Method for centering a contact glass and refractive surgical laser system

A method for centering a contact glass relative to an eye of a patient, the method comprising the following steps:

• a) providing a fixation light by the contact glass such that the eye of the patient fixating on the fixation light is aligned relative to the contact glass;
• b) capturing an image representation of a light pattern generated by a light source having a fixed spatial relationship relative to the contact glass, with the capturing the image representation of the light pattern being implemented via a reflection on a surface of the eye;
• c) displaying the image representation of the light pattern reflected via the surface of the eye through the contact glass with overlaid virtual markings, with a first marking of the overlaid virtual markings identifying a central axis of the contact glass and a second marking of the overlaid virtual markings identifying a reference marking which, from the image representation of the light pattern, is derived as being located on the central axis of the contact glass;
• d) laterally positioning the contact glass relative to the eye such that a distance between the first marking and the second marking is minimized;
• e) defining a location of the eye at which the first marking is situated when the first marking and the second marking are at the minimized distance from one another as a position of a vertex of the eye, and registering the position of the vertex based on a feature of the eye that is recognizable in the image representation of the eye.