It is unlikely that COVID-19 patients transmit the deadly novel coronavirus through their tears, according to a study which sheds more light on how the virus spreads via bodily fluids.
The study, published in the journal Ophthalmology, assessed tear samples collected from 17 patients with COVID-19 from the time they showed symptoms until they recovered about 20 days later.
Since none of the patients had conjunctivitis, also known as pink eye, the researchers, including those from the National Centre for Infectious Diseases in Singapore, said the risk of virus transmission through tears is low.
The scientists analysed the presence of the virus in tears samples from the patients throughout the two-week course of the disease.
Ivan Seah from the National University Hospital in Singapore also took samples from the back of the nose and throat during the same time period.
"Neither viral culture nor reverse transcription polymerase chain reaction (RT-PCR) detected the virus, suggesting a low risk of ocular transmission," the researchers wrote in the study.
More From This Section
While the patients' tears were clear of virus, their noses and throats were teeming with COVID-19, the study noted.
The scientists, however, cautioned that it's important for people to guard their eyes, as well as their hands and mouth, to slow the spread of respiratory viruses like the novel coronavirus.
They explained that when a sick person coughs or talks, virus particles can spray from their mouth or nose into another person's face.
While people are most likely to inhale droplets through the mouth or nose, these can also enter through your eyes, the researchers warned.
People can also become infected by touching surfaces that has the virus on it -- like a table or doorknob -- and then touching the eyes, they said.
The researchers said studies involving more COVID-19 patients are needed to validate the results.
"Future studies involving more patients with ocular symptoms should also be considered. Finally, future studies should consider the association between serum viral load and viral shedding in tears," they reported in the study.