page_title: Visual pathway lesions
section_title: Signs ans symptoms
hierarchical_section_title: Visual pathway lesions / Lesions of optic radiations / Signs ans symptoms
caption_attribution_description: Right superior quadrantanopia. The areas of the visual field lost in each eye are shown as black areas. This visual field defect is characteristic of damage to Meyer's loop (part of optic radiation) on the left side of the brain.
context_page_description: The visual pathway consists of structures that carry visual information from the retina to the brain. Lesions in that pathway cause a variety of visual field defects. In the visual system of human eye, the visual information processed by retinal photoreceptor cells travel in the following way:
  Retina→Optic nerve→Optic chiasm →Optic tract→Lateral geniculate nucleus→Optic radiation→Primary and secondary visual cortices.
  The type of field defect can help localize where the lesion is located.
context_section_description: Lesions of  right temporal lobe (meyer's Loop) of the optic radiation on one side produces a loss of the upper, outer quadrant of vision on the same side in both eyes, known as homonymous superior quadrantanopia or superior quadrantic hemianopia. This is also known as pie in the sky disorder.
  A lesion in the right parietal lobe cause inferior quadrantic hemianopia. It is also known as pie on the floor disorder.
  Complete homonymous hemianopia is produced when total fibres of optic radiations are involved.
  Pupillary reflexes are normal.
  Optic disc atrophy does not occur in lesions of optic radiations, as the second order neurons synapse in the LGN.
caption: Visual field-right superior quadrantanopia
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