COVID-19: No strong local response of the conjunctival immune system

Symptoms in the eye may not be substantial in patients with COVID-19.

Polish investigators, led by Anna Niedźwiedź, MD, from the Department of General Pathology, Pomeranian Medical University, Szczecin, Poland, reported that the SARS-CoV-2 virus does not cause a strong local response of the conjunctival immune system, meaning that symptoms in the eye may not be substantial in patients with COVID-19.1

The investigators conducted a study in which they assessed the presence and duration of ocular symptoms during early-phase COVID-19 infections to determine the local immune response on the ocular surface.

The study was based on concerns by clinicians that the SARS-CoV-2 virus was transmitted via the tears and conjunctival secretions. In addition, some patients had conjunctivitis as the first symptom of COVID-19, which the authors explained may indicate that the ocular route could be a probable transmission path of SARS-CoV-2 to the rest of the human body.

The main outcome among the 180 study patients compared with 160 healthy age-matched controls was the occurrence of ophthalmologic manifestations at hospital admission and during the previous 7 days before admission. The investigators measured the tear film concentrations of tumor necrosis factor-α, interleukin-1b, -2, -4, -5, -6, -8, -10, -12 p70, granulocyte-macrophage colony-stimulating factor, and interferon-gamma.

Among the patients, 13% and 24%, respectively, exhibited at least one ocular symptom at admission and symptoms within the 7 days before hospital admission, which was significant compared with controls(p < 0.001). The patients complained significantly more often about ocular tearing (p = 0.04) and pain (p = 0.01) than controls.

Multivariate analysis showed that COVID-19 was a significant independent factor associated with higher levels of vascular endothelial growth factor and interleukin-10 tear film concentrations (p = 0.047 and p < 0.001, respectively) and significantly lower levels of interleukin-1β, interleukin-8, and granulocyte-macrophage colony-stimulating factor (p < 0.001; p = 0.004; and p = 0.0, respectively).

Based on the results, the investigators, “SARS-CoV-2 does not attract a strong local response of the conjunctival immune system; therefore, ophthalmic symptoms may not constitute a substantial element in the clinical picture of novel COVID-19 infection.”

  1. Niedźwiedź A, Kawa M, Pius-Sadowska E, et al. Evaluating ocular symptoms and tear film cytokine profiles in symptomatic COVID-19 patients. J Clin Med. 2022;11:2647;