Abstract: In this paper, we explore the design space of eyelid gestures. We first present a framework for the design space based on the anatomy of the eye, human perception, and complexity of the eyelid gesture. Based on the framework we propose an algorithm to detect eyelid gestures with commodity cameras, already existing in laptops and mobile devices. We then populate the design space by demonstrating prototypes based on 3 form factors: mobile devices, desktop, and horizontal surfaces. These prototypes demonstrate the breadth of eyelid gestures as an input modality. We follow the scenarios with a discussion of how eyelid gestures can contribute to an interactive environment, and conclude with a discussion on insights, design recommendations, and limitations of the technique.