Even though conventional and customized laser refractive surgery techniques have proved to be effective in improving patient’s visual performance, a better understanding of the wave aberration induced by a laser ablation procedure is required to achieve greater improvement in vision. Refractive standard surgery changes the optical power of the eye by modifying the corneal surface (the cornea is made steeper for hyperopic astigmatic corrections and flatter for myopic astigmatic corrections) altering the curvature of the corneal surface and hence its asphericity. Although most patients are satisfied with their vision after standard astigmatic LASIK, some patients experience glare, halos and ghost images, particularly at night or in dim conditions. Aberrometry may be useful in refractive surgery in measuring the quality of vision and in creating a laser treatment which minimizes postoperative aberrations. In this chapter we compare standard ablation with customized ablation, obtaining better outcomes in astigmatic corrections in the customized ablation group.