Is there a word or phrase for nodding/agreeing with your eyes only, not head?

When you say someone has nodded in agreement it is meant that they are lowering and raising their head to signify their agreeance without needing to say anything. There is a more subtle version of this, quite common in film, where Character A is asked a question and Character B responds by essentially blinking in agreement or by nodding with their eyes/eyelids. They do not move their head, and they may say something, but usually when they don't it used to deliberately not make it 100% clear to the audience what Character B's intentions are. I can't think of a specific example but I have seen it especially in high tension situations when a group of characters are trying to determine what side of the fence each person is, or during interrogation scenes. Example 1 (bold part is what needs replacing): After the meeting, Paul walks straight up to John, deliberately menacing. "So I hear that you're going to fire Tom?" demands Paul. John nods with his eyes, wary of the attention from the other colleagues in the room. "Was that a yes then?" John nods with his eyes again, "We should talk about this privately, Paul. So we don't disturb the other workers." "You really are a coward John!" Example 2 (bold part is what needs replacing): "Paul, were you or were you not at the suspects house 2 nights ago?" asks Officer John. Paul nods with his eyes. "Was that a yes? Please verbally confirm for the audio recording." Paul again nods with his eyes, answering John but not letting his answer be recorded. "Dammit, you answer me Paul!"

• single-word-requests
• phrase-requests

I have never observed anybody doing this—if nodding with your eyes means moving your eyes up and down. It simply doesn't happen. (In my experience, anyway.)

As Chappo has pointed out below, it is like a blink. It is subtle but once you look out for it you will pick it up in film all over the place.

A blink is something completely different from a nod. They aren't the same thing at all. You already use the word blink several times in your question, so I don't see how that can be the answer. And if you are using nod in some fashion that isn't its standard usage, you should describe what you mean by it. Or simply not use either of those words—but say what the action actually is. Or, better yet, provide a link to a video clip.

There are now three votes to close this question, but I think this is misguided. Is there a single word that describes the action of indicating agreement using facial expression but not head movement? I think this is a valid question, I have no trouble in understanding that this is what is being asked, and my own research suggests the answer is not easily found using standard resources. My own answer is that there is not a single word to describe this. Our consideration should be: does this question and its answer provide a useful contribution, both to EL&U and the broader internet base?

I'm voting to close this question as off-topic because while we could correctly answer, "no," that isn't helpful within the context of this site. Honestly, I cannot ever imagine anyone doing a "nod" ith the eyes, or a blink meaning yes, unless that was a pre-agreed code.