MORIA SBK、90、110刀头切削角膜瓣的厚度变化及相关因素分析

Correlation analysis and corneal flap thickness changes among Moria SBK,90 and 110 microkeratome in laser in situ keratomileusis

目的探讨使用MORIA公司SBK、90、110刀头切削角膜瓣的厚度变化及相关影响因素。方法收集行准分子激光角膜原位磨镶术(LASIK)治疗的近视患者90例180眼,按术中使用刀头的不同分为SBK、90、110刀头组,每组30例60眼,均先右眼后左眼施行手术。术中测量角膜床厚度,对3组间角膜瓣厚度的差异进行比较,对角膜瓣厚度与年龄、屈光度、角膜厚度、曲率、角膜横径的相关性进行分析。结果 3组患者和手术眼的基线资料特征比较差异无统计学意义(P>0.05)。SBK刀头组右眼和左眼的角膜瓣厚度分别为(97.50±11.39)μm和(96.73±10.45)μm,差异无统计学意义(P>0.05)。逐步回归分析证实,SBK刀头组角膜瓣厚度与术前角膜厚度呈正相关(r=0.490,P=0.000)、与角膜横径呈负相关(r=-0.520,P=0.001)。在90刀头组中,患者右眼和左眼的角膜瓣厚度分别为(128.03±12.03)μm和(123.40±12.38)μm,差异有统计学意义(P<0.01)。角膜瓣厚度与术前角膜厚度呈正相关(r=0.430,P=0.000),与年龄呈负相关(r=-0.360,P=0.002)。110刀头组患者右眼和左眼的角膜瓣厚度分别为(140.53±15.14)μm和(135.23±18.03)μm,差异有统计学意义(P<0.01),角膜瓣厚度与术前角膜厚度呈正相关(r=0.710,P=0.000)。结论 MORIA角膜刀切削的角膜瓣厚度与术前角膜厚度有关,SBK刀头切削的角膜瓣厚度变异最小而110刀头者最大,LASIK术中用SBK刀头和90刀头能制作超薄或较薄的角膜瓣。术中应测量角膜床厚度,及时调整治疗方案,避免术后产生继发性圆锥角膜。

Background The average thickness and variation of corneal flap are very important to laser in situ keratomileusis（LASIK）because it is related to the predictability and safety of the surgery.ObjectiveThis study was to analyze the change of corneal flap thickness with Moria SBK,90 or 110 microkeratome after LASIK and identify the relevant factors to the flap thickness.MethodsDifferent corneal flaps were made with Moria SBK,90 or 110 microkeratome during the LASIK in bilaterial eyes of 30 patients separately and then divided into SBK microkeratome group,90 microkeratome group and 110 microkeratome group.Flap thickness was calculated by measuring the corneal stromal bed thickness.The change of flap thickness was analyzed and compared among these three groups.The relationship of flap thickness with age,refraction,preoperative corneal thickness,keratometry and diameter were evaluated.Informed consent was obtained from all participants before surgery.ResultsNo significant differences were found in age,refraction,corneal thickness,corneal horizontal diameter,cornea curvity among the three groups before LASIK（P0.05）.In SBK microkeratome group,the corneal flap thickness was 97.50±11.39μm in the right eyes and 96.73±10.45μm in the left eyes separately without significant difference（t=0.790,P=0.440）.The regression analysis revealed that flap thickness had a positive correlation with corneal thickness（r=0.490,P=0.000）and a negative correlation with corneal diameter（r=-0.520,P=0.002）or with age（r=-0.360,P=0.0023）.In 90 microkeratome group,the corneal flap thickness was 128.03±12.03μm and 123.40±12.38μm separately in the right eyes and left eyes with a statistically significant difference（t=2.890,P=0.007）.In 110 microkeratome group,the corneal flap thickness was 140.53±15.14μm and 135.23±18.03μm separately in the right eyes and left eyes,showing a.statistically significant difference（t=3.180,P=0.004）.The flap thickness was positive correlated with preoperative corneal thickness（r=0.710,P=0.000）.ConclusionCorneal flap thickness made by MORIA microkeratome is associated with preoperative corneal thickness.The least variation in flap thickness is SBK and the most one is 110 microkeratome.SBK and M2 90 microkeratome are more beneficial in making the ultrathin and thin corneal flap.Intraoperative corneal pachymetry should be measured to adjust the treatment regimen and avoid postoperative secondary keratoconus during the LASIK.