Saturday, October 21, 2017

Lesions of visual pathway

Visual pathway starting from retina consists of optic nerve , optic chiasma , optic tracts , lateral geniculate bodies , optic radiations and the visual cortex .
Courtesy :- Comprehensive Ophthalmology 6th edition ; AK Khurana ; Pg.314


Sl . no
Site of lesion
Type of lesion
1
Optic nerve
Complete blindness on ipsilateral side
2
Anterior Chiasma
Junctional scotoma
3
Central chiasma
Bitemporal hemianopia
4
Lateral chiasma
Binasal hemianopia
5
Optic tracts / LBG
Incongruous homonymous hemianopia
6
Part of optic radiations in temporal lobe
Superior quadrant hemianopia (pie in sky )
7
Part of optic radiations in parietal lobe
Inferior quadrant hemianopia (pie on floor )
8
Optic radiations
Complete homonymous hemianopia
9
Visual cortex sparing macula
Congruous homonymous hemianopia
10
Visual cortex , only macula
Congruous homonymous macular defect
11
Bilateral Visual cortex , only macula
Bilateral homonymous macular defect


`~ Pratheek Prabhu

2 comments:

  1. could you please tell why the lesion at proximal part of optic nerve (labelled '2' in the pic) would lead to ipsilateral central scotoma?
    From my understanding, the lesion should lead to ipilateral complete blindness and contralateral temporal hemianopia.

    ReplyDelete
    Replies
    1. also, a compressive lesion would affect the peripheral fibres of optic nerve first. and these fibres are carrying signals from peripheral retina, right?..

      Delete

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