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Cranial Nerves
 
Cranial Nerves
 

Peripheral Visual Fields

February 15th, 2021
 
 
 
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Overview

By identifying loss of vision in a particular field or group of fields, it is possible to localise an intracranial lesion and guide further investigation.
The visual fields extend 100 degrees laterally, 60 degrees medially, 60 degrees upward and 75 degrees downward.
  • How to Assess

  • Ask the patient to cover one eye. Slowly move a finger or white examination pin from the upper left, upper right, lower left and then lower right, asking the patient to state when they can see the finger / pin. Repeat with the other eye.
  • Interpretation

  • A
    Unilateral anopia - complete loss of vision in one eyeUnilateral optic nerve lesion or ocular pathology
  • B
    Bitemporal hemianopia - loss of lateral vision in both eyesOptic chiasmal compression
  • C
    Homonymous hemianopia - loss of left or right field in both eyesContralateral optic tract lesion
  • D
    Homonymous inferior quadrantanopia - loss of the left or right lower quarters of vision in both eyesContralateral lower optic radiation lesion
  • E
    Homonymous superior quadrantanopia- loss of the left or right upper quarters of vision in both eyesContralateral upper optic radiation lesion
  • F
    Homonymous hemianopia with macular sparingContralateral occipital lobe lesion

Unilateral Anopia

  • Look For

  • Complete loss of vision in one eye.
  • Causes of Unilateral Anopia

  • Unilateral optic nerve lesion - trauma, ischaemia, aneurysm, tumour, optic neuritis, hypoplasia
  • Corneal opacification - cataract, infection, trauma
  • Vitral opacification - intraocular haemorrhage
  • Retinal disorder - retinal detachment, retinal artery occlusion
  • Glaucoma

Bitemporal Hemianopia

  • Look For

  • Loss of the lateral visual fields in both eyes.
  • Significance

  • Suggests a lesion at the level of the optic chiasm.
  • Causes of Bitemporal Hemianopia

  • Pituitary mass lesion
  • Craniopharyngioma
  • Pituitary apoplexy

Homonymous Hemianopia

  • Look For

  • Loss of the left or right field in both eyes.
  • Significance

  • Suggests a lesion in the optic tract on the opposite side to the visual loss.

Homonymous Quadrantanopia

  • Look For

  • Loss of the upper or lower left or right quarters of vision in both eyes.
  • Interpretation

  • Loss of vision in the superior quadrants - suggests a lesion within the contralateral upper optic radiation
  • Loss of vision in the inferior quadrants - suggests a lesion within the contralateral lower optic radiation
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