and on Further Risks of Infection in Dry Eye Disease

Abstract

SARS-CoV-2 is a new coronavirus causing global pandemic COVID-19 throughout the world, the clinical manifestations of which may include not only respiratory syndrome and systemic manifestations, but also eye symptoms. The purpose of the study. This study processed and presented to the scientific community the latest scientific evidence from the world literature regarding the effect of tear film quality on protective properties against SARS-CoV-2 and on further risks of COVID-19 infection in dry eye disease. Many studies have proven the presence of ACE2 as well as TMPRSS2 expression in the conjunctival and corneal epithelium and detection of SARS-CoV-2 RNA in the tear fluid of infected patients, which indicates the ocular tissue tropism to the virus and its possible transmission through the ocular surface. The detection of SARS-CoV-2 in conjunctival or tear samples may depend on viral load and secretion, as well as on sampling time during the course of the disease. It has been suggested that SARS-CoV-2 is prone to exist on the surface of the eye in the early stages of conjunctivitis, and the viral load decreases after a few days. However, cases of virus detection without conjunctivitis may indicate that SARS-CoV-2 can cause latent and asymptomatic infection. With the introduction of protective anti-epidemic measures such as protective masks, the rapid increase and progression of dry eye disease has begun, which leads to decreased ocular surface immune mechanisms, and could potentially increase the risks of SARS-CoV-2 virus transmission. The mechanisms of protection of the healthy ocular surface and possible ways to combat SARS-CoV-2 were reviewed. And the potential causes of increased ocular surface infections during a pandemic were also shown. Through wearing of protective masks, there is additional dispersion of air around the eyes and accelerated evaporation of tear fluid with its thinning and rupture, which contributes to the progression of the prevalence of dry eye disease. The information confirmed by research has already appeared in the literature. This ocular surface condition has been defined by the term "MADE" – dry eye associated with wearing a mask. Dry eye disease, in turn, is a multifactorial ocular surface disease that results in tear film instability, hyperosmolar stress, and a cascade of inflammatory responses. This initiates ocular surface damage, impaired immune status, pathological apoptosis of conjunctival and corneal cells, and loss of basic protective function. Conclusion. Thus, given the obvious decrease in the immune defense mechanisms of the ocular surface in dry eye disease, which is a vulnerable place for virus penetration, this area deserves further in-depth study