I have a problem, because the impression eye grows when it is moved.
Looks like the pupil is mapped to the mesh which is being stretched by a lattice. Maybe you could parent a circle mesh to the bone and shrinkwrap it to the eye’s surface.
Well yeah, that won’t work. It’s important in 3D to know the difference between a circle and a sphere.
This is what I meant:
Just rotate the empty and the circle mesh will be projected onto the surface of the eye along its local Z axis.