Study In The Changes Of Corneal Topography And High Order Aberrations Of High Myopia With Lasik And Lasek

Objective: Through studying the uncorrected visual acuity, cornealectasia and corneal spherical aberration changes of the high myopia beforeand after surgery of laser in situ keratomileusis (LASIK), laser in situkeratomileusis with Q-value adjusted customized,(Q-LASIK), lasersubepithelial keratomileusis(LASEK) and Laser subepithelialkeratomileusis with Q-value adjusted customized (Q-LASEK), explore asuitable excimer laser surgery way for patients with high myopia.Methods: From the patients with high myopia who had underwent thesurgery of LASIK, Q-LASIK, LASEK or Q-LASEK between January2012to July2012, including11cases (19eyes) with conventional LASIK,14cases (27eyes)with Q-LASIK,12cases (21eyes), with conventionalLASEK,8cases (14eyes) with Q-LASEK..Check their uncorrected visualacuity(UCVA) and best corrected visual acuity(BCVA) respectively in thepreoperative and postoperative1week,,1month,3months and6months.Meanwhile,we use anterior segment systems to check the cornealthickness, the posterior corneal surface forebulge situation and corneal spherical aberration, and then statistical analysis was performed on theresults by using the chi-square test, t-test etc.Results: The postoperative uncorrected visual acuity of the four groupscomparing with preoperation all have enhanced obviously,a largeproportion of patients have achieved their corrected visual acuity beforesurgery, and the difference had no statistically significant (p>0.05). Thedifferences of the posterior cornea surface forebulge situation in the fourgroups were statistically significant (p <0.05). The posterior corneal surfaceforebulge height differences of the conventional LASIK and Q-LASIKgroup and the conventional LASEK and Q-LASEK group have asignificant statistical significance (P <0.05), after one week. Whilepostoperatively1month,3month and6months, there was no statisticallysignificant difference (p>0.05)). Compared with the preoperative cornealspherical aberration, the four groups had all increased after surgery. But thespherical aberration of the Q-LASIK group and the Q-LASEK groupincreased significantly less than the conventional LASIK group and theconventional LASEK group, the differences were statistically significant (p<0.05).Conclusion: Excimer laser surgery can effectively correct high myopia.Q-values guide ablation surgery can significantly reduce iatrogenic cornealspherical aberration. After highly myopic excimer surgery, posteriorcorneal surface both forebulge, but the LASEK were lighter than the LASIK, and it has a lower probability of iatrogenic keratoconus, so thehigh myopia LASEK is safer than LASIK.