Examples of the disclosure relate to an apparatus (101), a wearable electronic device and an optical arrangement for optical coherence tomography. The apparatus comprises an optical coherence tomography system (103) and an optical arrangement (105). The optical arrangement comprises at least one means for beam shaping (109) configured to shape a beam of light from the optical coherence tomography system. The optical arrangement also comprises at least one mirror (111) positioned so that light from the means for beam shaping is incident on the at least one mirror. The at least one mirror is configured to move in at least one direction relative to the optical coherence tomography system.