Facial Motion and Controls - Animating with Blender: How to Create Short Animations from Start to Finish - page 185

Summary
Any of the standard deformation methods will work for creating facial expressions, but one of the best ways
to approach them is to individually create the expressions with the use of Shape Keys and to bind the
various shapes to bone controls for animation. The shapes are attached to the controls through the use of
Drivers in the Ipo window . Using this system, you can construct a set of facial expression controls tailored
specifi cally to the needs of your character.
Eyes present a special case and can be easily rigged and controlled with the use of a target bone, IK sight lines
and, for nonspherical eyes, lattices.
Outbox
● A character model with a set of controls for facial expressions, including eyes