Conjunctival polymerase chain reactions in COVID-19 patients and its correlation with clinical and paraclinical indexes

This study aimed to detect SARS-CoV-2 in conjunctival samples of COVID-19 patients to investigate the transmission route of COVID-19 and its correlation with laboratory indexes.

In this cross-sectional study, 44 COVID-19 patients were tested for conjunctival PCR in Ayatollah Rouhani hospital of Babol, Iran, in January and February 2021. The conjunctival samples were collected using a conjunctival swab and suspended in a viral transport medium. After RNA extraction and cDNA synthesis, real-time PCR was performed to investigate the SARS-CoV-2 genome in samples. The ocular manifestations and laboratory indexes were evaluated for all patients.

Among 44 COVID-19 patients, 6 samples (13.63%) were positive in terms of conjunctival PCR. The mean ± SD age of conjunctival PCR-positive patients was 76.17 ± 16.61-year-old, while conjunctival PCR-negative COVID-19 patients were aged 57.54 ± 13.61-year-old (p <0.05). D-dimer serum level is significantly higher in conjunctival PCR-positive COVID-19 patients (4001.00 ± 3043.36 µg/ml) compared to normal individuals (496.80 ± 805.92 µg/ml, p <0.01).

Our study showed that the conjunctiva and tear contain the SARS-CoV-2 in COVID-19 patients as a possible transmission route.