Comparison Study Of Retaining Or Removing Negative Vertical Coma In WG-Lasik For Myopia And Astigmatism

Objective: The cornea refractive surgery correct refractive errors through altering the corneal curvature and has been received by more and more ametropic people. The complications which influence the visual quality such as contrast sensitivity decreasing, halos have been brought in at the same time with the visual acuity improving and all these have been thought to have the relationship with the aberrations in human eyes. But not all the aberrations are harmful to human's visual quality. So how to retain the beneficial aberrations and remove the harmful ones is the hot spot nowadays and is mean to the further improvement of visual quality. The study is to investigate the efficacy of wavefront-guided Lasik for the myopia and astigmatism, and compare the visual quality of retaining or removing the vertical coma during the WG-Lasik to provide objective gists for reasonable choises of WG-Lasik.Methods:42 cases (78 eyes) were collected in the study through the routine examinations and wavefront analysis, which were divided into two groups (A and B). The eyes that Z(3,-1) was less than -0.15 were taken as Group A; the eyes that Z(3,-1) was more than +0.15 were taken as Group B. Both A and B were also divided into two subgroups (test and control). WG-Lasik was performed in test group, and classic Lasik was performed in control group. Visual quality, wavefront examination, CSF were analyzed.Results: 1. In the earlier period of post-operation time, diopters of the two groups were both slightly overcorrected and then began to decrease slightly later and the diopters of both test group and control group were corrected perfectly and had no significant differences(P>0.05). 2. RMS oftest group increased higher than that of control group when Z(3,-1) was negative and the CSF in control group was better than that in test group after WG-Lasik in Group A. 3. RMS of test group increased lower than that of control group when Z(3,-1) was positive and the CSF in test group was better than that in control group after WG-Lasik in Group B. 4. The subject evaluation of both test group and control group had no significant differences no matter Z(3,-1) was positive or negative.Conclusions:The visual quality of control group was better than that of test group when Z(3,-1)was negative while the visual quality of test group was better than that of control group when Z(3,-1)was positive. So we suggested that retaining negative vertical coma and removing positive vertical coma was beneficial to the visual function after the WG-Lasik, which could help save the corneal tissue reasonably and avoid losing corneal tissue unnecessarily in order to improve visual quality telicly.