A control arrangement for an ophthalmic surgical system for phacoemulsification of an eye lens includes an optical system for generating an image of an object region. At least part of the eye lens to be emulsified and part of a needle of a phacoemulsification handpiece can be arranged in the image. An image evaluation unit evaluates the generated image in such a way that an evaluation variable is generated which is dependent on a property of a particle produced by phacoemulsification of the eye lens or is dependent on a relation of the particle to its surroundings. A control unit generates a control variable in dependence upon the evaluation variable and, with the control variable, the control unit controls an absolute value of ultrasound energy which is supplied to the phacoemulsification handpiece by an energy source for phacoemulsification of the eye lens.
