飞秒激光与角膜板层刀制作角膜瓣的厚度及形态比较

Comparison of corneal flap morphology in laser in situ keratomileusis with the WaveLight femtosecond laser versus the Moria mechanical microkeratome

目的应用前节光学相干断层扫描仪（OCT），比较waveLightFS200飞秒激光与MoriaM290角膜板层切开刀制作角膜瓣的厚度及形态特点。方法前瞻性病例对照研究。对61例行双眼准分子激光原位角膜磨镶术（LASIK）的近视患者分别采用WaveLightFS200飞秒激光制瓣（WaveLight组，36例）和MoriaM290角膜板层切开刀制瓣（Moria组，25例）。术后1周，采用Visante前节OCT测量180°、90°、45°、135。轴位上距离角膜顶点0、±2、±3．5mm处的角膜瓣厚度。运用独立样本t检验对2组数据进行统计学分析。结果WaveLight组中央角膜瓣厚度为（105．53±5．86）μm，而Moria组为（132．96±13．91）μm（t=-13．16，P〈0．01）。WaveLight组中央角膜瓣精确度为（6．17±3．98）μm，而Moria组为（23．60±2．64）μm（t=-15．20，P〈0．01）。WaveLight组角膜瓣均匀性指数为（4．07_＋0．94）μm，Moria组为（8．48±2．35）μm（t=12．60，P〈0．01）。WaveLight组角膜瓣的对称性指数[（33．81±11．28）μm]明显小于Moria组[（68．46±26．66）μm]，差异有统计学意义（t=8．67，P〈0．01）。结论前节OCT显示WaveLightFS200飞秒激光制作的角膜瓣与MoriaM290角膜板层切开刀相比，中央厚度更精确、重复性更好，角膜瓣形态更均匀。

Objective To evaluate and compare the thickness and morphology of laser in situ keratomileusis （LASIK） flaps created by either the WaveLight FS-200 femtosecond laser or the Moria microkeratome M2 90 using anterior segment optical coherence tomography （AS-OCT）. Methods This was a prospective case-control study. Bilateral LASIK was performed on 61 myopic patients. Flaps were created using the WaveLight FS-200 femtosecond laser in 72 eyes and the Moria M2 90 microkeratome in 50 eyes. The thickness at 17 points across each flap, 0 mm, ＋2 mm, and ＋3.5 mm to the corneal vertex on the horizontal, vertical, 45°and 135° meridians, were evaluated using a Visante AS-OCT at 1 week postoperatively. An independent t test was used. Results The central flap thickness of the WaveLight group was 105.53±5.86μm, while it was 132.96±13.91 μm in the Moria group （t=-13,16, P〈0.01）. The difference between the achieved and the intended flap thickness （accuracy） was 6.17±3.98 μm and 23.60±12.64μm, respectively （t=-15.20, P〈0.01）. The standard deviation of thickness in the 17 points within an individual flap （uniformity） was 4.07±0.94 μm in the WaveLight group and 8.48±2.35 μm in the Moria group （t=-12.60, P〈0.01）. The index S （Symmetry） of Moria group （33.81±11.28μm） was significantly smaller in the WaveLight group （68.46±26.66μm） （t=-8.67, P〈0.01）. Conclusion AS-OCT showed that the flaps created with the WaveLight FS-200 femtosecond laser were more accurate, reproducible, and uniform than those created with the Moria M2 90 microkeratome.