She has left homomynous hemianopia, which can be due to lesion of the contralateral optic tract or as in this case lesion to the contralateral occipital lobe. It is not mentioned explicitly but this causes macular sparing. (FA2020 p542 gives the visual field defects)
pontiacfeverLeft homonymous hemianopia w/o macular sparing can also occur due to damage to parietal and temporal lobes. But occipital lobe damage is more common.+
pakimdmacular sparing will only occur if there is an infarct of the posterior coronary artery supplying the occipital lobe. this is because the macular region of the visual cortex has a double blood supply from the middle cerebral artery and the posterior cerebral artery. this woman has breast cancer hence the mets are probably directly to the occipital lobe causing left homonymous hemianopia WITHOUT macular sparing.
FA pg 542 look at the illustration: it says number 3 (left homonymous hemianopia WITHOUT macular sparing) and 6 (if PCA infarct when there is left homonymous hemianopia WITH macular sparing)+3
shieldmaiden@pontiacfever is not only that, but the optic tract is not in the temporal lobe anyways. A lesion affecting the vision fibers in either the temporal or parietal will cause quadrantanopia+
chaosawaitsRight, because the LGN is located in the dorsal part of the thalamus, the optic tract is neither in the parietal nor the temporal lobe. So the description of the clinical presentation sounding familiar to an optic tract injury is nothing more than a distraction. Parietal and temporal lobe lesions would create quadrantanopia (pies either in the sky or on the floor). Those are automatically ruled out. Optic chiasm would show bitemporal hemianopia and optic nerve damage is obviously out. So, occipital lobe is the only answer remaining.+
submitted by โcassdawg(1780)
She has left homomynous hemianopia, which can be due to lesion of the contralateral optic tract or as in this case lesion to the contralateral occipital lobe. It is not mentioned explicitly but this causes macular sparing. (FA2020 p542 gives the visual field defects)