| BackgroundWith the change of people's living conditions and methods,incidence of myopia is increasing also,which give people in study,life,work brought great trouble,but also affects people's physical and mental health.With the continuous development of medical technology,refractive surgery has become an effective way to correct myopia,technical innovation and continuous improvement of surgical methods,so that the way of refractive surgery is no longer a single.The excimer laser in situ keratomileusis refractive surgery is the mainstream.Because it is relatively safe and effective,but with extensive surgery,triggered by the complications are also gradually emerging,such as broken flap,free flap,button flap and other abnormal corneal flap,dry eye,refractive regression,glare,decreased visual acuity at night etc.This requires refractive surgery not only to improve the patient's naked eye vision,but also to ensure good visual quality! The clinical significance of different methods of flap valve is also different.ObjectiveFemtosecond laser making corneal flap excimer laser in situ keratomileusis grinding keratomileusis(LASIK)and Bowman keratomileusis(SBK)corneal layer knives in the grinding layer of the cornea,two kinds of surgery after the visual quality of the comparison and analysis,draws the difference of effect of flap after LASIK in the postoperative.MethodsProspective cohort study.The retrospective analysis method,choose 2015.5-2015.11 in our hospital eye center accept femtosecond laser and SBK mechanical corneal layer of blade flap for correction of high myopia patients,select 50 cases(100 eyes)were divided into two groups: group A and group B,among them,a group representing accept femtosecond laser of the flap in the experimental group,group B representing accept microkeratome flap as the control group.Application of Nidek OPD scan wavefront analyzer in darker ambient light respectively before operation and after one week,one month and three month period,compared two groups of patients visual acuity,refractive status,high order aberrations(ocular high-order aberration,spherical aberration,coma aberration and trefoil difference)and contrast sensitivity sensitivity,and of femtosecond laser flap preparation and SBK mechanical corneal plate layer microkeratome postoperative visual quality assessment.ResultFemtosecond laser flap group and SBK plate layer knife group before operation in terms of age,spherical equivalent and higher-order aberrations(ocular high order aberration and coma difference C7,C8,spherical aberration C12)and contrast sensitivity differences had no statistical significance(P > 0.05).After first day,1 month,3 months and 6 months after operation,the visual acuity and the mean equivalent spherical lens of the two groups were compared with the groups,the difference was not statistically significant between the two groups(P>0.05).Postoperative 1 day,1 week,1 month,3 months and 6 months ocular high order aberration and coma difference(C7),spherical aberration C12,femtosecond laser flap group were lower than the SBK microkeratome group,the difference between the two groups has statistical significance(P < 0.05),coma(C8)in postoperative 1 week and 3 months,between the two groups differences have statistical significance(P < 0.05).Photopic state,the same time period after surgery two groups at all spatial frequency difference no statistical significance(P > 0.05);scotopic condition,1 week after surgery,the femtosecond laser group at 12 cpd and 18 cpd frequency is better than mechanical plate layer knife group.The difference between the two groups has statistical significance(P < 0.05),1.5 cpd,3.0 cpd,6.0cpd the low spatial frequency between two groups were compared,the difference of no statistical significance(P > 0.05);postoperative 1 month two groups of contrast sensitivity higher than 1 week after surgery,but differences between the two groups in each spatial frequency no statistical significance(P > 0.05).There was no significant difference in the contrast sensitivity(P> 0.05)between the two groups at 3 months after operation.Complications: there are 1 cases of corneal limbal bleeding in group A and 3 cases in group B;1 cases of corneal foreign body in group A and 3 cases in group B;2 cases of conjunctival hemorrhage in group A and 1 case of group B;after operation,there are 2 cases night glare ?1 case of partial cutting center and 1 case of refractive regression in group B;there are 2 cases dry eye in group A and 4 cases in group B,the difference between the two groups has statistical significance(P < 0.05).Conclusion1.The high order aberration of the LASIK operation was introduced by femtosecond laser.2,After femtosecond laser surgery and SBK mechanical plate compared with the knife showed a relatively high contrast sensitivity,can significantly improve the visual quality.3 Femtosecond laser has better safety,less complications and postoperative complications. |
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