The present application relates to a phacoemulsification system, comprising: a surgical handpiece； an irrigation fluid source adapted to supply irrigation fluid to the eye； an aspiration source adapted to aspirate the irrigation fluid from the eye through the handpiece； and a control unit comprising a flow rate sensor, wherein the flow rate sensor is configured to sense a flow rate corresponding to an occlusion of the handpiece； wherein the control unit is configured to control a vacuum based in part on the flow rate corresponding to the occlusion； and wherein the control unit is configured to control the vacuum by lowering the maximum level of vacuum level allowed during a surgical procedure.
