The invention is directed to a device for determining the thickness, distance and/or profile of areas of a transparent and/or diffuse object that are spaced apart, in particular for measuring distances in the eye. In the device for determining position using an interferometer arrangement based on the Michelson principle, a scanning unit is arranged for the change in path length in the reference beam or measurement beam path. The scanning unit comprises a scan table which is movable translationally in corresponding guides, the movement direction enclosing an angle α to the reference beam. At least two reference mirrors having a distance d in direction of the reference beam and slightly overlapping laterally are arranged on the scan table so that during the oscillating movement of the scan table carried out by a motor the reference beam is reflected in itself first by the first reference mirror and then by the second reference mirror.