A method and an apparatus for operating a screening wheel filter for high-viscosity melts with pressures of >10 bar and temperatures of >90° C., wherein a screening wheel (1) is rotationally driven step by step, and screening inserts (2) arranged in the screening wheel (1) are successively subjected to a stream of cleaning agent produced by a cleaning agent drive (9) in a backflushing cleaning station, are to be optimized in such a way that less cleaning agent is used, better cleaning of the screening inserts takes place and a saving of energy is ensured. For this purpose it is proposed that the cleaning backflushing in the backflushing cleaning station takes place during the rotation of the screening wheel (1), wherein an open-loop or closed-loop control device (7) assigned to the cleaning agent drive (9) is used to set the amount of cleaning agent and/or the pressure of the cleaning agent and/or the flow rate of the cleaning agent in dependence on the rotational speed of the screening wheel (1) and/or in dependence on a differential pressure prevailing at the screening inserts (2) located in the melt channel (4) and the effective opening of the slot die normal to the radial is less than the distance covered by the screening wheel (1) during a driving step.