11 Visual Pathway Flashcards
(20 cards)
Visual Pathway
Explain visual pathway
Retina → Optic Nerve → Optic Chiasm → Optic Tract → Lateral Geniculate Nucleus (LGN) →
Optic Radiations (Meyer’s + Baum’s loops) → Primary Visual Cortex (Occipital Lobe)
Visual Pathway
Describe lesion in orbital apex
2,3,4,5(V1),6 one sided visual, ptosis, proptosis, Chemosis (conjunctival injection), Abduction (nerve 6) paralysis, mydriasis, pale left optic disk, reduced corneal reflex
Visual Pathway
Optic Disc swelling Causes and result?
(ICP papilledema, Inflammation optic neuritis, Ischemia ): Enlarged blind spot
Visual Pathway
Superior Orbital fissure
3,4,5 (V1), 6
Visual Pathway
Retina defect?
Scotoma, patch; Retinal detachment: Curtain-like visual loss
Visual Pathway
Central Retinal Artery Occlusion
Sudden, Painless vision loss, Pale retina + Cherry red spot
Visual Pathway
Optic nerve
Mono Ocular Blindness -> MS. Ischemia, tumor, trauma
Visual Pathway
Optic chiasma
Bitemporal hemianopia, Pituitary adenoma, craniopharyngioma, Aneurysm of Anterior communicating artery
Visual Pathway
Bitemporal superior quadrantanopia
early stages of macroadenoma, Craniopharyngioma
Visual Pathway
Optic tract
Contra lateral Homonymous hemianopia + rare Relative afferent pupillary defect ( when swinging light, the afected eye constricts less or even dilate slightly)
Visual Pathway
Bitemporal Inferior Quadrantopia
Anterior communicating artery aneurysm
Visual Pathway
Hypothalamus LGN
Contralateral homonymous hemianopia
Visual Pathway
optic radiation
Temporal (meyer’s loop): Superior quadrantanopia Opposite side (pie the sky), Propagnosia (right, not realizing family faces) , dysphasia left
Causes: HSV, encephalitis, tumor, epilepsy surgery
Parietal (Baum’s loop): Inferior quadrantanopia opposite side, or ignores opposite side(visual spatial junction), pie on the floor
Visual Pathway
Occipital lobe
Homonymous hemianopia opposite side with central sparing, often due to PCA stroke, if bilateral PCA stroke (end of basilar) or Post long hypotension can cause Anton syndrome (claims can see), NL pupillary response, Impaired visual evoked potential and optokinetic nystagmus
Gunbarrel vision, cannot see a door but can see a pin
Visual Pathway
What does cortical blindness mean
Bilateral Occipital
Visual Pathway
Frontal
ipsilateral deviation toward the lesion
Visual Pathway
Symmetric vs Asymmetric ?
Incongruous(asymmetric): Optic tract
Congruous(symmetrical): optic radiation/occipital
Ischemic optic neuropathy
NAION (HTN DM atherosclerosis, small cup to disk ratio), AAION (Giant cell arteritis) Altitudinal field defects/ more common loss of inferior hemifield
loss of inferior hemifield
NAION (HTN DM atherosclerosis, small cup to disk ratio), AAION (Giant cell arteritis)
Altitudinal field defects/ more common loss of inferior hemifield
Saccadic (delay, slow, disconjugate movement, inaccuracy in refixation)/ smooth pursuit eye movement:
Cerebellar peduncle
