A system (OCT12 - OCT12") is provided for optically measuring internal dimensions of a sample object (10), for example an eye (20), said object comprising internal interfaces (14, 14, 14") at which the refraction index changes so that a portion of incident light is backreflected and/or backscattered and can be detected, by means of optical coherence tomography (OCT), comprising at least one first OCT device (OCT1) adapted to measure internal dimensions in a first partial volume (17) of the object (10), characterized by a combination with at least one second OCT device (OCT2) adapted to measure internal dimensions in a second partial volume (19) of the same object (10), wherein the second partial volume (19) is at least partially different from the first partial volume (17). The first and second OCT devices (OCT1, OCT2) may share at least partially spatially superimposed first and second sample arms (SA1, SA2), which may have respective different focal lengths (f1, f2) and pass through a common optical lens system (L12) toward the object, and which may share a common light source (LS12). Internal dimensions in a first partial volume (17) of the object and internal dimensions in a second partial volume (19) of the same object (10) are measured by means of optical coherence tomography (OCT) in a single measurement operation, but with different spatial resolution.
