Retrograde Trans-Synaptic Degeneration from a Longstanding Occipital Lobe Tumor

This is an illustrated guide that (1) discusses the localization of paracentral homonymous hemianopic scotomatous visual field defects and (2) discusses the concept of trans-synaptic retrograde degeneration. A 43-year-old woman was assessed for longstanding blurred vision in both eyes. Her examination showed: visual acuity: 20/20 OU; pupils: equal and reactive with no relative afferent pupillary defect; color vision: 14/14 plates correct OU; ocular motility: full. Humphrey visual fields (HVF, 24-2 SITA Fast) showed left homonymous hemianopic paracentral scotomatous defects, suggesting a lesion involving the right occipital pole. Her optic discs showed mild bilateral optic nerve pallor. T1 post-contrast axial MRI showed a lobular mass extending into the right occipital lobe.