准分子激光双面式切削原位角膜磨镶术治疗近视的实验研究

目的:探讨准分子激光双面式切削原位角膜磨镶术(both-sided LASIK,BSL)的角膜创口愈合过程。方法:24只新西兰大白兔右眼按-3.00D行LASIK,左眼角膜瓣上基质和基质床上分别按-1.50D行BSL,分别于术后1,7d;1,3mo随机选取6只动物,行裂隙灯、活体共焦显微镜、组织病理学及透射电镜检查。结果:BSL术后角膜中央区透明,没有雾状浑浊(haze),早期角膜瓣边缘上皮增厚,变厚的上皮下角膜基质轻度不规则,随时间逐渐趋于正常。术后各时间均未见炎性细胞浸润。活体共焦显微镜下:BSL术后角膜瓣层间出现散在高反光颗粒,早期部分基质细胞激活,BSL组与LASIK组比较上皮基底细胞、创面后基质细胞、反光颗粒、激活细胞、神经纤维及内皮细胞数量与术后同时期比较均无显著性差异(P>0.05)。透射电镜下:BSL术后早期上皮细胞轻微变性,少量纤维细胞核染色质边集,角膜瓣边缘局部胶原排列稍紊乱。1mo时基质胶原纤维排列整齐,直径大小一致。角膜各细胞的超微结构改变程度、角膜愈合的组织病理学变化与普通LASIK术后相似。结论:准分子激光双面式切削原位角膜磨镶术后角膜生物组织反应轻微,角膜愈合反应程度与普通LASIK术后相似,同时为最大限度的保留角膜基质床的剩余厚度创造了条件,是治疗近视的一种好的选择。

Basic study of both-sided LASIK for myopia

AIM: To investigate the corneal wound healing process of both-sided LASIK on rabbits·METHODS: Twenty-four adult New Zealand white rabbits were chosen as animal model. LASIK were perfor-med on the right eyes to attempt a correction of -3.00D and both-sided LASIK were performed on the left eyes to attempt a correction of -3.00D also. All the rabbits were examined with slit-lamp microscope and in vivo confocal microscopy before surgery and at 1 day, 1 week, 1 and 3 months after surgery. At each time of post operation examination, 6 operated rabbits were killed randomly, and all the corneas were removed for histopathological observation of transmission electron microscopy and light microscopy. ·RESULTS: Slit-lamp microscopy examination: After both-sided LASIK, the cornea central region was transparency and had no haze. At early stage, epithelium thickened at the edge of the flaps and corneal stroma was slightly irregular, which tended to normal with the time. There was no inflammatory cell infiltration at each time. Confocal microscopy examination: postoperatively, highly reflective particles appeared in layers of flaps and a part of stromal cells were activated. Compared with LASIK, there were no significant difference on the number of epithelium stromal cells, activated cells, fibroblast cells and endothelial cells after both-sided LASIK (P>0.05). Transmission electron microscopy examination: epithelium cells degeneration, chromatin margination and collagen arrangement disorder could be observed at early stage after both-sided LASIK. One month later, collagen arrangement became order and had same diameter. Ultrastructure and histopathology changes were similar with LASIK.·CONCLUSION: In both-sided LASIK, the corneal wound healing response is slight and is similar with LASIK. It creates the condition for preserving thickness of cornea stroma after surgery and is a good way to myopia treatment.