The Ocular Surface and the Coronavirus Disease 2019: Does a Dual ‘Ocular Route’ Exist?

Coronavirus disease 2019 (COVID-19) is an important health problem that was definedas a pandemic by the World Health Organization on 11 March 2020. Although great concern hasbeen expressed about COVID-19 infection acquired through ocular transmission, its underlyingmechanism has not currently been clarified. In the current work, we analyzed and elucidated the twomain elements that should be taken into account to understand the “ocular route”, both from a clinicaland molecular point of view. They are represented by the dynamism of the ocular surface system(e.g., the tear film turnover) and the distribution of ACE2 receptors and TMPRSS2 protein. Althoughit seems, at the moment, that there is a low risk of coronavirus spreading through tears, it may survivefor a long time or replicate in the conjunctiva, even in absence of conjunctivitis signs, indicating thateye protection (e.g., protective goggles alone or in association with face shield) is advisable to preventcontamination from external droplets and aerosol.