LASIK术中3种飞秒激光制作的角膜瓣的比较研究

Comparison of corneal flaps created by three femtosecond lasers during LASIK surgery

目的评价和比较准分子激光原位角膜磨镶术(LASIK)中应用VisuMax、鹰视WaveLight FS200和Ziemer FEMTO LDV飞秒激光仪制作角膜瓣的均一性、规整度和可预测性。方法前瞻性病例对照研究。收集81例(160只眼)行LASIK手术的屈光不正患者,根据制瓣方式分为VisuMax组(23例45只眼)、FS200(flap=100μm)组(20例39只眼)、FS200(flap=110μm)组(19例37只眼)和Femto LDV组(19例36只眼),按预期角膜瓣厚度,将4组再分为2个亚组,分别为100μm组(VisuMax组和FS200(flap=100μm)组)和110μm组(FS200(flap=110μm)和Femto LDV组)。收集患者年龄、术前角膜中心厚度(CCT)、平均角膜曲率、等效球镜度数等资料,术后1周运用RTVue-OCT测量术眼角膜0°和90°两条子午线所在截面上特定7个点的角膜瓣厚度值,并对角膜瓣上14个测量点的厚度进行对比。运用SPSS 22.0进行统计学分析。结果VisuMax组和FS200(flap=100μm)组中央区角膜瓣厚度分别为(109.23±7.05)μm、(107.23±8.45)μm,之间比较无统计学意义(t=-1.96,P=0.05),FS200(flap=110μm)组和Femto LDV组中央区角膜瓣厚度分别为(111.05±9.1)μm,(106.88±6.73)μm,之间比较有统计学意义(t=-2.7,P=0.01);四组平均全角膜瓣厚度分别为(109.76±7.7)μm,(107.78±11.44)μm,(116.15±11.01)μm,(107.38±7.13)μm,两两间比较均有统计学意义(t=3.2,P=0.001),(t=-13.3,P<0.001);VisuMax组和FS200(flap=100μm)组在0°和90°截面的角膜瓣厚度值分别是(109.51±7.31)μm、(110.14±8.07)μm和(106.62±10.86)μm、(108.16±11.87)μm,FS200(flap=110μm)和Femto LDV组在0°和90°经线的角膜瓣厚度值分别是(115.78±10.9)μm、(116.53±11.31)μm和(107.9±6.41)μm、(106.77±7.75)μm,之间比较均有统计学意义(P<0.05)。各组与角膜瓣预测值差值分别是(10.33±7)μm、(9.22±8.71)μm、(10.08±9.54)μm和(5.6±5.1)μm,各组角膜瓣测量点中与预测值差值≤5μm的比例为25%、33%、43%、59%,与预测值差值≥10μm的测量点比例为41%、37%、22%和16%。结论在LASIK术后早期,Ziemer FEMTO LDV飞秒激光仪制作出的角膜瓣最规整和均匀,可预测性最好,比预计角膜瓣偏薄,鹰视WaveLight FS200和VisuMax飞秒激光仪制作的角膜瓣比预定角膜瓣偏厚。

Objective To evaluate the uniformity,regularity and predictability of corneal flap made by VisuMax,WaveLight FS200 and Ziemer FEMTO LDV in laser in situ keratomileusis(LASIK).Methods This was a retrospective study.81 patients(160 eyes)with ametropia undergoing LASIK were collected and divided into VisuMax subgroup(23 cases,45 eyes),FS200 subgroup(flap=100μm,20 cases,39 eyes),FS200 subgroup(flap=110μm,19 cases,37 eyes)and FEMTO LDV subgroup(19 cases,36 eyes).According to intended thickness of flaps,these four subgroups were divided into two groups.The 100μm group including VisuMax subgroup and FS200 subroup(flap=100μm)and the 110μm group including FS200 subgroup(flap=110μm)and FEMTO LDV subgroup.Informations such as age,preoperative central corneal thickness(CCT),mean corneal curvature and equivalent spherical power were collected.At one week after operation,the flap thickness at 7 specific points on the cross section of 0°and 90°cornea was measured by RTVue-OCT,and the thickness of 14 measuring points on the corneal flap was statistically analyzed by SPSS 22.0.Results The thickness of central corneal flap in VisuMax subgroup and FS200 subgroup(flap=100μm)were(109.23±7.05)μm and(107.23±8.45)μm respectively,which was no statistically different(t=-1.96,P=0.05).The thickness of central corneal flap in FS200 subgroup(flap=110μm)and FEMTO LDV subgroup were(111.05±9.1)μm and(106.88±6.73)μm respectively,which was statistically significant(t=-2.7,P=0.007).The average thickness of corneal flap in these four subgroups were(109.76±7.7)μm,(07.78±11.44)μm,(116.15±11.01)μm and(107.38±7.13)μm respectively,and there was statistical significance between the two groups(t=3.2,P<0.001)&(t=-13.3,P<0.001).The corneal flap thickness of VisuMax subgroup and FS200 subgroup(flap=100μm)at 0°and 90°sections were(109.51±7.31)μm,(110.14±8.07)μm,(106.62±10.86)μm and(108.16±11.87)μm,respectively.The corneal flap thickness of FS200 subgroup(flap=110μm)and FEMTO LDV subgroup at 0°and 90°longitudes were(115.78±10.9)μm,(116.53±11.31)μm,(107.9±6.41)μm,and(106.77±7.75)μm,respectively.The comparison has statistically significance(P<0.05).The difference between the achieved and attempted flap thickness in each subgroup was(10.33±7)μm,(9.22±8.71)μm,(10.08±9.54)μm and(5.6±5.1)μm,respectively.The proportion of difference(≤5μm)between the intended and the measured flap thickness was 25%,33%,43%,and 59%,respectively.The proportion of difference(≥10μm)was 41%,37%,22%,and 16%,respectively.Conclusions In the early stage of LASIK,the corneal flap produced by Ziemer FEMTO LDV femtosecond laser is the most regular,uniform and predictable,which thickness is thinner than the expected.The corneal flap produced by WaveLight FS200 and VisuMax femtosecond laser is thicker than the expected.