Lesions of the Visual System- Graf Flashcards
Pathway lesions are very clear cut. Cognitive lesions are not so clear cut
???
Patches in diabetic retinopathy
?????
Glaucoma can be monocular (primarily) or biocular
???
What is scotoma?
loss of a part of the visual field
What is nyctalopia?
poor night vision (with extreme myopia, cataract, vitamin A deficiency)
What is diplopia?
double vision
What is photopic vision?
daylight- cone (color) vision
What is scotopic vision?
night-rod (black/white) vision
What are the normal limits of the visual field?
160 degrees horizontally
135 degrees vertically
The right visual hemifield corresponds to?
right nasal retina and left temporal retina
The left visual hemifield corresponds to?
left nasal retina and right temporal retina
What are the optic radiations?
The optic radiation (also known as the geniculocalcarine tract, the geniculostriate pathway, and posterior thalamic radiation) are axons from the neurons in the lateral geniculate nucleus to the primary visual cortex.
The optic radiations can be divided into what two pathways?
retrolenticular pathway
sublenticular pathway or the “temporal detour”
The optic radiations can be divided into what two pathways?
retrolenticular pathway
sublenticular pathway or the “temporal detour”
What is the Meyer’s loop?
they are fibers from the superior retina
What fibers do the retrolenticular pathway represent?
fibers representing superior retinal quadrants
What fibers do the sublenticular pathway represent?
fibers representing inferior retinal quadrants
Describe the projection of input from the retina to the visual cortex.
The inferior halves of the retina receives what information from the visual hemifields? Where is this information transmitted to in the primary visual cortex?
- information from the superior visual hemifields
- information is transmitted via MEYER’S LOOP to the inferior banks (lingual gyrus) of the primary visual cortex
Describe the projection of input from the retina to the visual cortex.
The superior halves of the retina receives what information from the visual hemifields? Where is this information transmitted to in the primary visual cortex?
- information from the inferior visual hemifields
- information is transmitted to the superior banks (cuneus gyrus) of the primary visual cortex
If there is lesion of the right optic nerve, how is the visual field disrupted?
right eye blindness
If there is lesion of the right optic nerve, how is the visual field disrupted?
right eye blindness AKA
monocular blindness
If there is a coronal lesion of the optic chiasm, how is the visual field disrupted?
complete blindness
If there is lesion in the left optic tract?
right temporal and left nasal region is affected AKA
bilateral right hemianopia
If there is lesion in the left optic tract, how is the visual field affected?
right temporal and left nasal region is affected AKA
bilateral right hemianopia AKA contralateral homonymous hemianopsia