中低度近视LASEK术后角膜地形图分析

Corneal topography analysis after laser subepithelial keratomileusis for low to moderate myopia

目的 探讨中低度近视准分子激光上皮瓣下角膜磨镶术 (LASEK)后的角膜地形图变化。方法 中低度近视LASEK术 40例 (80眼 ) ,术前及术后 1、3、6月行角膜地形图检查 ,与综合验光结果进行相关分析。结果 LASEK术后 6月裸眼视力≥ 0 .6者占 10 0 .0 0 % ,其中≥ 1.0者占 97.5 0 %。 80眼术前角膜地形图表现最多者为对称领结形 ,依次为非对称领结形 ,圆形 ,椭圆形及不规则形。术后 6月检查时角膜地形图主要表现为圆形或椭圆形 (75 .0 0 % ) ,肾形 (2 1.2 5 % )及半环形 (3 .75 % )。LASEK术后 (SAI)、SimK等效值和SimK的差值较术前变化显著 (P <0 .0 5 ) ,SRI改变则不显著。结论 LASEK治疗中低度近视疗效佳。角膜地形图的定量分析对术后角膜表面球面性状的评价、手术设计的改进和疗效的预测具有重要意义。

Objective To study the changes of corneal topography after laser subepithelial keratomileusis(LASEK) for low to moderate myopia.Methods LASEK was performed in 80 eyes of 40 patients with low to moderate myopia. Corneal topography was examined before and 1 month, 3 month, 6 month after LASEK. The comparative analysis was performed with visual acuity and refractive outcome at the same period.Results Uncorrected visual acuity of 0.6 or better was achieved in 100% of eyes and of 1.0 or better achieved in 97.50% at 6 months after surgery. The corneal surface sphericity was changed after LASEK, the surface regularity index (SRI) was not significant, while the surface asymmetry index (SAI) had changed postoperatively; simulated keratoscope reading (Simk) and the margin of SimK significantly decreased postoperatively. At the 6-month postoperative examination,corneal topography showed three main patterns of ablation: round or oblong (75.00%), kidney shape (21.25%), semi-cicular (3.75%).Conclusion LASEK is an effective and safe refractive surgery for the correction of low to moderate myopia. The quantitative analysis of corneal topography is essential and helpful for evaluating surface changes after LASEK, the surgical design, and predicting the refractive outcome with greater precision.