Download MBBS Ophthalmology PPT 8 Visual Pathway Lesions Lecture Notes

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

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This post was last modified on 07 April 2022