COVID-19 does not infiltrate eyes

The novel coronavirus disease (COVID-19) seems to spare the eyes, with no significant levels of SARS-CoV-2 RNA detected in the retinal and vitreous fluid, a recent study has found.

Researchers conducted a post-mortem analysis on 10 eyes from patients who had had COVID-19, as confirmed through pharyngeal swabs and broncho-alveolar fluids. Retinal tissues and vitreous fluid underwent histopathological assessments and quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) for viral RNA detection.

In both left and right eyes, qRT-PCR was not able to detect SARS-CoV-2 viral RNA in the retina and vitreous fluid. Histopathological analysis likewise showed no signs of ischaemic sequelae or lytic cellular lesions, indicative of viral infection.

Haematoxylin and eosin stains also showed generally normal extra- and intra-ocular morphology with no clear evidence of retinal inflammation or vessel occlusion.

To make sure that the absence of viral RNA was indeed true, and not an artefact of sample contamination or a compromised kit, the researchers also ran their qRT-PCR with positive and internal controls. In all cases, they encountered no problems with the controls, further suggesting that SARS-CoV-2 does not infiltrate the eyes.

“[I]n our small cohort of COVID-19 deceased patients, retinal histopathology appeared normal. Further studies are needed to confirm or refute the results and should also include additional markers to detect immunopathological changes and inflammation in the eye,” the researchers said.