Vesaluoma M H, Sankila E M, Gallar J, Müller L J, Petroll W M, Moilanen J A, Forsius H, Tervo T M
Department of Ophthalmology, University of Helsinki, Eye Bank, Finland.
Invest Ophthalmol Vis Sci. 2000 Jul;41(8):2120-6.
Autosomal recessive corneal plana (RCP) is a rare corneal anomaly with unknown pathogenesis and a high incidence in Finland. The aim was to examine corneal sensitivity and the morphology of different corneal layers and subbasal nerves in RCP patients.
Three patients with a diagnosed autosomal recessive cornea plana were examined. Corneal sensitivity to different modalities of stimulation was tested in four corneas using noncontact esthesiometry. Tissue morphology of three corneas was evaluated, and in two corneas thickness of corneal layers was measured using in vivo confocal microscopy.
Corneas of RCP patients appear to have mechanosensory, polymodal, and cold-sensitive nerve terminals. RCP patients had normal sensation thresholds for chemical, heat, and cold stimulation but a high threshold for mechanical stimulation. Their capacity to discriminate increasing intensities of stimulus was reduced, except for cold stimuli. Thickness of the epithelial layer was reduced, whereas total corneal and stromal thicknesses were slightly reduced or close to normal values. In all cases Bowman's layer was absent. Subbasal nerves had abnormal branching patterns. The arrangement of anterior keratocytes was altered, showing clustered and irregularly shaped nuclei. Increased backscattering of light in confocal microscopy through focusing (CMTF) profiles was observed throughout the stroma. Epithelial and endothelial cells appeared to be regular in shape.
The present study revealed qualitative and quantitative alterations in corneal sensitivity, cellular morphology, and the thickness of corneal layers in RCP patients.
常染色体隐性遗传性扁平角膜（RCP）是一种罕见的角膜异常，其发病机制不明，在芬兰发病率较高。本研究旨在检查RCP患者的角膜敏感性以及不同角膜层和基底膜下神经的形态。
对3例诊断为常染色体隐性遗传性扁平角膜的患者进行检查。使用非接触式眼压计在4只角膜上测试角膜对不同刺激方式的敏感性。评估了3只角膜的组织形态，并使用活体共聚焦显微镜测量了2只角膜的各层厚度。
RCP患者的角膜似乎具有机械感觉、多模式和冷敏神经末梢。RCP患者对化学、热和冷刺激的感觉阈值正常，但对机械刺激的阈值较高。除冷刺激外，他们区分刺激强度增加的能力降低。上皮层厚度减少，而角膜总厚度和基质厚度略有减少或接近正常值。在所有病例中，Bowman层均缺失。基底膜下神经具有异常的分支模式。前角膜细胞的排列发生改变，细胞核呈簇状且形状不规则。在共聚焦显微镜下，整个基质中观察到通过聚焦（CMTF）轮廓的光后向散射增加。上皮细胞和内皮细胞形状似乎正常。
本研究揭示了RCP患者在角膜敏感性、细胞形态和角膜层厚度方面的定性和定量改变。
