To the Editor We read with interest the article by Wu et al1 evaluating the ocular manifestations in 38 patients with coronavirus disease 2019 (COVID-19). Contrary to another recent article reporting only 8 of 121 patients (6.6%) having ocular symptoms,2 Wu reported a higher proportion: 12 of 38 patients (31.6%) with conjunctival hyperemia, chemosis, epiphora, or increased secretions, which they described as “consistent with conjunctivitis.”1(p575) We have reservations about their clinical descriptions of these ocular manifestations, independent of the COVID-19 laboratory findings from the conjunctival swabs.
In their article, two-thirds of these 12 patients were considered to have severe or critical cases. The constellation of manifestations described is compatible with signs of ocular surface disease (OSD), which are present in a variable proportion of patients in intensive care units.3 Chemosis, or conjunctival edema, also termed ventilator eye, can be present in 9% to 60% of patients in the intensive care unit.4 Positive pressure in mechanical ventilation and tight endotracheal tube taping increases jugular venous pressure, which decreases venous return from ocular vessels and results in the sequestration of fluid in the conjunctiva. A high positive end-expiratory pressure during mechanical ventilation encourages sodium and water retention, further provoking chemosis. A prone position can improve the ventilation-to-perfusion ratio. The gravitational force during the prone position can lead to venous pooling in the dependent area, potentially giving rise to facial and conjunctival edema. Sedation and muscle relaxant used in these patients also can impair the blink reflex and eyelid muscle tone, which can increase the risk of developing OSD. Patients who are critically ill often have electrolyte disturbances and fluid overload. This loss of fluid equilibrium between the intravascular and extravascular compartments normally maintained by osmotic and hydrostatic forces can lead to chemosis. Chemosis itself can lead to lagophthalmos and tear film disruption. We believe that exposure keratopathy or OSD are common in this setting and may be more likely than infectious conjunctivitis to produce these manifestations. It would be of interest if the authors1 could provide data regarding patients receiving mechanical ventilation, in the prone position, or receiving prophylactic eye ointment or eyelid-taping treatment. Such data might help differentiate the real causative mechanisms of the ocular manifestations.
We agree with the authors1 that not carrying out a detailed ocular examination to exclude intraocular diseases is justified to minimize the spread of transmission.5 However, without a detailed examination to evaluate the defining features of conjunctivitis, such as conjunctival papillae or follicles, it may be premature to attribute these ophthalmic manifestations observed by the authors to conjunctivitis.
Corresponding Author: Dennis S. C. Lam, MD, C-MER Dennis Lam & Partners Eye Center, C-MER International Eye Care Group, 1-3 Pedder St, Central Building, Ste 1515, Central, Hong Kong (dennislam@hkcmer.com).
Published Online: December 23, 2020. doi:10.1001/jamaophthalmol.2020.5819
Conflict of Interest Disclosures: None reported.