Actualización desde la anatomía funcional y clínica del sistema visual: énfasis en la vía y la corteza visual

Abstract

The visual system is conformed by the eyeball, visual pathway, and visual cortex. Their integration supports the spectrum of visual functions: visual acuity, chromatic vision, stereopsis and contrast sensitivity. However, the visual pathway and cortex are responsible not only for the transmission and basic interpretation of visual stimuli, but for their perception and high-order association. The regional, systemic and functional neuroanatomy of the visual system, especially of the visual pathway and cortex, are essential to understand neuro-ophthalmological disorders. This is a review article of the functional and clinical anatomy of the visual system centered on the visual pathway and cortex. Historical aspects are discussed, as well as the conformation of the visual pathway and the primary and extrastriate visual cortex, with respective clinical correlations of the retina, optic nerve, chiasm, optic tracts and lateral geniculate nucleus, optic radiation and visual cortex. The visual pathway begins from the retinal photoreceptors, and it’s divided into extra and intracerebral segments according to their position in regard to the lateral geniculate nucleus. The retina, pathway and visual cortex have a high level of organization and both a structural and functional retinotopic representation, existing several subsystems and connections within the visual system, and about 30 cortical zones, with specific activities that enable the phenomenon of vision. In general, visual pathway injuries affect the visual fields, and extrastriate cortical damages produce visual agnosias.