[Technical aspects of measurement for optically sophisticated eyeglasses]

This paper deals with the question of how aspherical ophthalmic lenses can be measured outside the reference point given by the manufacturer in order to make a lens comparison or to test the shape faithfulness of the lens surface. Three procedures are presented with measuring examples - vertex power measurement with swiveled lens mount, probe scan in a three-coordinate measurement, and interferometer measurement using a non-ideal reference lens. The basic problem inherent in an application-related interpretation of the measuring data sets gained by these methods is shown.