The invention relates to a replaceable cartridge (1) for an ophthamological apparatus (2), comprising at least one hard region as a housing and at least one soft region, the hard region and the soft region forming inner liquid channels of the replacement cartridge (1). The soft region embodies functional elements of the replacement cartridge (1), said functional elements comprising at least one pump device for pumping liquid into the liquid channels, a valve device for modifying a through-flow cross-section in at least one of the liquid channels, and a pressure-detecting device for determining a liquid pressure in at least one of the liquid channels. The pressure-detecting device comprises a pressure chamber which is connected to one of the liquid channels, and a flexible membrane which peripherally surrounds a coupling element. The coupling element is designed with a recess such that a fork-shaped arm of a force-measuring device, which is oriented substantially parallel to the membrane, can be inserted into the recess in such a way that the coupling element has at least two sides, and with the arm, a force effect occurring in a substantially normal direction in relation to the membrane can be detected on the membrane.
