EyeExpress: Expanding Hands-free Input Vocabulary using Eye Expressions

The muscles surrounding the human eye are capable of performing a wide range of expressions such as squinting, blinking, frowning, and raising eyebrows. This work explores the use of these ocular expressions to expand the input vocabularies of hands-free interactions. We conducted a series of user studies: 1) to understand which eye expressions users could consistently perform among all possible expressions, 2) to explore how these expressions can be used for hands-free interactions through a user-defined design process. Our study results showed that most participants could consistently perform 9 of the 18 possible eye expressions. Also, in the user define study the participants used the eye expressions to create hands-free interactions for the state-of-the-art augmented reality (AR) head-mounted displays.