%0 Journal Article
%T Ablation Resolution in Laser Corneal Refractive Surgery: The Dual Fluence Concept of the AMARIS Platform
%A Samuel Arba-Mosquera
%A Thomas Hollerbach
%J Advances in Optical Technologies
%D 2010
%I Hindawi Publishing Corporation
%R 10.1155/2010/538541
%X Purpose. To evaluate to which extent individual Zernike terms can be corrected. Methods. Ablation time and fidelity was analysed using different fluence levels (range 90¨C2000£¿mJ/ ) and aspheric ablation profiles. With optimal parameters, the extent to which individual Zernike modes can be corrected was evaluated. Results. The range 188¨C565£¿mJ/ resulted as optimum fluence level with an optimum proportion range 50%¨C90% for high fluence. With optimal parameters, it corresponds to 2.4 s/D at 6£¿mm OZ, with fidelity variance of 53£¿ m RMS, and average ablation error of 0.5£¿ m for each location. Ablation simulation of coma Z[3, 1] showed 98,4% accuracy and 98% fit quality; trefoil Z[3, 3], 99,9% accuracy and 98% fit quality; spherical aberration Z[4,0], 96,6% accuracy and 97% fit quality; secondary astigmatism Z[4, 2], 97,9% accuracy and 98% fit quality. Real ablation on a flat plate of PMMA of coma Z[3, 1] showed 96,7% accuracy and 96% fit quality; trefoil Z[3, 3], 97,1% accuracy and 96% fit quality; spherical aberration Z[4,0], with 93,9% accuracy and 90% fit quality; secondary astigmatism Z[4, 2], with 96,0% accuracy and 96% fit quality. Conclusions. Ablation of aspherical and customised shapes based upon Zernike polynomials up to the the 8th order seems accurate using the dual fluence concept implemented at the AMARIS platform. 1. Introduction With the introduction of the laser technologies for refractive surgery, the change of the corneal curvature to compensate in a controlled manner for refractive errors of the eye [1] is more accurate than ever. The procedure is nowadays a successful technique, due to its submicrometric precision and the high predictability and repeatability of corneal ablation accompanied by minimal side effects. Standard ablation profiles based on the removal of convex-concave tissue lenticules with spherocylindrical surfaces proved to be effective in the compensation of primary refractive errors. However, the quality of vision deteriorated significantly, especially under mesopic and low-contrast conditions [2]. With the introduction of wavefront analysis, it was proved that the conventional refractive LASER techniques were far from ideal, by measuring the aberrations induced by conventional algorithms and the aberrations induced by the LASIK flap cut itself. With the LASIK (Laser in Situ Keratomileusis [3]) treatment, we have an accepted method to correct refractive errors such myopia [4], hyperopia [5], and astigmatism [6]. One of the most significant side effects in myopic LASIK, is the induction of spherical aberration [7], which
%U http://www.hindawi.com/journals/aot/2010/538541/