EyeWorld India December 2021 Issue

CORNEA 34 EWAP DECEMBER 2021 for screening that has been reviewed and refined. These criteria incorporated information from the CDC and FDA and were updated as knowledge about the virus increased. The goal, Dr. Mian continued, is to “make sure that we are addressing the concern with risk of transmission from donors who are COVID-19 positive or could be COVID-19 positive,” he said. “But it’s also important to balance the fact that we have patients blind from corneal disease who need their eye surgeries to be able to see.” Dr. Khandelwal mentioned that evidence has shown that SARS-CoV-2 can be killed with a variety of agents, including betadine. “Ocular tissue, when recovered, goes through a betadine prep, so COVID-19 on the tissue is likely killed,” she said. “However, once again, the recommendation is not to recover COVID-19 positive or COVID-19 suspects, adding a layer of safety for recipients but also for our recovery technicians.” Evolving recommendations from the EBAA Dr. Aldave is chair of the EBAA Medical Advisory Board (MAB) Subcommittee that has developed guidelines for eye banks to determine donor eligibility during the pandemic to help ensure the safety of corneal tissues. The EBAA MAB released their initial guidelines on 3 February 2020. Updated guidelines included a decision table that used the result of reverse transcriptase-polymerase chain reaction (RT-PCR) testing as primary determination of eligibility for ocular tissue donation. Guidelines were further revised with input from eye bank technicians, eye bank medical directors, and others to allow for medical director review for eligibility in the presence of signs and/or symptoms of COVID-19, the existence of a plausible alternative etiology for signs and symptoms, and the absence of close contact with an infected individual. The FDA updated guidelines on 4 January 2021, to say they don’t recommend testing on asymptomatic potential donors, but the donor should be tested if they had specific risk factors. A recent publication by the EBAA MAB Subcommittee chaired by Dr. Aldave noted that COVID-19 has been a strain on the eye banking system around the world, but screening demands are also a huge burden. 2 Testing has been an ongoing issue, whether it’s required or not. Early on, testing was not readily available, and some considered postmortem testing of tissue donors an irresponsible use of these limited testing capacity at the time, he noted. Testing still needs to be approached with caution because there are challenges in interpreting results. Some results are inconclusive, Dr. Aldave noted, and these donors could not be used because repeat testing isn’t possible. The false positive rate with RT-PCR is relatively low, but donor tissue could be wasted because those who have been infected with COVID-19 may still test positive even though they are not shedding replicating virus. This wasted tissue could impact international supply. One argument for universal testing was data showing how long the infection lasts postmortem, which could help with a guideline for collecting samples. The EBAA does not require eye banks to perform donor RT-PCR testing for SARS-CoV-2, but other organizations around the world are. Still others advise against it. Dr. Aldave noted that results on postmortem donors could take up to several days, which could delay tissue placement and processing, and universal testing could also increase costs. Although Dr. Aldave and colleagues have reported eight cases of corneal transplantation using tissue from donors who tested positive for SARS-CoV-2, only one of the recipients developed COVID-19, which was attributed to a community- acquired infection. 2 These cases highlight the importance of eye banks establishing a protocol to ensure timely communication with testing agencies about testing notification and results. COVID-19 has been found in the tear film, and the presence of SARS-CoV-2 viral entry factors have been noted on the ocular surface and in the cornea. Studies have found that it can infect cells in vitro, it remains viable for several days, and it can be found in postmortem tissue. The current EBAA medical standard requires double exposure of povidone-iodine to the ocular surface before tissue recovery. This is thought to help inactivate infectious virus found on the ocular surface, but it is not known if the virus in deeper tissues remain. Overall supply of donor tissue Dr. Mian said that some areas, particularly outside the U.S., are starting to feel the impacts of these more stringent screening guidelines for corneal tissue. Initially, there wasn’t much of an issue, he said. Through June 2020, the demand was fairly low, as most elective surgeries were canceled, hospitals shut down except for emergency care, and a lot of patients were scared to have surgery, Dr. Mian said. “Although supply decreased,