Allgeier Stephan, Winter Karsten, Bretthauer Georg, Guthoff Rudolf F, Peschel Sabine, Reichert Klaus-Martin, Stachs Oliver, Köhler Bernd
a Institute for Applied Computer Science , Karlsruhe Institute of Technology (KIT) , Karlsruhe , Germany.
b Institute of Anatomy , University of Leipzig , Leipzig , Germany.
Curr Eye Res. 2017 Apr;42(4):549-556. doi: 10.1080/02713683.2016.1221977. Epub 2016 Oct 21.
Purpose/Aim of the study: A recently proposed technique enables the generation of continuously increasing mosaic images of the corneal sub-basal nerve plexus (SNP) using in vivo corneal confocal microscopy (CCM). The aim of the present study was to investigate the progression of the corneal nerve fiber length (CNFL) measured in the growing mosaic images with regard to their increasing area.
Five large datasets from three healthy volunteers were examined using the proposed CCM technique. Intermediate mosaic images were created and assessed for CNFL.
The measured CNFL progression shows both over- and underestimation of the CNFL for small observed areas. Increasing the mosaic image area stabilizes the CNFL values and reduces the moving variance in all five datasets. The relative deviation of means from values of first and second examination of two of the subjects shows high differences for an observed area of <1.5 mm.
The present examination provides two measures to quantify different area-dependent aspects of the CNFL measured in an expanding mosaic image. The moving variance measures how stable the CNFL can be considered at a certain mosaic size. The relative deviation of means from two repeated CCM examinations on the other hand gives some indication on the level of reliability that can be expected from the measured CNFL. The progression of CNFL in the examined datasets manifests a potentially very high variability for mosaic sizes of less than about 1.5 mm. Above that size, CNFL progression and the intra-patient relative deviations both stabilize significantly in all five datasets. The results of the present examination suggest a recommendation for a minimum sampled area of the central SNP of 1.5 mm for reliable and meaningful measurement of CNFL.
研究目的：最近提出的一种技术能够使用活体角膜共焦显微镜（CCM）生成不断增大的角膜基底神经丛（SNP）镶嵌图像。本研究的目的是研究在不断增大的镶嵌图像中测量的角膜神经纤维长度（CNFL）随图像面积增加的变化情况。
使用所提出的CCM技术检查了来自三名健康志愿者的五个大型数据集。创建中间镶嵌图像并评估CNFL。
测量的CNFL进展显示，对于小观察区域，CNFL存在高估和低估情况。增加镶嵌图像面积可稳定CNFL值并减少所有五个数据集中的移动方差。两名受试者第一次和第二次检查值的均值相对偏差在观察区域<1.5 mm时显示出很大差异。
本研究提供了两种方法来量化在扩展镶嵌图像中测量的CNFL的不同面积相关方面。移动方差衡量在特定镶嵌大小下CNFL的稳定程度。另一方面，两次重复CCM检查均值的相对偏差给出了测量的CNFL预期可靠性水平的一些指示。在所检查的数据集中，CNFL在镶嵌大小小于约1.5 mm时表现出潜在的非常高的变异性。超过该大小，CNFL进展和患者内相对偏差在所有五个数据集中均显著稳定。本研究结果建议，为可靠且有意义地测量CNFL，中央SNP的最小采样面积为1.5 mm。
