School of Engineering and Technology, University of New South Wales, Canberra, NSW, Australia.
School of Medicine and Psychology, Australian National University, Canberra, NSW, Australia.
Eye (Lond). 2024 Aug;38(12):2457-2471. doi: 10.1038/s41433-024-03137-7. Epub 2024 Jun 7.
A recent anatomical study of the human optic chiasm cast doubt on the widespread assumption that nerve fibres travelling in the human optic nerve and chiasm are arranged retinotopically. Accordingly, a scoping literature review was performed to determine what is known about the nerve fibre arrangement in these structures. Meta-analysis suggested that the average number of fibres in each optic nerve was 1.023 million with an inter-individual range of approximately 50% of the mean. Loss of nerve fibres with age (approximately 3,400 fibres/year) could not account for this variability. The review suggested that there might be a retinotopic arrangement of nerve fibres in the orbital portion of the optic nerve but that this arrangement is most likely to be lost posteriorly with a more random distribution of nerve fibres at the chiasm. Limited studies have looked at nerve fibre arrangement in the chiasm. In summary, the chiasm is more 'H-shaped' than 'X-shaped': nerve fibre crossings occur paracentrally with nerves in the centre of the chiasm travelling coronally and in parallel. There is interaction between crossed and uncrossed fibres which are widely distributed. The review supports the non-existence of Wilbrand's knee. Considerable further work is required to provide more precise anatomical information, but this review suggests that the assumed preservation of retinotopy in the human optic nerve and chiasm is probably not correct.
最近一项关于人类视交叉的解剖研究对广泛存在的假设提出了质疑，即穿行于人类视神经和视交叉的神经纤维是按照视网膜节细胞层排列的。因此，进行了范围广泛的文献综述，以确定人们对这些结构中的神经纤维排列的了解。元分析表明，每条视神经中的纤维平均数量为 102.3 万根，个体间差异约为平均值的 50%。神经纤维随年龄的丢失（每年约 3400 根）不能解释这种变异性。该综述表明，视神经眶内段可能存在神经纤维的视网膜节细胞层排列，但这种排列很可能在后部丢失，视交叉处的神经纤维呈更随机的分布。有限的研究观察了视交叉处的神经纤维排列。总之，视交叉的形状更接近“H”形而不是“X”形：神经纤维在视交叉的中央交叉，中心的神经纤维呈冠状和平行排列。交叉和未交叉的纤维之间存在相互作用，且分布广泛。该综述支持威尔布兰德膝并不存在。需要进行更多的研究工作以提供更精确的解剖学信息，但本综述表明，人类视神经和视交叉中保留视网膜节细胞层排列的假设可能不正确。
