What I'm saying is, he shut his eyes and then opened them. There's a difference in narrowing your eyes, and not opening them as far as they were. There's also the fact that when anyone looks down just by moving their eyes, their eyelids will pretty much automatically shift with the direction of their gaze.
So what I mean when I say the drawings didn't account for this, is that they remove the context of what's in motion in the scene. Basically, Emet blinked into averting his gaze, and the gaze aversion keeps his eyes from fully opening. It would be better communicated if they could more realistically portray how eyelashes shift with eyelid movement, but that's a bit beyond FFXIV's graphics engine.
If you're not sure what I'm on about, or want a more real example, take the guy in this video for instance:
Reading Eyes Guy
He's going on about blink rate and things, but that's not what I care about. Look at his eyes while he speaks. Whenever he needs to find a word, his gaze averts, and it carries his eyelids with it. Most people's eyes function like this.
They somewhat accomplish this in XIV through a partial illusion related to the thick blackness of Emet-selch's eyelashes. His eyes don't actually open less in our scene than they were before. His irises move, being covered by more black and his bottom lids, giving the impression that his eyes are narrowed, but they're not, not really. This is also part of the reason they used the angle that they did.
