Lecture 13: Visual Pathways (p1-31) Flashcards
The risk factors for developing primary angle-closure glaucoma are:
- increasing age
- increasing lens thickness
- female gender
- hyperopia
- ethnicity (Eskimo, East Asian)
Acute angle-closure glaucoma is characterized by
rapid increase in IOP
A patient suffering from acute angle closure will usually present with:
- severe pain, tearing, photophobia
- blurry vision, halos around lights
- corneal edema, a fixed mid-dilated pupil
- IOP of 50-70 mmHg.
Human visual system is comprised of the (8):
- Retina
- optic nerves
- optic chiasm
- optic tracts
- lateral geniculate nuclei
- geniculostriate radiations
- striate (visual) cortex
- visual association areas & related interhemispheral connections.
T/F: vision is not the dominant sense
F: Vision may be considered the dominant sense
why is vision considered to be the dominant sense?
the number of axons devoted to the optic nerve alone is 1 million to 2.2 million vs. acoustic nerve that has ~31,000
what are the retinal cells?
- PR
- horizontal
- bipolar
- amacrine
- ganglion
A lesion in the retina will cause a field defect that is
similar
in shape to the lesion and is in the corresponding location in the field
travels contralateral or ipsilateral: inferior nasal fibers
contralateral
travels contralateral or ipsilateral: superior nasal fibers
contralateral
travels contralateral or ipsilateral: superior temporal
ipsilateral
travels contralateral or ipsilateral: inferior temporal fibers
ipsilateral
central visual pathway
- retina
- optic nerve
- optic chiasm
- optic tract
- LGN
- optic radiation
- visual cortex
central visual pathway
- retina
- optic nerve
- optic chiasm
- optic tract
- LGN
- optic radiation
- visual cortex
lesion of left optic nerve
total blindness in left eye (ipsilateral blindness)
lesion on the left optic tract
contralateral hemianopia (both of the ride sides of the circles are dark)
lesion at chiasm
bitemporal hemianopia
optic chiasm compression
binasal hemianopia
a complete transection of the right optic nerve fiber will most likely result in
right homonymous hemianopia
A CT scan showing pituitary adenoma will most likely
result in
binasal hemianopia
Complete interruption of left optic nerve
resulting in
complete loss of visual field for left eye.
Interruption in midline of optic chiasm
resulting in
bitemporal hemianopia.
Interruption in right optic nerve at junction with chiasm,
resulting in complete loss of visual field for right eye and
superior temporal loss in field for left eye (due to anterior
knees).
Interruption in left optic tract,
causing incongruent
right homonymous hemianopia.
