Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia.
School of Computing and Information Systems, The University of Melbourne, Parkville, Victoria, Australia.
Invest Ophthalmol Vis Sci. 2019 Nov 1;60(14):4896-4903. doi: 10.1167/iovs.19-27539.
The geometry of retinal nerve fibers may be altered with myopia, a known risk factor for glaucoma. Recent developments in high resolution imaging have enabled direct visualization of nerve fiber bundles at the temporal raphe with clinical hardware, providing evidence that this area is sensitive to glaucomatous damage. Here, we test the hypothesis that nerve fiber geometry is altered by myopia, both at the temporal raphe and surrounding the optic nerve head.
Seventy-eight healthy individuals participated, with refractive errors distributed between emmetropia and high myopia (+0 to -13 DS). Custom high-density OCT scans were used to visualize RFNL bundle trajectory at the temporal raphe. A standard clinical OCT protocol was used to assess papillary minimum rim width (MRW) and peripapillary retinal nerve fiber layer (RNFL) thickness.
Measures of raphe shape-including position, orientation, and width-did not depend significantly on axial length. In 7.5% of subjects, the raphe was rotated sufficiently that inversion of structure-function mapping to visual field space is predicted in the nasal step region. Low concordance to ISNT and related rules was observed in myopia (e.g., for RNFL, 8% of high axial myopes compared with 67% of emmetropes). Greater robustness to refractive error was observed for the IT rule.
High density OCT scans enabled visualization of marked interindividual variation in temporal raphe geometry; however, these variations were not well predicted by degree of myopia as represented by axial length. That said, degree of myopia was associated with abnormal thickness profiles for the papillary and peripapillary nerve fiber layer.
视网膜神经纤维的几何形状可能会因近视而改变，近视是青光眼的已知危险因素。高分辨率成像的最新发展使临床硬件能够直接可视化 temporal raphe 处的神经纤维束，这为该区域对青光眼损伤敏感提供了证据。在这里，我们测试了以下假设：即近视会改变 temporal raphe 处和视神经头周围的神经纤维几何形状。
78 名健康个体参与了研究，他们的屈光不正分布在正视眼和高度近视（+0 至-13 DS）之间。使用定制的高密度 OCT 扫描来可视化 temporal raphe 处的 RFNL 束轨迹。使用标准临床 OCT 方案评估视乳头最小边缘宽度（MRW）和视乳头周围视网膜神经纤维层（RNFL）厚度。
纹状体形状的测量指标，包括位置、方向和宽度，与眼轴长度没有显著关系。在 7.5%的受试者中，纹状体的旋转角度足够大，以至于在鼻侧步区预测结构-功能映射到视野空间会发生反转。在近视患者中观察到 ISNT 及其相关规则的低一致性（例如，对于 RNFL，8%的高度轴性近视患者与 67%的正视眼患者相比）。IT 规则表现出对屈光不正更强的稳健性。
高密度 OCT 扫描能够可视化 temporal raphe 几何形状的个体间显著差异；然而，这些差异不能很好地由眼轴长度代表的近视程度来预测。也就是说，近视程度与视乳头和视乳头周围神经纤维层的异常厚度分布有关。
