Though it is well known that coronavirus can spread through droplets and aerosols, a new study by Victoria Hospital has found that its viral RNA can also spread through teardrops.
The study involving a test group of 45 COVID-19 patients at the hospital found that none of the patients had “ocular manifestations” of the disease such as conjunctivitis (pink eye), but one tested positive for SARS-CoV-2 in the conjunctival swab.
“Though the positivity rate of detecting SARS-CoV 2 in the conjunctival swabs is very less, care should be exercised during the ocular examination of patients of COVID-19,” the authors wrote.
“The most direct implication of this is that ophthalmologists now needed to take precautions while examining patients. However, the finding also indicated that a person with undiagnosed COVID-19 can inadvertently spread the disease by smearing vitreous eye fluid on common surfaces,” explained one of the authors, Dr Ambica Rangaiah of the Department of Microbiology, Bangalore Medical College and Research Institute (BMRCI).
A researcher involved in the study added that chances of spreading the virus through conjunctival secretions are higher if the individual had redness of the eyes, sticky discharge, burning, or watering eyes, especially if the secretion has active viral RNA.
The implications are telling, said BMRCI dean Dr C R Jayanthi. “Common people are unaware that the virus is present in tears. So, they tend to touch their eyes with unclean hands and can thereby transmit the virus,” she said.
The 45 test subjects ranged in the six to 75 age group, with the majority falling into the age group of 21 to 40. Suspect cases and those patients who were critically ill had been excluded from the study.
The COVID patient who tested positive for the conjunctival swab was a 24-year-old asymptomatic man known to have several COVID-19 contacts, indicating his ability to transmit the disease.
An earlier study of 30 patients in Zhejiang, China, who suffered from COVID-induced pneumonia, also discovered a single patient with conjunctivitis who tested positive in a conjunctival swab.
“This shows that as in asymptomatic COVID-19 patients, that there could be no outward ocular manifestation of the disease,” Dr Ambica said.
The study was published in the Indian Journal of Ophthalmology.