近视准分子激光术后远期角膜知觉变化及危险因素分析

The long-term change of corneal sensation and the related risk factors after the excimer laser eye surgery for myopia

目的研究准分子激光角膜切削术（PRK）、角膜瓣蒂止上方的准分子激光原位角膜磨镶术（LASIK）（Superior—hinged LASIK，S-H-LASIK）及角膜瓣蒂止鼻侧的LASIK（Nasal—hinged LASIK，N—H—LASIK）术后远期角膜知觉的改变并分析其相关危险因素。方法对93例186只眼接受近视激光手术患者，其中PRK58只眼、N—H—LASIK102只眼、S-H—LASIK26只眼，随访3-10年，检测干眼症相关指标中央角膜知觉（COS），对获得的数据差异的比较采用Kaplan—Meier法进行生存分析，角膜触觉影响因素的分析采用COX回归模型。结果（1）PRK、N—H—LASIK、S—H—LASIK术后出现半数CCS改变的时间是3462、2721、1383d。（2）角膜触觉的主要影响因素有患者的年龄（OR-0．965，95％CI：0．938。0．992）、术前等量球镜（OR=1．385，95％CI：1．149～1．669）、术前平均角膜曲率（OR=1．392，95％CI：1．088～1．780）、术后平均角膜曲率（OR=0．881，95％CI：0．781。0．994）、角膜切削厚度（OR=1．028，95％CI：1．009～1．047）。（3）N—H—LASIK手术引起角膜触觉改变的可能性是PRK手术方法的96．074倍（95％CI：12．090～763．451），S-H—LASIK手术引起角膜触觉改变的可能性是PRK手术方法的633．364倍（95％CI：61．807～6490．401）。结论近视激光手术可以导致患者术后远期角膜知觉的下降；相对于PRK手术，LASIK手术尤其是角膜瓣的蒂位于上方者，是术后角膜知觉下降的高危因素，其他的危险因素主要与手术中激光切削的角膜组织面积和深度有关．

Objective To investigate the long-term change of corneal sensation after the myopic correction by excimer laser eye surgery and analyze the related risk factors. Methods A total of 186 eyes of 93 patients that had undergone eye surgery were evaluated, 58 eyes were treated with photorefractive keratectomy （PRK） and 102 eyes received the nasal-hinged flap （N-H-LASIK） procedure, while superior-hinged flap （S-H-LASIK） procedure was performed on the other 26 eyes. After the operation, all the patients were followed up from three to ten years. The central corneal sensitivity （CCS） was examined to determine the occurrence of dry eye symptoms. Kaplan-Meier survival analysis was evaluated. COX regression was used to observe the factors that might affect the central comeat sensitivity. Results First, The median survival time of CCS after the surgery in patients with PRK, N-H-LAS1K and S-H-LASIK was 3462 days, 2721 days and 1383 days respectively. Second, the factors that mainly contributed to the change of central corneal sensation involved the pa- tient＇s age （OR=0.965, 95% CI： 0.938-0.992）, the preoperative spherical equivalent （OR=1.385, 95% CI： 1.149-1.669）, the average corneal curvature at preoperative （OR=1.392, 95%CI： 1.088-1.780）, postoperative corneal curvature （OR=0.881, 95%CI： 0.781-0.994） and the thickness of ablated cornea （OR=1.028, 95%CI： 1. 009-1.047）. Fourth, the possibility of N-H-LASIK and S-H-LAS1K that contributed to thechange of central corneal sensation was 96.074 times （95%CI： 12.090-763.451） and 633.364 times （95%CI： 61.807-6490.401） of PRK respectively. Conclusions The excimer laser eye surgery for myopia could lead to a long term decrease of central corneal sensation. Compared with PPK, S-H-LASIK procedure should be considered as a high risk factor that contributes to the decrease of corneal sensation. In addition to this reason, the size and depth of corneal tissue that were cut during the procedure also contribute to the decrease of corneal sensation.