准分子激光角膜上皮瓣下磨镶术中角膜上皮瓣的活性

Viability of corneal epithelial flap in laser subepithelial keratomileusis

背景:保证角膜上皮瓣活性的最佳乙醇浸润时间是准分子激光角膜上皮瓣下磨镶术研究的热点。目的:观察准分子激光角膜上皮瓣下磨镶术后影响角膜上皮瓣活性的相关因素。方法:应用前瞻性研究方法选取50例(100眼)行准分子激光角膜上皮瓣下磨镶术患者,术眼按度数分为轻度近视(<-3.00m-1)40眼和中度近视(-3.00～-6.00m-1)60眼。术中乙醇作用时间分别为15,25s。结果与结论:术后1周、1,6,12个月时,相同近视度数下,与乙醇作用25s比较,术中乙醇作用15s眼的裸眼视力明显提高,角膜上皮愈合时间加快(P<0.01),角膜荧光素染色评分降低,雾状角膜混浊程度降低(P<0.05或P<0.01)。相关性分析显示,角膜荧光素染色评分与雾状角膜混浊程度呈正相关(P<0.01)。说明准分子激光角膜上皮瓣下磨镶术中切削深度相当情况下,乙醇浸润时间越短,角膜上皮瓣制作质量越高,术后角膜上皮瓣活性越好,愈合较快、视力易恢复。

BACKGROUND：The optimum ethanol exposure time to ensure the viability of corneal epithelial flap is the research hotspot for laser subepithelial keratomileusis. OBJECTIVE：To investigate the factors influencing the viability of corneal epithelial flap in laser subepithelial keratomileusis （LASEK）.METHODS：A standard LASEK was performed on 100 eyes of 50 myopic patients prospectively. The preoperative spherical equivalent ranged from -1.37 m-1 to -6.00 m-1, with the mean value of （-4.09 m-1±2.12 m-1）. Eyes were divided to two groups, low myopic group A （-3.00 m-1, 40 eyes） and moderate myopic group B （-3.00 m-1-6.00 m-1, 60 eyes）. All of the eyes were exposed to 20% ethanol for 15 and 25 seconds, so group A was divided to group A1（15 seconds） and group A2 （25 seconds） （20 eyes for each group）, and group B was divided to group B1 （15 seconds） and group B2 （25 seconds） （30 eyes for each group）. Uncorrected visual acuity （UCVA） and corneal fluorescein staining and corneal haze were noticed and compared at the 12 months of follow-up. RESULTS AND CONCLUSION：The healing time of epithelium of group A1 was significantly longer than that of group A2, and the healing time of epithelium of group B1 was significantly longer than that of group B2 （P 0.01）. In terms of Haze grade 2, there was significant difference between group A1 and group A2 （P 0.05） and between group B1 and group B2 （P 0.01）. Score of corneal fluorescein staining was positively correlated with Haze frequency. Under corresponding cutting depth of corneal matrix in LASEK, we obtained high quality and fine viability of corneal epithelial lap if we shortened the ethanol expose time, so we were satisfied with the healing time of cornea and vision and decreased frequency of Haze. These findings suggest that in the LASEK, under proper cutting depth of corneal matrix, shorter ethanol expose time leads to better quality of corneal epithelial flap prepared, better flap viability, and faster healing, which contribute to recovery of vision.