J Refract Surg. 2022 Sep;38(9):602-608. doi: 10.3928/1081597X-20220718-01. Epub 2022 Sep 1.
To evaluate the postoperative changes in corneal epithelium thickness and refractive power after femtosecond laser-assisted laser in situ keratomileusis (LASIK) and small incision lenticule extraction (SMILE) for myopia correction using anterior segment optical coherence tomography (OCT) with an integrated Placido disc topographer.
The VisuMax 500-kHz femtosecond laser (Carl Zeiss Meditec AG) and Amaris 750 excimer laser (SCHWIND eye-tech-solutions) were used. Central, paracentral, and 6-mm epithelial thickness values were obtained, and the change in the value of epithelial thickness was calculated. Changes in the refractive power of the epithelium were also evaluated. The repeatability of this new measurement was also analyzed using the intraclass correlation (ICC). The total follow-up period was 6 months.
A total of 77 LASIK eyes were matched with 77 SMILE eyes. Mean spherical equivalent was -3.92 ± 1.67 diopters (D) for LASIK versus -4.02 ± 1.63 D for SMILE ( = .356). Epithelial thickness parameters significantly and equally thickened in both types of surgery. The change in the value of epithelial thickness was positively correlated with spherical aberration. Analysis of the refractive power of the corneal epithelial layer (ICC > 0.70) showed a tendency for the postoperative myopization of the refractive component of this layer (-0.11 D for SMILE and -0.53 D for LASIK at 3 mm) and an increase in its cylinder and aberrometry. Increasing postoperative spherical aberration and epithelial thickness increased myopization of the epithelial refractive sphere ( < .05).
Corneal epithelium thickens similarly after LASIK and SMILE, being slightly higher after SMILE. This correlates with the induced spherical aberration. Corneal epithelium thickening induces myopization of its refractive power, which accounts for a slight regression of the net refractive power change on the treated cornea. .
使用集成 Placido 盘 topography 的前节光学相干断层扫描（OCT）评估飞秒激光辅助准分子激光原位角膜磨镶术（LASIK）和小切口微透镜提取（SMILE）治疗近视术后角膜上皮厚度和屈光力的变化。
使用 VisuMax 500-kHz 飞秒激光（卡尔蔡司医学技术公司）和 Amaris 750 准分子激光（SCHWIND eye-tech-solutions）。获得中央、旁中央和 6mm 上皮厚度值，并计算上皮厚度值的变化。还评估了上皮层屈光力的变化。使用组内相关系数（ICC）分析这种新测量方法的重复性。总随访期为 6 个月。
共 77 只 LASIK 眼与 77 只 SMILE 眼相匹配。LASIK 的平均等效球镜为-3.92±1.67 屈光度（D），SMILE 为-4.02±1.63 D（=.356）。两种手术类型的上皮厚度参数均显著且均匀增厚。上皮厚度值的变化与球差呈正相关。角膜上皮层屈光力的分析（ICC > 0.70）显示，术后该层的折射成分向近视方向发展（SMILE 为-0.11 D，LASIK 为-0.53 D，在 3mm 处），其柱镜和像差增加。术后球差和上皮厚度的增加增加了上皮折射球的近视化（<.05）。
LASIK 和 SMILE 后角膜上皮厚度相似，SMILE 后略高。这与诱导的球差有关。角膜上皮增厚引起其屈光力的近视化，这导致治疗角膜的净屈光力变化略有回归。
