At present we are facing a situation that is unprecedented and unknown in our lifetime from Covid-19.1 While there is some undisputed information available, a lot is still not known. Symptomatic patients present with widely documented symptoms including respiratory diseases, fever, etc.2 Other symptoms such as those affecting the eyes have been less documented. It is, however, widely believed that transmission of Covid-19 occurs through direct or indirect contact with mucous membranes in the eyes, mouth, or nose. As a result, possible involvement of the ocular surface including the cornea, conjunctiva and the lacrimal system into the nasal duct must not be ignored.3-5

It has been shown that the S-protein of Covid-19 virus interacts with human ACE2 protein in respiratory cells, and that the human cornea and conjunctiva do express the ACE2 receptor.6 Recent studies by Huang et al (2020) and Liang and Wu (2020)7,2 reported a number of cases in which nucleic acid tests in the conjunctival sac were positive. Another recent case study (cited by 3) reports a person with pneumonia from Covid-19. Although he had previously worn an N95 mask, his eyes were unprotected and several days before the onset of pneumonia, he had complained of redness of eyes, and it is stipulated that the unprotected exposure of the eyes to Covid-19 virus might have resulted in the infection. While some studies suggest that it is the very close proximity of the patient to the practitioner that is the cause of transmission, possibly through the lacrimal duct rather than the cornea, the risk cannot be ignored. It is already known that exposed mucous membranes and unprotected eyes increased the risk of previous SARS-CoV transmission, and as a result it has been advised that infection measures should be stepped up and procedures such as micro-aerosol and nasal endoscopy procedures should be stopped.8 Ophthalmologists examining suspected cases should wear protective eyewear.9 However, I would argue that it is not just ophthalmologists who need this as other eye care professionals including optometrists are taking an increasingly vital role in dealing with acute and minor eye conditions including conjunctivitis (bacterial and viral).

In addition it is increasingly clear that asymptomatic patients can be a source of infection, and we know that a significant number of patients carrying the virus do not present with any symptoms.10, 11 While there has been a number of guidelines regarding screening potentially at risk patients (to
Covid-19) including asking a number of questions around symptoms and travel12 and disinfecting ophthalmological equipment, I would argue that this is not enough.13

We must learn from past pandemics,14 and if optometrists and other eye care practitioners are being asked to see these patients with ocular signs and symptoms then it is vital that they must also be given personal protective equipment.

Professor Shahina Pardhan, director, Vision and Eye Research Institute School of Medicine, Anglia Ruskin University

References

  1. Habibzadeh, P and EK Stoneman, The Novel Coronavirus: A Bird’s Eye View. Int J Occup Environ Med, 2020. 11(2): p. 65-71.
  2. Huang, Y, et al, Clinical characteristics of laboratory confirmed positive cases of SARS-CoV-2 infection in Wuhan, China: A retrospective single center analysis. Travel Med Infect Dis, 2020: p. 101606.
  3. Lu, CW, XF Liu, and ZF Jia, 2019-nCoV transmission through the ocular surface must not be ignored. Lancet, 2020. 395(10224): p. e39.
  4. Qing, H, et al, The possibility of COVID-19 transmission from eye to nose. Acta Ophthalmol, 2020.
  5. Seah, I and R Agrawal, Can the Coronavirus Disease 2019 (COVID-19) Affect the Eyes? A Review of Coronaviruses and Ocular Implications in Humans and Animals. Ocul Immunol Inflamm, 2020: p. 1-5.
  6. Ge, XY, et al, Isolation and characterization of a bat SARS-like coronavirus that uses the ACE2 receptor. Nature, 2013. 503(7477): p. 535-8.
  7. Liang, L and P Wu, There may be virus in conjunctival secretion of patients with COVID-19. Acta Ophthalmol, 2020.
  8. Lai, THT, et al, Stepping up infection control measures in ophthalmology during the novel coronavirus outbreak: an experience from Hong Kong. Graefes Arch Clin Exp Ophthalmol, 2020.
  9. Li, JO, et al, Novel Coronavirus disease 2019 (COVID-19): The importance of recognising possible early ocular manifestation and using protective eyewear. Br J Ophthalmol, 2020. 104(3): p. 297-298.
  10. Hu, Z, et al, Clinical characteristics of 24 asymptomatic infections with COVID-19 screened among close contacts in Nanjing, China. Sci China Life Sci, 2020.
  11. Hu, ZB and C Ci, [Screening and management of asymptomatic infection of corona virus disease 2019 (COVID-19)]. Zhonghua Yu Fang Yi Xue Za Zhi, 2020. 54(0): p. E025.
  12. Zeri, F and SA Naroo, Contact lens practice in the time of COVID-19. Cont Lens Anterior Eye, 2020.
  13. Zhang, MC, et al, [Suggestions for disinfection of ophthalmic examination equipment and protection of ophthalmologist against 2019 novel coronavirus infection]. Zhonghua Yan Ke Za Zhi, 2020. 56(0): p. E001.
  14. Bhadelia, N, Coronavirus: hospitals must learn from past pandemics. Nature, 2020. 578(7794): p. 193.