AIM:To explore the importance of preoperative exa-mination of LASIK or LASEK for preventing and reducing the surgery complications and improving the success rate. METHODS:Data of 1000 cases (2000 eyes) treated by excimer laser were analyzed retrospectively.RESULTS:Posterior corneal surface Diff≥ 50μm were in 25 cases,pathological changes of optical fundus were in 46 cases,the average central corneal refractive more than 47.50D was in 17 cases. Thin cornea (central thickness <450μm) was in 13 cases,and there were 4 cases with glaucoma and 2 cases with keratitis.CONCLUSION:Detailed and thorough preoperative examina-tion is an important guarantee for success of the operation.