J Refract Surg. 2022 Nov;38(11):708-715. doi: 10.3928/1081597X-20221005-02. Epub 2022 Nov 1.
To investigate changes in corneal curvature in different zones of the posterior corneal surface during a 6-month follow-up period after transepithelial photorefractive keratectomy (tPRK), femtosecond laser-assisted excimer laser in situ keratomileusis (FS-LASIK), and small incision lenticule extraction (SMILE).
The study included a total of 202 eyes, including 65, 77, and 60 that underwent tPRK, FS-LASIK, and SMILE, respectively. Elevation data for the posterior surface were obtained preoperatively (pre), as well as 1 week (pos1w), 1 month (pos1m), 3 months (pos3m), and 6 months (pos6m) postoperatively. Changes in posterior corneal curvature (M) were analyzed in the central (diameter: 0 to 3 mm), paracentral (diameter: 3 to 6 mm), and peripheral (diameter: 6 to 9 mm) regions.
Over all follow-up periods, the central region of the posterior surface in all patients became flatter ( < .05), with FS-LASIK showing the largest change, whereas the paracentral and peripheral regions became steeper. The posterior curvature changes between pre and pos6m, determined before and after correction for ablated stromal depth, tended to follow similar trends in the three regions and after the three surgeries. There was also no significant correlation ( > .05) between the changes in the mean curvature (M, recorded between pre and pos6m) and each of the refractive error corrections, the changes in spherical aberration postoperatively, the optical zone diameter, ablated stromal depth, and residual stromal bed thickness in the central and peripheral regions, but the correlation was significant in the paracentral region.
The postoperative changes in posterior corneal shape followed different trends in the central, paracentral, and peripheral regions. The FS-LASIK group exhibited the most notable changes in posterior corneal curvature, especially in the central region. These changes were statistically correlated with variations in spherical aberration, and ablated and residential stromal thickness in the paracentral region. .
研究经上皮准分子激光角膜切削术（tPRK）、飞秒激光辅助准分子激光原位角膜磨镶术（FS-LASIK）和小切口角膜透镜取出术（SMILE）后 6 个月内后角膜表面不同区域角膜曲率的变化。
本研究共纳入 202 只眼，分别行 tPRK、FS-LASIK 和 SMILE 治疗，每组分别为 65、77 和 60 只眼。术前（pre）及术后 1 周（pos1w）、1 个月（pos1m）、3 个月（pos3m）和 6 个月（pos6m）获得后表面的高度数据。分析中央（直径：0 至 3mm）、旁中央（直径：3 至 6mm）和周边（直径：6 至 9mm）区域的后角膜曲率（M）变化。
在整个随访期间，所有患者的后表面中央区域变平（ <.05），FS-LASIK 变化最大，而旁中央和周边区域变陡。校正消融基质深度前后的后表面曲率变化（pre 与 pos6m 之间）在三个区域和三种手术后呈现出相似的趋势。在中央和周边区域，平均曲率（M，记录在 pre 与 pos6m 之间）的变化与每个屈光不正矫正、术后球差变化、光学区直径、消融基质深度和中央及周边区域的剩余基质床厚度之间均无显著相关性（ >.05），但在旁中央区域相关性显著。
后角膜形态的术后变化在中央、旁中央和周边区域呈现不同的趋势。FS-LASIK 组后角膜曲率变化最明显，尤其是在中央区域。这些变化与球差变化以及旁中央区域的消融和剩余基质厚度变化具有统计学相关性。
