The COVID-19 Red Eye: An Algorithm for Differential Diagnosis and Management

As of October 5, 2020, the world had recorded 36 million confirmed cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with 237,302 of them in the Caribbean and 4,887 in Trinidad and Tobago. [1, 2] Novel coronavirus disease (COVID-19) can have various presentations not in keeping with its more common respiratory natural course. An uncommon presentation which has been reported originates in the eye in the form of keratoconjunctivitis. Other presentations include myalgia, fatigue, sputum production, headache, haemoptysis, diarrhoea and loss of taste or smell.


INTRODUCTON
As of October 5 th , 2020, the world had recorded 36 million confirmed cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with 237,302 of them in the Caribbean and 4,887 in Trinidad and Tobago. [1,2] Novel coronavirus disease (COVID-19) can have various presentations not in keeping with its more common respiratory natural course. An uncommon presentation which has been reported originates in the eye in the form of keratoconjunctivitis. [3] Other presentations include myalgia, fatigue, sputum production, headache, haemoptysis, diarrhoea and loss of taste or smell. [4] Why is conjunctivitis or redness of the eyes an important sign during this COVID-19 pandemic?
The involvement of the eye in this current COVID-19 pandemic should not be overlooked. In fact, an ophthalmologist was one of the first persons to recognize the outbreak of COVID-19. On December 30, 2019, Dr. Li Wenliang highlighted his findings to fellow doctors suggesting the emergence of a SARS-like illness in Wuhan, China, where he worked. He died on February 7, 2020, aged 33 years, after becoming infected with SARS-CoV-2. [5] There are several published reports which suggest that SARS-CoV-2 can cause conjunctivitis. It may present as an early sign of the infection, or during the hospitalization period of those with more severe COVID-19. A review of data from 1,099 patients across 552 hospitals in China, published in the New England Journal of Medicine, reported the incidence of this unusual presentation as 0.8%. [6] Another case series reported ocular symptoms in 12 of 38 (31%) hospitalized patients in Hubei province, China. These symptoms included, hyperemia, chemosis, epiphora, or increased secretions. Of those patients with ocular manifestations, 16% tested positive for SARS-CoV-2 on reverse transcription polymerase chain reaction (RT-PCR) by conjunctival and nasopharyngeal swab. [7] One case report by Cheema  This is an open access article under the terms of the Creative Commons Attribution License which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
keratoconjunctivitis, but subsequently developed acute pharyngitis for which a nasopharyngeal swab was performed. Her nasopharyngeal swab was positive of SARS-CoV-2 and RT-PCR on her initial eye swab which was sent for gonococcal/chlamydial assessment was also positive for the novel coronavirus. [8] Inflammation of the conjunctiva is not only thought to be a potential sign of SARS-CoV-2 infection, but the conjunctiva and, more specifically, the tears, may be a potential source of infection. The virus has been isolated in eye swabs in patients confirmed positive by nasopharyngeal swab. [8,9] Angiotensin-converting enzyme 2 (ACE2) receptors have been found to be integral in the virulence of this coronavirus. These receptors have been found in the conjunctiva and cornea. [9,10] Viral conjunctivitis is a common, self-limiting, relatively low-risk diagnosis among differentials of the acute red eye. However, some of the other life or sight-threatening diseases associated with acute red eye such as acute angle closure glaucoma, corneal ulceration, acute iritis or scleritis, may be missed due to the concern of spreading the coronavirus. This trend has already been noticed in other fields. For example, a significant decline in the incidence of cancer has been noted, likely due to decreased screening when compared to pre-pandemic data. [11] In these unprecedented times, it is important to identify those patients with acute red eye who require further evaluation whether for SARS-CoV-2 or another potentially harmful condition, while minimizing exposure of health care workers.
Consider the following: • Routine examination by the ophthalmologist utilizing slit lamp biomicroscopy, involves close face-to-face contact between patient and examiner (40-50cm).
This places the ophthalmologist at high risk of exposure. Dr Li Wenliang, a Chinese ophthalmologist, who is remembered today as a 'whistleblower', died of 2019-nCoV. [12] • Telemedicine and specifically teleophthalmology, involves the use of electronic communications and software to provide clinical services to patients without an in-person visit.
• Viral conjunctivitis (including that associated with 2019-nCoV) is self-limiting and usually runs a mild course, making it appropriate for remote consultation by telemedicine.
• Acute red eye has many differentials, some of which can result in significant morbidity if missed. Health care professionals should be confident in assessment of the acute red eye and make appropriate referrals to ophthalmology.
In light of the above considerations an assessment algorithm was formulated by doctors at the Port-of-Spain General Hospital eye clinic ( Figure 1).