A new study has revealed the potential for asymptomatic carriers who have passed COVID-19 triage to leave traces of viral material in the ophthalmology exam room – even after wiping down chin and forehead rests between patients.
The small study, published in the The Journal of the American Medical Association this week, investigated the presence of SARS-CoV-2 at the biomicroscope stage, slit lamp breath shield, phoropter, tonometer and door handles after visits by patients who had no symptoms.
Author Dr Hasan Aytoğan, from the Department of Ophthalmology at the İzmir Tepecik Training and Research Hospital in Turkey, said there appeared to be no objective data demonstrating the risks of encountering individuals carrying the virus asymptomatically in maintained elective examinations.
According to the study, after COVID-19 triaging, 31 people visited the room, with 22 of those undergoing ophthalmic examination and nine being companions. The average examination time was nine minutes.
Seven samples were taken before examinations and returned negative results. Another seven were taken after the exam, with two samples found to be positive for COVID-19; one from the slit lamp breath shield and the other from the phoropter.
This was despite the room being cleaned with hydrogen peroxide 3% after the last exam and there being no visitors for approximately 18 hours after cleaning. No room cleaning was done between patients, but chin and forehead rests were wiped with isopropyl alcohol 70% between patients.
“This study showed the presence of COVID-19 viral material in a circle one metre in diameter around where the patients sat,” the study noted.
“In conclusion, this study provided objective data about the potential for patients who are asymptomatic, those accompanying them, or healthcare personnel in an eye examination room to leave viral material on the surfaces tested. Further studies are needed to determine the clinical relevance of these findings.”
In terms of limitations, the virus testing method establishes only the presence of viral material but did not provide information about infectivity, virulence, viability, or viral load. This is why Aytoğan cannot comment on the potential infection risk of encountering an asymptomatic carrier during a routine eye examination.
Additionally, the study had a small sample size, due to it being conducted over one day. Finally, it was not known whether patients, companions, and the healthcare worker developed symptoms.