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Image Based Question-66023

Question

ldentify the visual defect shown in the photograph below ?

A. Right homonymous hemianopia.

B. Right homonymous hemianopia.

C. Right inferior homonymous quadrantanopia.

D. Right incongruous hemianopia.

 

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Correct Answer » C

Explanation

Ans:C. Right inferior homonymous quadrantanopia.

Types of visual field loss

Scotoma

  • This is a defect surrounded by normal visual field. It may begin as a gradual enlargement of the blind spot.
  • Relative scotoma – an area where objects of low luminance cannot be seen but larger or brighter ones can.
  • Absolute scotoma – nothing can be seen at all within that area.

Hemianopia

  • This is a binocular visual defect in each eye’s hemifield.
  • Bitemporal hemianopia – the two halves lost are on the outside of each eye’s peripheral vision, effectively creating a central visual tunnel.
  • Homonymous hemianopia – the two halves lost are on the corresponding area of the visual field in both eyes, i.e either the left or the right half of the visual field.
  • Quadrantanopia – this is an incomplete hemianopia referring to a quarter of the schematic ‘pie’ of visual field loss.
  • Right homonymous inferior quadrantanopia : Both lower right quadrants of the visual field experience loss of visual function; the cause of this visual defect is commonly located in the left hemisphere.
  • Left homonymous inferior quadrantanopia involves visual defects in the lower left quadrant of each eye, with the cause usually being located in the right hemisphere of the brain.
Defect Location
Loss of vision in one eye Ipsilateral Optic Nerve
Bitemporal Hemianopia Optic chiasm
Binasal hemianopia Optic chiasm
Left homonymous hemianopia Right optic tract / radiation
Right homonymous hemianopia Left optic tract / radiation
Homonymous quadrantopia
Contralateral optic radiation
  • Upper – temporal region
  • Lower – parietal region
Scotoma Occipital region
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