Frequency domain optical coherence tomography (FD-OCT) systems and methods are provided. Thereby, a first measurement and a second measurement is performed, wherein in the first measurement an object region is illuminated by measuring light having a spectrum with a first spectral width and in the second measurement the object region is illuminated with measuring light having a spectrum with a second spectral width, wherein the first spectral width is at least 10% greater than the second spectral width. Further, during the first measurement intensities of spectral ranges of light having interacted with the object and being superimposed with reference light are detected, wherein a width of these spectral ranges is greater than a corresponding width during the second measurement. Thus, switching an axial field of view of structural information of the object across a depth direction is enabled upon minimizing radiation damage at the object.