The clinical introduction of aberration-sensing and wavefront-guided refractive surgery opens new ways in diagnostic and therapy of high order optical aberrations of the human eye. The main application is the optimization of current treatment methods such as LASIK or PRK. The aim of wavefront-guided treatments is to omit the deterioration of the optical performance under mesopic conditions of the eye by the refractive treatment and, if possible, to increase contrast sensitivity by correcting the higher order aberrations. First clinical trails on wavefront-guided corneal laser surgery demonstrate the possibility of improving the optical quality of the eye by LASIK or PRK and to correct irregular astigmatism.