An ophthalmic surgical system utilizes a needle through which fluid is aspirated from a surgical site, and a sleeve coaxially received over the needle to define a flow passage between the sleeve and needle through which fluid is communicated to the surgical site. The system further includes a container that provides an adjustable infusion pressure for urging the flow of irrigation fluid to the surgical site. An aspiration pump urges aspiration of fluid from the surgical site, and a sensor detects the rate of aspiration flow. A controller is configured to calculate an intraocular eye pressure based on the infusion pressure and a pressure drop due to a resistance to the flow rate, which flow includes the sensed flow rate and a predicted leakage selected from a look-up table based on a size of the needle, a size of a sleeve, and a size of an incision through which the needle and the sleeve are placed.
