VisuMax飞秒激光准分子激光角膜原位磨镶术术后角膜反应的共焦显微镜观察

目的观察VisuMax飞秒激光制瓣的准分子激光角膜原位磨镶术（LASIK）术后角膜反应的动态变化。方法等效球镜为-6.75～-12.50D的近视患者6例12眼行VisuMax飞秒激光制瓣的LASIK。飞秒激光参数设置为脉冲频率200kHz,脉冲能量100～150nJ,瓣直径7.9～8.3mm,预计瓣厚度80～100μm。分别于术后1周、1个月、3个月用裂隙灯检查角膜中央区域的形态,并用共焦显微镜观察中央区域的角膜反应。结果术后1周、1个月、3个月裂隙灯检查所有手术眼未见haze或瓣皱褶,共焦显微镜下观察所有眼未见明显角膜上皮细胞的形态改变。术后1周,4例6眼观察到近切削界面的基质细胞轻度激活,表现为细胞核反光增强,细胞轮廓可见,切削面反光轻度增强,其余眼未观察到明显的基质细胞激活。角膜基质细胞激活在术后1个月减轻,至术后3个月基本消失。术后所有手术眼均可在切削面持续观察到高反光沉积物,1眼（预期角膜瓣厚度80μm）在共焦显微镜下可见角膜微皱褶。结论 VisuMax飞秒激光LASIK术后存在角膜细胞水平反应的变化,其角膜基质细胞激活程度较轻可能与脉冲能量较低有关。

Corneal tissue responses under confocal microscopy after VisuMax femtosecond laser assisted LASIK

Background Several studies suggested that high power laser may induce severe damage to corneal keratocytes,resulting in corneal haze and transient light sensitivity syndrome （TISS） after the femtosecond laser-assisted LASIK.VisuMax femtosecond laser has a low laser energy level of 100-150 nJ and its effect on the corneal response has not been well studied.Objective The aim of this study was to investigate the dynamic response of cornea after the VisuMax femtosecond laser-assisted LASIK using in vivo confocal microscopy.Methods Twelve eyes of six subjects with spherical equivalent refraction of （-6.75 D--12.50 D） underwent the VisuMax femtosecond laser-assisted LASIK for myopic correction.The surgical parameters were set as follows：laser frequency 200 kHz,laser energy 100-150 nJ,flap diameter 7.9-8.3 mm and expected flap thickness 80-100 μm.Corneal central morphologic changes were examined with slit-lamp,and the corneal responses were evaluated with in vivo confocal microscope in 1 week,1 month and 3 months after operation.Written informed consent was obtained from each patient prior to the clinical procedure.Results No obvious corneal haze or flap microfolds were detected by slit-lamp examination and no morphological alterations occurred in corneal epithelial cells under the confocal microscope through the obsertvation duration.The highly reflective nuclei in keratocytes were observed near the flap interface in 6 eyes of 4 subjects 1 week postoperatively.The responses of corneal keratocytes gradually diminished with time.Irregular highly reflective flap interface particles were seen in all eyes through the visit period after operation.The microfolds were noted in one eye （expected corneal flap thickness of 80 μm） after surgery.Conclusion The responses of cornea appears the dynamic changes after VisuMax femtosecond laser-assisted LASIK.The mild corneal keratocyte activation is likely related to the lower energy of VisuMax femtosecond laser.