ABSTRACT
Purpose : <div style='direction: ltr;'>A key challenge in limiting the spread of Covid-19 is the absence of a fast non-invasive tool to detect infected individuals in the general population. Using polymerase chain reaction (PCR) testing, it has been demonstrated that SARS-CoV-2 is present in the tear film of patients with ocular symptoms. The presence of virions in or next to the lipid layer of the tear film would theoretically cause a measurable interruption of the normal tear bi-layer structure. The goal of this pilot study is to test the hypothesis that a specialized version of Tear Film Imager (vTFI) could be used for detection of infected individuals, in a quick, non-invasive manner. It is important to note that vTFI findings are not specific to SARS-Cov-2, and similar enveloped virions might cause a comparable disturbance.</div> Methods : <div style='direction: ltr;'>In our pilot study, twenty eyes of ten patients that were hospitalized due to Covid-19 infection in a designated quarantine department were compared to twenty eyes of ten healthy control patients. The study was approved by the Wolfson medical center's Institutional Review Board. All participants had a nasopharyngeal PCR swab confirming infection status up to 72 hours prior to examination by vTFI. Any patients with chronic viral infection (i.e. HIV, HBV etc'), corneal abnormalities, or corneal/refractive surgery were excluded to ensure uniformity of the data and focus on virion detection</div> Results : <div style='direction: ltr;'>Using vTFI 16 out of 20 healthy eyes correctly tested negative. 15 out of 20 Covid-positive eyes were correctly identified positive using TFI. In total 70% of the control group were correctly categorized by TFI algorithm as healthy (positive if one eye positive) and 80% of the Covid-infected individuals were positively identified.</div> Conclusions : <div style='direction: ltr;'>Identification of Covid-19 status from the tear film layer using ultra-fast non-invasive vTFI shows promise and a larger sample blinded study should be performed to assess its implementation in an outpatient setting. Being a nonspecific test, the use of vTFI is not dependent on special primers and may offer a modality for diagnosing individuals suspected of being infected with other emerging pathogens. </div>.