Plastic castings molds

The invention relates to a process for the preparation of mouldings, especially optical lenses and in particular contact lenses, to a corresponding device for the preparation of mouldings, and to the mouldings that have been prepared or are obtainable by the process or using the device, especially optical lenses and in particular contact lenses, in accordance with the preamble of each independent patent claim. The invention is concerned with the problem that with known plastic casting moulds, especially those of polypropylene, the lenses produced with these moulds have a slippery surface. The invention solves this problem through the use of polymers which are notable for their very low oxygen permeability.