Stability Of Corneal Topography And Aberrometry After Hyperopic Laser In Situ Keratomileusis With A 500-Hz Excimer Laser Platform: A 3-Year Follow-Up Study

Purpose: The aim of this study is to analyze the long-term stability of the corneal topography, the functional optical zone, and the refractive stability throughout 3 years following laser in situ keratomileusis surgery for hyperopia using a 500-Hz excimer laser system. Methods: This retrospective consecutive observational case series study comprised 66 eyes that underwent laser in situ keratomileusis to correct hyperopia with a postoperative follow-up of 3 years. Laser in situ keratomileusis procedures were performed using the SCHWIND Amaris 500-Hz excimer laser. Main outcomes measured were stability of the functional optical zone at corneal topography and corneal aberrometry. Results: Statistically significant differences were found in simulated keratometry (K2 (steep meridian) and Km (mean keratometry)) between 3 and 36 months postoperatively (p <= 0.01); these differences disappeared at 12 and 36 months (p > 0.18). No statistically significant changes were observed in the horizontal and vertical diameter of the functional optical zone throughout the whole follow-up (p > 0.07). A statistically significant difference was found in the spherical aberration between 3 and 36 months (p = 0.02); this difference disappeared when compared between 12 and 36 months (p = 0.72). Statistically significant correlations were detected between the vertical functional optical zone and coma root mean square (r = -0.510, p < 0.01) and between the vertical functional optical zone and spherical aberration (r = 0.441, p = 0.02) 36 months after surgery. Conclusion: Following 3 years of hyperopic laser in situ keratomileusis with a 500-Hz Amaris excimer laser, keratometry, functional optical zone, and corneal aberrations remain stable from 1 year after surgery. Topographical regression is not observed in hyperopic laser in situ keratomileusis with this excimer laser technology from 1 year after surgery.