Let me clarify.

Not eye contact while one or ther other is speaking.

I am asking about deliberate eye contact while neither is speaking, and for a prolonged period. Not for one second, three, five seconds; say 20-30 seconds or even longer.
An extended ,silent, mutual gaze, such as a mother and newborn might exchange.

I have seen my sister in law do this with her babies; it was very moving even to me, a bystander.