I modelled one half of his glasses, with a hollow polygon cylinder and then extruded arms and a bridge from the cylinder. The lens is simply a NURBS curve.
I then Mirrored the geometry of the gorilla's head, and then I modelled his headband, again with a hollow polygon cylinder. I then moved the vertices so the headband fit around his head more.
Lastly I modelled his eyeballs, Polygon spheres.
Here is how Cornelius looks at present, fully modelled.