Huang Minna, Ilsen Pauline F
San Diego VA Healthcare Center, San Diego, California 92161, USA.
Optometry. 2007 Jul;78(7):356-64. doi: 10.1016/j.optm.2006.11.013.
The lateral geniculate nucleus (LGN) is the site at which ganglion cell axons of the optic tract synapse with neurons that form the optic radiations. Lesions of the perigeniculate visual pathway are characterized by distinct pupillary, visual field, and ophthalmoscopic findings. Such findings, combined with results from neuroimaging, enable one to precisely locate the area of the visual pathway that is involved.
A patient who presented to our clinic with a complaint of narrowly missing several motor vehicle accidents recently was found to have a left horizontal sectoranopia on a screening visual field. Magnetic resonance imaging confirmed the presence of an old infarct involving the optic radiations. The patient's medical history was significant for high homocysteine levels that likely contributed to his having had several cerebral vascular accidents in the past, one of which affected the optic radiations.
Damage to the LGN and optic radiations can produce sectoranopic visual field defects. Although it may not be possible to specify the exact location of a lesion, understanding the blood supply of the visual pathway and retinotopic organization of the LGN aids in the localization of infarcts that cause characteristic visual field defects.
外侧膝状体核（LGN）是视束神经节细胞轴突与形成视辐射的神经元发生突触联系的部位。膝状体周围视觉通路的病变具有独特的瞳孔、视野和检眼镜检查表现。这些表现与神经影像学结果相结合，能够使人们精确地定位受累的视觉通路区域。
一名近期因险些撞上多起机动车事故前来我院就诊的患者，在筛查视野时发现有左侧水平扇形视野缺损。磁共振成像证实存在一处累及视辐射的陈旧性梗死灶。患者的病史中高同型半胱氨酸水平显著，这可能是其过去发生多次脑血管意外的原因，其中一次影响了视辐射。
外侧膝状体核和视辐射受损可导致扇形视野缺损。尽管可能无法明确病变的确切位置，但了解视觉通路的血液供应和外侧膝状体核的视网膜定位组织有助于定位导致特征性视野缺损的梗死灶。
