Corneal Ectasia After Excimer Laser Keratorefractive Surgery: Histopathology, Ultrastructure, and Pathophysiology
Corneal Ectasia After Excimer Laser Keratorefractive Surgery: Histopathology, Ultrastructure, and Pathophysiology
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DOI：
10.1016/j.ophtha.2008.06.008
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发表时间：
2008-12-01
期刊：
影响因子：
13.7
通讯作者：
Edelhauser, Henry F.
中科院分区：
文献类型：
--
作者：
Dawson, Daniel G.;Randleman, J. Bradley;Edelhauser, Henry F.
目的：评估 LASIK 或屈光性角膜切除术 (PRK) 后发生角膜扩张的组织病理学和超微结构。设计：回顾性病例系列。参与者：从 12 名因 LASIK 术后进行性扩张而接受角膜移植的患者（12 份）或 PRK（1 份）中获取 13 份标本，用于组织病理学和超微结构评估。方法：所有 13 个扩张角膜均提交给用于光学显微镜的福尔马林。将 9 个标本一分为二，后半部分置于 2.5% 戊二醛中进行透射电子显微镜 (TEM)。主要指标：角膜组织病理学、超微结构和病理生理学。结果：LASIK 术后标本光镜显示角膜上皮发育不全，偶见上皮增生灶、Bowman 层破裂、LASIK 瓣基质厚度正常、角膜瓣厚度正常。细胞减少的原始间质疤痕、变薄的残余间质床 (RSB) 以及扩张区域 RSB 中比正常更大的人工板间裂隙。 PRK 后的标本显示出类似的发现，增加了一个变薄的细胞过多的纤维化基质疤痕。 TEM 显示 LASIK 术后扩张角膜的 RSB 或 PRK 术后扩张角膜的整个角膜基质床中的胶原片变薄和片层数量减少，其中角膜基质的后部受影响最严重。结论：组织病理学和超微结构研究表明，当 LASIK 或 PRK 术后角膜扩张时，会发生层间和纤维间生物力学滑移。在术后角膜基质的受力区域。这种两相慢性生物力学衰竭过程与圆锥角膜相似。复合科学将这种慢性生物力学失效过程归类为纤维间断裂。 财务披露：作者对本文讨论的任何材料没有专有或商业利益。眼科学2008; 115:2181-2191 (C) 2008 年，美国眼科学会。
Purpose: To evaluate the histopathology and ultrastructure of corneas developing ectasia after LASIK or photorefractive keratectomy (PRK).Design: Retrospective case series.Participants: Thirteen specimens from 12 patients undergoing corneal transplantation for progressive ectasia after LASIK (12 specimens) or PRK (1 specimen) were obtained for histopathologic and ultrastructural evaluation.Methods: All 13 ectatic corneas were submitted in formalin for light microscopy. Nine specimens were bisected, and the second half was placed in 2.5% glutaraldehyde for transmission electron microscopy (TEM).Main Outcome Measures: Corneal histopathology, ultrastructure, and pathophysiology.Results: Light microscopy of the post-LASIK specimens showed corneal epithelial hypoplasia and occasional foci of epithelial hyperplasia, Bowman's layer breaks, a normal stromal thickness of the LASIK flap, a normal thickness of the hypocellular primitive stromal scar, a thinned residual stromal bed (RSB), and larger than normal artifacteous interlamellar clefts in the RSB of the ectatic region. The post-PRK specimen showed similar findings with the addition of a thinned hypercellular fibrotic stromal scar. TEM showed thinning of the collagen lamellae and loss of lamellar number in the RSB of post-LASIK ectasia corneas or throughout the entire corneal stromal bed in the post-PRK ectasia cornea, with the posterior aspect of the corneal stroma being most affected.Conclusions: Histopathologic and ultrastructural studies suggest that interlamellar and interfibrillar biomechanical slippage occurs when the cornea becomes ectatic after LASIK or PRK in the postoperative stress-bearing regions of the corneal stroma. This 2-phase chronic biomechanical failure process is similar to that seen in keratoconus. Composite sciences classify this chronic biomechanical failure process as interfiber fracture.Financial Disclosure(s): The authors have no proprietary or commercial interest in any materials discussed in this article. Ophthalmology 2008; 115:2181-2191 (C) 2008 by the American Academy of Ophthalmology.