Objective: To determine whether ectasia after laser in situ keratomileusis (LASIK) is related to residual corneal bed thickness. Design: Retrospective noncomparative case series. Participants: Thirty-two eyes of 16 patients with refractive errors of -4.00 to -18.00 diopters were examined. Intervention: LASIK was performed. The topography of the posterior corneal surface was examined with the Orbscan slit scanning corneal topography/pachymetry system. Main Outcome Measures: The difference in the elevation of posterior corneal surface regarding the best-fit sphere was measured. Results: After surgery, mean bulge of 17.2±7.2μm was found in eyes with residual corneal bed of 250μm or greater, whereas 41.0±22.1μm was seen in eyes with bed thickness less than 250μm (t=4.29; P=0.000). Conclusion: Posterior corneal bulge is correlated with the residual corneal bed thickness. The risk of ectasia may be increased if the residual corneal bed is thinner than 250μm.

目的：探讨LASlK术后严重角膜上皮内生所致角膜瓣融解缺损的治疗方法。病例和方法：LASlK术后经本院确诊为角膜上皮内生合并角膜瓣融解的12例13眼，根据角膜瓣厚度及角膜瓣融解的程度，9眼接受翻开角膜瓣清除层间上皮的治疗，3眼行异体角膜磨镶术，1眼去除角膜瓣。结果：翻开角膜瓣清除角膜上皮的9眼中，2眼复发，但再次治疗后正常愈合。异体角膜磨镶术组的3眼角膜瓣均正常愈合。去除角膜瓣的1眼角膜上皮正常，但出现2级角膜雾状混浊。所有患眼术后均获得0.3-1.0的裸眼视力，而矫正视力较LASlK术前下降0～4行。结论：LASlK术后角膜上皮内生合并角膜瓣融解是一较严重并发症，针对不同情况采用相应治疗方案可有效恢复患者视力。

Objective To evaluate the treatment of under correction after the excimer laser in situ keratomileusis (LASIK) for correcting moderate and high myopia. Methods An enhancement ablation was per-formed in 48 eyes of 39 patients who had undergone LASIK but remained in undercorrection. Four proce-dures were performed within 1 month pOStOpoera-tively, and the others performed between 3 and 10 months. The surgical technique includes the re-invert of the corneal cap from the temporal side, the excimer laser ablation, and the re-position of the cap. Results The undercorrection (spherical equiva-lent) ranged from-2.00 to-11.00 D, with a mean of-4.34D

目的：观察LAslK术后角膜后曲率的改变，并研究其与残留角膜床厚度的关系。方法：采用ORBscAN裂隙扫描角膜地形图系统对32只眼LAslK手术前和手术后三个月角膜后表面曲率进行测定。结果：LAslK术后角膜后表面均有不同程度的向前突出残留角膜床厚度大于250μm者，平均前突7±6μm，而在高度近视患者剩余角膜床厚度小于250μm，术后角膜后表面中央前突达22±9μm结论：LAslK术后角膜后表面前凸增加残留角膜床小于250μm者术后发生角膜扩张的危险性可能增加。

近10年来，角膜屈光手术在眼科临床发展迅速，其中准分子激光角膜屈光手术的效果得到临床肯定，尤其准分子激光原位角膜磨镶术（laser in situ kemtomileuis, LASIK）以其安全、有效等特点，得到近视患者的广泛接受，成为当前角膜屈光手术的主流术式。在我国每年角膜屈光手术的数量达到数十万之多。随着手术技术的发展和相关研究的深入，角膜屈光手术“成功”的标准亦在不断提高。20世纪80年代以前，术后裸眼视力>0.5即为手术成功；而今天手术成功的标准已提高至裸眼视力≥1.0。但是，临床医师和近视患者对角膜屈光手术疗效的期望仍在不断提高，对术后视觉质量提出了更多的要求。