A new study finds that it is unlikely that infected patients are shedding the virus through their tears.
While it is certain that the new coronavirus spreads through mucus and droplets borne from coughs and sneezes, what has been less certain is whether or not it can be spread through other fluids sent forth from the body, like tears.
Noting that "Transmission through infected ocular tissue or fluid has been a controversy," Dr. Ivan Seah, MBBS, and a team of colleagues from the National University Hospital in Singapore set out to better understand if the virus that causes COVID-19 might be spread through tears.For their study, which was published in the journal Ophthalmology, the team collected tear samples from 17 patients with COVID-19. The samples were gathered from the time the patients showed symptoms until the time they had recovered, around 20 days later.
With two tests – a viral culture and reverse transcription polymerase chain reaction (RT-PCR) – the researchers detected none of the virus in tears throughout the course of the disease, according to the American Academy of Ophthalmology.
The study authors note, "A total of 64 samples were taken over the study period, with 12, 28 and 24 samples taken from first, second and third week of initial symptoms respectively. All tested negative for the SARS-CoV-2 [the virus that causes COVID-19]..."
The team also took samples from the back of the nose and throat during the same time period – and while the tears showed no presence of the virus, the patients' noses and throats were "teeming" with the COVID-19 virus.
The authors note that the study had some limitations. For one, they decided not to collect samples of conjunctival tissue. "In the pandemic setting, COVID-19 patients are already emotionally distraught with their diagnosis. Hence, conjunctival tissue sampling was avoided to reduce patient distress." Good call. They also note that it was a small sample size due to the logistical limitations of the outbreak response.
Regardless, Dr. Seah said he hopes the work "helps to guide more research into preventing virus transmission through more significant routes, such as droplets and fecal-oral spread."
In the meantime, the Academy wants to stress the importance of understanding that guarding your eyes – as well as your hands and mouth – can slow the spread of respiratory viruses like the coronavirus.
Even though tears may not shed the virus, the virus can enter through the eyes. The Academy writes:
"When a sick person coughs or talks, virus particles can spray from their mouth or nose into another person's face. You're most likely to inhale these droplets through your mouth or nose, but they can also enter through your eyes. You can also become infected by touching something that has the virus on it – like a table or doorknob – and then touching your eyes."
For more on the coronavirus and eye health, visit the Academy's EyeSmart page on coronavirus.