A wearable electronic device includes an adjustment structure configured to adjust a distance between a first lens and a second lens. A user may wear the wearable electronic device and adjust an inter-lense distance so that there is a good match with the positions of their own eyes. The adjustment structure may include a lever, a first adjustment gear configured to be engaged with a first gear in a first position of the lever, a second adjustment gear configured to be engaged with the first gear and a second gear in a second position of the lever, and a third adjustment gear configured to be engaged with the second gear in a third position of the lever. The user may move the lever in or out to engage a different gear and then rotate the lever to adjust the inter-lense distance.