Effects Of LASEK And LASIK On Corneal Higher-order Aberrations

Objective: To evaluate the effects of corneal wavefront-guided laser subepithelial keratomileusis (LASEK) and laser in situ keratomileusis (LASIK) on higher-order aberrations (HOAs) in order to obtain better visual quality and choose the suitable surgical approach for the correction of high myopia.Methods: Data was analyzed from 54 patients (108 eyes) in accordance with Chronological order and the standard of choice to high myopia who underwent the corneal wavefront-guided excimer laser surgery , 54 eyes of 27 patients had LASIK and 54 eyes of 27 patients had LASEK. We measured respectively RMS values of Corneal Coma, SpAb, RMSh on 6mm pupil diameter at 1 week, 1 month, 3 months before and after surgery by using OPTIKON-2000 corneal topography device based the ORK-CAM software. The two sets of Preoperative information were all tested on the balance, and the results were no difference.Results: 1.Vision: The uncorrected visual acuity after 3 months on LASEK was better than those on LASIK (P<0.05) .2. Corneal aberrations: (1) Comparison in the group: Group A: The RMS values of Corneal Coma, SpAb, RMSh at 1 week, 1 month, 3 months after LASEK were higher than that before operation; The largest increase was at 1 week after surgery (P<0.05) ,there was no statistic significance between I week and 1 month after surgery (P>0.05) , the increase after 3 months was significantly reduced than that after 1 month (P<0.05) . Group B: The RMS values of Corneal Coma, SpAb, RMSh at 1 week, 1 month, 3 months after LASIK were higher than those before surgery, there was significant statistical significance ; the increase of Corneal Coma, SpAb after 1 month was largest (P<0.05), the increase after 3 months was significantly reduced than that after 1 month (P<0.05) . The RMS values of corneal coma after 1 week, 1 month, 3 months were an increasing trend. There was a significant statistical significance among every two groups (P=0.000 ) .(2). Comparison between the two groups: The RMS values of corneal Coma : Group A after 1 week was significantly higher than those of group B (P = 0.003 ) , group A after 1 month were slightly higher than the group B (P = 0.246) , group A after 3 months were significantly less than those of group A (P = 0.000) ; The RMS values of corneal SpAb : When observating in different time periods after surgery , Group A is less than group B, and there was a significant difference after 1 month, 3 months ( P = 0.000, 0.000) ;The RMS values of corneal RMSh: Group A were less than Group B after 1 week, 1 month, 3 months,and it was statistically significant After 1 month, 3 month (P = 0.002, 0.005) .The increase of RMS values of Corneal Coma, SpA of Group A after 3 month was lower than the group B, and it was statistically significant (P=0.012,0.014,0.000) . Therefore,it illustrates that the increase of corneal HOAs after LASEK is smaller than that after LASEK.Conclusion: High myopia is corrected by corneal wavefront guided refractive surgery:1. The visual acuity at 3 months after LASEK is better than that after LASIK.2. LASEK and LASIK surgery both increase corneal HOAs.3. The increase of corneal HOAs after LASEK is less than that after LASIK, it may be an ideal surgical method.