Chiasmal Syndromes
Dysfunction of the optic chiasm typically produces bitemporal hemianopic visual field defects. Optic chiasmal dysfunction most often results from compression by extrinsic lesions, such as pituitary macroadenomas and meningiomas. In this chapter, we begin by describing the various bitemporal hemianopic visual field defects that can occur with optic chiasmal dysfunction. We next list potential causes of optic chiasmal dysfunction. We then review the clinical features and evaluation of pituitary apoplexy, which results from infarction of (or hemorrhage into) a pituitary macroadenoma. Lastly, we discuss the management of pituitary apoplexy, including the indications for and timing of surgical decompression, and review factors that affect the prognosis for visual recovery.