Anatomy of the visual pathway and visual field defects
How the retina, optic nerve, chiasm, tract, lateral geniculate nucleus, optic radiations and occipital cortex are arranged, why each site produces its own field defect, and how congruity, macular sparing and the relative afferent pupillary defect localise a lesion.
Tier 2Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- The visual field is projected inverted and reversed on the retina. Nasal retina sees the temporal field; inferior retina sees the superior field.
- Nasal fibres cross at the chiasm. Everything behind the chiasm carries the opposite half-field of both eyes.
- So: lesion before the chiasm gives a monocular defect, at the chiasm a bitemporal defect, behind the chiasm a homonymous defect.
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Sources
- Horton JC. Wilbrand's knee: to be or not to be a knee? J Neuroophthalmol 2020;40 Suppl 1:S7-S14Journal of Neuro-Ophthalmology, 2020
- Principles of Neural Science (6th ed.)McGraw Hill (Kandel, Koester, Mack, Siegelbaum, 2021), 2021
- Walsh and Hoyt's Clinical Neuro-Ophthalmology (6th ed.)Lippincott Williams and Wilkins (Miller, Newman, Biousse and Kerrison, eds, 2005), 2005
- Localization in Clinical Neurology (8th ed.)Wolters Kluwer (Brazis, Masdeu and Biller), 2022
- Last updated
- 14 November 2026
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- 14 November 2026 Personal emails, About story and Australian-style copy