An eye surgery system, comprising: a user interface; a measuring system (7, 9) configured to determine at least preoperative values (55, 57, 59) and intraoperative values (69, 71, 73) of an eye; a first computing module configured to determine a first value based on preoperative values, wherein the first value represents a property of an intraocular lens; a second computing module configured to determine a second value based on the intraoperative values (69, 71, 73) and at least some of the preoperative values (55, 57, 59) by performing a simulation on an eye model, wherein the second value represents a postoperative visual defect of an eye, and wherein the eye model includes plural parameters; a controller configured - to trigger the measuring system to determine preoperative values, - to trigger the first computing module to determine the first value representing the property of the intraocular lens, based on the preoperative values, - to trigger the user interface to display the first value representing the property of the intraocular lens, - to trigger the measuring system to determine intraoperative values, - to trigger the second computing module to determine the second value representing the postoperative visual defect of the eye, wherein the preoperative values of the eye are assigned to a first subset of the plural parameters and wherein the intraoperative values of the eye are assigned to a second subset of the plural parameters of the eye model, and - to trigger the user interface to display the second value representing the postoperative visual defect of the eye. a user interface; a measuring system (7, 9) configured to determine at least preoperative values (55, 57, 59) and intraoperative values (69, 71, 73) of an eye; a first computing module configured to determine a first value based on preoperative values, wherein the first value represents a property of an intraocular lens; a second computing module configured to determine a second value based on the intraoperative values (69, 71, 73) and at least some of the preoperative values (55, 57, 59) by performing a simulation on an eye model, wherein the second value represents a postoperative visual defect of an eye, and wherein the eye model includes plural parameters; a controller configured - to trigger the measuring system to determine preoperative values, - to trigger the first computing module to determine the first value representing the property of the intraocular lens, based on the preoperative values, - to trigger the user interface to display the first value representing the property of the intraocular lens, - to trigger the measuring system to determine intraoperative values, - to trigger the second computing module to determine the second value representing the postoperative visual defect of the eye, wherein the preoperative values of the eye are assigned to a first subset of the plural parameters and wherein the intraoperative values of the eye are assigned to a second subset of the plural parameters of the eye model, and - to trigger the user interface to display the second value representing the postoperative visual defect of the eye. - to trigger the measuring system to determine preoperative values, - to trigger the first computing module to determine the first value representing the property of the intraocular lens, based on the preoperative values, - to trigger the user interface to display the first value representing the property of the intraocular lens, - to trigger the measuring system to determine intraoperative values, - to trigger the second computing module to determine the second value representing the postoperative visual defect of the eye, wherein the preoperative values of the eye are assigned to a first subset of the plural parameters and wherein the intraoperative values of the eye are assigned to a second subset of the plural parameters of the eye model, and - to trigger the user interface to display the second value representing the postoperative visual defect of the eye.