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 non-specific 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>
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.