Background Corneal epithelial remodeling will happen after laser refractive surgery,But there have been few studies to evaluate the changes of the corneal epithelial thickness after integrated transepithelial photorefractive keratectomy (TranspRK).Objective This study was to evaluate the changes in epithelial thickness profile within the optical zone and its related factors following TransPRK for myopia.Methods In this retrospective non-randomized controlled study,forty-three patients (43 eyes) who underwent TransPRK with the spherical equivalent refraction-1.25 to-6.25 D from August 2014 to May 2015 in Jinan Mingshui Eye Hospital were included under the informed consent.Epithelial thickness was measured using spectral-domain optical coherence tomography in different corneal zones (central,2 mm;paracentral,2-5 mm,and mid-peripheral,5-6 mm) preoperatively at 1 week and 1,3,and 6 months postoperatively.Correlations between epithelial thickness changes and the amount of correction,optical zone,and Q-value changes (△Q) were analyzed 6 months postoperatively.Results The mean epithelial thickness in the central zone were (53.97±4.33),(51.03 ±4.11),(55.14±5.46) and (56.68 ± 5.09) μm at 1 week,1 month,3 months and 6 months after surgery,respectively.The epithelium were thicker at 3 months and 6 months after surgery compared to preoperative measurements ([52.37±3.42] μm),with significant differences between them (both at P＜0.05).Compared to preoperative values,the epithelial thickness at 6 months after surgery was (3.69 ±4.23),(5.19 ±3.88) and (6.23 ±3.91) μm thicker in the center,paracenter,and midperiphery zone,respectively,with significant differences between them (all at P ＜ 0.01).Epithelial thickness was positively correlated with programmed spherial equivalent correction and △Q (all at P＜0.05).A significant positive relationship was observed between epithelial thickening and ablation depth paracentrally and mid-peripherally (r=0.380,0.383;both at P＜0.05).Significantly negative relationships were observed between epithelial thickening and optical zone at the center,paracenter,and mid-periphery,respectively (r =0.405,0.485,0.384;all at P＜0.05).No correlation betwcen epithelial thickness change and ablation depth at the central zone was detected (P＞0.05).Conclusions The epithelial thickness shows a lenticular change with more thickening mid-Peripherally after TransPRK,which results in increased oblateness postoperatively.Epithelial remodeling may modify the profile after surface ablation.%背景 准分子激光角膜屈光手术矫治近视后角膜上皮会发生重塑效应,主要表现为上皮厚度的变化,目前关于单一步骤的经角膜上皮的准分子激光屈光性角膜切削术(TransPRK)后角膜上皮厚度变化的研究鲜见报道. 目的 探讨TransPRK矫治近视术后角膜光学区内不同区域上皮厚度的变化及其相关影响因素.方法 采用回顾性研究设计,收集2014年8月至2015年6月在济南市明水眼科医院行TransPRK手术的近视及近视散光患者43例43眼,术前等效球镜度为-1.25～-6.25 D.分别于术前及术后1周、1个月、3个月及6个月应用频域眼前节光相干断层扫描仪(OCT)对患者角膜0～2、2～5及5～6 mm范围内的上皮厚度进行测量,研究术后不同时间角膜上皮厚度的变化规律并分析其与屈光度、切削深度、光学区大小以及角膜非球面性变化(Q值)等因素的相关性.结果 术前及术后1周、1个月、3个月及6个月角膜中央上皮厚度分别为(52.37±3.42)、(53.97±4.33)、(51.03±4.11)、(55.14±5.46)和(56.68±5.09)μm,术后3个月与6个月角膜上皮厚度与术前比较差异均有统计学意义(均P＜0.05).术后6个月,角膜0～2、2～5及5～6 mm范围内角膜上皮厚度较术前分别增厚(3.69±4.23)、(5.19±3.88)和(6.23±3.91) μm,与术前比较差异均有统计学意义(均P＜0.01);角膜上皮厚度与屈光度和Q值变化量均呈正相关,与光学区大小呈负相关(均P＜0.05);2～5 mm区和5～6 mm区上皮厚度变化与切削深度均呈正相关(r=0.380、0.383,均P＜0.05),而中央区角膜上皮厚度与切削深度无相关性(P＞0.05).结论 TransPRK术后角膜光学区内上皮增厚的分布呈“负透镜式”的变化,越接近光学区周边增厚越显著,上皮厚度变化量受屈光度、切削区大小及切削深度的影响,且这种不均匀增厚会影响角膜的非球面特性,可能会在一定程度上掩藏个性化手术应该达到的效果.
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