I, too, was an eye roller and can remember thinking my mother was ridiculous for getting upset. Now, being on the other side, I can see how annoying it is. You realize the primary goal is to annoy you, so there are two possible courses of action: 1)completely ignore it, or 2)tell her how adorable it is. I mean, make her gag -- "Have I ever told you just how cutesy, wutesy it is when you woll your wittle eyes? I just wuv it, I do. Come on, let's see it some more? Puhleeze?" And try to catch her just before she does it -- "Let's see the wittle eye rolls, okay?" All the while be sure you use the voice you usually reserve for speaking to an infant. Maybe even clap.
You will either start to break her of the habit or at least can get comfort in annoying her as much as she is annoying you!