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目的探讨薄角膜(<500μm)近视散光眼行准分子激光原位角膜磨镶术(laser in situ keratomileusis,LASIK)后长期(≥60个月)的角膜生物力学状态、手术的安全性、有效性及准确性。方法选取1998年9月至2010年9月,行LASIK手术且资料完整的薄角膜患者89例175只眼,观察术前及术后末次的裸眼视力(uncorrected visual acuity,UCVA)、矫正视力(corrected distance visual acuity,CDVA)、球镜度数、散光度数、等效球镜度数(spherical equivalent,SE),以及术前的中央角膜厚度(central corneal thickness,CCT)及术后末次复查时的CCT、角膜瓣厚度与剩余基质床厚度(residual stromal bed thickness,RSBT)及角膜地形图。计算安全指数、有效指数、准确性以及角膜瓣厚度+切削深度)/术前中央角膜厚度(Percent Tissue Altered,PTA)与剩余基质床厚度/术前中央角膜厚度(Percentage stromal bed thickness,PSBT)结果安全指数为1.09,有效指数为0.99,末次复查的SE在±0.50D、±1.00D范围之内的百分比分别为71.2%、87.7%,PTA为20%~55%(40%±6%),PSBT为51%~85%(61%±9%),无术眼发生继发性圆锥角膜。结论 PSBT达到50%及以上时,薄角膜(459~499μm)近视散光眼行LASIK术后角膜生物力学状态长期稳定,且安全有效。
Objective To investigate the long-term (≥60 months) corneal biomechanical status, surgical safety and efficacy after laser in situ keratomileusis (LASIK) with thin cornea (<500μm) myopic astigmatism And accuracy. Methods A total of 175 eyes of 89 patients with thin cornea underwent LASIK from September 1998 to September 2010 were enrolled in this study. Uncorrected visual acuity (UCVA), corrected visual acuity (UCVA) and corrected visual acuity distance visual acuity (CDVA), degree of spherical aberration, degree of astigmatism, spherical equivalent (SE), and preoperative central corneal thickness (CCT) and postoperative CCT Flap thickness and residual stromal bed thickness (RSBT) and corneal topography. Calculate the safety index, effective index, accuracy and corneal flap thickness plus depth of cut) / Preoperative Central Tissue Thickness (Percent Tissue Altered, PTA) and Percentage of Stomal Bed Thickness (PSBT) The safety index was 1.09 and the effective index was 0.99. The percentage of SEs within the range of ± 0.50D and ± 1.00D in the last review were 71.2% and 87.7% respectively, PTA was 20% -55% (40% ± 6%), PSBT was 51% ~ 85% (61% ± 9%), no secondary ocular keratoconus occurred. Conclusions When the PSBT reaches 50% and above, cornea biomechanics after long - term myopic astigmatism with thin cornea (459 ~ 499μm) have long - term stability and safety.