Visual Field Defects

Question 1

What visual defect would come with a pre-chiasmal lesion

Answer 1

‣ Would lead to ipsilateral visual field defects
‣ E.g an optic nerve lesion would result in Ipsilateral Monocular blindness (if right optic tract affected, then there would be complete blindness in the right eye)

Question 2

What visual defect would come with an optic chiasm lesion

Answer 2

‣ Would result in bitemporal hemianopia
‣ Can be due to pituitary adenoma compressing the optic chiasm

Question 3

What visual defect would come with a lateral top optic chiasm defect

Answer 3

‣ Would affect the temporal tract on one side; hence leading to Ipsilateral mononuclear nasal hemianopia

Question 4

What visual defect would come with an optic tract lesion

Answer 4

◦ Would lead to Contralateral Homonymous Hemianopia
◦ If lesion in right optic tract, would result in left homonymous hemianopia (the left field of both eyes is affected)
◦ Can be caused by middle cerebral artery stroke, tumours etc

Question 5

What visual defect would come with an optic radiation lesion

Answer 5

◦ A lesion here would result in Contralateral homonymous quadrantanopia
◦ If affecting Meyerys loop, then would lead to upper quadrantanopia (pie in the sky)
◦ Affecting parietal lobe would cause lower quadrantanopia (Pie on the floor)

Question 6

What visual defect would come with an occipital cortex lesion

Answer 6

◦ A lesion here would lead to Contralateral Homonymous Hemianopia with Macular Sparing
◦ Left occipital cortex lesion would lead to right homonymous hemianopia with macular sparing
◦ Can be caused by posterior communicating artery stroke, trauma etc