目的：探究不同程度近视患者飞秒激光小切口角膜基质透镜取出术(SMILE)术后有效光学区(EOZ)的变化情况及其影响因素。方法：回顾性研究。选择2019-10/2020-10于南昌大学附属眼科医院接受SMILE手术且术前光学区直径设计为6.5mm的近视患者50例92眼。根据术前等效球镜度数(SE)进行分组，低度近视组：-0.50D<SE≤-3.00D 18例34眼； 中度近视组：-3.00D<SE≤-6.00D 20例36眼； 高度近视组：SE>-6.00D 12例22眼。收集3组患者术前，术后3mo裸眼视力、最佳矫正视力、SE、光学区直径、角膜Q值及高阶像差。结果：低、中及高度近视组患者术后3mo EOZ分别为5.07±0.69、5.08±0.43、4.50±0.58mm； 角膜Q值分别为0.22±0.17、0.57±0.34、0.63±0.73，三组间比较差异均有统计学意义(P<0.05)。三组患者术后EOZ直径均低于术前的6.5mm预计光学区(P<0.001)。三组患者术后角膜总高阶像差、球差、垂直彗差比较有差异(P<0.05)。SMILE术后EOZ直径与术前SE、剩余角膜基质床厚度均呈正相关(r=0.357、0.275，均P<0.05)，与中央角膜切削深度、术后角膜Q值均呈负相关(r=-0.316、-0.353，均P<0.05)，术后3mo角膜球差变化量与EOZ变化量成负相关(r=-0.336，P<0.05)。结论：SMILE术后EOZ均低于术前预计光学区，且术前SE越高，术后光学区越小，术后角膜球差增加越多。另外，角膜切削深度、剩余角膜基质床厚度、角膜非球面性改变均可影响术后EOZ大小。

AIM: To explore the changes and influencing factors of effective optical zone(EOZ)after femtosecond laser small incision lenticule extraction(SMILE)in patients with different degrees of myopia.METHODS:Retrospective study. From October 2019 to October 2020, fifty patients(92 eyes)with myopia who underwent SMILE surgery in the Affiliated Eye Hospital of Nanchang University and whose preoperative optical zone diameter was designed to be 6.5mm were selected. According to the preoperative equivalent spherical diopter, the patients were divided into three groups: low myopia group(-0.50D to -3.00D, 18 cases, 34 eyes), moderate myopia group(>-3.00D to -6.00D, 20 cases, 36 eyes)and high myopia group(>-6.00D, 12 cases, 22 eyes). The uncorrected visual acuity, best corrected visual acuity, manifest refraction spherical equivalent, optical zone diameter, corneal Q-value and high-order aberrations(HOA)were collected before and 3mo after operation.RESULTS:The postoperative 3mo EOZ of patients with low, moderate and high myopia were 5.07±0.69, 5.08±0.43 and 4.50±0.58 mm, respectively, and the corneal Q-values were 0.22±0.17, 0.57±0.34 and 0.63±0.73, there were significant differences among the three groups(all P<0.05). The diameter of effective optical zones after operation in all three groups was lower than that predicted by 6.5mm before operation(P<0.001). There were significant differences in postoperative total HOA, spherical aberration(Z40)and vertical coma(Z3-1)among the three groups(P<0.05). The diameter of effective optical zone after SMILE was positively correlated with preoperative manifest refraction spherical equivalent and residual corneal thickness(r=0.357, 0.275,all P<0.05), and negatively correlated with central corneal ablation depth and postoperative corneal Q-value(r= -0.316, -0.353, all P<0.05). After operation, ΔZ40 was negatively correlated with ΔEOZ(r= -0.336, P<0.05).CONCLUSION:The EOZ after SMILE was lower than that expected before operation, and the higher the myopia was, the smaller the optical area was and the more the postoperative corneal spherical aberration increased. In addition, the depth of corneal ablation, residual corneal thickness and aspheric changes of cornea can affect the size of EOZ after operation.

江西省教育厅科学技术研究项目(No.190162)