Corneal transplantation in the aftermath of the COVID-19 pandemic: an international perspective

To date, the SARS-CoV-2 has infected close to 13 million people and led to more than 560000 deaths worldwide in a short space of 6 months (WHO COVID-2019 situation report as of July 13, 2020). Since its emergence in Wuhan China, the SARS-CoV-2 has been reported to cause conjunctivitis and detected in tears or conjunctival secretions. 5 The potential for SARS-CoV-2 to affect the ocular surface had immediate implications for eye banking around the world. Furthermore, travel restrictions and curtailed elective procedures have led to the reduction in the supply, retrieval and demand for corneal transplantation. 6 Thus, the future of corneal transplantation faces an unprecedented threat, as access to this sight-restoring surgery is affected on a global scale. 7 Beyond the pandemic, COVID-19 may have lasting effects on corneal transplantation, as healthcare services resume to face long waiting lists and a potential shortage of donors. [...]there is an urgent need for a consensus on recommendations for restoring corneal transplantation services, even as the outbreak evolves and we learn more about the SARS-CoV-2. The next issue is whether the SARS-CoV-2 virus infects ocular tissue, which may affect the potential for transmission from corneal donor to recipient. 14 SARS-CoV-2 gains cellular entry through the ACE2 receptor after cellular protease priming via transmembrane serine protease 2 (TMPRSS2) and other co-mediators. 15 While the ACE2 receptor and TMPRSS2 were found to be significantly expressed in conjunctival tissue using immunohistochemistry based on mouse and human studies, 16 17 high throughput sequencing of mRNA and protein levels suggested no significant expression in healthy and diseased human conjunctiva biopsies for melanoma and squamous cell carcinoma. 18 Nonetheless, emerging studies have now shown both ACE2 and TMPRSS2 expression in cornea and conjunctival epithelium, 19 with expression of other proteins such as cysteine proteases cathepsin B and L that may enable viral entry. 20 Hence, the potential ocular infectivity of SARS-CoV-2 transmission through the ocular surface remains a concern based on these molecular and animal studies. 21 Given the prevalence of asymptomatic carriers, high transmission rates and a possible conjunctival infectivity, current recommendations to exclude potential donors who are PCR positive for SARS-CoV-2 and the duration needed from symptom resolution, requires further discussion. European Eye Bank Association (in lin