飞秒透镜切除术治疗近视和近视散光的临床研究

目的评价飞秒激光透镜切除术（femtosecond lenticule extraction,FLEx）治疗近视和近视散光的临床效果。方法采用前瞻性病例对照研究,行角膜屈光手术的近视及近视散光患者30例（60只眼）,按照非随机自愿原则分为两组：FS-LASIK组患者30只眼,采用飞秒手术系统制作角膜板层瓣联合准分子激光仪进行屈光治疗。FLEx组患者30只眼,采用飞秒手术系统制作角膜板层瓣并同时完成角膜基质透镜切除术。两组患者术前测量中央角膜厚度≥500μm,计划治疗后剩余角膜基质床厚度≥300μm。术后跟踪随访6个月。记录术后1周,1、3和6个月时的裸眼视力、最佳矫正视力、客观验光值、眼的高阶像差值、对比敏感度值。结果两组患者的平均年龄及术前屈光度差异均无显著意义（P〉0.05）。全部患者手术进行顺利,术中和术后均无危害视力的并发症发生。术后6个月时,FLEx组30只眼,96.7%的欲矫正屈光度与实际矫正的屈光度值相差在±0.75 D以内,93.3%的裸眼logMAR视力在4.9及4.9以上（平均4.99±0.13）,80.0%的最佳矫正视力未变,13.3%的最佳矫正视力提高一行,3.3%的最佳矫正视力提高两行,3.3%的BSCVA下降一行。FS-LASIK组30只眼,90.0%的欲矫正屈光度与实际矫正的屈光度值相差在±0.75 D以内,86.7%的裸眼logMAR视力在4.9及4.9以上（平均4.98±0.12）,83.3%的最佳矫正视力未变,6.7%的最佳矫正视力提高一行,6.7%的最佳矫正视力提高两行,3.3%的最佳矫正视力下降一行。两组中均未出现最佳矫正视力下降两行及两行以上的情况。观察两组患者术后半年内屈光度的变化：FLEx组的平均屈光度术后1周时为（＋0.25±0.79）D,术后半年时为（-0.05±0.56）D,半年内平均屈光度数变化0.30 D。FS-LASIK组的平均屈光度术后1周时为（＋0.72±0.92）D,术后6个月时为（-0.15±0.65）D,半年内平均屈光度数变化0.87 D,向近视方向漂移,表明FLEx组术后屈光度比FS-LASIK组更稳定。在6 mm瞳孔直径下检查术后眼的高阶像差值,无论是总高阶像差值还是球差值,FLEx组均明显小于FS-LASIK组（P〈0.01）。在暗光5 mm瞳孔直径状态下,FLEx组术后6个月时各空间频率（1.5、3、6、12、18 c/d）下的对比敏感度值均高于FS-LASIK组（P〈0.01）。结论 FLEx术治疗近视和近视散光安全、有效;在术后屈光度的稳定性、避免术后高阶像差增加、以及提高术后对比敏感度方面,FLEx术比FS-LASIK术更有优势。

Clinical Analysis on Correction of Myopia and Myopic Astigmatism with Femtosecond Lenticule Extraction

Objective To evaluate the clinical outcome of femtosecond lenticule extraction（FLEx） in treating myopia and myopic astigmatism. Methods In this prospective study,30 eyes underwent femtosecond laserassisted laser in situ keratomileusis（FS-LASIK）,where all flaps were created with the VisuMax femtosecond system followed by refractive treatment with MEL 80 excimer laser,and 30 eyes underwent femtosecond lenticule extraction（FLEx）,where a flap and a refractive lenticule of intrastromal corneal tissue were simultaneously cut with the VisuMax femtosecond system. The followup lasted for six months when uncorrected visual acuity（UCVA）,best spectacle-corrected visual acuity（BSCVA）,objective and manifest refractions,higher-order aberrations（HOAs）,contrast sensitivity function（CSF） curves were gathered and analyzed one week,one month,three months,and six months after surgery respectively. Results There were no statistically significant differences both in mean age and preoperative mean refraction between FLEx group and FS-LASIK group（P 0. 05）. No complications occurred during the surgery or the postoperative period in both groups. At 6 months postoperatively,of the 30 eyes treated with FLEx,96. 7% were within ± 0. 75 D of intended correction,93. 3% had an UCVA of 4. 9（logMAR） or better,the mean UCVA was（4. 99 ±0. 13）,80. 0% remained unchanged,13. 3% gained one line,3. 3% gained two lines of BSCVA,and 3. 3% lost one line of BSCVA. Of the 30 eyes treated with FS-LASIK,90. 0% were within ± 0. 75 D of intended correction,86. 7% had an UCVA of 4. 9（logMAR） or better,the mean UCVA was（4. 98 ± 0. 12）,83. 3% remained unchanged, 6. 7% gained one line,6. 7% gained two lines of BSCVA,and 3. 3% lost one line of BSCVA. No eye lost 2 or more lines of BSCVA in both groups. With regard to the changes of spherical equivalent（SE） from 1 week to 6 months after surgery,the mean SE after FLEx changed from（＋ 0. 25 ± 0. 79） D to（0. 05 ± 0. 56） D,and after FS-LASIK from（＋ 0. 72 ± 0. 92） D to（0. 15 ± 0. 65） D. The mean change was 0. 30 D in FLEx treated eyes（P 0. 05）,and 0. 87 D in FS-LASIK treated eyes（P 0. 01）,demonstrating the results of FLEx were more stable than those of FS-LASIK. For a 6 mm pupil,the root mean square（RMS） values of total HOAs and spherical aberrations after FLEx were significantly less than those after FS-LASIK（P 0. 01）. In night environment（for a 5 mm pupil size condition）,the CSF values for FLEx treated eyes were higher than those for the FS-LASIK treated eyes at 1. 5,3,6,12 and 18 cpd space frequency（P 0. 01）.Conclusions FLEx is a safe,effective,and predictable procedure for the treatment of myopia and myopic astigmatism. FLEx features more stable refractive results,less induction of HOAs and better contrast sensitivity than the FSLASIK.