A new study has shown coronavirus doesn’t appear to be present in people’s tears and thus transmission through tears is low.
Responding to the controversy surrounding the potential transmission through infected ocular tissue or fluid, Singapore National University Hospital researchers set out to determine if the virus is transmitted in tears by assessing its presence using quantitative reverse transcription polymerase chain reaction (RT-PCR).
The prospective study included 17 patients who had tested positive for infection by RT-PCR analysis of nasopharyngeal swabs. Investigators analysed 64 tear samples, derived from patients (both eyes) using Schirmer’s test strips, during the first, second and third week of initial symptoms. They found no evidence of severe acute respiratory syndrome coronavirus-2 (Sars-CoV-2) shedding in tears through the course of the disease.
“All tear samples showed negative results, even when nasopharyngeal swab samples continued to show positive results,” lead author Dr Ivan Jun told Ophthalmology Times. “Furthermore, patients with symptoms of upper respiratory tract infections did not demonstrate any viral shedding in tears, suggesting that the hypothesis of the lacrimal duct as a viral conduit may not be true. Most importantly, only one patient showed ocular symptoms during the disease course, and no evidence of Sars-CoV-2 could be found in the tear samples. This suggests that transmission through tears regardless of the phase of infection likely is low.”
Further studies are required to ensure eye care services can be provided safely, he concluded, adding these findings are likely to continue to be revised as more information about Covid-19 emerges.
