The optic nerve (ON) is constituted by the axons of the retinal ganglion cells (RGCs). These axons are distributed in an organized pattern from the soma of the RGC to the lateral geniculated nucleus (where most of the neurons synapse). The key points of the ON are the optic nerve head and chiasm. This chapter will include a detailed and updated review of the ON different parts: RGC axons, glial cells, connective tissue of the lamina cribrosa and the septum and the blood vessels derivate from the central retina artery and from the ciliary system. There will be an up-to-date description about the superficial nerve fibre layer, including their organization, and about prelaminar, laminar and retrolaminar regions, emphasizing the axoplasmic flow, glial barriers, biomechanics of the lamina cribrosa and the role of the macro- and microglia in their working.
Part of the book: Optic Nerve
Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disease that severely impairs the patient’s mobility, as it mainly affects the upper and lower motor neurons in the spinal cord. In addition, alterations have also been demonstrated in different parts of the central nervous system (CNS), such as the brain and brainstem. The retina is a projection to the brain and is considered as a “window” to the CNS. Moreover, it is possible to use the retina as a biomarker in several neurodegenerative diseases, even in the absence of major visual impairment. Classically, it was thought that the eyes were not affected in ALS, with respect to extraocular muscles, whereas the remainder of the muscles of the body were distressed. Nevertheless, retinal changes have recently been found in this pathology and could help in diagnosis, follow-up, and even monitoring therapies in this disease.
Part of the book: Animal Models and Experimental Research in Medicine