A short coherence interferometer for measuring several axially spaced-apart regions of a sample, especially of an eye, which has a measuring optical path, through which the measuring radiation falls on the sample, a tunable interferometer for the axial, relative retardation of parts of the radiation, wherein the axial relative retardation is assigned to the axial spacing of the regions and a detector for producing an interference signal from interfering measurement radiation, scattered or reflected back from the sample as sample radiation. The tunable interferometer divides the sample radiation into two parts, which are axially relatively retarded and superimposed so as to interfere. During the superimposition, the tunable interferometer forms individual radiations, which represent quadrature components of the sample radiation, and the detector detects the individual radiations.