A team of researchers found that the coronavirus that causes COVID-19 can be detected in tears sampled by ocular swabs, a new study has shown.

The researchers analysed samples from patients diagnosed with the disease by conventional methods and admitted to the Hospital, according to the study published in the Journal of Clinical Medicine.

SARS-CoV-2 was detected in 18.2 per cent of the samples, suggesting this method could be an alternative to the conventional swabbing method, which is unpleasant.

"Initially, we set out to develop a diagnostic test based on an easier collection of material without causing patient discomfort. Nasal and nasopharyngeal swabbing is not only unpleasant but also often performed incorrectly. For people with a nasal septum deviation, it can be a problem," said Luiz Fernando Manzoni Lourencone, the last author of the article.

"We took the view that tear sampling would be easy to execute and more tolerable. We succeeded in showing this to be feasible. Among the limitations of the study was not knowing whether the amount of liquid collected for the test influences its result," he added.

Moreover, the study cohort comprised 61 hospitalised patients, with 28 testing negative and 33 positives for COVID-19 by RT-qPCR via nasopharyngeal swab.

Tears were analysed from all 33 positives and from 14 of the 28 negatives. The findings suggest that the probability of detecting the virus in tears is greater when the patient has a high viral load, which can lead to viremia in body fluids, Lourencone said.