Karabatsas C H, Cook S D
University of Bristol, Department of Ophthalmology, Bristol Eye Hospital, UK.
Eye (Lond). 1996;10 ( Pt 4):451-5. doi: 10.1038/eye.1996.99.
Pellucid marginal corneal degeneration (PMCD) is an uncommon cause of inferior peripheral corneal ectasia, affecting patients between the ages of 20 and 40 years. Although histopathologically it is considered a variant of keratoconus, it differs in that the marked corneal steepening occurs more inferiorly, above a narrow band of corneal stromal thinning concentric to the inferior limbus. Here we present two cases. The first case is a clinically typical bilateral PMCD with a characteristic pattern of irregular against-the-rule astigmatism on corneal topography. The second case had an uncommon presentation of hydrops in a clinically keratoglobic eye which showed a marked steepening of the inferior corneal periphery on corneal topography. The other eye showed both clinically and topographically the features of PMCD. Corneal topography suggested that in the second patient, PMCD may have preceded the development of keratoglobus. Keratoconus, PMCD and keratoglobus are considered to be associated as part of the spectrum of non-inflammatory corneal thinning disorders. However, although the finding of PMCD and keratoconus in fellow eyes has been reported, to the best of our knowledge progression from PMCD to keratoglobus has not previously been shown.
透明边缘角膜变性（PMCD）是周边下角膜扩张的一种罕见病因，影响20至40岁的患者。尽管在组织病理学上它被认为是圆锥角膜的一种变体，但其不同之处在于明显的角膜陡峭更发生在下方，位于与下角膜缘同心的窄带状角膜基质变薄之上。在此我们展示两个病例。第一个病例是临床上典型的双侧PMCD，在角膜地形图上具有不规则逆规散光的特征性模式。第二个病例是在临床上呈球形角膜的眼中出现了罕见的角膜水肿表现，在角膜地形图上显示下角膜周边明显陡峭。另一只眼在临床和地形图上均显示出PMCD的特征。角膜地形图提示，在第二个患者中，PMCD可能先于球形角膜的发展。圆锥角膜、PMCD和球形角膜被认为是作为非炎性角膜变薄疾病谱的一部分而相关联。然而，尽管已有报道在对侧眼中发现PMCD和圆锥角膜，但据我们所知，此前尚未显示PMCD向球形角膜的进展。
