准分子激光原位角膜磨镶术中采用飞秒激光和角膜刀制作角膜瓣的对比分析

Comparison of cornea flap made by femtosecond laser and microkeratome in laser in situ keratomileusis

目的探讨准分子激光原位角膜磨镶术（LASIK）中采用飞秒激光和前弹力层下准分子激光原位角膜磨镶术（SBK）角膜刀制作110μm角膜瓣的相关影响因素。方法病例对照研究。在对60例（120只眼）近视眼患者进行LASIK，术中分别使用飞秒激光（FS200型，美国Alcon公司）和SBK角膜刀（法国Moria公司）制作110μm角膜瓣各30例（60只眼），先右眼后左眼，术中测量制瓣前中心角膜及制瓣后中心角膜厚度。样本均数的方差齐性检验采用Levene法，各组样本均数的正态性分布检验经Kolmogorov—Smirnov法结果为正态性分布。术前的基线资料比较采用单因素方差分析；患者左右眼间角膜瓣厚度的比较采用配对t检验。角膜瓣厚度与手术前各种相关因素的关系分析采用逐步回归分析。结果飞秒激光组患者右眼和左眼的平均角膜瓣厚度分别为（114．0±6．6）和（111．4±7．6）μm，差异无统计学意义（t=1．59，P=0．12）。经逐步回归证实飞秒激光制作角膜瓣厚度与手术前年龄、屈光度、角膜厚度、曲率、角膜横径等均无关。角膜刀组患者右眼和左眼的角膜瓣厚度分别为（110．6±7．4）和（108．2±6．1）μm，差异无统计学意义（t=2．019，P=0．054）。经逐步回归，只有手术前角膜厚度纳入方程，与年龄、曲率、角膜直径、角膜瓣直径等无关：角膜瓣厚度=67．769＋0．076×角膜厚度（F=5．626，P=0．021）。角膜瓣厚度和手术前角膜厚度呈正相关（r=0．297，P=0．021）。结论FS200飞秒激光和SBK角膜刀均可很好制作出110μm左右厚度的角膜瓣。FS200飞秒激光制瓣个性化程度更高，SBK角膜刀的角膜瓣厚度与术前角膜厚度呈正相关。

Objective To determine flap thickness variation in 110μm thickness flap made by FS200 femtosecond laser and sub-Bowman keratiomileusis （SBK） microkeratome for studying the potential factors that affect the flap thickness. Methods It was a case-control study. Sixty patients were divided into two groups for laser in situ keratomileusis. The corneal flaps were made by using Alcon Wavelight FS200 femtosecond laser or MORIA SBK microkeratome. Central corneal flap thickness was calculated by subtraction pachymetry. Age, central corneal thickness （CCT）, spherical equivalent refraction, mean keratometry and corneal diameter were recorded preoperatively for statistics. Results This study comprised 120 eyes of 60 patients; 60 eyes were treated with each group. In Alcon Wavelight FS200 femtosecond laser group, the mean corneal flap thickness in the right and left eyes was （ 114.0±6. 6） and （ 111.4±7.6 ）μm, respectively. The difference in corneal flap thickness between the right eye and the left eye （2. 6±9. 1 ） μm was not statistically significant （t = 1.59, P = 0. 12 ）. Corneal flap thickness had no relationship with the age, preoperatively CCT, spherical equivalent refraction, corneal cuivature and corneal diameter through stepwise regression analysis. In SBK microkeratome group, the mean corneal flap thickness in the right eye and the left eye was （ 110. 6±7.4） and （ 108. 2±6. 1 ） μm respectively. The difference in corneal flap thickness between the right eye and the left eye （ 2. 4 ±6. 6 ）μm was not statistically significant （ t = 2. 019, P = 0. 054）. Corneal flap thiekness was positively correlated with preoperative CCT through stepwise regression analysis （r =0. 29, P =0. 021 ）. Corneal flap thickness equaled to 67.77±0. 076 ·CCT （F = 5. 63, P =0. 021 ）. Corneal flap thickness had no relationship with the age, spherical equivalent refraction, corneal curvature and corneal diameter. Conclusions Both FS200 femtosecond laser and SBK mierokeratome can be used for making a good 110μm thickness flap. Central corneal flap thickness was positively correlated with the preoperative CCT using the SBK microkeratome.