Factors that influence outcomes of hyperopic laser in situ keratomileusis

PURPOSE: To analyze the influence of preoperative corneal curvature, postoperative keratometric power, and the amount of correction on the outcomes of hyperopic laser in situ keratomileusis (LASIK). SETTING: Clínica Baviera, Instituto Oftalmológico Europeo, Madrid, Spain. METHODS: In this retrospective study, the records of 376 eyes that had LASIK for hyperopia using the Moria LSK-One microkeratome and the Technolas-Keracor 217C excimer laser were reviewed. The results were analyzed by preoperative hyperopia (5 subgroups) and by preoperative (more than and less than 43.0 diopters [D]) and postoperative (more than and less than 48.0 D) mean keratometry. RESULTS: A statistically significant keratometry regression was found in the +3.00 to +3.90 D range (P <.01), a significant decrease in predictability in the +4.00 to +4.90 D range (P <.05), and a significant worsening in safety in the highest range (+6.00 to +7.90 D; P <.05). Comparative analysis of the > or = +4.00 D and <+4.00 D groups showed statistically significant differences in most measurement parameters. The preoperative keratometry did not influence postoperative results with the exception of poorer predictability in the group of preoperative flat corneas in which a high degree of hyperopia was corrected; ie, spherical equivalents within +/-0.50 D were found in 40.4% and 61.0% of cases with flat and steep corneas, respectively (P <.05). The efficacy and safety in eyes that achieved a postoperative keratometry >48.00 D did not differ significantly from the efficacy and safety in eyes that had a lower final keratometric power. CONCLUSIONS: The factor that negatively influenced the outcome of hyperopic LASIK was the degree of hyperopia corrected. Preoperative keratometry did not significantly influence the postoperative results, and postoperative keratometry >48 D did not result in significant worsening of visual results when the attempted correction was less than +4.00 D.