by Liz Hillman Editorial Co-Director
The COVID-19 pandemic has affected all areas of medicine, including eye banking. While much more is known about SARS-CoV-2 and the illness it causes, there are still several unknowns that continue to be investigated as they pertain to the safety of donor tissue.
The COVID-19 pandemic has affected all areas of medicine, including eye banking. While much more is known about SARS-CoV-2 and the illness it causes, there are still several unknowns that continue to be investigated as they pertain to the safety of donor tissue.
The reduction of corneal surgeries when elective surgeries were canceled and ongoing social distancing decreased the demand for corneal tissue overall, but it has crept back up. Winston Chamberlain, MD, PhD, said in mid-April that tissue demand was down about 90% nationwide; it’s now returned to pre-COVID level in his area. Kevin Corcoran said in June that the U.S. has been fortunate to have a surplus of donor tissue, allowing EBAA eye banks to fulfill requests without delays or waiting lists, but the lack of demand affected every eye bank in the early stages of the pandemic.
However, more stringent screening requirements have reduced the overall donor pool by 25–30% and may lead to isolated challenges in providing tissue on demand, Mr. Corcoran continued, adding that the association offers an online platform that allows eye banks with surplus supply to offer it to those that might be in need.
“Stricter donor criteria and enhanced donor screening are in place to ensure donor tissue is safer,” said Clara Chan, MD, explaining that the surgeon has to discuss potential risks with the recipient, similar to how they would with a blood transfusion. “We have done some epidemiological models, which predict a very low likelihood of transmission from donor cornea tissue, approximately <1/109,000 chance. Povidone-iodine is used for 2 minutes twice to clean the ocular surface prior to in situ recovery of corneal tissue.” A study of 33 donor corneas that were excluded from surgical use due to not meeting EBAA screening guidelines, medical director review, or a positive COVID-19 test found that of the 20 eyes that came from donors who were positive for COVID-19, three conjunctival swabs, one anterior corneal, five posterior corneal, and three vitreous swabs were positive for the viral RNA.1 The researchers also detected SARS-CoV-2 spike and envelope proteins in corneal epithelium in eyes that were not disinfected with povidone-iodine. The authors of the pre-press study concluded that there is a “small but noteworthy prevalence of SARS-CoV-2 in ocular tissues from COVID-19 donors,” which highlights the importance of donor screening guidelines, post-mortem testing, and povidone-iodine disinfection.
A paper by Desautels et al. on the topic of donor corneal tissue said, “Current recommendations from the United States and global eye bank associations call for the outright avoidance of tissues from donors recently infected with or exposed to COVID-19. This conservative recommendation is currently appropriate given the reported ocular sequelae, tear film viral detectability, and transmissibility of COVID-19.”