Clinical Study On Characteristics Changes Of High-order Aberrations Between Before And After Femtosecond Laser In Corneal Refractive Surgery

Purpose:To compare and analysis the changes of higher-order aberrations after the LASIK with femtosecond laser(Femtosecond laser in situ keratomileusis,FS-LASIK)and mechanical microkeratome(Sub-Bowman's Keratomileusis,SBK)at longer term after surgery,and to investigate the possible influence of higher-order aberrations of different flap parameters setting and the complications in the LASIK with femtosecond laser;to compare the changes of higher-order aberrations after the All-in-one femtosecond laser refractive surgery—Small Incision Lenticule Extraction(SMILE)and Femtosecond laser Lengticule Extraction(FLEx)and the LASIK with femtosecond laser(FS-LASIK)at the early stage postoperatively.Methods:In this random and prospective study included 101 myopia and myopic astigmatism subjects(201 eyes).60 cases were scheduled to perform FS-LASIK,41 cases were scheduled to perform SBK.There were 24 patients 24 eyes with a thinner flap,and 15 patients 25 eyes with OBL in the FS-LASIK group;In another random and prospective study included 112 myopia and myopic astigmatism(191 eyes)subjects.34 cases were scheduled to perform SMILE,32 cases were scheduled to SBK,and 46 cases were scheduled to FS-LASIK.WaveScan aberration meter and Pentacam were used to measure the higher-order aberration and other parameters.Subjects underwent FS-LASIK and SBK were followed at 1 month,3 month and 6 month postoperatively,who underwent SMILE and FLEx were followed at 1 month and 3 month.Paired t test,independent t test and One-way analysis of variance(ANOVA),repeated measure were used to analyze variables.Results:1.In the FS-LASIK group,the total higher-order aberrations and the mean of the square root values of the Zermike coefficient significantly increased at 1th,3th,6th month postoperatively,especially for the total higher-order aberrations(Sh),the spherical aberration(C40)and the 4th-order aberration(S4)(P<0.05);in the 3th month postoperatively,the S3 was higher than the one in the 1th month(P<0.05);in the 6th month postoperatively,the C31,C40.and S4 was higher than the one in the 3th month(P<0.05).2.Comparison of the control group,the coma(C31)and the 3th-order aberration(S3)in the FS-LASIK group were lower than the SBK group at the early stage postoperatively(P<0.05);only the S3 in the FS-LASIK group were lower than the SBK group at the 3th and 6th month postoperatively(P<0.05).3.For the thin-flap group,the total higher-order aberrations(Sh),the spherical aberration(C40)and the 4th-order aberration(S4)were obviously higher than the control group at the 1th,3th and 6th month postoperatively(P<0.05).4.The occurrence of the OBL was significantly correlated with the CCT,Km and the thickness of the flap(P<0.05).5.In the OBL group,the total higher-order aberrations(Sh),the coma(C31),the spherical aberration(C40)and the 4th-order aberration(S4)were higher than the control group at the early stage postoperatively(P<0.05);the coma(C31)were higher than the control group at the 3th and 6th month postoperatively(/P<0.05);However,only the S3 was significant higher than the control group at the 3th month postoperatively(P<0.05),there is no significantly difference between the two group at the 6th month postoperatively(P>0.05).6.For the All-in-one group,the total higher-order aberrations and the mean of the square root values of the Zernike coefficient significantly increased at 1th,3th month postoperatively,especially for the total higher-order aberrations(Sh),the coma(C3-1?C31),the spherical aberration(C40)and the 4th-order aberration(S4)(P<0.05).In the SMILE group,the Sth,the C40 and the S4 were decreased at 3 months which had significant difference with 1 month values(P<0.05).However,it had no significant difference in the FLEx group(P= 0.47).7.In the SMILE group,the total higher-order aberrations(Sh),the spherical aberration(C40)and the 6th-order aberration(S6)were lower than the FLEx group at 1th?3th month postoperatively(P<0.05);but the coma(C3')was higher than the FLEx group(P<0.05).8.In the FLEx group,the total higher-order aberrations(Sh)and the spherical aberration(C4°)were lower than the FS-LASIK group at 1th and 3th month postoperatively;it also showed that the Sh,the C40 and the S4 of the SMILE group were lower than the FS-LASIK group postoperatively(P<0.05).Conclusion:1.FS-LASIK can effectively corrected myopia and astigmatism,it also can induce some higher-order aberrations,but superior than the control group.2.In the FS-LASIK,the thinner flap can induce more higher-order aberrations postoperatively(especially for the spherical aberrations).3.The occurrence of the OBL was significantly correlated with the CCT,Km and the thickness of the flap.And the OBL can induce more higher-order aberrations especially for coma postoperatively.4.The All-in-one femtosecond laser refractive surgery can effectively corrected myopia and astigmatism,it also can induce some higher-order aberrations.However,as the woulding of the cornea,the higher-order aberrations become stably and decreased.5.In the All-in-one group,the "small incision" can induce less higher-order aberrations at the early stage postoperatively.It can make the patients gain superior visual performance..6.Comparison of the FS-LASIK group,the All-in-one group can induce less higher-order aberrations at the early stage postoperatively.It's necessary to enlarge the sample and prolong the follow-up to further research.