准分子激光角膜切削术后角膜地形图的分析

Analysis of corneal topography after excimer laser photorefractive keratectomy

目的：准分子激光角膜切削术（ＰＲＫ）后角膜性状和视力质量的研究。方法：对２３例（３８只眼）近视患者于术后１、３、６个月进行角膜地形图随访。结果：ＰＲＫ术后角膜表面的球面性状发生一定改变。随着时间推移，角膜表面规则指数（ＳＲＩ）和表面不规则指数（ＳＡＩ）均逐渐降低，角膜变得更加平滑；模拟角膜计读数（ＳｉｍＫ）表现一定的回退。术后６个月时，角膜地形图主要表现为四种形态：圆形或椭圆形（５０．００％）、哑铃形（２３．６８％）、半环形（１８．４２％）、中央小岛形（７．８９％），且各种形态与最佳视力有着一定的关系。结论：角膜地形图定量分析对ＰＲＫ术后角膜表面性状的评价、手术设计的改进、手术疗效的预测等是必要的。

To evaluate the changes of corneal surface and visual quality after photorefractive keratectomy (PRK) for myopia,analysis of corneal topography was performed on 23 patients(38 eyes) with myopia after PRK at the 1,3 and 6 month The corneal sphericity changed after PRK With time passing,the surface regularity index(SRI) and the surface asymmetry index(SAI) decreased gradually and corneal surface became more smooth;simulated keratoscope reading(Sim K) showed a gradual recession Four main patterns of ablation were noted through subtraction analysis 6 months later,a“round or oblong”ablation as present in 50 55% of eyes and “collar button”ablation was present in 23 68% of eyes,“semicircular”ablation was present in 18 42% of eyes,and “central island” ablation was present in 7 89% eyes Patterns of ablations were correlated with visual acuity So we conclude that quantitative analysis of corneal topography is essential to evaluate surface changes after PRK and helpful to design PRK and predicate the refractive outcome with greater precision