SEP 02, 2020
This prospective, observational study investigated the presence of SARS-CoV-2 on the environmental surfaces of an ophthalmology examination room after visits by asymptomatic patients who had passed COVID-19 triage.
Researchers excluded patients who traveled to affected areas, had contact with any confirmed or suspected cases of COVID-19 and who were symptomatic with fever, coughing or general illness. Conducted at a single center in Turkey, researchers used real-time PCR (RT-PCR) to detect the presence of viral RNA material in samples collected at the biomicroscope stage, slit lamp breath shield, phoropter, tonometer and door handles. The first group of samples was taken before the beginning of the examinations, and the second group of the samples was taken after the last patient had left the room. The main outcome was the presence of viral material on surfaces in 5 circular zones with a diameter of 1 m each around where the patients sat.
Twenty-two of the 31 individuals who visited the room underwent ophthalmic examinations while the other 9 were companions. The average examination time was 9 minutes (range 5-13 minutes). Of the 7 samples collected after examinations, 2 were positive for COVID-19: 1 from the slit lamp breath shield and 1 from the phoropter. The negative sample that was closest to the patient was taken at the tonometer, at a distance of 1.5 m; the other negative samples were from 3 to 4 m and 5 m
The authors only used RT-PCR to establish the presence of SARS-CoV-2 but do not provide information about infectivity, virulence, viability or viral load. The study had a small sample size and did not determine whether patients, companions and health care workers developed symptoms following the eye examinations. Finally, the low positivity rate of PCR may have caused some viral material to be missed.
This study provides objective data about the potential for asymptomatic patients, those accompanying the patients, or health care personnel in an eye examination room to shed COVID-19 viral material, despite the presence of a triage system to exclude patients with COVID-19.