Band atrophy of the optic nerve: A report on different anatomical locations in three patients

Nerve fibre organisation in the human optic nerve and chiasm: what do we really know?

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.

[Modern treatment of different forms of optic nerve atrophy]

Optic nerve atrophy (ONA) is one of the most common causes of blindness and low vision in the world. The disease occurs in 60-68% of cases. The causes of optic nerve atrophy are diverse: inflammatory and vascular diseases of the optic nerve and retina, glaucoma, atherosclerosis of the main vessels of head and neck, diseases of central nervous system, intoxication of various etiologies, as well as congenital and hereditary diseases. The literature review presents data on the diagnosis and classification of optic nerve atrophy, as well as on drug and non-drug treatment in combination with physiotherapy.