准分子激光原位角膜磨镶术不同厚度角膜瓣的临床评估

Clinical evaluation on the cornea flap with different thickness after LASIK

目的利用共焦显微镜观察厚、薄角膜瓣各层组织在形态学方面改变的区别，同时比较准分子激光原位角膜磨镶术（LASIK）后厚、薄角膜瓣的视功能差异，以期为临床合理化手术提供客观依据。方法病例对照研究。收集行LASIK手术的患者70例（70只眼），平均年龄（23±5）岁。按照角膜瓣厚度分为两组：薄角膜瓣组（A组，36只眼）和厚角膜瓣组（B组，34只眼），术前平均等值球镜屈光度数分别为（-4．76±2．30）和（-3．03±2．20）D。术前术后均进行视力、屈光度、波阵面像差、对比敏感度等视功能检查，同时应用共焦显微镜（海德堡视网膜断层扫描仪角膜模块，HRTⅢ）检测角膜中央各层组织。数据应用配对t检验进行统计学分析，以P〈0．05作为差异有统计学意义。结果术后3—6个月A、B组屈光度数分别为（0．35±0．21）及（0．45±0．69）D，差异无统计学意义（t=0．78，P〉0．05）。LASIK术后两组角膜瓣厚度分别为（107．37±20．5）和（149±25．2）μm，皱褶厚度分别为（63．71±15．8）和（48．16±20．7）μm，无细胞区厚度分别为（69．93±15．8）和（55．63±23．7）μm，激活角膜细胞区厚度分别为（60．15±30．9）和（51．86±27．9）μm；前基质细胞密度分别为（825．14±156．9）和（853．54±126．8）个／mm^2；各项差异均有统计学意义（t=2．679，1．974，3．051，2．196，3．146；P〈0．01）。而角膜后基质细胞密度差异无统计学意义（t=0．953，P〉0．05）。术前及术后不同时间两组的各阶像差及对比敏感度差异均无统计学意义（P〉0．05）。结论准分子激光原位角膜磨镶术中采用的角膜瓣厚度不同，术后虽然其临床视功能比较并无明显差异，但是厚、薄角膜瓣愈合时在细胞水平存在较大差异，角膜瓣与基质之间是非瘢痕性愈合。角膜薄瓣在细胞水平对角膜组织损伤的程度重于角膜厚瓣。

Objective To investigate morphologically the different changes of cornea tissue between thick and thin cornea flap with confocal microscope, and to compare visual function between thick and thin cornea flap after LASIK. Methods 70 cases （70 eyes） who had received LASIK were divided into the thin cornea flap group （36eyes, group A）and the thick cornea flap group （34 eyes, group B）. The age was （23 ± 5 ） years old, spherical equivalent diaopter （SE） were （ - 4. 76 ± 2. 30 ） D and （ - 3.03 ± 2. 20 ） D. Inspection items included visual acuity （VA） , refraction, wave-front analysis, contrast sensitivity analysis （KONTRASTOMETER BA-4, Germany ） during pre-and post-LASIK, at the same time, all eyes were examined by eonfoeal microcopy （HRTⅢ, Germany）. Using Moria 90 μm and 130 μm keratome with Allegretto Exeimer laser machine. Results Refraction： there was no difference between the two groups. Post-LASIK 3 to 6 months： group A （0. 35 ±0. 21 ） D; group B （0.45 ±0. 69） D （P 〉0. 05）. Comparison results by confocal microscope. The thickness of cornea flap ： group A （ 107.37 ± 20. 5 ） μm, group B （ 149 ±25.2） μm（P 〈0. 05）. The thickness of wrinkle： group A （63.71 ± 15.8） μm; group B （48. 16 ± 20. 7） μm （P 〈 0. 05 ）. The thickness of acellular area ： group A （69.93 ± 15. 8 ） μm ; group B （55.63 ± 23.7） μm（P 〈 0. 05 ）. The thickness of activation cornea ceils： group A （60. 15 ± 30. 9）μm; group B（ 51.86 ± 27. 9 ） μm （ P 〈 0.05 ）. The density of anterior stromal ： group A （ 825. 14 ± 156. 9 ）mm^2 ; group B （853.54 ± 126. 8） mm^2 （ P 〈 0.05 ）. There were significant differences on the thickness of cornea flap, the thickness of wrinkle, the thickness of acellular area, the thickness of activation cornea cells, the density of anterioer stromal, but there was no difference on posterior stromal（ P 〉 0. 05 ）. Wavefront analysis ： there was no difference between two groups in Z3 ^-3, Z3^-1, Z3^1, Z3^3, Z4^0, RMS3, RMS4, RMS5, RMS6, RMSh （P 〉 0.05 ） pre-and post-operation. Contrast sensitivity analysis： there was also no difference between two groups（P 〉 0. 05 ） pre-and post-LASIK 1-6 month. Conclusions From the point of confocal microscope view, morphologic changes of cornea was significant with different thick flap. It is not cicatrical healing between the cornea flap and stromal. The cell injury of cornea tissue in the thin cornea flap was severe than that of in the thick cornea flap even though there was no significant difference between thin and thick cornea flap group in clinical refraction correction, wavefront and contrast sensitivity.