We tend to synchronize our movements to the person we are talking to during face-to-face conversation. Higher interpersonal synchrony is linked to greater empathy and more effortless interactions. This paper presents a first method and a corresponding dataset to explore synchrony in natural conversation by capturing eye and head movement using commodity smart eyewear. We present a 17 hour dataset, using Electrooculography and inertial sensing, of 42 people in conversation (21 dyads: 10 in Japanese, 10 in English, 1 in Chinese). Initial results on 18 dyads show significant interpersonal synchrony of blink and head nod behaviour during conversation (at frequencies of 0.2 to 0.5 Hz). We also find that people are more likely to synchronise blinks at around 1 Hz when conversing back-to-back than when face-to-face.