去瓣与留瓣机械法准分子激光上皮瓣下角膜磨镶术后泪液炎症因子的比较

目的研究去瓣机械法准分子激光上皮瓣下角膜磨镶术（Epi-LASIK）眼与留瓣Epi-LASIK眼术后泪液中炎症因子释放率及临床结果的差异，并探讨导致差异的可能原因。方法前瞻性随机双盲对照研究。18名近视患者纳入本研究，一眼接受去瓣Epi-LASIK（去瓣组），对侧眼接受传统Epi-LASIK（留瓣组）。术前、术后2h、术后1d、术后5d分别收集每只眼的泪液。采用多通道免疫微珠分析测定泪液中IL-1β、IL-6、IL-8及肿瘤坏死因子α（TNFα）的浓度，并以浓度乘上泪液流量计算炎症因子的释放率。评估患者的裸眼视力、屈光状态、最佳矫正视力、角膜haze分级、角膜上皮愈合百分比。数据采用配对t检验、Wilcoxon秩和检验及卡方检验进行比较。结果与留瓣组相比，去瓣组在术后第5天裸眼视力更好（t=-4．832，P〈0．01），角膜上皮愈合百分比更高（压5．861，P〈0．01）；术后1个月角膜haze程度更轻（U=6．045，P〈0．05）。术前。2组泪液中各个炎症因子的释放率差异均无统计学意义；术后2h，去瓣组泪液中IL-8和TNFα的平均释放率显著低于留瓣组（Z=-1．965、-2．145，P〈0．05），术后1d和5d2组泪液炎症因子差异无统计学意义。结论去瓣Epi-LASIK术后角膜上皮愈合及视力恢复更快，角膜haze程度更轻。去瓣组术后2h泪液IL-8和TNFα释放率较低可能是2组存在临床差异的原因之一。

Comparison of inflammatory cytokines in tears when off-flap and on-flap Epi-LASIK are used

Objective To compare the release rate of inflammatory cytokines in tears and the clinical outcomes for off-flap epi-LASIK eyes and the contralateral on-flap Epi-LASIK eyes; to explore the possible mechanisms for the clinical differences. Methods This prospective and randomized study enrolled 18 myopic patients who underwent off-flap Epi-LASIK in one eye （off-flap group） and on-flap Epi-LASIK in the contralateral eye （on-flap group）. Tears were collected from each eye preoperatively and 2 hours, 1 day and 5 days postoperatively. Concentrations of interleukin-1β （IL-1β）, IL-6, IL-8 and tumor necrosis factor α （TNFα） were measured by a multiplex immunobead assay. The release rate （tear fluid flow-corrected concentration） was calculated by multiplying the concentration by tear fluid flow. Uncorrected visual acuity （UCVA）, refraction, best-corrected visual acuity, haze score, and percentage of corneal epithelial healing were also evaluated. Data were analyzed using a paired t test, Wilcoxon rank sum test, and a chi-square test. Results Compared with the on-flap group, the off-flap group had better UCVA outcomes （t=-4.832, P〈0.01 ） and higher percentages of epithelial healing （Z=5.861, P〈0.01） at 5 days after surgery, and lower levels of haze at 1 month after surgery （U=6.045, P〈0.05）. Preoperatively, there were no significant differences in the release rate of all tear cytokines between the two groups. At 2 hours postoperatively, the mean release rates of IL-8 and TNFct in the off-flap group were significantly lower than those in the on-flap group （Z=-1.965, -2.145, P〈0.05）. On postoperative clays 1 and 5, no significant differences were observed in the release rate of all cytokines between the 2 groups. Conclusion Off-flap Epi-LASIK offers faster corneal epithelial healing and visual recovery, and temporarily less haze than from on-flap Epi-LASIK. The lower tear levels of IL-8 and TNFα in the off-flap group 2 hours after surgery may suggest a possible mechanism for the clinical differences.