A planning device produces control data for a treatment device for eye surgery which produces at least one cutting surface in a cornea of the eye using a laser device. The planning device includes a calculation module for establishing a cornea cutting surface. The calculation module is configured to establish the cornea cutting surface based on data of a refraction correction, to produce a control data set for actuating the laser device for the cornea cutting surface, and to determine the cornea cutting surface in such a way that it consists of a plurality of sub-surfaces, each of which make a contribution to the refraction correction.
