:rolleyes:

A seemingly normal prosthetic eye with a wireless connection to a button somewhere on the user's clothing. Perhaps on a ring or a shirt or blouse button. Pressing this button would activate a gyroscope within the eye that causes the pupil part to roll up to the top of the eye before returning to its original place.

You could show exxagerated contempt to those who know about your glass eye by overtly going to the effort of activating this. Or you could impress people who don't know about it by being able to roll your eyes one at a time.