不同直径光学区对飞秒激光小切口角膜基质内透镜取出术（SMILE）后患者早期视觉质量的影响

目的　观察不同直径光学区对飞秒激光小切口角膜基质内透镜取出术（small incision lenticule extraction，SMILE）后患者早期视觉质量的影响。方法　选取2017年6月至9月在中国人民解放军南京总医院眼科视光中心行SMILE的手术患者26例（51眼）。其中小光圈组11例（21眼），光学区6.1~6.4 mm；大光圈组15例（30眼），光学区6.5~6.8 mm。所有患者分别在术前和术后1个月测量裸眼视力（uncorrected visual acuity，UCVA）、球镜度数、柱镜度数，各级像差、调制传递函数（modulation transfer function，MTF）、MTF截止频率（MTF_cutoff）、斯特列尔比（strehl ratio，SR）、客观散射指数（objective scatter index，OSI），对比度视力（visual acuity，VA）包括VA100%、VA20%、VA9%，VA均换算成LogMAR表示。对测得指标进行统计学分析。结果　术前两组间患者的UCVA、球镜度数、柱镜度数差异均无统计学意义（均为P>0.05）。术后1个月复查两组间患者UCVA、球镜度数、柱镜度数差异亦均无统计学意义（均为P>0.05）。术前两组患者全眼总像差（total aberrations，TA）、总低阶像差（total low order aberrations，tLOAs）、总高阶像差（total high order aberrations，tHOAs）、离焦、彗差、球差、三叶草差异均无统计学意义（均为P>0.05），散光度数差异有统计学意义（P＜0.05）。术后1个月复查两组患者离焦值差异有统计学意义（P＜0.05），而TA、tLOAs、tHOAs、散光度数、彗差、球差、三叶草差异均无统计学意义（均为P>0.05）。术前除了20 c·d^-1频率上两组患者MTF值差异无统计学意义（P>0.05）外，其余各空间频率大光圈组的MTF值均高于小光圈组（均为P＜0.05）。术后1个月复查各空间频率的MTF值发现在各空间频率上两组差异均无统计学意义（均为P>0.05）。术前两组MTF_cutoff、SR、OSI、VA100%、VA20%、VA9%差异均无统计学意义（均为P>0.05），术后1个月MTF_cutoff、OSI、VA100%、VA20%差异仍均无统计学意义（均为P>0.05），仅SR和VA9%差异有统计学意义（均为P＜0.05）。两组术后的TA、tLOA、离焦、tHOA和三叶草均低于术前，差异均有统计学意义（均为P＜0.05），而彗差和球差的术前术后差异均无统计学意义（均为P>0.05）。两组内术前术后各指标变化的不一致出现在散光和MTF值上，小光圈组术后散光与术前有明显差异（P＜0.05），而大光圈组无差异（P=0.054）；小光圈组术后在低频段上的MTF值（5~10 c·d^-1）较术前提高（均为P＜0.05），而在中高频段术前术后差异不明显（均为P>0.05）。大光圈组在所有空间频率上术前术后MTF值差异均无统计学意义（均为P>0.05）。两组的MTF_cutoff、OSI、SR和VA100%、VA20%、VA9%在术前术后差异均无统计学意义（均为P>0.05）。结论　SMILE手术可改善近视患者的视觉质量，术中使用较小的光学区，仅对夜间视力产生轻度影响。

Comparison of early visual quality in patients with moderate myopia using different optic zone in SMILE

Objective　To observe the early visual quality of patients withmorderatemyopia after small incision lenticule extraction (SMILE) using different optical zones.Methods　Together 26 patients (51 eyes) were selected，including 11 patients in the small aperture group (21 eyes) with 6.1-6.4 mm of optic zone，and 15 patients in the large aperture group (30 eyes) with 6.5-6.8 mm of optic zone.The following items were examined preoperatively and 1 month postoperatively:UCVA，spherical diopters，cylinder diopters，ocular aberrations in all levels，modulation transfer function (MTF)，MTF_cutoff，strehl ratio (SR)，objective scatter index (OSI)，contrast visual acuity (VA100%，VA20%，VA9%).VA values were expressed by LogMAR.Results　UCVA，spherical and cylinder diopters had no significant differences preoperatively and 1 month postoperatively (all P>0.05).The comparison of ocular aberrations of two groups showed no significant differences in TA，tLOAs，tHOAs，defocus，coma，spherical and clover preoperatively (all P>0.05)，while astigmatism had a statistically significant difference (P<0.05).The TA，tLOAs，tHOAs，astigmatism，coma，spherical and clover had no significant differences between the two groups 1 month postoperatively (all P>0.05)，while defocus had a statistically significant difference(P<0.05).There were significant differences in MTF values at 5 c·d^-1，10 c·d^-1，15 c·d^-1，25 c·d^-1，30 c·d^-1 between the two groups before the operations (all P<0.05)，and no difference at the frequency of 20 c·d^-1 preoperatively (P>0.05).The MTF values of the two groups in all frequencies 1 month postoperatively had no differences (all P>0.05).There were no significant differences in MTF_cutoff，SR，OSI，VA100%，VA20%，VA9% between the two groups preoperatively (all P>0.05).MTFcutoff，OSI，VA100% and VA20% showed no difference1 month after the operations (all P>0.05)，while the differences existed in SR and VA9% (both P<0.05).The TA，tLOAs，defocus，tHOAs and clover of the two groups were lower postoperatively than those before the operations respectively (all P<0.05).Coma and spherical of the two groups before and after operations showed no significant differences(P>0.05).The changes of astigmatism and MTF values before and after the operations in each group appeared inconsistent.Astigmatism of the small aperture group 1 month postoperatively was lower than preoperatively (all P<0.05)，while no difference showed in the large aperture group(P=0.054).Comparing the changes of the preoperative and postoperative MTF values in each group，the results showed that there were significant differences in low frequencies (5-10 c·d^-1) (all P<0.05) and no difference in moderate and high frequencies (15-30 c·d^-1) (all P>0.05) in the small aperture group.The large aperture group showed no significant difference in all frequencies before and after the operations (all P>0.05).Compared the changes of MTF_cutoff，OSI，SR，VA100%，VA20% and VA9% before and after the operations，there were no significant differences in each group (all P>0.05).Conclusion　SMILE improves the visual quality of moderate myopia patients.The reduced optical zone has only produced a slight decrease in night vision.