Department of Radiology, Scheie Eye Institute, Penn Presbyterian Medical Center, Philadelphia, PA, USA.
Department of Neurology, Scheie Eye Institute, Penn Presbyterian Medical Center, Philadelphia, PA, USA.
Transl Vis Sci Technol. 2020 Dec 7;9(13):9. doi: 10.1167/tvst.9.13.9. eCollection 2020 Dec.
Variation in retinal thickness with eye size complicates efforts to estimate retinal ganglion cell number from optical coherence tomography (OCT) measures. We examined the relationship among axial length, the thickness and volume of the ganglion cell layer (GCL), and the size of the optic chiasm.
We used OCT to measure GCL thickness over 50 degrees of the horizontal meridian in 50 healthy participants with a wide range of axial lengths. Using a model eye informed by individual biometry, we converted GCL thickness to tissue volume per square degree. We also measured the volume of the optic chiasm for 40 participants using magnetic resonance imaging (MRI).
There is a positive relationship between GCL tissue volume and axial length. Given prior psychophysical results, we conclude that increased axial length is associated with increased retinal ganglion cell size, decreased cell packing, or both. We characterize how retinal ganglion cell tissue varies systematically in volume and spatial distribution as a function of axial length. This model allows us to remove the effect of axial length from individual difference measures of GCL volume. We find that variation in this adjusted GCL volume correlates well with the size of the optic chiasm.
Our results provide the volume of ganglion cell tissue in the retina, adjusted for the presumed effects of axial length upon ganglion cell size and/or packing. The resulting volume measure accounts for individual differences in the size of the optic chiasm, supporting its use to characterize the post-retinal visual pathway.
Variations in ametropia can confound clinical measures of retinal features. We present a framework within which the thickness and volume of retinal structures can be measured and corrected for the effects of axial length.
眼球尺寸的变化会使从光学相干断层扫描（OCT）测量结果估计视网膜神经节细胞数量的工作变得复杂。我们研究了眼轴长度、神经节细胞层（GCL）的厚度和体积以及视交叉大小之间的关系。
我们使用 OCT 在 50 名具有广泛眼轴长度的健康参与者的水平子午线的 50 度范围内测量 GCL 厚度。使用个体生物测量学提供的模型眼，我们将 GCL 厚度转换为每平方度的组织体积。我们还使用磁共振成像（MRI）测量了 40 名参与者的视交叉体积。
GCL 组织体积与眼轴长度呈正相关。鉴于先前的心理物理学结果，我们得出结论，眼轴长度的增加与视网膜神经节细胞大小的增加、细胞密度的降低或两者兼有关。我们描述了视网膜神经节细胞组织如何作为眼轴长度的函数在体积和空间分布上系统地变化。该模型使我们能够从 GCL 体积的个体差异测量中去除眼轴长度的影响。我们发现，经调整的 GCL 体积的变化与视交叉的大小密切相关。
我们的结果提供了视网膜神经节细胞组织的体积，该体积针对眼轴长度对神经节细胞大小和/或密度的假定影响进行了调整。所得的体积测量值考虑了视交叉大小的个体差异，支持其用于描述视网膜后视觉通路的特征。
本文描述了如何从视网膜神经节细胞层（GCL）的厚度和体积的 OCT 测量结果中去除眼轴长度的影响，并提供了一种方法来调整 GCL 体积，以考虑到视交叉大小的个体差异。该研究为研究和诊断与眼轴长度相关的眼部疾病提供了新的思路和方法。
