Abstract

Purpose

Current methods to analyse the globe position, including Hertel exophthalmometry and computed tomography (CT), are limited to the axial plane and require the lateral orbital rim and cornea as landmarks. This pilot study aimed to design a method to measure the position of the globe in the axial, coronal and sagittal plane and independent from orbital bony and corneal references.

Methods

With the aid of three-dimensional CT reconstruction technology, we determined the globe position in the orbit based on the centre of the globe. Method validation was performed using data of consecutive orbital CT scans from the control group and from the patients with Graves’ orbitopathy who underwent orbital decompression surgery with removal of the lateral orbital margin.

Results

The inter- and intra-observer reliability was excellent with a high intraclass correlation coefficient (> 0.99, 95% CI [0.97; 1.00]). In the decompressed orbits, there was a statistically significant globe position shift along the anterior-posterior axis (P = 0.0005, 95% CI [0.63; 3.66]), but not along the medial-lateral and superior-inferior axis.

Conclusion

The 3D CT method can accurately and reliably characterise the globe position shift in the three dimensions without using orbital and corneal anatomical landmarks. The method can be useful to determine the globe shift in proptosis, enophthalmos, hypoglobus and hyperglobus, even in the presence of strabismus and orbital bone defects.

中文翻译：

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地球在轨道上的位置的三维表征。

摘要

目的

目前分析眼球位置的方法，包括 Hertel 眼球突出测量法和计算机断层扫描 (CT)，仅限于轴向平面，需要外侧眶缘和角膜作为地标。这项初步研究旨在设计一种方法来测量地球在轴向、冠状和矢状平面中的位置，并且独立于眼眶骨和角膜参考。

方法

借助三维CT重建技术，我们根据地球中心确定了地球在轨道上的位置。使用来自对照组和 Graves 眼眶病患者的连续眼眶 CT 扫描数据进行方法验证，这些患者接受了眶外减压手术并切除了眶外侧缘。

结果

观察者间和观察者内的可靠性非常好，具有较高的组内相关系数（> 0.99, 95% CI [0.97; 1.00]）。在减压眼眶中，沿前后轴（P  = 0.0005, 95% CI [0.63; 3.66]）存在统计学上显着的眼球位置偏移，但不沿内外轴和上下轴发生变化。

结论

3D CT 方法无需使用眼眶和角膜解剖标志，即可在三个维度上准确可靠地表征球体位置偏移。即使在存在斜视和眼眶骨缺损的情况下，该方法也可用于确定眼球突出、眼球内陷、眼球不足和眼球突出。