圆锥角膜在高度地形图上的地形模式和顶点位置。

Topographic pattern and apex location of keratoconus on elevation topography maps.

作者信息

Demirbas N H, Pflugfelder S C

机构信息

Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami School of Medicine, Florida 33136, USA.

出版信息

Cornea. 1998 Sep;17(5):476-84. doi: 10.1097/00003226-199809000-00004.

DOI:10.1097/00003226-199809000-00004

PMID:9756441

Abstract

PURPOSE

To compare topography pattern and apex location in elevation and axial curvature topographic maps of keratoconic corneas.

METHODS

We prospectively evaluated 72 corneas of 42 patients who had one or more corneal findings of keratoconus with the elevation and axial curvature displays of the PAR Corneal Topography System (PAR-CTS) and 66 of these corneas with the axial curvature display of the Tomey Topographic Modeling System (TMS-1). Topography maps were evaluated for topography pattern and location of the cone apex.

RESULTS

Axial curvature displays of the PAR-CTS and the TMS-1 showed good concordance in terms of topographic patterns (96% for right, 86% for left corneas) and apex locations of cones (92% for right, 80% for left corneas). On the other hand, low concordances were noted when comparing topographic patterns (35.3% for right, 36.8% for left corneas) and apex locations (47% for right, 38% for left corneas) on curvature and elevation mode displays of PAR-CTS. Apices were found in the inferotemporal quadrant in 65% of corneas evaluated with the PAR-CTS. This distribution is significantly different from the apex location in axial curvature maps (p < 0.04). Twenty-nine percent of corneas that showed an apex on the axial curvature mode of the PAR-CTS had a normal pattern, without a detectable cone apex, on the elevation mode display.

CONCLUSIONS

The results of this study clearly show the difference between elevation and curvature-based corneal topographic evaluation of keratoconus. Unlike axial curvature maps, the majority of apices on elevation maps are clustered in the inferotemporal quadrant. This new information about apex location in keratoconic corneas provided by elevation topography may have better diagnostic specificity than regional differences of curvature on axial curvature maps. Because elevation mapping shows the physical location of the cone, it may improve results of contact lens fitting and surgical management.

摘要

目的

比较圆锥角膜的高度图和轴向曲率地形图中的地形模式及顶点位置。

方法

我们前瞻性地评估了42例患者的72只角膜，这些患者有一项或多项圆锥角膜的角膜表现，使用PAR角膜地形图系统（PAR-CTS）的高度和轴向曲率显示进行评估，其中66只角膜使用托米地形建模系统（TMS-1）的轴向曲率显示进行评估。评估地形图的地形模式和圆锥顶点的位置。

结果

PAR-CTS和TMS-1的轴向曲率显示在地形模式（右眼96%，左眼86%）和圆锥顶点位置（右眼92%，左眼80%）方面显示出良好的一致性。另一方面，比较PAR-CTS的曲率和高度模式显示时，在地形模式（右眼35.3%，左眼36.8%）和顶点位置（右眼47%，左眼38%）方面发现一致性较低。在用PAR-CTS评估的角膜中，65%的角膜顶点位于颞下象限。这种分布与轴向曲率图中的顶点位置有显著差异（p < 0.04）。在PAR-CTS的轴向曲率模式上显示有顶点的角膜中，29%在高度模式显示上具有正常模式，没有可检测到的圆锥顶点。

结论

本研究结果清楚地表明了基于高度和曲率的圆锥角膜角膜地形图评估之间的差异。与轴向曲率图不同，高度图上的大多数顶点聚集在颞下象限。高度地形图提供的关于圆锥角膜顶点位置的这一新信息可能比轴向曲率图上曲率的区域差异具有更好的诊断特异性。由于高度映射显示了圆锥的实际位置，它可能会改善隐形眼镜验配和手术管理的结果。