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During the past decade, the field of refractive surgery has been flooded with dramatic advances introduced by new technologies. Aside from new applications of the femtosecond laser, further improvements were achieved with the development of new excimer laser platforms with higher repetition rates, faster eye trackers, and customized ablation profiles. Along with this rapid development, the primary goal of refractive surgery has evolved and today aims to provide "super vision" in terms of visual performance.
The quest for "super vision" has generated a surge of interest, leading to the development of new algorithms of treatment and numerous technological improvements in the newer generations of excimer lasers. A large number of studies comparing different ablation profiles and different excimer laser platforms have been published. However, has an ideal algorithm of treatment emerged from these studies? Does one ablation profile clearly demonstrate superiority compared to the other in regards to visual acuity, contrast sensitivity, or night symptoms?
After describing the technical properties of the various treatment algorithms using wavefront technology, we attempted to provide an overview of the clinical results available among several comparative studies. The factors tending to limit the success of these new procedures were also discussed along with future perspectives in the field. Studies reporting results of such profiles for retreatments, highly aberrated eyes, keratoconus, or transplant as well as results of topography-guided treatments were not included in this review.
Technical Considerations of Ablation Profiles
The technical aspects of excimer laser ablation have evolved considerably since the introduction of the formula for standard sphere-cylindrical correction described by Munnerlyn in 1988.1 Over the years, and with the surge of interest generated by wavefront technology, advanced laser treatment algorithms based on different concepts have been developed, aiming to correct not only lower but also higher order wavefront aberration errors.
Wavefront-Guided Treatment Requirements
Towards the end of the past decade, a new era began with the introduction of ablation profiles guided by the wavefront map to sculpt the cornea in a way to correct preexisting aberrations and reduce surgically induced aberrations. To achieve the precision required for this profile, advancements in excimer laser technology were needed.
The broad beam cannot treat small irregularities in the cornea and most current devices use flying-spot technology, in which...