Biomechanical and wound healing characteristics of corneas after excimer laser keratorefractive surgery: Is there a difference between advanced surface ablation and sub-Bowman's keratomileusis?
Biomechanical and wound healing characteristics of corneas after excimer laser keratorefractive surgery: Is there a difference between advanced surface ablation and sub-Bowman's keratomileusis?
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DOI：
10.3928/1081597x-20080101-16
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发表时间：
2008-01-01
影响因子：
2.4
通讯作者：
Edelhauser, Henry F.
中科院分区：
文献类型：
--
作者：
Dawson, Daniel G.;Grossniklaus, Hans E.;Edelhauser, Henry F.
目的：探讨准分子激光角膜屈光术后角膜的生物力学及创面愈合特点。方法:对25例正常角膜标本、206例简单LASIK标本、17例简单亚鲍曼角膜磨除术（SBK）标本、4例简单光屈光性角膜切除术（PRK）标本、2例简单晚期表面消融（ASA）标本、5例锥形角膜标本、12例术后LASIK扩张标本和1例术后PRK扩张标本进行组织学、超微结构和内聚抗拉强度评价，并与先前发表的研究进行比较。结果：正常角膜的组织学和超微结构研究显示，在鲍曼层、角膜间质前三分之一、角膜间质后三分之二和Descemet膜中，胶原原纤维的方向和/或板层交织程度存在显著差异。内聚抗拉强度测试直接支持这些形态学发现，因为更强，更刚性的区域位于前眼和周围。这表明，就术后引起角膜扩张的风险而言，PRK和ASA，其次是SBK，在生物力学上应该比传统LASIK更安全。由于成人角膜间质创面愈合缓慢且不完全，所有准分子激光角膜屈光手术技术由于创面的修复性愈合不足，仍然存在一些明显的缺点。尽管与传统的PRK相比，ASA降低了一些角膜雾霭的风险，但ASA病例仍然可以由高细胞纤维化间质瘢痕形成角膜雾霭或突破性雾霭。相比之下，与传统LASIK类似，SBK仍有短期和长期潜在的低细胞原始间质瘢痕界面伤口并发症。结论：眼科病理学和基础科学研究表明，与传统LASIK或PRK相比，SBK和ASA是准分子激光角膜屈光手术的改进，特别是在维持角膜生物力学和可能适度降低角膜雾霭风险方面。然而，大多数由伤口愈合问题引起的缺点仍然存在。
PURPOSE: To describe the biomechanical and wound healing characteristics of corneas after excimer laser keratorefractive surgery.METHODS: Histologic, ultrastructural, and cohesive tensile strength evaluations were performed on 25 normal human corneal specimens, 206 uncomplicated LASIK specimens, 17 uncomplicated sub-Bowman's keratomileusis (SBK) specimens, 4 uncomplicated photorefractive keratectomy (PRK) specimens, 2 uncomplicated advanced surface ablation (ASA) specimens, 5 keratoconus specimens, 12 postoperative LASIK ectasia specimens, and 1 postoperative PRK ectasia specimen and compared to previously published studies.RESULTS: Histologic and ultrastructural studies of normal corneas showed significant differences in the direction of collagen fibrils and/or the degree of lamellar interweaving in Bowman's layer, the anterior third of the corneal stroma, the ' posterior two-thirds of the corneal stroma, and Descemet's membrane. Cohesive tensile strength testing directly supported these morphologic findings as the stronger, more rigid regions of the comea were located anteriorly and peripherally. This suggests that PRK and ASA, and secondarily SBK, should be biomechanically safer than conventional LASIK with regard to risk for causing keratectasia after surgery. Because adult human corneal stromal wounds heal slowly and incompletely, all excimer laser keratorefractive surgical techniques still have some distinct disadvantages due to inadequate reparative wound healing. Despite reducing some of the risk for corneal haze compared to conventional PRK, ASA cases still can develop corneal haze or breakthrouh haze from the hypercellular fibrotic stromal scarring. In contrast, similar to conventional LASIK, SBK still has the short- and long-term potential for interface wound complications from the hypocellular primitive stromal scar.CONCLUSIONS: Ophthalmic pathology and basic science research show that SBK and ASA are improvements in excimer laser keratorefractive surgery compared to conventional LASIK or PRK, particularly with regard to maintaining corneal biomechanics and perhaps moderately reducing the risk of corneal haze. However, most of the disadvantages caused by wound healing issues remain.