A vacuum device comprises a vacuum generator and a vacuum interface for fluidically coupling the vacuum generator to a vacuum cavity for affixing an ophthalmological patient interface on a patient's eye. The vacuum device comprises a movement detector which is configured to detect movements of the patient's eye and a control unit that is configured to detect a faulty fluidic coupling of the vacuum cavity on the basis of a pressure that is ascertained by a coupled pressure sensor and to produce a control signal for interrupting an ophthalmological treatment that is carried out by an ophthalmological treatment device if an eye movement is detected by the movement detector at the same time as the detected faulty fluidic coupling of the vacuum cavity.