It is not all of eyelids, but is associating a lower half and a bone, and is visible to a natural motion.
>A certain number of frames from open to close to open?
The eyelid is closed at first.
It opens completely by 6 frames.
It is in the state opened to 72 frames.
The eyelid animation channel has a cycle duration of 72 frames.
Sorry,I cannot do English well.
Do you understand by this explanation?
After 1 cycle finishes(the eyelid has opened),
it begins from 0 frame(the eyelid has closed).
That is, 1 frame is not used after opening until it closes.
Since it is earlier to close rather than it opens man's eyelid,
I think that it is not necessary to draw.