Visual field defects Flashcards
What is bi-temporal hemianopia?
loss of vision in half of each eye’s acuity (opposite sides e.g. loss of outer field in both)
What is nasal hemianopia?
loss of vision in the medial visual field
What is homonymous hemianopia?
loss of visual acuity in the same field of each eye
What is homonymous hemianopia with macular sparing?
loss of visual acuity in both eyes but macula is functioning
Pre optic chiasmal lesions (optic nerve damage) result in what type of defect?
Ipsilateral monocular visual field defect e.g. total right eye visual loss if pre-chiasm lesion on the right occurs
Post chiasmal lesions generally result in…
homonymous visual defects of the contralateral side e.g. injury to the left lateral chiasma gives right homonymous hemaniopia
Lesions of the optic chiasm mostly result in
bitemporal hemianopia
loss of outer visual field in both eyes
What are the 5 causes of monocular blindness?
optic neuritis amaurosis fugax optic atrophy retrobulbar optic neuropathy trauma
What are the 2 causes of bitemporal hemianopia?
- pituitary adenoma
2. suprasellar aneurysm
What is the main cause of nasal hemianopia?
distention of the 3rd ventricle
What is the main cause of contralateral homonymous hemianopia?
Middle Cerebral artery stroke
e.g. if the left MCA is infarcted, there will be loss of right visual field in both eyes
Why is a lesion to the calcarine sulcus of the occipital lobe sparing of the macula?
There is dual blood supply to the anterior portion of the visual centre (from PCA and MCA)
What causes contralateral homonymous quadrantopia?
MCA stroke, tumour and trauma
What is homonymous upper quadrantanopia
only the outermost, upper most quadrant is visible
“pie in the sky” vision caused by lesion to the meyer’s loop in the temporal lobe
What is homonymous lower quadrantanopia? (only the lower most, outermost quadrant is visible)
“pie on the floor” affecting the parietal lobe
