The invention relates to compounds of general formula I as well as their production and use as a medication. The resin composition comprises an acrylic graft copolymer including a rubbery acrylic ester polymer and a methacrylic polymer comprising 80 wt. In addition to providing separate groups of registers for multiple threads, a group of program address registers pointing to different threads are provided. Of application to the grinding of ophthalmic lenses. A control unit indicates one of the first information reading unit and the second information reading unit to re-read the information sheet when the other one of the information reading unit is unable to read the information.