| PurposeTo explore the distribution of the higher order aberrations of myopia and findsome relationship between the wavefront aberrations and some factors, to verifywhether there are any differences in visual outcome,including higher orderaberrations,after performing laser in situ keratomileusis with conventional ablationand wavefront-guided ablation in myopia.Methods1.Wavefront aberrations in 176 subjects(351 eyes) who underwent myopicLASIK from January to October in 2006 were taken by WaveScan aberrometer. Weanalyzed the mean of every aberration, the relationship between the aberrations andage,diopter of myopia and astigmatism,central comeal thickness et al,and theinfluence of wearing contact lens on aberrations.2.One hundred and fifty eyes of 75 myopic subjects were selected as trialgroup,which underwent wavefront-guided LASIK and another one hundred and fiftyeyes of 75 myopic subjects were selected as control group,which underwentconventional LASIK.In each group,the eyes were divided into three group accordingto myopia diopter. The visual outcome,the refractive results and higher orderaberrations were compared postoperatively at 1 month,3 months and 6 months.3.Statistical method:The data were analyzed by the 11.0 statistical software.Thestatistical methods included independent-sample t test,Pearson correlation,one-wayANOVA(analysis of variance) and chi square test.Results1.Most of the wavefront aberrations are lower order aberrations,the higher orderaberrations take just 4.96% of the whole aberration.2.C6,C7,C8,C9,C12 are important aberrations, other aberrations are near 0.3. RMSg has positive correlation with age,the axial length of eye ball,the sphere and cylinder(p＜0.05).RMSh has positive correlation with age(p＜0.05),has nocorrelation with the sphere and cylinder(p＞0.05).H% has negative correlation with theaxial length of eye ball and the sphere(p＜0.05). The correlation coefficients of Z6,Z7,Z8,Z9,Z12 and all of the factors are small,and the correlation coefficients ofcentral corneal thickness,the intraoculai pressure,the curvature and the aberrationsare small.4.There is no influence of wearing contact lens as long as taking them off 1 weekbefore wavefront examination(p＞0.05).5.At 6 months,39.33% of eyes in trial group achieved uncorrected visualacuity(UCVA) of 1.5 or better while 18.00% in control group(p＜0.05).6.In trial group,all of the low myopia were within±0.5D at 1,3 and 6 months.The moderate and high myopia in trial group were more undercorrected comparedwith the control group, but the trial group had lower residual astigmatism than thecontrol group(p＜0.05).7. At 1,3 and 6 months,the outcome of whole wavefront aberrations and thehigher order aberrations of the trial group were statistically lower than the controlgroup(p＜0.05).8.Z6,Z7 and Z12 of low myopia in the trial group were lower than the controlgroup postoperatively; Z7,Z9 and Z12 of moderate myopia in the trial group werelower than the control group postoperatively; Z6,Z7 and Z12 of high myopia in thetrial group were lower than the control group postoperatively(p＜0.05).Conclusion1.Most of the wavefront aberrations are lower order aberrations,the higher orderaberrations take just 4.96% of the whole aberration.C6,C7,C8,C9,C12 are importantaberrations.2.RMSg has positive correlation with age,the axial length of eye ball,the sphereand cylinder.RMSh has positive correlation with age,and has no correlation with thesphere and cylinder.H% has negative correlation with the axial length of eye ball andthe sphere. There is no influence of wearing contact lens as long as taking them off 1week before wavefront examination. 3.The vision results of wavefront-guided LASIK are better than the conventionalLASIK.4.Moderate and high myopa are undercorrected slightly after wavefront-guidedLASIK,but the astigmatism can be corrected more completely, all of the low myopiaafter wavefront-guided LASIK are within±0.5D.5.The wavefront-guided LASIK has more advantage in correcting the wholeaberration,the higher order aberration especially the third and the fourth orderaberration than conventional LASIK.
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