全飞秒小切口透镜取出术矫正高度近视术后像差初步分析

Analysis of spherical aberrations after small incision lenticule extraction for high myopia

目的探讨全飞秒小切口角膜透镜取出术（SMILE）矫正高度近视及近视散光术后像差的变化情况。方法前瞻性病例对照研究。入选病例23例，分为2组，A组为15例（22眼）接受SMILE的中高度近视及近视散光患者（男性6例、女性9例），术前平均等效球镜为（-7．13±0．91）D。SMILE采用500kHzVisuMax飞秒激光完成，采用上方4．2mm弧形切口，角膜帽厚度设定为100μm，透镜直径6．3～6．5mm。B组为8例（14眼）接受飞秒激光制瓣准分子激光原位角膜磨镶术（FS-LASIK）的近视患者作为对照组（男性3例、女性5例），术前等效球镜为（-7．53±0．22）D。FS—LASIK采用蒂位于上方、厚度为100μm的角膜瓣。术前、术后采用Hartmann·Shark原理的WASCA波前像差仪（CarlZeiss）检测高阶像差。平均随访时间为1年。结果所有术眼术后均获得1．0以上裸眼视力，2组相比无显著差异。无一眼发生最佳矫正视力的丢失，13．6％的A组（SMILE组）术眼提高2行。94．1％的A组术眼及92．8％的B组（FS．LASIK组）术眼获得±0．50D以内的等效球镜。术后残余屈光不正，2组间差异无统计学意义（P〉0．05）。2种手术方式术后总体高阶像差均增加，SMILE术后以彗差为主，FS-LASIK术后高阶像差增加以球差和5阶高阶像差为主。结论SMILE矫正高度近视及近视具有良好的预测性及安全性，术后总体高阶像差增加以彗差为主，并无显著增加球差的作用，其机制值得进一步探讨。

Objective To evaluate the changes of wavefront aberrations after small incision lenticule extraction （SMILE） for high myopia. Methods This is a prospective case series study. Twenty-two eyes of 15 patients （6 males and 9 females） underwent SMILE with 4.2 mm superior incision, 100 μm cap thickness and 6.3 --6.5 mm lenticule diameter, whose mean preoperative spherical equivalent were （-7.13±0.91 ） D. Another 14 eyes of 8 femtosecond laser assisted laser in situ keractomileusis （FS-LASIK） patients （3 males and 5 females） with superior hinge and 100μm flap thickness were enrolled as the control group, whose preoperative spherical equivalent were （-7.53 ±0.22） D. The wavefront aberrations was obtained with WASCA system（Hartmann-Shark） preoperatively and postoperatively. The mean follow-up time was 1 year. Results At 1 year follow-up, all eyes in both groups obtained uncorrected distant visual acuity （UDVA） of 1.0 or better. There was no significant difference in UDVA between the two groups. There were 13.6% SMILE eyes that gained 2 lines and none lost any line of corrected distant visual acuity. Ninety-four point one percent SMILE eyes and 92.8 % FS-LASIK eyes had spherical equivalent （SE） within ＋ 0.50 D. There was no significant difference in residual spherical equivalent between the two groups. Among the components of wavefront aberrations, higher order aberrations （HOA） significantly increased in both groups. SMILE eyes obtained more HOA and coma while FS-LASIK eyes obtained more spherical aberrations and 5th order aberrations. Conclusions SMILE procedure is safe, effective and predictive for high myopia. The higher order aberrations increased after SMILE and there was more change of coma but not spherical aberrations when compared with FS-LASIK. The mechanism of this phenomenon needs further study.