Visual loss due to optic chiasm and retrochiasmal visual pathway lesions

Building on the anatomic and diagnostic approaches presented elsewhere in this issue of CONTINUUM, this article presents important differential considerations for chiasmal and retrochiasmal vision loss, useful strategies for confirming the underlying etiology, principles of their natural history, and, where appropriate, treatment strategies.

Although a wide variety of pathologic processes can affect the optic chiasm and retrochiasmal visual pathways, those commonly seen in neurologic practice are comparatively fewer in number. This article updates current understanding of vision loss localizing to the optic chiasm, including pituitary adenoma, sellar meningiomas, and aneurysms. Important causes of retrochiasmal vision loss, including stroke and posterior reversible encephalopathy syndrome, are also presented.

The optic chiasm and retrochiasmal visual pathways are susceptible to various forms of injury, with resultant patterns of vision loss that can be precisely localized on the basis of clinical and neuroimaging findings. Accurate localization, in association with other clinical features, allows for consideration of relevant differential diagnoses, which can be confirmed through the judicious application of appropriate diagnostic studies. Accurate localization, diagnosis, and robust clinical surveillance are essential to the effective management and treatment of these causes of vision loss.