目的：观察 NIDEK EC5000 准分子激光治疗系统准分子激光原位角膜磨镶术(Laser in sitkeratomileusis, LASIK) 角膜切削深度的可预测性。
方法：采用 NIDEK EC5000 准分子激光系统对 79 例近视和(或)近视散光患者进行标准 LASIK 手术，术中使用超声角膜测厚仪分别测量制瓣后和激光切削后的剩余角膜床厚度，计算实际角膜切削深度，比较实际角膜切削深度同理论预测角膜切削深度的差异。
结果：LASIK 术中实际切削深度(92.32±29.86) μm，预测切削深度(74.16±25.95) μm，两者差值(18.16 ± 14.71) μm 有统计学意义(P < 0.001)。实际切削深度与预测切削深度具有较好的相关性，相关系数为0.87 (P < 0.001)，其直线回归方程为Y = 18.06 + 1.001X。按术前角膜 K 值、术前等效球镜绝对值及术前中央角膜厚度值分组的实际切削深度与预测切削深度的差值均有统计学意义。实际切削深度与术前等效球镜有关，与术前中央角膜厚度和 K 值无关。实际切削深度与预测切削深度差值同 K 值、等效球镜，术前中央角膜厚度均无关。
结论：NIDEK EC5000 准分子激光系统 LASIK 术中实际角膜切削深度比预测角膜切削深度高 (18.16±14.71) μm，在手术设计时要考虑实际切削与机器标示值存在偏差，应尽可能多的预留剩余角膜基质床厚度，以提高手术安全性。

Purpose: To assess the predictability of corneal ablation depth in LASIK using NIDEK EC5000 excimer laser.
Method: Standard LASlK surgery was performed in 79 myopic patients with or without astigmatism with the NDEK EC5000 excimer laser system. Ultrasonic cornealpachymetry was performed immediately after flap creation and after laser ablation during LASIK procedure, by which the actual corneal ablation depth was calculated.The values of actual and predicted ablation depth were compared.
Results: The actual ablation depth was (92.32+29.86) μm, the predicted ablationdepth was (74.16+25.95) μm. The differences between them (18.16+14.71) μm were statistically significance (P < 0.001 ). Linear regression suggested that the actual ablation depth correlated closely with the predicted ablation depth (r = 0.87 , P < 0.001 ). The regression model was Y = 18.06+1.001X. The differences remained statistically significant and were independent of the levels of preoperative corneal keratometry, absolute preoperative spherical equivalent and the preoperative central cornea thickness.
Conclusion: The actual ablation depth was about (18.16+14.71) μm thicker than thepredicted ablation depth in the NlDEK EC5000 excimer laser system. We may have totake into account this deviation in order to ensure sufficient thickness of residualstromal bed.