目的：评估FS-LASIK Xtra治疗中高度近视患者术后2 a的矫正效果及角膜形态的稳定性。

方法：回顾性病例对照研究。纳入2019-08/2020-08在我院拟行屈光手术的中高度近视合并散光患者30例58眼，根据术前角膜地形图中圆锥角膜筛查相关指数行不同手术方式，分为FS-LASIK Xtra组15例29眼，FS-LASIK组15例29眼。术前，术后3 mo，1、2 a观察裸眼视力(UCVA)、最佳矫正视力(BCVA)、等效球镜度(SE)及Sirius三维角膜地形图仪测量的不同直径区域(3、5、7 mm)前后表面角膜曲率。

结果：两组患者术后不同时间点UCVA均较术前明显提高(均P<0.01)，两组间UCVA和SE比较均无差异(P>0.05)。术后2 a，FS-LASIK Xtra组25眼(86%)，FS-LASIK组24眼(83%)残余散光为-0.25-0 D。两组实际矫正SE与预矫正SE均呈正相关(均P<0.05)。两组患者术后3 mo，1、2 a不同直径区域(3、5、7 mm)前后表面角膜曲率均较术前有差异(均P<0.05)，术后1、2 a FS-LASIK Xtra组角膜直径3、5 mm后表面曲率均高于FS-LASIK组(P<0.05)。

结论：FS-LASIK Xtra 治疗中高度近视患者有良好的安全性、有效性及可预测性。

METHODS:Retrospective case-control study. A total of 30 cases(58 eyes)Patients with moderate to high myopia combined with astigmatism who planned to undergo refractive surgery in our hospital from August 2019 to August 2020 were included, and different types of surgery were performed respectively based on the relevant index of keratoconus screening in the preoperative corneal topography. They were divided into FS-LASIK group and Xtra group, with 15 cases(29 eyes)in each group. Uncorrected visual acuity(UCVA), best corrected visual acuity(BCVA), spherical equivalent(SE)and the corneal curvature of the anterior and posterior surfaces of different diameters(3, 5 and 7 mm)measured by Sirius three-dimensional corneal topography were observed preoperatively and 3 mo, 1 and 2 a postoperatively.

RESULTS: The UCVA of the two groups of patients at different time points after surgery was significantly increased compared with preoperatively(both P<0.01), and there was no difference in UCVA and SE between the two groups(P>0.05). After 2 a postoperatively, residual astigmatism was -0.25-0 D in 25 eyes(86%)of the FS-LASIK Xtra group and 24 eyes(83%)of the FS-LASIK group. The actual corrected SE and expected corrected SE of both groups were positively correlated(both P<0.05). There were differences in corneal curvature on the surface of different diameter areas(3, 5, and 7 mm)between the two groups at 3 mo, 1, and 2 a postoperatively compared with preoperatively. After 1 and 2 a postoperatively, the corneal posterior surface curvature of the FS-LASIK Xtra group with corneal diameter of 3 and 5 mm was higher than that of the FS-LASIK group(P<0.05).

CONCLUSIONS:FS-LASIK Xtra has good safety, efficacy and predictability in correcting patients with moderate to high myopia.