数字角膜内皮显微镜反射光测量角膜厚度的重要性。

Criticality of the measurement of corneal thickness in specular reflection by digital biomicroscope.

机构信息

University of Milano Bicocca, Department of Materials Science, via R. Cozzi 55, I-20125 Milan, Italy.

University of Milano Bicocca, Department of Materials Science, via R. Cozzi 55, I-20125 Milan, Italy; University of Milano Bicocca, COMiB Research Centre in Optics and Optometry, via R. Cozzi 55, I-20125 Milan, Italy.

出版信息

Cont Lens Anterior Eye. 2018 Dec;41(6):531-537. doi: 10.1016/j.clae.2018.08.008. Epub 2018 Sep 7.

DOI:10.1016/j.clae.2018.08.008

PMID:30197039

Abstract

PURPOSE

The aim was to evaluate the effects on corneal thickness (t) measurement, of asymmetry of the CCD position for a digital biomicroscope in specular reflection.

METHODS

t was deduced from the distance between reflexes from anterior and posterior corneal surfaces using a biomicroscope (Takagi SM70 N), with the illuminator either, (a) farther from sensor side (150 eyes) or, (b) closer to it (134 eyes). The distance between reflexes was also measured on a glass slide and a reference lens, with nominal thicknesses of 1580 and 520 μm, respectively. Corneal thickness (t) was also measured by pachymeter (Canon TX-20 P).

RESULTS

When biomicroscope asymmetry was ignored, t for the glass slide was (a) 1760 and (b) 1404 μm. Correcting for the asymmetry provided corresponding values of 1588 and 1591 μm. For the lens, t was (a) 696 and (b) 543 μm, or 642 and 497 μm, when using the approximation of parallel surfaces (APS). Correcting for the asymmetry gave 565 and 552 μm (578 and 564 μm, with APS). Mean corneal t was (a) 560 and (b) 467 μm, (564 and 468 μm, with APS). Correcting for asymmetry gave (a) 506 and (b) 529 μm (508 and 530 μm, with APS). Mean t was 552 μm.

CONCLUSION

Biomicroscope asymmetry critically affects corneal thickness measurement in specular reflection. Induced errors can be accounted for and corrected, however. While the correction to the curvature radius is clinically relevant, it plays a minor role compared to asymmetry.

摘要

目的

评估数字生物显微镜反射光条件下，角膜共聚焦显微镜位置不对称对角膜厚度（t）测量的影响。

方法

使用生物显微镜（Takagi SM70N），在照明器分别位于传感器侧（150 只眼）或更靠近传感器侧（134 只眼）时，从前后角膜表面反射之间的距离推导出 t。还在玻璃载玻片和标称厚度分别为 1580μm 和 520μm 的参考透镜上测量了反射之间的距离。使用角膜测厚仪（Canon TX-20P）测量角膜厚度（t）。

结果

忽略生物显微镜的不对称性时，玻璃载玻片的 t 为（a）1760μm 和（b）1404μm。校正不对称性后，相应的值为 1588μm 和 1591μm。对于透镜，当使用平行表面近似（APS）时，t 为（a）696μm 和（b）543μm，或（a）642μm 和（b）497μm，校正不对称性后，t 为 565μm 和 552μm（使用 APS 时为 578μm 和 564μm）。角膜平均 t 为（a）560μm 和（b）467μm（使用 APS 时为 564μm 和 468μm）。校正不对称性后，t 为（a）506μm 和（b）529μm（使用 APS 时为 508μm 和 530μm）。平均 t 为 552μm。