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

Abstract

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.

Keywords: ACE2; COVID conjunctivitis; COVID-19; SARS-CoV-2; ocular transmission; virus entry.

Figure 1

Overview of SARS-CoV-2 entry molecules, clinical manifestations, and transmission on the ocular surface with references. Figure created with BioRender.com. COVID-19: Coronavirus disease 2019, SARS-CoV-2: Severe acute respiratory syndrome coronavirus 2, OCT: Optical Coherence Tomography, RVO: Retinal Vein Occlusion, qRT-PCR: Quantitative reverse transcription polymerase chain reaction, Ct: Cycle threshold, ACE2: Angiotensin-converting enzyme 2, TMPRSS2: Transmembrane serine protease 2, CTSL: Cathepsin L, DPP4: Dipeptidyl peptidase-4, IFN: Interferon.