A great deal of progress has been made since the publication of the first edition of Aberration-Free Refractive Surgery. It is now generally accepted that wavefront technology is defining a new standard of practice. The second edition of Aberration-Free Refractive Surgery expands on the first with in­ depth descriptions of advances made in this exciting field as well as glimpses of what to expect next. This volume provides the practitioner with solid background information from top researchers. The book will be indispensable to those practitioners and other optics professionals who wish to extend their knowledge of customi­ zed refractive surgery into an understanding of the underpinning technology. New subjects covered in this edition include cyclotorsional eye tracking, cy­ clotorsional registration, Variable Spot Scanning algorithms and underlying mathematical principles, and recent clinical results that support the conten­ tion that wavefront guided procedures are the new standard of practice for refractive surgery. In comparison to the first edition, due to the addition of new chapters the numbering of the previous chapters occasionally has been changed. For ex­ ample, Chap. 11, Wavefront Driven Custom Ablation: First Clinical Results, the so-called Heidelberg Study, was previously Chap. 7 in the first edition, whereas in this second edition the current clinical status of customized re­ fractive surgery results is presented in Chap. 13: Reviewing the Wavefmnt Clinical Trials: Myopia, Huperopia, and Eyes with Reduced Acuity.