Bulk changes in posterior scleral collagen microstructure in human high myopia
Bulk changes in posterior scleral collagen microstructure in human high myopia
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发表时间：
2018-12
期刊：
影响因子：
2.2
通讯作者：
Petar P. Markov;Ashkan Eliasy;J. Pijanka;H. Htoon;N. Paterson;T. Sorensen;A. Elsheikh;M. Girard;C. Boote
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作者：
Petar P. Markov;Ashkan Eliasy;J. Pijanka;H. Htoon;N. Paterson;T. Sorensen;A. Elsheikh;M. Girard;C. Boote
目的研究高度近视眼后巩膜胶原纤维束结构的变化。方法应用广角X射线散射（WAXS）技术对7只正常人眼和3只高度近视眼（屈光度>6D）的后巩膜进行0.5mm × 0.5mm间距的胶原定位。在每个采样点，WAXS提供了组织平面内优先排列的胶原原纤维的角分布和各向异性比例（优先排列与总胶原散射的比率）的厚度平均测量。结果非近视眼标本的显微结构特征保存良好，包括沿中后巩膜眼外肌附着点沿着的强单轴胶原排列，以及围绕视乳头周围巩膜神经头的高度各向异性的胶原环。所有三个近视标本表现出显着的改变，在视乳头周围巩膜，包括部分损失的圆周胶原对齐和重新分布的正常观察到的区域模式的胶原蛋白各向异性的比例。线性混合模型分析显示高度近视眼视乳头周围巩膜纤维角偏离圆周方向的平均值（23.9° ± 18.2）显著高于对照眼（17.9° ± 12.0; p<0.05）。结论高度近视眼正常后巩膜胶原微结构发生大量改变。这些变化可以反映在轴向延长期间后巩膜的重塑和/或对由流体压力或眼睛运动引起的组织应力的机械适应，所述流体压力或眼睛运动可能在放大的眼睛中加剧。
Purpose We aimed to characterize any bulk changes in posterior scleral collagen fibril bundle architecture in human eyes with high myopia. Methods Wide-angle X-ray scattering (WAXS) was employed to map collagen orientation at 0.5 mm × 0.5 mm spatial intervals across the posterior sclera of seven non-myopic human eyes and three eyes with high myopia (>6D of refractive error). At each sampled point, WAXS provided thickness-averaged measures of the angular distribution of preferentially aligned collagen fibrils within the tissue plane and the anisotropic proportion (the ratio of preferentially aligned to total collagen scatter). Results Non-myopic specimens featured well-conserved microstructural features, including strong uniaxial collagen alignment along the extraocular muscle insertion sites of the mid-posterior sclera and a highly anisotropic annulus of collagen circumscribing the nerve head in the peripapillary sclera. All three myopic specimens exhibited notable alterations in the peripapillary sclera, including a partial loss of circumferential collagen alignment and a redistribution of the normally observed regional pattern of collagen anisotropic proportion. Linear mixed-model analysis indicated that the mean fiber angle deviation from the circumferential orientation in the peripapillary sclera of highly myopic eyes (23.9° ± 18.2) was statistically significantly higher than that of controls (17.9° ± 12.0; p<0.05). Conclusions Bulk alterations in the normal posterior scleral collagen microstructure occur in human eyes with high myopia. These changes could reflect remodeling of the posterior sclera during axial lengthening and/or a mechanical adaption to tissue stresses induced by fluid pressure or eye movements that may be exacerbated in enlarged eyes.