DO CURRENT LASERS POSSESS SUFFICIENT ACCURAcy AND SPATIAL RESOLUTION TO TREAT HIGHER-ORDER ABERRATIONS?
Dr. Mrochen states that current lasers can correct for third-order, coma-like aberrations and fourth-order spherical aberration, and Drs. Williams and MacRae cite a study9 showing that current laser spots of 1 mm in diameter or less can correct up to fifth-order aberrations, the most important aberrations in typical human eyes. In a similar vein, Dr. Thibos raises the issue of whether current aberrometers have adequate resolution. He believes they do for presurgical eyes but perhaps not for postsurgical eyes. Although he says some new lasers are capable of achieving good results on a theoretical surface, Dr. Lipshitz stresses10 that the cornea is not a piece of plastic. He argues that mechanical (eg, tracking and registration), biological (eg, wound healing and intraeye biological differences), and surgeon-dependent problems prevent lasers from adequately treating higher-order errors.11 Dr. Smolek notes the submicron precision of femtosecond lasers, which have been used to replicate LA
