Table 1.
Ocular transmission associated with COVID-19 studies
| Study | Age (years), | Sampling | ||||||
|---|---|---|---|---|---|---|---|---|
| no. | Author | Study title | Country | Design | N | mean±SD | technique | Findings |
| 1 | Zhou et al.27 | To investigate the possible transmission of SARS-CoV-2 through aerosol contact with the conjunctiva | China | Retrospective cohort | 67 | 35.7±10.6 | Nasopharyngeal and conjunctival swabs, RT-PCR | A total of 3 (4%) (1 case had positive PCR and 2 cases probable positive) |
| 2 | Deng et al.28 | To investigate the possible transmission of SARS-CoV-2 through the ocular conjunctival pathway | China | Cross-sectional | 114 | 61.4±16.7 | Nasopharyngeal swabs and conjunctival swabs, RT-PCR | No ocular complications or signs of ocular transmissible routes were reported |
| 3 | Seah et al.17 | To determine the possibility of transmission through tears by assessing for the presence of SARS-CoV-2 with viral isolation and quantitative RT-PCR analysis | Singapore | Prospective | 17 | Median 37 (range 20–75) | Collected by Schirmer test strip and analysed by RT-PCR | Risk of COVID-19 transmission through tears is low |
| 4 | Xia et al.29 | To assess the presence of novel coronavirus in tears and conjunctival secretions | China | Prospective | 30 | 54.50±14.17 | Sputum samples and conjunctival swabs, RT-PCR | All patients showed negative conjunctival swabs but one patient showed positive results |
| 5 | Karimi et al.30 | To assess the presence of SARS-CoV-2 in the tears of patients with COVID-19 | Iran | Prospective | 43 | 56±13 | Nasopharyngeal swabs and tear samples, RT-PCR | 3 (7%) patients had positive tear RT-PCR results |
| 6 | Sun et al.31 | To identify whether SARS-CoV-2 infected the ocular surface | China | Cross-sectional | 102 | 57.63±14.90 | Nasopharyngeal swabs and conjunctival swabs, RT-PCR | 1 (1.39%) patient showed positive RT-PCR results |
| 7 | Wu et al.32 | To investigate ocular manifestations and viral prevalence in the conjunctiva of patients with COVID-19 | China | Retrospective | 38 | Median 68 (interquartile range 53–76) | Nasopharyngeal swabs and conjunctival swabs, RT-PCR | 2 (5.26%) patients had positive RT-PCR results |
| 8 | Atum et al.4 | To identify SARS-CoV-2 RNA in conjunctival swabs from patients with confirmed SARS-CoV-2 infection | Turkey | Prospective | 40 | 41.38±23.72 | Nasopharyngeal, oropharyngeal and conjunctival swabs, RT-PCR | 3 (7.5%) patients had positive tear RT-PCR results |