Differential Diagnosis for Inner Retinal Layer Loss that Obeys the Vertical Midline

• Single most likely diagnosis:
  • Optic Chiasm Lesion: This is the most likely diagnosis because lesions affecting the optic chiasm, such as pituitary tumors or other sellar/suprasellar masses, can cause bitemporal hemianopia, which may manifest as inner retinal layer loss that respects the vertical midline on imaging studies like OCT.
• Other Likely diagnoses:
  • Binasal Hemianopic Defects: Though less common, conditions causing binasal hemianopia, such as bilateral lateral rectus muscle paresis or certain types of cerebral blindness, could potentially present with inner retinal layer changes that obey the vertical midline, albeit this is less typical.
  • Chiasmal Syndromes: Various chiasmal syndromes, including those caused by trauma, inflammation, or vascular lesions, can lead to visual field defects that might correlate with inner retinal layer loss respecting the midline.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
  • Pituitary Apoplexy: A medical emergency that requires immediate attention. It can cause sudden visual loss and field defects, including those that obey the vertical midline, due to hemorrhage or infarction of a pituitary adenoma.
  • Meningioma: Especially those located near the optic chiasm, can cause progressive visual field defects, including bitemporal hemianopia, and are critical to diagnose due to their potential for significant morbidity if left untreated.
• Rare diagnoses:
  • Sarcoidosis: Can involve the optic chiasm and nerves, leading to a variety of visual field defects, including those that might respect the vertical midline, though this is uncommon.
  • Lymphoma: Certain types of lymphoma can affect the central nervous system, including the optic chiasm, and cause visual disturbances, though this is a rare presentation.