A phacoemulsification system includes a console connected to a hand piece that has an ultrasonically vibrated cutting tip. The console generates an ultrasonic electrical signal for the cutting tip, provides irrigation fluid and is the source of aspiration force. The console also has a pressure sensor. The control system has automatic operation such that the aspiration force lowers when a first preset pressure limit is reached, and the aspiration force and ultrasonic vibration are turned off at a second preset pressure limit higher than the first. The control system also lowers the aspiration force initially when a change in pressure per unit of time exceeds a preset limit and then increases the aspiration flow if the pressure level drops below the limit.