No secret hiding place? Absence of SARS-CoV-2 on the ocular surface of 1145 hospitalized patients in a pandemic area

Graefes Arch Clin Exp Ophthalmol. 2021 Jun;259(6):1605-1608. doi: 10.1007/s00417-021-05086-3. Epub 2021 Jan 29.


Objectives: The aims of this study were to evaluate the isolated prevalence of real-time reverse transcriptase-polymerase chain reaction (RT-PCR)-confirmed SARS-CoV-2 on the ocular surface without systemic infection in hospitalized asymptomatic patients and to determine the risk for ophthalmologists and medical staff to be infected by prescreened asymptomatic patients in a tertiary eye care center.

Methods: In this prospective, observational study, bilateral swaps of the conjunctiva in the lower fornices as well as nasopharyngeal swaps were collected in 1145 hospitalized asymptomatic patients of a tertiary eye care center. Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) analysis was performed for each swap to evaluate the prevalence of SARS-CoV-2. Demographic data and potential risk factors for an isolated infection of the ocular surface were noted.

Results: Two thousand two hundred eighty-eight (99.9%) of all 2290 tested eyes had negative results in the RT-PCR analysis of the conjunctival swabs. One patient had bilateral false-positive results in the conjunctival swabs. None of the 1145 patients had any positive RT-PCR-confirmed result in the nasopharyngeal swabs.

Conclusions: The risk for an isolated conjunctival viral activity in patients with a negative nasopharyngeal swab-based RT-PCR seems to be absent or extremely low, suggesting no need to perform additional conjunctival swabs in patients with negative nasopharyngeal swabs. Furthermore, the risk of a work-related SARS-CoV-2 infection due to direct contact with preselected asymptomatic patients in an eye care center is very low, especially when additional hygiene standards and safe distances are respected carefully. This might reassure medical staff and reduce the fear of SARS-CoV-2 infection.

Keywords: COVID-19; Conjunctival swaps; Coronavirus; Nasopharyngeal swaps; Ocular surface; SARS-CoV-2.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Asymptomatic Infections
  • COVID-19 / diagnosis*
  • COVID-19 / epidemiology
  • COVID-19 / virology*
  • COVID-19 Nucleic Acid Testing
  • Child
  • Child, Preschool
  • Conjunctiva / virology*
  • Eyelids / virology*
  • Female
  • Germany / epidemiology
  • Hospitalization
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Middle Aged
  • Nasopharynx / virology*
  • Prospective Studies
  • RNA, Viral / genetics
  • SARS-CoV-2 / genetics
  • SARS-CoV-2 / isolation & purification*
  • Tertiary Care Centers


  • RNA, Viral