Schirmer strip and conjunctival swab for viral detection on the ocular surface of adults: a scoping review

Purpose Schirmer Strips and Conjunctival swabs are used in ophthalmology for tears and fluids collection. During the COVID-19 pandemic, one of the biggest challenges is accurate diagnosis, and it is known that, in some cases, ocular manifestations are one of the first symptoms. In this context, this study has the objective of raising scientific evidence that highlights the use of Schirmer strips and conjunctival swabs as a method of sample collection for viral analysis to support future research on this theme. Methods A literature search was conducted in the PubMed, Web of Science and BVS databases, following the Scoping Review protocol defined by Joanna Briggs Institute (JBI) after the guiding question “Is it possible to detect viruses on the ocular surface with Schirmer Test and/or conjunctival swab?”.Results A total of 418 studies were identified, and after discerning analysis, 36 English written studies were selected. Three researchers analyzed studies after virus research, collection methods, and sample analysis. Publications were mainly on adenovirus, herpes simplex virus and SARS-CoV-2, and there is also evidence of ocular detection of more viruses types. Conjuntival swab analyzed through Polymerase Chain Reaction (PCR) or Reverse Transcriptase-PCR (RT-PCR) were the most used methods.Conclusions Studies have generally been conducted to understand viral infection, to develop accurate diagnostic methods and to follow the patients’ response to treatment. Most studies were performed with a small number of patients and lacked clear definitions of collection time and viral persistence since the onset of diseases. Viruses can be detected on the ocular surface through the analysis of Schirmer strips and conjunctival swabs. However, additional studies with larger populations and time permanence are necessary to develop more assertive conclusions on the theme.