I think at the Cl website there's a mini explanation of how to set up a reflection. You have to create a new node in the material room, anyway I found it helpful. Maybe try your tests on a closeup eyeball, that should give you a good idea. I was also hoping that just pushing a slightly more expensive 'render' button would do the trick ;-).

"Your work is to keep cranking the flywheel that turns the gears that spin the belt in the engine of belief that keeps you and your desk in midair."

Annie Dillard