  Since the launch of Google Glass in 2014, smart glasses have mainly been
designed to support micro-interactions. The ultimate goal for them to become an
augmented reality interface has not yet been attained due to an encumbrance of
controls. Augmented reality involves superimposing interactive computer
graphics images onto physical objects in the real world. This survey reviews
current research issues in the area of human computer interaction for smart
glasses. The survey first studies the smart glasses available in the market and
afterwards investigates the interaction methods proposed in the wide body of
literature. The interaction methods can be classified into hand-held, touch,
and touchless input. This paper mainly focuses on the touch and touchless
input. Touch input can be further divided into on-device and on-body, while
touchless input can be classified into hands-free and freehand. Next, we
summarize the existing research efforts and trends, in which touch and
touchless input are evaluated by a total of eight interaction goals. Finally,
we discuss several key design challenges and the possibility of multi-modal
input for smart glasses.
