RE: Can the Ophthalmologist contribute to the point-of-care testing for COVID-19?
References
Andreas Laupacis. Working together to contain and manage COVID-19. CMAJ 2020;192:E340-E341.
2. Xia J, Tong J, Liu M, Shen Y, Guo D. Evaluation of coronavirus in tears and conjunctival secretions of patients with SARS-CoV-2 infection. J Med Virol. 2020 Feb 26; doi: 10.1002/jmv.25725. Epub ahead of print. PMID: 32100876.
3. Colavita F, Lapa D, Carletti F, Lalle E, Bordi L, Marsella P, et al. SARS-CoV-2 Isolation From Ocular Secretions of a Patient With COVID-19 in Italy With Prolonged Viral RNA Detection. Ann Intern Med. 2020 Apr 17;M20-1176. doi: 10.7326/M20-1176.
4. Loon S-C, Teoh SCB, Oon LLE, Se-Thoe S-Y, Ling A-E, Leo Y-S, et al. The severe acute respiratory syndrome coronavirus in tears. Br J Ophthalmol. 2004 Jul;88(7):861–3.
5. Wu P, Duan F, Luo C, Liu Q, Qu X, Liang L, et al. Characteristics of Ocular Findings of Patients With Coronavirus Disease 2019 (COVID-19) in Hubei Province, China. JAMA Ophthalmol. 2020 Mar 31;e201291. doi:10.1001/jamaophthalmol.2020.1291
Coronavirus disease 2019 (COVID-19) has emerged as a global pandemic due to infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2).1 Considering presence of the virus in body fluids of patients, a potential risk of tear and conjunctival transmission of exists.2 However the transmission route of this virus remains unclear yet believed through aerosols.2 As-on-date, we have a limited understanding of the ocular complications of SARS-CoV-2 infection. The point worth writing this letter was to understand whether subjecting the conjunctival and tear secretions using disposable sampling swabs to laboratory testing by the Ophthalmologist be helpful? Anecdotal reports have given a pointer that SARS-CoV-2 may exist in samples in novel coronavirus pneumonia patients with conjunctivitis.2,3 Research in Singapore also revealed positive test results in three out of 34 highly suspected COVID-19 cases.4 An isolated report from a case in China suggested that viral loads in conjunctival specimens and the potential for transmission gradually decrease over time.5The standard conjunctival swab technique is used to collect the samples by wiping the conjunctiva of the lower eyelid fornix of the patient's eyes without anesthesia. The transfer and storage of these samples in virus transport media is as per routine COVID-19 testing protocol.1In many centers testing for the usual adenoviral conjunctivitis using real transcriptase polymerase chain reaction (RT-PCR) technique is a standard operating procedure. This technique detects viral nucleic acid and has a high sensitivity and specificity with added advantage of being simple, convenient, efficient when compared to culture. Sample contamination and damage to genetic material are standard risks. To add, researchers in Hong Kong obtained negative results on PCR from conjunctival sample in all their confirmed study subjects of COVID-19. World Health organization does not currently recommend the use of antigen-detecting rapid diagnostic tests for patient care, although research into their diagnostic utility is highly encouraged. Clinical decision making should not be based on these tests unless specific evidence exists. Unless the virus is seen to be causing significant ophthalmic manifestations as seen in ZIKA, conjunctival swabs as a routine to merely understand viral tropism in the eye may not be ideal. Conjunctival swab may be helpful to distinguish the cause for isolated conjunctivitis as a presenting feature of COVID-19 in high risk zones but needs further validation. It would be wise to realize that regional viral extent will direct personal protective equipment usage. Future research will define the infectious potential and mechanism of tropism of SARS-CoV-2 within ocular tissues. What we can understand as of now is that testing to see whether tears alone will transmit the virus in asymptomatic cases may be considered but this risk in miniscule especially if the patient is totally asymptomatic.