摘要
目的研究准分子激光原位角膜磨镶术(LASIK)术前角膜后表面形态,为近视筛选病例提高手术的安全性提供参考。方法应用Orbscan_Ⅱ眼前段分析系统观察近视230例(455眼),分成3组:Ⅰ组-1.50D^6.00D者210眼,占46.15%;Ⅱ组-6.25 D^-10.00 D者190眼,占41.76%;Ⅲ组-10.25D^-15.00D者55眼,占12.09%。得出角膜后表面地形图分布情况,比较3组角膜后表面前凸极值(Diff)值的变化。结果各组角膜后表面高度地形图中以岛形居多,前凸极点多位于颞下方,其次为鼻下、颞上、鼻上方;角膜后表面Diff值3组间相差不显著,同一患者左右眼Diff值无显著差别;角膜后表面Diff值大小、前凸极点距视轴距离与近视程度无关,角膜厚度的最薄点与角膜后表面前凸极点并非完全对应。结论Orbscan-Ⅱ检查系统对角膜后表面高度地形图的特征以及Diff值,前凸极点距视轴距离以及前凸极点分布位置的测量为术前制定合理的手术方案、筛选异常角膜、尽早发现角膜后圆锥提供参考。
Objective To study the changes of corneal posterior surface before laser in situ keratomileusis （LASIK）. Methods Orbscan-Ⅱ corneal topography system was used to investigate corneal posterior surface topography on 455 myopic eyes（230 cases）. The degree of myopia was from - 1.50 to - 15.0D（spherical equivalent）. Results Islandshap was most in the corneal topography of posterior corneal surface; the protrusion pole of posterior surface was mostly in inferotemporal followed by inferonasal, superotemporal and superonasal. Distance from the top point of the posterior surface in the posterior elevation map of the posterior surface of the cornea to the perfect spherical surface （diff value）,the distance of protrusive pole away from visual axis. The resulting data wasstatistically different （P 〉 0.05）.The thinnest point of corneal thickness corresponded uncompletely to the top point of the corneal posterior surface. Conclusion The changes of corneal posterior surface shape are not related with diopter of myopia but related with corneal thickness and the changes are the well indicators for evaluating corneal surface. Orbscan-Ⅱ system is an useful instrument for the evaluation of corneal surface in corneal refractive surgeries to prevent a tapered cornea developing after LASIK surgery.
出处
《眼外伤职业眼病杂志》
北大核心
2005年第12期905-907,共3页
Journal of Injuries and Occupational Diseases of the Eye with Ophthalmic Surgeries
