I stepped over to her table and asked, "Pardon me, but aren't you Liz Wardian?" Indeed, she was.

In the first few weeks of COVID restrictions in Beijing in 2020, I struggled to recognize colleagues who might be passing me on the street as I strolled outside the office or apartment building. This was all the more difficult because it was February, and most people in the city were bundled up in winter coats, hats and scarves.

That is when I began to watch instead for telltale characteristics, either the type and style of clothing or the way a person walked.

I have become so good at analyzing someone's particular gait－no two people walk exactly alike－that even on a darkened street I can usually recognize the body movement of someone I know.

But let's get back to the eyes. The constant wearing of masks has transformed us, in most encounters, into－to borrow from the title of a famous Western horror movie-"eyes without a face".

This has merely reinforced how we can, through our eyes only, express so much. No one can see whether, behind the mask, you are smiling or frowning, but the eyes lighting up or glaring say more than enough.

Consider the term "poker face", which refers to someone who has become highly adept at showing no emotional reaction, a useful ability when dealt a new hand in a card game. But no matter how stoic a person might be regarding control of facial muscles, the eyes have a much harder time telling a lie.