方法：收集LASIK术后视力下降病例134例175眼，统计各种原因的构成比，分别将治疗前后的UCVA进行配对t检验。

结果：LASIK术后视力下降的总体发生率为1.86%，其中屈光回退的构成比为51.43%，治疗后UCVA由0.61±0.22上升为0.90±0.38(t=8.00，P<0.001)； 角膜上皮点状缺损构成比为32.57%，治疗后UCVA由0.60±0.19上升为1.20±0.24(t=20.00，P<0.001)； 调节痉挛构成比为5.14%，治疗后UCVA由0.76±0.21上升为1.32±0.22(t=8.14，P<0.001)； 角膜瓣移位和皱褶构成比为4%，治疗后UCVA由0.29±0.26上升为1.24±0.28(t=6.33，P<0.001)； 激素性高眼压构成比为4%，治疗后UCVA由0.57±0.05上升为1.0±0.16(t=2.53，P<0.05)； 眼底病变和弥漫性板层角膜炎(diffuse lamellar keratitis， DLK)构成比共为2.86%，经治疗后UCVA均有不同程度提高。

结论：LASIK术后视力下降的原因多种多样，及时发现和处理可获得良好疗效，恰当的预防措施也必不可少。

METHODS: In this retrospective study, 175 eyes of 134 patients whose vision was decreased after LASIK were included. The constituent ratio of every reason was counted and uncorrected visual acuity(UCVA)between pre-treatment and post-treatment were compared by paired t-test respectively.

RESULTS: The overall incidence of impaired vision after LASIK was 1.86%. The constituent ratio of regression was 51.43% and UCVA increased from 0.61±0.22 to 0.90±0.38(t=8.00, P<0.001)after treatment. The constituent ratio of punctate corneal epithelial defect was 32.57% and UCVA increased from 0.60±0.19 to 1.20±0.24(t=20.00, P<0.001)after treatment. The constituent ratio of accommodative spasm was 5.14% and UCVA increased from 0.76±0.21 to 1.32±0.22(t=8.14, P<0.001)after treatment. The constituent ratio of corneal flap shift and gauffer was 4% and UCVA increased from 0.29±0.26 to 1.24±0.28(t=6.33, P<0.001)after treatment. The constituent ratio of corticosteroid-induced ocular hypertension was 4% and UCVA increased from 0.57±0.05 to 1.0±0.16(t=2.53, P<0.05)after treatment. The constituent ratio of fundus lesions and diffuse lamellar keratitis(DLK)was 2.86% and UCVA all increased by different degrees after treatment.

CONCLUSION: The reasons of impaired vision after LASIK are many and varied. These cases could recover their vision by discovery and treatment in time, and the appropriate preventive measures were essential.