Updated: 12/9/2018

Visual Field Defects

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Introduction
 

 
Central Scotoma
  • Scotoma
    • noticeable blind spot in a normal visual field
      • normal blind spot is on the retina where the optic nerve is due to NO photoreceptors and is not noticeable
      • central scotoma is due to lesion of macula
        • causes loss of central vision
Optic Nerve Transection
  • Transection of the optic nerve
    • loss of nasal and temporal visual fields of single eye
    • loss of all visual information from 1 eye
Lesion/Compression of Optic Chiasm (Bitemporal Hemianopsia)
  • Patient unable to see in bilateral temporal fields
    • Usually caused by lesion in optic chiasm
      • most commonly associated with pituitary tumors
      • also occurs with craniopharyngiomas, meningiomas, anterior communicating artery aneurysms
Lesion of Optic Tract
  • Optic tract contains visual information from:
    • ipsilateral nasal field
    • contralateral temporal field
      • this results in homonymous hemianopsia 
Lesion of Meyer's Loop
  • Meyer's loop innervates the inferior ipsilateral part of the retina serving the upper contralateral wedge of vision (pie in the sky
Dorsal Optic Radiation Lesion
  • Dorsal optic radiations innervate the ipsilateral superior part of the retina
    • this means that the contralateral inferior wedge of vision is lost
Visual Cortex Lesion
  • Unilateral lesion of the visual cortex causes vision loss of the contralateral visual field
    • the central area of vision is often spared because of redundant coverage of this area with the contralateral visual cortex

 

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