A wearable device includes a light source and a display unit. The display unit includes an image engine (13) that controls the light source to generate image content for display, and a plurality of optical elements (3) that direct the image content into a viewing zone. An eye monitor (7) measures information pertaining to an eye configuration of a user wearing the wearable device, and the image content is visible to the user when the eye is aligned with respect to the viewing zone. A spatial light modulator (SLM) (4) moves a position of the viewing zone based on the eye configuration information measured by the eye monitor (7). The eye monitor (7) measures pupil size of the user, and the optical elements direct the image content into the viewing zone that is smaller in at least one dimension than twice the measured pupil size. The light source may include a micro-electro-mechanical systems (MEMS) scanning mirror (2).