Method for machining optical workpieces, in particular, plastic spectacle lenses

A method of processing a workpiece that is a spectacle lens of plastic, having a first surface and a second surface which faces away therefrom and is to be processed, comprising the following principal steps carried out in the indicated sequence:

• (i) blocking the workpiece with the aid of a blocking material on a blocking member as holder during the processing so that the blocking material is located between the blocking member and the first surface of the workpiece,
• (ii) processing the workpiece by a geometrically defined cutting edge for achieving the desired macrogeometry at the second surface of the workpiece,
• (iii) processing the workpiece by a geometrically undefined cutting edge for achieving the desired microgeometry at the second surface of the workpiece and
• (iv) deblocking the workpiece from the blocking member,
• characterized in that the step (ii) of processing of the workpiece by a geometrically defined cutting edge comprises a plunge-cutting sub-step (ii.2) in which by a geometrically defined cutting edge starting from the second surface an encircling plunge cut is produced which extends through the first surface into the blocking material so that the workpiece with a predetermined edge profile remains on the blocking member radially within the plunge cut.