1. The arrangement for carrying out a surgical treatment of an eye, comprising: a diagnostic instrument adapted to register eye-structure data, a data processing unit adapted to generate, on the basis of the eye-structure data registered by the diagnostic instrument, a structural image that contains at least one mapping of a characteristic eye structure and also at least one positional marking arranged relative to the mapping of the characteristic eye structure, an image-data fade-in device which is adapted to fade the structural image generated by the data processing unit into an image generated by a surgical microscope during the implementation of a surgical treatment of the eye.