SARS-CoV-2 and the ocular surface: test accuracy and viral load

• Published in: Arquivos brasileiros de oftalmologia 2023, Vol.87 (5), p.e20220172
• Main Authors: Santoro, Dalton de Freitas, Hirai, Flavio Eduardo, Tochetto, Lucas Baldissera, Conte, Danielle Dias, Lima, Ana Luísa Hofling, Sousa, Luciene Barbosa de, Bellei, Nancy Cristina Junqueira, Freitas, Denise, Oliveira, Lauro Augusto de
• Format: Article
• Language: English
• Subjects: Adult; Aged; Conjunctiva - virology; COVID-19 - diagnosis; COVID-19 - virology; COVID-19 Nucleic Acid Testing - methods; Female; Humans; Male; Middle Aged; Nasopharynx - virology; Real-Time Polymerase Chain Reaction - methods; Reproducibility of Results; Reverse Transcriptase Polymerase Chain Reaction - methods; RNA, Viral - analysis; SARS-CoV-2 - isolation & purification; Sensitivity and Specificity; Specimen Handling - methods; Tears - virology; Viral Load; Young Adult
• ISSN: 1678-2925

This study aimed to evaluate the pre-sence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in the ocular surface of individuals clinically suspected of coronavirus disease 2019 (COVID-19) and determine the accuracy of different approaches of molecular testing on the ocular surface based on the nasopharyngeal positivity status for COVID-19. A total of 152 individuals with suspected COVID-19 symptoms who simultaneously underwent nasopharyngeal and two different tear film collection techniques for quantitative reverse-transcriptase polymerase chain reaction (RT-qPCR) were included. Tears were collected and randomized: one eye had the filter strip for the Schirmer test and the contralateral eye had conjunctival swab/cytology in the inferior fornix. All patients underwent slit lamp biomicroscopy. The accuracy of various ocular surface collection techniques used for the detection of SARS-CoV-2 RNA was determined. Of the 152 patients enrolled in the study, 86 (56.6%) had COVID-19 confirmed by nasopharyngeal PCR. Both tear film collection techniques detected viral particles: the Schirmer test was positive in 16.3% (14/86) and the conjunctival swab/cytology in 17.4% (15/86), with no statistically significant differences. No positive ocular tests were found among those with negative nasopharyngeal PCR tests. The overall agreement of the ocular tests was 92.7%, and in combination, the sensitivity would increase to 23.2%. The mean cycle threshold values in the nasopharyngeal, Schirmer, and conjunctival swab/cytology tests were 18.2 ± 5.3, 35.6 ± 1.4, and 36.4 ± 3.9, respectively. Compared with the nasopharyngeal test, the Schirmer (p=0.001) and conjunctival swab/cytology (p