A control apparatus for an ophthalmic surgical system includes a measuring device with which, at a first time point and a second time point, the volume of an anterior chamber of the eye of an eye to be treated by phacoemulsification is determined. A control unit, dependent on the determined volume at the first time point and at the second time point, calculates a control variable to control a pressure or a volumetric flow rate in an irrigation line and/or an aspiration line of the ophthalmic surgical system.
