Retrochiasmal
Retrochiasmal refers to structures located behind the optic chiasm in the visual pathway. This region includes the optic tract, the lateral geniculate nucleus, the optic radiations (the fibers traveling to the occipital cortex), and portions of the occipital cortex itself. Lesions in these areas are collectively described as retrochiasmal and typically produce homonymous visual field defects, because the fibers carrying information from the two eyes have already crossed at the chiasm.
The most common clinical manifestation of retrochiasmal disease is contralateral homonymous hemianopia, meaning the same half
Macular sparing—preservation of central vision despite a large retrochiasmal lesion—occurs with some occipital lobe or proximal
Etiologies include cerebrovascular events (notably posterior cerebral artery territory strokes), tumors or tumor-related edema, demyelinating disease,