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Coronavirus disease-19 (COVID-19) has reached pandemic status, and its pathogeny is the 2019 novel coronavirus (2019-nCoV).2019-nCoV mainly causes human respiratory infection and pulmonary inflammation; however, some COVID-19 patients are found to present viral conjunctivitis.Bilateral viral conjunctivitis is an initial symptom in some other cases.It is therefore, vital to understand whether the eye can be directly infected by the virus, as well as the consequences of the viral infection in the ocular tissue.2019-nCoV invades human cells primarily by binding to the angiotensin-converting enzyme 2 (ACE2) receptors.ACE2 expresses, not only in the lungs, kidneys, and cardiovascular system, but also in human conjunctiva, cornea, aqueous humor, and retina.Therefore, it is crucial to comprehensively expand the present understanding of the COVID-19 infection mechanism and pathogenesis by clarifying the distribution of ACE2 in the eye.ACE2 is not only the receptor of 2019-nCoV, but also a key enzyme in the renin-angiotensin system (RAS). RAS, which appears relatively independent in the eye, plays a modulating role and is associated with many common eye diseases.This article reviews the distribution and clinical significance of ACE2 in ocular tissues.