The planning device for determining control data for a treatment device enables surgical tattooing of the cornea of an eye. Based on the measurement data and functional data introduced, a substantially annular surface is defined, which is located inside the cornea and which is delimited by a circular internal edge with an interior diameter and by a circular external edge with an exterior diameter. The annular surface has a distance and an incline with regard to the surface of the cornea, and for this annular surface, a set of control data for controlling the laser device is generated which defines a pattern of target points in the cornea with perforation zones partially or completely intersecting. Upon application of the pulsed laser beam, the tissue of the cornea is cut, and the external edge of the annular surface has a constant distance relative to the external edge of the iris.
