2020–2021 BCSC Basic and Clinical Science Course™
5 Neuro-Ophthalmology
Chapter 4: The Patient With Decreased Vision: Classification and Management
Retrochiasmal Lesions
Lateral Geniculate Body
The lateral geniculate body (LGB) is a highly organized and layered retinotopic structure; therefore, lesions in this region can cause highly localized visual field defects. A congruous horizontal sectoranopia results from disruption within the vascular distribution of the posterolateral choroidal artery, a branch of the posterior cerebral artery. Loss of the upper and lower homonymous quadrants (also known as quadruple sectoranopia) with preservation of a horizontal wedge occurs with disruption of the anterior choroidal artery, a branch of the middle cerebral artery (Fig 4-30; see also Chapter 1, Fig 1-11). These visual field defects respect the vertical meridian, unlike the uncommon wedge defect observed in glaucoma. Sectoral optic atrophy occurs with LGB lesions, and in rare cases, bilateral LGB lesions cause blindness.
Luco C, Hoppe A, Schweitzer M, Vicuña X, Fantin A. Visual field defects in vascular lesions of the lateral geniculate body. J Neurol Neurosurg Psychiatry. 1992;55(1): 12–15.
Excerpted from BCSC 2020-2021 series: Section 5 - Neuro-Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.