飞秒激光小切口角膜基质透镜取出术矫正中高度近视眼术后早期角膜后表面高度变化及影响因素的临床研究

目的探讨飞秒激光小切口角膜基质透镜取出术(SMILE)矫正中高度近视眼术后角膜后表面高度的变化情况及其可能的影响因素。 方法本研究为回顾性研究。收集2017年9月至2018年5月在广西医科大学第一附属医院眼科接受SMILE手术的63例(110只眼)中高度近视眼患者的病例资料，提取术前术后1 d、1周、1个月及3个月Pentacam眼前节分析系统的检查结果，包括角膜顶点及以顶点为圆心2 mm与4 mm直径范围上45°、135°、225°、315°角膜后表面高度，以此9点处角膜后表面高度的平均值作为角膜中央后表面高度。采用单因素重复测量方差分析比较不同时间点角膜顶点后表面高度及角膜中央后表面的高度，采用Pearson相关系数评价角膜顶点后表面高度的变化量和角膜中央后表面高度的变化量与年龄、术前等效球镜度数、角膜中央厚度、平均手术切削深度、平均剩余角膜厚度及角膜切削比之间的相关性。 结果角膜顶点后表面高度及角膜中央后表面高度在术后1个月内呈下降趋势并在术后1个月时开始恢复，术前术后1 d、1周、1个月及3个月角膜顶点后表面高度分别为(0.52±2.46) mm、(0.39±2.21) mm、(0.33±2.33) mm、(-0.06±2.18) mm及(0.00±2.72) mm，角膜中央后表面高度分别为(1.18±0.90) mm、(1.16±0.76) mm、(1.06±0.76) mm、(1.04±0.74) mm及(1.09±0.89) mm，差异均无统计学意义(F＝1.24，0.62；P>0.05)。术后1 d、1周、1个月及3个月角膜顶点后表面高度平均变化量分别为(-0.13±1.43) mm、(-0.19±1.74) mm、(-0.58±1.65) mm及(-0.52±1.96) mm，角膜中央后表面高度平均变化量分别为(-0.02±0.68) mm、(-0.12±0.74) mm、(-0.14±0.78) mm及(-0.09±0.95) mm，差异均无统计学意义(F＝1.98，0.47；P>0.05)。各时间点角膜顶点后表面高度的变化量及角膜中央后表面高度的变化量与患者年龄、术前等效球镜度数、角膜中央厚度、平均手术切削深度、平均剩余角膜厚度及角膜切削比均无明显相关性(P>0.05)。 结论SMILE矫正中高度近视眼术后角膜后表面高度无明显变化，并在术后早期恢复，对角膜后表面形态的影响小，安全性和稳定性良好。

Early changes of posterior corneal elevation and possible influencing factors in moderate and high myopia after small incision lenticule extraction

ObjectiveThe aim of this study was to investigate the early changes of posterior corneal elevation and possible influencing factors in moderate and high myopia after small incision lenticule extraction (SMILE). MethodsThis was a retrospective study. From Sep. 2017 to May 2018, case data of 63 patients (110 eyes) with moderate and high myopia who received SMILE in The First Affiliated Hospital of Guangxi Medical University were collected; parameters obtained by Pentacam Scheimpflug system of preoperation and postoperative 1 d, 1 week, 1 month and 3 months were selected, including the posterior corneal elevation at corneal apex and 45°, 135°, 225°, 315° points of two zones (centered on corneal apex 2 mm, 4 mm diameter), the mean of the 9 points above was taken as the central posterior corneal elevation. One-way repeated measures ANOVA was used to analysis the posterior corneal elevation at corneal apex and central corneal of different time pints, and Pearson product moment coefficient was used to analysis the correlation of the change of posterior corneal elevation at corneal apex and central corneal and the age of patients, preoperative spherical equivalent, central corneal thickness, corneal cutting depth, residual corneal thickness or corneal cutting ratio. ResultsThe posterior corneal elevation at corneal apex and central corneal declined within postoperative 1 month and turn back after postoperation for 1 month. After preoperation for 1 day, 1 week, 1 month and 3 months, the posterior corneal elevation at corneal apex were (0.52±2.46) mm, (0.39±2.21) mm, (0.33±2.33) mm, (-0.06±2.18) mm and (0.00±2.72) mm, respectively; the posterior corneal elevation at central corneal were (1.18±0.90) mm, (1.16±0.76) mm, (1.06±0.76) mm, (1.04±0.74) mm, (1.09±0.89) mm at postoperative for 1 day, 1 week, 1 month and 3 months, respectively; the difference was no significant among them (F=1.24, 0.62; P>0.05). At postoperative 1 day, 1 week, 1 and 3 months, the average changes of posterior corneal elevation at corneal apex (-0.13±1.43) mm, (-0.19±1.74) mm, (-0.58±1.65) mm, (-0.52±1.96) mm, respectively; and the average changes of posterior corneal elevation at central corneal (-0.02±0.68) mm, (-0.12±0.74) mm, (-0.14±0.78) mm, (-0.09±0.95) mm, respectively; the difference was also no significant among them (F=1.98, 0.47; P>0.05). There was no correlation between the change of posterior corneal elevation at corneal apex and central corneal and the age of patients, preoperative spherical equivalent, central corneal thickness, corneal cutting depth, residual corneal thickness or corneal cutting ratio at each time point (P>0.05). ConclusionThere was no obvious change in the posterior corneal elevation which recovered in the early postoperative period. SMILE has little effect on the posterior corneal morphology, which is safe and stable for patients with moderate and high myopia.