Tan Ou, Liu Liang, Liu Li, Huang David
Casey Eye Institute, Oregon Health and Science University, Portland, OR, USA.
Transl Vis Sci Technol. 2018 Feb 7;7(1):16. doi: 10.1167/tvst.7.1.16. eCollection 2018 Feb.
To devise a method to quantify nerve fibers over their arcuate courses over an extended peripapillary area using optical coherence tomography (OCT).
Participants were imaged with 8 × 8-mm volumetric OCT scans centered at the optic disc. A new quantity, nerve fiber flux (NFF), represents the cross-sectional area transected perpendicular to the nerve fibers. The peripapillary area was divided into 64 tracks with equal flux. An iterative algorithm traced the trajectory of the tracks assuming that the relative distribution of the NFF was conserved with compensation for fiber connections to ganglion cells on the macular side. Average trajectory was averaged from normal eyes and use to calculate the NFF maps for glaucomatous eyes. The NFF maps were divided into eight sectors that correspond to visual field regions.
There were 24 healthy and 10 glaucomatous eyes enrolled. The algorithm converged on similar patterns of NFL tracks for all healthy eyes. In glaucomatous eyes, NFF correlated with visual field sensitivity in the arcuate sectors (Spearman ρ = 0.53-0.62). Focal nerve fiber loss in glaucomatous eyes appeared as uniform tracks of NFF defects that followed the expected arcuate fiber trajectory.
Using an algorithm based on the conservation of flux, we derived nerve fiber trajectories in the peripapillary area. The NFF map is useful for the visualization of focal defects and quantification of sector nerve fiber loss from wide-area volumetric OCT scans.
NFF provides a cumulative measure of volumetric loss along nerve fiber tracks and could improve the detection of focal glaucoma damage.
设计一种方法，利用光学相干断层扫描（OCT）对视盘周围扩展区域内呈弓形走行的神经纤维进行定量分析。
对参与者进行以视盘为中心的8×8毫米容积OCT扫描成像。一个新的量，即神经纤维通量（NFF），代表垂直于神经纤维横切的横截面积。视盘周围区域被划分为64条通量相等的轨迹。一种迭代算法追踪这些轨迹的路径，假设NFF的相对分布是守恒的，同时对黄斑侧与神经节细胞相连的纤维进行补偿。从正常眼睛中计算平均轨迹，并用于计算青光眼患者眼睛的NFF图。NFF图被划分为八个对应视野区域的扇区。
纳入24只健康眼睛和10只青光眼眼睛。该算法在所有健康眼睛上收敛于类似的神经纤维层（NFL）轨迹模式。在青光眼患者的眼睛中，NFF与弓形扇区的视野敏感度相关（Spearman ρ = 0.53 - 0.62）。青光眼患者眼睛中的局灶性神经纤维丢失表现为沿着预期弓形纤维轨迹的NFF缺陷均匀轨迹。
使用基于通量守恒的算法，我们得出了视盘周围区域的神经纤维轨迹。NFF图有助于可视化局灶性缺陷，并对广域容积OCT扫描中的扇形神经纤维丢失进行定量分析。
NFF提供了沿神经纤维轨迹的容积性损失的累积测量值，可改善对青光眼局灶性损伤的检测。
