Cortical blindness syndrome

Daniel Loh et al.

Cortical blindness is a condition resulting from lesions in the primary visual cortex (V1) characterised by visual impairment but with an intact anterior visual pathway (normal pupillary reflexes and fundal appearance).

Clinical features

The degree of visual impairment is related to the extent of cortical involvement1:

  • Complete lesions in both V1 areas lead to binocular blindness
  • Complete lesions in either the right or left V1 lead to a homonymous hemianopia
  • Incomplete lesions in V1 lead to scotomas in the visual field

Although patients lose any conscious visual awareness, at least 70% retain some functional awareness, known as 'blindsight'1. These patients are able to discriminate the presence, location and movement of objects under forced-choice conditions despite denying any awareness of them2

2 subtypes have been reported1:

  1. Type 1
    • ​​complete absence of visual awareness
  2. Type 2
    • ​​residual awareness of "feeling" or "knowing" of the presented visual stimuli

Associated syndromes

  1. Anton-Babinski syndrome3
    • bilateral cortical blindness
    • visual anosognosia (denial of vision loss)
    • visual confabulation
  2. Riddoch syndrome4
    • preservation of light and motion perception but not static objects within hemianopic field
  3. Dide-Botcazo syndrome4
    • ​​Anton-Babinski syndrome associated with memory impairment

 

 

 

 

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Article information

rID: 53272
Section: Syndromes
Synonyms or Alternate Spellings:

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