VisuMax飞秒激光制作角膜瓣的OCT临床观察

Preliminary study on clinical outcomes of VisuMax femtosecond laser flap thickness measured by optical coherence tomography

目的探讨用VisuMax飞秒激光系统制作角膜瓣OCT临床观察的初步结果，评价其制瓣的精确性、可重复性、均一性和规整性，研究术后不同时间角膜瓣厚度的变化及其影响因素。方法拟行飞秒LASIK手术的近视及近视散光患者38例（68只眼），根据术中设定角膜瓣厚度的不同分为100μm组和105μm组。术前术后患者行常规检查并记录检查结果。采用光学相干断层扫描仪（opti．calcoherence tomography，OCT）于术后1周、1月和6个月测量角膜瓣厚度，取OCT图像中过角膜中央水平线，记录距离角膜中央1mm、2mm和3mm及角膜中央共7个点的角膜瓣厚度和剩余基质床厚度。对术后不同时间及不同区域的角膜瓣厚度进行对比分析，并对其可能的影响因素进行相关陛分析。结果100μm组和105μm组中术后1周、1月和6个月时角膜瓣厚度分别为（107．92±5．56）μm、（108．79±4．78）μm、（106．69±5．74）μm和（109．36±6．26）μm、（112．21±4．37）μm、（108．53±7．27）μm。100μm组和105μm组患者术后1周、1月、6个月角膜瓣厚度值与设定瓣厚度值比较差异结果分别为（，=4．995，P=0．000；F=1．918，P=0．051；F=1．806，P=0．114）和（F=1．739，P=0．213；F=1．931，P=O．049；F=1．810，P=O．083）。100μm组和105μm组患者术后1周、1月、64＂月角膜瓣厚度的标准差分别为5．56μm，4．78μm，5．74μm和6．26μm，4．37μm，7．27μm。100阻m组和105μm组术后1周、1月和6个月各点角膜瓣厚度比较结果分别为（F=5．410，P=0．000；F=8．914，P=O．000；F=3．084，P=0．052）和（F=2．000，P=0．143；F=3．431，P=0．048；F=1．786，P=0．211）。100μm组和105μm组术后1周、1月和6个月中央、旁中央和周边区域角膜瓣厚度比较结果分别为（F=O．919，P=0．409；F=0．701，P=0．504；F=0．547，P=O．584）和（F=1．990，P=0．142；F=4．079，P=0．020；F=1．770，P=0．175）。105μm组中术后1月时观察到上皮粗糙的有6眼，其角膜瓣厚度为（116．26±1．80）μm，与术后1月时角膜瓣厚度均值比较差异有统计学意义（t=2．042，P=0．048）。术后6个月时角膜瓣厚度与相应时间视力和后表面Q值有相关性（P〈0．05）。结论随着术后时间延长，飞秒制瓣术后视觉质量稳定，VisuMax飞秒激光制瓣表现出良好的精确性、可重复性，角膜瓣形态具有较好的均一性和规整性。

Objective To investigate the clinical outcomes of VisuMax femtosecond laser flap measured by OCT, to assess the accuracy, repeatability, and regularity of VisuMax femtoseeond laser flap. To investigate the change of flap thickness and the factors influencing flap thickness. Methods Sixty-eight eyes of 38 patients who underwent femtosecond LASIK were enrolled in this study and divided into 2 groulas depending on the intended flap thicknesses （100μm and 105μm）, OCT was used to assess flap thicknesses 1 week, 1 month and 6 months postoperatively. The thicknesses of flap and residual bed in the seven measuring points were 1mm, 2mm, 3mm away from center of cornea on the horizontal and the center of cornea itself. The results were analyzed with t-tset, ANO- VA or Pearson correlations test. Results At 1 week, 1 month and 6 months after surgery, the thickness of flaps in 100μm and 105μm group was （107.92--5.56）μm, （108.79±4.78）μm, （106.69±5.74）μm and （109.36±6.26）μm, （112.21±4.37）μm, （108.53±7.27）μm respectively. The results of accuracy in 100μm and 105gm groups were （F =4.995, P=0.000; F =1.918, P =0.051; F =1.806, P =0.114） and （F =1.739, P =0.213; F =1.931, P =0.049; F =1.810, P =0.083）. Standard deviation of flap thickness in the two groups was 5.56μm, 4.78gm, 5.74μm and 6.26μm, 4.37μm, 7.27μm. The results of uniformity in 100gm and 105μm group were （F =5.410, P =0.000; F =8.914, P =0.000; F =3.084, P = 0.052） and （F =2.000, P =0.143; F =3.431, P =0.048; F =1.786, P =0.211）. The results of comparison of flap thickness in different zones in 100gm and 105μm group were （F =0.919, P =0.409; F = 0.701, P =0.504; F =0.547, P =0.584） and （F =1.990, P =0.142; F =4.079, P =0.020; F =1.770, P = 0.175） 1 week, 1 month and 6 months postoperatively. There was a correlation between uncorrected visual acuity, Q value of back surface of cornea and the thickness of corneal flap measured 6 months after surgery. Conclusions With the time go by, patients have stable visual acuity, Visual femtosecond laser flap thickness has good accuracy, repeatability, the architecture of flaps are uni- form and regular.