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Development of an Advanced Nomogram for Myopic Astigmatic Wavefront-Guided Laser in Situ Keratomileusis (LASIK)

2011; Volume: 42; Issue: 3 Linguagem: Inglês

10.3928/15428877-20110303-01

2325-8179

Jesse B. Biebesheimer, Terry S. Kang, Cynthia Y. Huang, Fei Yu, D. Rex Hamilton,

Intraocular Surgery and Lenses

Background and Objective: To identify the relationship between preoperative parameters and postoperative overcorrection or undercorrection in eyes with myopic astigmatism treated with wavefront-guided laser in situ keratomileusis (LASIK), and to develop an advanced surgical nomogram. Patients and Methods: A retrospective chart review of 468 eyes that underwent wavefront-guided LASIK for myopia with astigmatism with the Alcon LADARVision 4000 (Alcon Laboratories, Fort Worth, TX), of which 235 had flaps created by microkeratome (OneUse; Moria Surgical, Doylestown, PA) and 233 by femtosecond laser (Intralase; AMO, Santa Ana, CA). Manifest sphere, cylinder, and spherical equivalent were recorded preoperatively and 3 months postoperatively. Various parameters from patient records were analyzed to identify which had greatest influence on outcomes. Results: Manifest spherical equivalent was the most important predictor of surgical overcorrection, with the second being spherical aberration. In both groups, there was a statistically significant ( P < .0001) correlation of spherical aberration with the amount of overcorrection. Using these two parameters, compensatory nomograms were derived. Conclusion: Surgical overcorrection in wavefront-guided LASIK for myopic astigmatism correlates positively with the amount of spherical equivalent treated and preoperative spherical aberration. Nomograms incorporating spherical aberration may improve accuracy of outcomes.