In the current CoVid-19 situation, many may be wondering how far we go in protecting ourselves and our staff in our day-to-day work. Some of us remain in operation, seeing urgent cases and this may involve patients with acute problems including red eyes, epiphora, allergies, "conjunctivitis" and other ocular presentations which themselves may be a small part of the spectrum of symptoms experienced by patients with CoVid-19. Or, these or other symptoms, may co-exist in patients who have more mainstream features of the disease (hopefully, these latter patients would have been screened out by procedures detailed in my previous post, and have been referred to the local hospital for further assessment).
In any case, what protective equipment should we be donning to shield ourselves from potential infection?
The following is information from RANZCO, which I think applies to most Optometrists in the South West and Western Districts of Victoria, most of whom practice clinical Optometry to an extent that, I think exposes you to some risk. Hopefully you will find this of some help (for 'ophthalmologist', read 'optometrist'):
When should I use PPE?
The use of PPE by ophthalmologists seeing asymptomatic patients remains contentious. Thus far the Australian Government Department of Health has only recommended use of PPE for healthcare workers caring for suspect or confirmed COVID-19 cases. New Zealand has similar advice. There is strong evidence from other respiratory viral epidemics that wearing PPE (including mask and eye protection) minimizes the risk of infection.1-3 It is likely ophthalmologists are at higher risk of being infected by SARS-CoV-2 compared to the general population. This is based on the following:
1. COVID-19 is known to cause conjunctival congestion. In a large Chinese cohort of 1099 patients with laboratory confirmed COVID-19, this was reported in 0.8% of patients.4 In a smaller cohort from Hubei, China, 12 out of 38 (31.6%) of COVID-19 patients had ocular manifestations consistent with conjunctivitis. 5
2. SARS-CoV-2 has been isolated in tear and conjunctival secretions (although this is infrequent and one study failed to detect it in tears of 17 patients with COVID-19). 6
3. The virus has shown viability in aerosols for hours and surfaces for days.2
4. Infected patients can be asymptomatic. 3,7,8. In a testing of the entire population of Vo, Italy, almost 3% of residents tested COVID-19 positive and most were asymptomatic.9 In Yokohama, Japan, within a cruise ship holding 3711 passengers, 634 passengers tested positive for COVID-19. It was estimated that 17.6% of these were asymptomatic.10 One paper has suggested an undocumented infection rate of up to 86%. 11
5. Ophthalmologists come into close contact with our patients, closer than the 1.5m or 2m social distancing that is being recommended by the Australian and New Zealand governments respectively. This occurs at the slit lamp and for longer periods whilst operating.
6. Ophthalmologists have died from COVID-19, and at least 3 from the Central Hospital of Wuhan, including one after contact with an asymptomatic patient.11-14
Given the fact that ophthalmologists may themselves be asymptomatic carriers and see multiple patients, mask-wearing may prevent infection of patients. This is particularly relevant for our patients who tend to be older and co-morbid (the most vulnerable to COVID-19).
A retrospective review of 493 medical staff at Zhongnan Hospital of Wuhan University found none of 278 staff became infected by SARS-CoV-2 when wearing N95 respirators versus 10 of 213 staff who were infected when they did not wear a mask. This is despite the fact that the non-mask wearers worked in departments that were considered to be of lower risk than the group that wore N95 masks (who worked in the Departments of Respiratory Medicine, ICU and Infectious Disease).15
Surgical masks are currently recommended for ophthalmologists seeing asymptomatic routine patients in the following countries: USA, UK, China, Italy, South Korea and Singapore.16 They are recommended in some, but not all Local Health Districts in Australia for health care workers caring for patients in a vicinity closer than 1.5m.
When face to face consultations are required, ophthalmologists are advised to use their own judgement regarding use of PPE in asymptomatic, routine patients. They should be able to assess infection risk on a case by case basis, taking into consideration RANZCO guidance about how to assess patients, and be permitted to wear their own PPE if they feel this is clinically justified. Any decision should acknowledge the need to preserve critically low supplies of PPE in Australia and New Zealand.
1. Yu Jun IS, Anderson DE, Zheng Kang AE, et al. Assessing Viral Shedding and Infectivity of Tears in
Coronavirus Disease 2019 (COVID-19) Patients. . Ophthalmology 2020.
2. van Doremalen N, Bushmaker T, Morris DH. Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1. N Engl J Med 2020 2020;28.
3. Lauer SA GK, Bi Q, et al. The Incubation Period of Coronavirus Disease 2019 (COVID-19) From Publicly Reported Confirmed Cases: Estimation and Application. Ann Intern Med 2020;10.
4. Guan W, Ni Z, Liang W, et al. Clinical Characteristics of Coronavirus Disease 2019 in China. N Engl J Med 2020;28:28 2020.
5. Wu P, Duan F, Luo C, et al. Characteristics of Ocular Findings of Patients With Coronavirus Disease 2019 (COVID-19) in Hubei Province, China. JAMA Ophthalmology 2020.
6. Xia J, Tong J, Liu M, Shen Y, D G. Evaluation of coronavirus in tears and conjunctival secretions of patients with SARS-CoV-2 infection. J Med Virol 2020;26:26.
7. Lee K, J. Coronavirus kills Chinese whistleblower ophthalmologist. American Academy of Ophthalmology 2020.
8. Bai Y, Yao L, Wei T, et al. Presumed Asymptomatic Carrier Transmission of COVID-19. . Jama;21.
9. Crisante A, Crisone A. Coronavirus outbreak: In one Italian town, we showed mass testing could eradicate the coronavirus. Guardian 2020 8/03/2020.
10. Mizumoto K, Kagaya K, Zarebski A, G. C. Estimating the asymptomatic proportion of coronavirus disease 2019 (COVID-19) cases on board the Diamond Princess cruise ship, Yokohama, Japan, 2019. Euro Surveill 2020;25.
11. Cai J. Wuhan doctor who worked with whistle-blower Li Wenliang dies after contracting coronavirus on front line. South China Morning Post 2020 03/03/2020.
12. Parrish RK n, Stewart MW, Duncan Powers SL. Ophthalmologists Are More Than Eye Doctors-In Memoriam Li Wenliang. Am J Ophthalmol 2020;;09.
13. Green AL. Obituary Wenliang. Lancet 2020;295.
14. Global Times 2020 09/03/2020.
15. Healthcare Infection Society. Association between 2019-nCoV transmission and N95 respirator use. Journal of Hospital Infection. Letters to the Editor 2020:2020. https://doi.org/10.1016/j.jhin.2020.02.021
16. Li J, Shantha J, Wong Y, et al. Preparedness of Ophthalmologists during and beyond COVID-19 pandemic. Ophthalmology 2020.
Dr Vincent Lee,