The Optic Pathway
The optic pathway includes the retina, optic nerve, optic chiasm, optic radiations, and occipital cortex (see figure Higher visual pathways). Damage along the optic pathway causes a variety of visual field defects. The type of field defect can help localize the lesion (see table Types of Field Defects).
Types of Field Defects
Type* |
Description |
Causes |
|
Altitudinal field defect |
Loss of all or part of the superior or inferior half of the visual field; does not cross the horizontal median |
More common: Ischemic optic neuropathy, hemicentral retinal artery occlusion, retinal detachment Less common: Glaucoma, optic nerve lesion, optic nerve coloboma |
|
Arcuate scotoma |
A small, bow-shaped (arcuate) visual field defect that follows the arcuate pattern of the retinal nerve fibers; does not cross the horizontal median |
Damage to ganglion cells that feed into a particular part of the optic nerve head More common: Glaucoma Less common: Ischemic optic neuropathy (usually nonarteritic), optic disk drusen, high myopia |
|
Binasal field defect (uncommon) |
Loss of all or part of the medial half of both visual fields; does not cross the vertical median |
More common: Glaucoma, bitemporal retinal disease (eg, retinitis pigmentosa), nonphysiologic vision loss Rare: Bilateral occipital disease, tumor or aneurysm compressing both optic nerves |
|
Bitemporal hemianopia |
Loss of all or part of the lateral half of both visual fields; does not cross the vertical median |
More common: Chiasmal lesion (eg, pituitary adenoma, meningioma, craniopharyngioma, aneurysm, glioma) Less common: Tilted optic disks Rare: Nasal retinitis pigmentosa |
|
Blind-spot enlargement |
Enlargement of the normal blind spot at the optic nerve head |
Papilledema, optic nerve drusen, optic nerve coloboma, myelinated nerve fibers at the optic disk, drugs, myopic disk with a crescent |
|
Central scotoma |
A loss of visual function in the middle of the visual field |
Macular disease, optic neuropathy (eg, ischemic or Leber hereditary neuropathy, optic neuritis-multiple sclerosis), optic atrophy (eg, due to tumor compressing the nerve or toxic-metabolic disorders) |
|
Constriction of the peripheral fields, leaving only a small residual central field |
Loss of the outer part of the entire visual field in one or both eyes |
Glaucoma, retinitis pigmentosa or another peripheral retinal disorder, chronic papilledema, following panretinal photocoagulation, central retinal artery occlusion with cilioretinal artery sparing, bilateral occipital lobe infarction with macular sparing, nonphysiologic vision loss, carcinoma-associated retinopathy Rare: Drugs |
|
Homonymous hemianopia |
Loss of part or all of the left half or right half of both visual fields; does not cross the vertical median |
Optic tract or lateral geniculate body lesion; lesion in temporal, parietal, or occipital lobe (more commonly, stroke or tumor; less commonly, aneurysm or trauma); migraine (which may cause transient homonymous hemianopia) |
|
* Migraine can cause various visual field defects, although it most commonly causes transient homonymous hemianopia. |
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Adapted from Bagheri N, Duraani AK: The Wills Eye Manual, ed. 7. Philadelphia, Wolters Kluwer, 2017. |
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