准分子激光屈光性角膜术对泪膜稳定性的影响

目的：研究准分子激光屈光性角膜术（ＰＲＫ与ＬＡＳＩＫ）前后泪膜的变化。方法：选择８７ 眼近视眼患者分两组进行ＰＲＫ和ＬＡＳＩＫ术，分别观察患眼术前和术后３ 天、１０ 天、１ 月、３ 月及６ 月（ＬＡＳＩＫ组未查） 的主观感觉、上皮缺损情况、泪膜形态、非侵犯性泪膜破裂时间（ＮＩＢＵＴ） 和侵犯性泪膜破裂时间（ＢＵＴ） ，并对结果作统计学分析。结果：①ＰＲＫ 组有１８ 眼感觉较术前干燥，ＬＡＳＩＫ 组无一例出现症状，两组相比有显著性差异（ Ｐ＜ ０ ．０１） 。②术后３ 天、１０ 天ＰＲＫ组术后上皮缺损者明显多于ＬＡＳＩＫ组，两组相比有显著性差异（ Ｐ＜０．０１） 。③两组各眼术前、术后的泪膜形态均无改变。④ＰＲＫ组ＢＵＴ术后３ 天、１０ 天、１ 月较术前明显缩短，有显著性差异（Ｐ＜０．０１）；ＬＡＳＩＫ 组术前、术后各期相比均无显著性差异（ Ｐ＞ ０．０５）。结论：ＰＲＫ可影响泪膜的稳定性，但随着角膜的愈合而逐渐恢复，ＬＡＳＩＫ由于保留了角膜上皮的完整性而不影响其稳定性。角膜上皮层结构的改变是引起泪膜稳定性下降的主要原因。

The effects of photorefractive keratectomy and laser in situ keratomileusis on tear film stability

Objective:To investigate the changes in tear film stability after PRK and LASIK.Methods:We chose 87 myopic eyes that were undergoing PRK or LASIK.These eyes were divided into the PRK group and the LASIK group.The eyes were observed for subjective complaints,epithelial defect,tear film pattern,non-invasive tear break-up time (NTBUT) and invasive tear break-up time (BUT) preoperatively and 3 days,10 days,1 month,3 months and 6 months postoperatively.Results:18 eyes felt dry in the postoperative PRK group and no eyes felt dry in the LASIK group.This difference between the two groups was statistically significant (P<0.01).There were significant differences in subjective complaints between the preoperative group and the postoperative group at 3 days and 10 days (P<0.1) due to the epithelial defect.There were no changes in tear film pattern between preoperative and postoperative in either group.There were obvious decreases in BUT at 3 days,10 days and 1 month postoperatively relative to the preoperative level (P<0.01) in the PRK group and there was a significant difference between 3 days and 10 days postoperatively in BUT.However,no changes were observed between the preoperatives and postoperatives in the LASIK group (P>0.05).Conclusion:PRK may lead to changes in tear film stability.The main cause is a change in corneal epithelial structures.