Diagrammed From Patient's Viewpoint
Occlusion of a branch of the central retinal artery may cause a horizontal (altitudinal) defect. Shown is the lower field defect associated with occlusion of the superior branch of this artery.
2 Blind Right Eye (right optic nerve)
A lesion of the optic nerve, and of course of the eye itself, produces unilateral blindness.
A lesion at the optic chiasm may involve only the fibers that are crossing over to the opposite side. Since these fibers originate in the nasal half of each retina, visual loss involves the temporal half of each field.
4 Left Homonymous Hemianopsia (right optic tract)
A lesion of the optic tract interrupts fibers originating on the same side of both eyes. Visual loss in the eyes is therefore similar (homonymous) and involves half of each field (hemianopsia).
5 Homonymous Left Superior Quadrantic Defect (right optic radiation, partial)
A partial lesion of the optic radiation may involve only a portion of the nerve fibers, producing, for example, a homonymous quadrantic defect.
6 Left Homonymous Hemianopsia (right optic radiation)
A complete interruption of fibers in the optic radiation produces a visual defect similar to that produced by a lesion of the optic tract.
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