Asymptomatic COVID-19 Patients Left Viral RNA After Eye Exams

SARS-CoV-2 was detected on a minority of environmental samples from an exam room where asymptomatic patients underwent a routine ophthalmology exam, a small study from Turkey found.

Of the seven samples taken after examinations of patients who passed COVID-19 triage questions, two samples of seven — one from the slit lamp breath shield and one from the phoropter, tested positive for SARS-CoV-2, reported Hasan Aytoğan, MD, of İzmir Tepecik Training and Research Hospital in Turkey, and colleagues, writing in JAMA Ophthalmology.

However, the authors only measured detectable virus, and were unable to determine if it was infectious virus, they noted.

They examined two threads of research to conduct their study: how long the virus lasts on surfaces, as well as the role of asymptomatic transmission by looking at an examination day in an outpatient ophthalmology clinic “without interventions for patients who were asymptomatic.”

“Since we were examining patients who are asymptomatic during the pandemic, we wanted to know if we could detect COVID-19 viral material at the end of a day of examinations of patients who were asymptomatic and seen in an eye examination room,” they wrote.

The room was cleaned with a hydrogen peroxide solution and had no visitors for 18 hours after cleaning. Importantly, the authors noted the room was not cleaned between patients, but chin and forehead rests were wiped with isopropyl alcohol, 70%.

Researchers used real-time polymerase chain reaction (RT-PCR) testing to detect viral RNA in samples from the biomicroscope stage, slit lamp breath shield, phoropter, tonometer, and door handles.

A total of 31 people entered the exam room, including 22 patients who passed COVID-19 triage and nine companions. Mean examination time was about 9 minutes. Seven samples were taken prior to all examinations that day and seven samples were taken after the last patient left the room.

While all samples taken at the beginning of each visit were negative, two of seven were positive at the end of the day. The samples from the slit lamp breath shield and phoropter were within a few feet (within 1 meter) of the patient versus other zones that were further away.

Other than RT-PCR only measuring viral material, not infectious virus or even viral load, the authors also noted it was not known whether patients, companions, and healthcare workers developed symptoms.