Current Affairs

Issue

Researchers have found that the cornea, which covers the iris and pupil – appears to be resistant to coronavirus infection in experiment.

 

Background

The novel coronavirus, SARS-CoV-2, mainly spreads through droplet transmission when a person coughs, talks or sneezes. But there were doubts regarding transmission through eyes.

 

Details

• SARS-CoV-2 RNA was found in the tears and conjunctival sac of some patients. Pink eye or mild conjunctivitis has also been seen in some patients with COVID-19. 

• Experts indicate that the presence of RNA does not mean that the virus was actively replicating inside the conjunctiva; it may have just been the person shedding the virus from the conjunctiva.

• In experiments using corneal tissue from 25 human donors and also mice corneas, the researchers exposed the eye tissue to three separate viruses: SARS-CoV-2, Zika virus, and herpes simplex virus 1.

• In the human cornea explants, the experiment showed that herpes and Zika virus were able to replicate in the tissue but tests showed no sign of SARS-CoV-2 replication.

• As for how the human cornea and conjunctiva might be capable of resisting SARS-CoV-2, the team isn't entirely sure.

• A potential molecular inhibitor of viruses in the eye – called interferon lambda – was able to limit virus growth in the human cornea for HSV-1 and Zika virus, but blocking the protein didn't seem to boost SARS-CoV-2's ability to replicate.

• Health professionals should use protective eyewear until there is enough proof to indicate that the virus cannot enter the body through eyes.