Method for compensating positioning errors in an edging process, or in a fastening operation for a raw-edged, finished spectacle lens, and device therefor

A method for compensating for positioning errors in an edging process or in a fastening process of a raw-edged finished spectacle lens having a curvature, the method comprising:

• fastening the lens with a fastener at a fastening point consisting of a contact surface of the lens where the fastener contacts the lens, wherein, due to the lens curvature, there is formed a geometric prism in the fastening point,
• determining centering deviation parameters, wherein the centering deviation parameters are indicative of the occurrence of positioning errors of the raw-edged finished spectacle lens during a fastening operation and/or during a subsequent edging process and wherein determination of the deviation parameters encompasses a calculation of the geometric prism in the fastening point, wherein the contact surface constitutes an extent of which the geometric prism is to be calculated, and
• changing control information with the help of the determined centering deviation parameters, such that the positioning errors of the raw-edged finished spectacle lens are compensated and/or accounted for and a path of a grinder is altered during the edging process based on the changing control information.