I could probably make 10 posts just about eyes, but here's a primer.
Like all constructed objects, eyes and eyebrows follow a hierarchy.
Pupils sit on the eyeballs. So do the irises. The irises follow the pupils where ever they travel on the eyeballs, so they all have to relate to each other and be in agreement.
Daffy's pupils are not exactly the same shape as the eyeballs, but they sit along the same path the eyes take.
Sorry for the wiggly lines. I'm trying to draw directly on the computer and I don't have as much dexterity as I do with a pencil.
Eyebrow wrinkles are folds of flesh; they aren't just floating lines.
Eyes, eyebrows and wrinkles are all related...Smee's eyebrow wrinkles are very carefully drawn in perspective; they aren't parallel to his eyebrows.
Hook's eye and eyebrow details follow the forms of his eyeballs and expression.
Woody's pupils are pulling the eyes and irises along with them.
The Warner Bros. animators also use this logic, although their inking is not always as careful as Disney's. So the final details sometimes float a little.When drawing cute girls, I avoid drawing the eyebrow wrinkles unless the girl is making an extreme expression.
I try to make the eyeballs bulge out no matter what angle we see her from - even from the front. I do it by the way I draw the shapes of the pupils and irises riding the eyeballs. Note that I don't use perfect ovals or symmetry. That would make the characters look dead or robotic.
These are Katie's designs but my poses. All drawn with hierarchy in mind.
See Eye theories at work in this here post: