System for refractive ophthalmic surgery, comprising a) a first laser for ablating corneal tissue, b) means (22, 24, 24') for temporally and spatially controlled guidance of the radiation of the first laser onto the eye, c) a device for optical coherence tomography, comprising a second laser for carrying out optical coherence tomography on the eye, d) means (38, 40) for temporally and spatially controlled guidance of the radiation of the second laser onto the eye, and comprising e) a computer, which e1) controls the first laser and the aforementioned means (22, 24, 24') for temporally and spatially controlled guidance of the radiation of the first laser onto the eye during the ablation of corneal tissue in accordance with a program for the purposes of obtaining a reformation of the cornea, e2) controls the device for optical coherence tomography and is programmed in such a way that during the ablation, and before and after the ablation of corneal tissue, measurements are performed on the cornea, e4) controls the program sequence for ablating corneal tissue under predeterminable conditions following a measurement by means of optical coherence tomography, depending on the result of the measurement, wherein the computer e3) is programmed to display measurement results obtained during optical coherence tomography on a display device during the ablation of corneal tissue, characterized in that the computer e3') is programmed to display measurement results obtained during optical coherence tomography on a display device even before the ablation of corneal tissue, and in that provision is made of an input device, by means of which a user is able to prompt the computer to effect an additional ablation of corneal tissue with the first laser in a selected region (M1, M2) of the depicted measurement results of optical coherence tomography or to reduce the ablation of corneal tissue in a selected region; wherein the computer is programmed in such a way that the measurement results obtained with optical coherence tomography are analysed as to whether a corneal surface to be ablated has an irregularity (I, N), wherein the aforementioned analysis contains ascertaining gradients of the corneal surface. a) a first laser for ablating corneal tissue, b) means (22, 24, 24') for temporally and spatially controlled guidance of the radiation of the first laser onto the eye, c) a device for optical coherence tomography, comprising a second laser for carrying out optical coherence tomography on the eye, d) means (38, 40) for temporally and spatially controlled guidance of the radiation of the second laser onto the eye, and comprising e) a computer, which e1) controls the first laser and the aforementioned means (22, 24, 24') for temporally and spatially controlled guidance of the radiation of the first laser onto the eye during the ablation of corneal tissue in accordance with a program for the purposes of obtaining a reformation of the cornea, e2) controls the device for optical coherence tomography and is programmed in such a way that during the ablation, and before and after the ablation of corneal tissue, measurements are performed on the cornea, e4) controls the program sequence for ablating corneal tissue under predeterminable conditions following a measurement by means of optical coherence tomography, depending on the result of the measurement, wherein the computer e3) is programmed to display measurement results obtained during optical coherence tomography on a display device during the ablation of corneal tissue, characterized in that the computer e3') is programmed to display measurement results obtained during optical coherence tomography on a display device even before the ablation of corneal tissue, e1) controls the first laser and the aforementioned means (22, 24, 24') for temporally and spatially controlled guidance of the radiation of the first laser onto the eye during the ablation of corneal tissue in accordance with a program for the purposes of obtaining a reformation of the cornea, e2) controls the device for optical coherence tomography and is programmed in such a way that during the ablation, and before and after the ablation of corneal tissue, measurements are performed on the cornea, e4) controls the program sequence for ablating corneal tissue under predeterminable conditions following a measurement by means of optical coherence tomography, depending on the result of the measurement, e3) is programmed to display measurement results obtained during optical coherence tomography on a display device during the ablation of corneal tissue, e3') is programmed to display measurement results obtained during optical coherence tomography on a display device even before the ablation of corneal tissue,