Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Ophthalmology PPT 8 Visual Pathway Lesions Lecture Notes
Visual Pathway: Lesions
VISUAL PATHWAY ANATOMY
COMPONENTS OF VISUAL PATHWAY
VISUAL
PATHWAY
Anopia
?Hemianopia: Loss of vision in one half of
visual field
Heteronymous hemianopia
Quadrantanopia
Homonynous hemianopia
Congruous
Incongruous
eg-Optic tract &
LGB lesions
eg-Post optic
radiation lesions
inverted
reversed
LESIONS
OF VISUAL
PATHWAY
Field Defects in Lesions of Optic Nerve
Cause:
traumatic avulsion or optic atrophy
Clinical features:
?Ipsilateral anopia
(loss of vision)
?Loss of direct pupillary reaction
(same side)
?loss of consensual pupillary reaction
(other side)
?Near or accommodation reflex is
present
Field Defects in Lesions of Optic Chiasma
(Less common)
? I Ird ventricle
enlargement /
dilatation
? Atheroma of carotids or
posterior
communicating arteries
Pituitary Adenoma
Craniopharyngioma
Field Defects in Lesions of Optic Tract
left optic tract lesion
involving left cerebral
peduncle and left 3rd nerve.
Causes of optic tract lesion
Field Defects in Lesions of
Lateral geniculate Body (LGB)
sparing of pupillary
reflexes
Lesion of optic radiations
Pie in the sky
Pie on the floor
Common causes of lesions of optic
radiations
lesions of optic radiations-Clinical
presentation
Field Defects in Lesions of Visual Cortex
Common causes of lesions of Visual
Cortex
Clinical presentation in Visual Cortex
Lesions (Cortical blindness)
[Anton syndrome]
[Riddoch phenomenon]
[Alexia]
Differences between occipital lobe and
optic tract lesions
Clinical Features
Occipital lobe
Optic tract lesion
lesion
Pupillary reaction
Normal
Abnormal
Field defect
Congruous
Incongruous
Macular involvement Sparing
Involved
Optic atrophy
-
+
This post was last modified on 07 April 2022