Evidence of SARS-CoV-2 Transmission Through the Ocular Route

Abstract

Purpose

Currently, the coronavirus disease 2019 (COVID-19) pandemic is raging around the world. However, the transmission of its pathogen, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is not fully clear. It is still controversial whether the ocular transmission of SARS-CoV-2 exists. This review aimed to summarize the evidence of SARS-CoV-2 ocular transmission.

Methods

Online articles were searched till October 23, 2020 in Pubmed, Embase, and websites of World Health Organization, Centers for Disease Control and Prevention COVID-19, American Academy of Ophthalmology, and American Society of Cataract and Refractive Surgery under the search strategy of ((((“COVID-19”[Mesh]) OR (“SARS-CoV-2”[Mesh])) OR (2019 novel coronavirus)) OR (2019-nCoV)) AND ((((“Conjunctivitis”[Mesh]) OR (Ocular Surface)) OR (“Eye”[Mesh])) OR (“Ophthalmology”[Mesh])). The language was not restricted. After screening, 1445 records were excluded and 168 references original articles were finally included.

Results

Cells of ocular surface express both the receptor of angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2), offering molecular bases for the ocular susceptibility to SARS-CoV-2. Accumulated COVID-19 patients presented conjunctivitis as the initial or the only symptom. Whether COVID-19 patients had ocular symptoms or not, SARS-CoV-2 was detectable on the ocular surface, and the isolated virus was infectious, proving that the ocular surface can not only be a reservoir but also a source of contagion. SARS-CoV-2 may reach the ocular surface by hand-eye contact and aerosols. Once SARS-CoV-2 reaches the ocular surface, it may transfer to other systems through the nasolacrimal system or hematogenous metastasis.

Conclusion

The ocular surface can serve as a reservoir and source of contagion for SARS-CoV-2. SARS-CoV-2 can be transmitted to the ocular surface through hand-eye contact and aerosols, and then transfer to other systems through nasolacrimal route and hematogenous metastasis. The possibility of ocular transmission of SARS-CoV-2 cannot be ignored.

Keywords:

• COVID-19
• SARS-CoV-2
• ocular transmission
• conjunctivitis
• ACE2
• TMPRSS2

Data Sharing Statement

The data supporting the findings of this study are available from the corresponding authors Ming-Chang Zhang and Hua-Tao Xie on request.

Ethics Approval and Informed Consent

This article do not contain any studies with human participants or animals.

Consent for Publication

This article does not contain any studies with human participants.

Acknowledgments

This study was supported by National Key Research and Development Program of China (2017YFE0103500), National Natural Science Foundation of China (82070934), Fundamental Research Funds for the Central Universities (HUST: 2019kfyXMBZ065), and Research Foundation of Union Hospital (2018xhyn106). We thank Xiao-Na Jian M.D. for her assistance during the revision of the manuscript.

Disclosure

The authors have no conflicts of interest to declare for this work.

Additional information

Funding

Supported by National Key Research and Development Program of China (2017YFE0103500), National Natural Science Foundation of China (82070934), Fundamental Research Funds for the Central Universities (HUST: 2019kfyXMBZ065), and Research Foundation of Union Hospital (2018xhyn106).