How to make smoothing-friendly indentations?

#1

I have this robot model Im trying to create, and it has indentations where its eyes are. Here it is unsmothed.

And here it is smoothed.

My problem is I want the sides to be harder edges and dont want curves. How can I edit the topology in a way that it smooths the sides, without messing up the fidelity of the overall cylinder? If I just add edges along the side, it messes up the overall shape. If I chamfer the corners, then that adds a bunch of nasty vertices and edges.

#2

Creases, a quick search gave me this:

www.youtube.com/watch?v=zDln3ESrPEY

www.mr-cad.com/Making-Crease-Using-3D-Studio-Max-p-1099.html