Purpose

To determine if ocular ductions deform intrapapillary and peripapillary tissues in optic nerve head drusen (ONHD) and to compare these deformations with healthy eyes and eyes with other optic neuropathies.

Design

Observational case series.

Participants

Twenty patients with ONHD.

Methods

Axial rasters of the optic nerve from a spectral-domain OCT device (Cirrus 5000; Carl Zeiss Meditec, Inc, Dublin, CA) were used to analyze the shape of the peripapillary basement membrane (ppBM) layer in 20 confirmed cases of ONHD. We compared registered images obtained from 2 eye positions: 10° to 15° in adduction and 30° to 40° in abduction. Geometric morphometrics was used to analyze the shape of the ppBM layer defined by placing 10 equidistant landmarks extending 2500 μm on both sides of the basement membrane opening. We also adapted an image strain tracking technique to measure regional intrapapillary strains in 6 patients. Using manually placed nodes on the reference image (in adduction), an iterative, block-matching algorithm is used to determine local displacements between the reference and its paired image in abduction. Displacement vectors were used to calculate the mean shear and effective strain (percent change).

Main Outcome Measures

Peripapillary shape deformations, intrapapillary shear strains, and effective strains.

Results

We found a statistically significant difference in the shape of the ppBM layer between abduction and adduction (P < 0.01). The deformation was characterized by a relative posterior displacement temporally in adduction that reversed in abduction. Strain tracking in all 6 patients showed substantial gaze-induced shearing and effective strains. Mean effective strains were 7.5% outside the drusen. Shear and effective strains were significantly larger outside versus within the drusen (P < 0.003 and P < 0.01, respectively).

Conclusions

This study demonstrates that horizontal ocular ductions induce significant shearing deformations of the peripapillary retina and prelaminar intrapapillary tissues. We also found that the deformations in healthy persons are similar in magnitude to ONHD. Based on these findings, we speculate that patients with intrapapillary calcifications exposed to the long-term effects of repetitive shearing (induced by ocular ductions) may contribute to the progressive axonal loss and vascular complications associated with ONHD.

中文翻译：

---

视神经头玻璃疣的凝视引起的变形

目的

为了确定眼内引出物是否使视神经乳头炎（ONHD）内的乳头内和周围的组织变形，并将这些变形与健康的眼睛以及其他视神经病变的眼睛进行比较。

设计

观察箱系列。

参加者

二十名ONHD患者。

方法

来自频谱域OCT设备（Cirrus 5000； Carl Zeiss Meditec，Inc，都柏林，加利福尼亚）的视神经轴状栅格用于分析20例确诊的ONHD病例的乳头周围基底膜（ppBM）的形状。我们比较了从两个眼睛位置获得的配准图像：内收10°至15°和外展30°至40°。几何形态计量学用于分析ppBM层的形状，该层是通过在基底膜开口的两侧放置10个等距地标延伸2500μm来定义的。我们还采用了图像应变跟踪技术来测量6例患者的区域性乳头内应变。使用参考图像上的人工放置的节点（内收），使用迭代的块匹配算法来确定外展中参考图像及其配对图像之间的局部位移。

主要观察指标

乳头周围形状变形，乳头内剪切应变和有效应变。

结果

我们发现外展和内收之间ppBM层的形状在统计学上有显着差异（P <0.01）。变形的特征是内收在时间上相对后移，而外展则相反。在所有6例患者中进行的应变追踪均显示出大量凝视诱导的剪切力和有效应变。玻璃疣以外的平均有效应变为7.5％。与玻璃疣内部相比，外部的剪切力和有效应变要大得多（分别为P <0.003和P <0.01）。

结论

这项研究表明，水平眼导引可引起乳头周围视网膜和椎板内乳头前组织的明显剪切变形。我们还发现，健康人的变形幅度与ONHD相似。根据这些发现，我们推测患有乳头内钙化的患者长期受到重复剪切（由眼内引出物引起）的长期作用，可能会导致进行性轴索丢失和与ONHD相关的血管并发症。