DLA 26 +27 + Lecture 25+26 Flashcards
horner’s syndrome
loss of sympathetic innervation
symptoms:
miosis
ptosis
anhidrosis
myopia correction
nearsightedness; image focused before retina
correct with concave lens
hyperopia correction
farsightedness; image focused behind retina
correct with concave lens
Dyschromatopsia
red-green color blindness
rare in women; mostly seen in men
protanopia
defective long-wavelength cones (L-cones)
results in varying degree of color blindness
hard to determine difference between blue and green and red and green
Deuteranopia
medium-wavelength (green) cones are missing
dichromat (no green cones at all) anomalous trichromat (defective green cones)
most common
red and green are hardest to detect
papilledema
swelling of the optic disk
almost always bilateral
due to increased intracranial pressure
short issues with vision, headache, vomiting
optic disk will be white and elevated; not normal yellow
associated with: tumors in brainstem and cerebellum hematoma cerebral edema (TBI) increased CSF
Diabetic retinopathy
chronically high blood sugar levels from diabetes is damaging to the small retinal blood vessels
early stage:
micro-aneurysms
weakness in the walls of vessels; will leak fluid
late stage:
proliferation of new vessels
scar tissue
floaters
will be seen in both eyes usually
treatment aimed at slowing or stopping progression
Age-related macular degeneration (AMD)
macula:
area of the retina dedicated to central vision
no large blood vessels
leading cause of vision loss
blurred vision in central field
affects one or both eyes over time
no effective treatment
Risk factors include age, smoking, stroke or coronary heart disease, obesity, family history
where in the visual field is the blind spot
blind spot is in the temporal visual hemifield since optic disk is in nasal hemiretina
what part of the brain is required for vision experience
lateral geniculate nucleus (thalamus)
others (projections, not needed for experience)
hypothalamus - suprachiasmatic nucleus
mid brain - pretectal nucleus
mid brain - superior colliculus
what area is the primary visual cortex
area 17
what pathway involves color
ventral (inferior temporal) pathway
Cerebral Achromatopsia
a type of color blindness that is due to damage to the cerebral cortex
Cerebral Hemiachromatopsia
a type of color blindness that affects one half of the visual field due to cerebral damage
Visual word form area (VWFA)
specialized for visual word processing
located in the ventral occipitotemporal cortex (left bias)
letter form area
area that is used for letter processing
located in the left OTC posterior to the VWFA
lesion of the VWFA
lesion leads to alexia
selective impairment in reading with other language functions in tact
Fusiform face area (FFA)
ventral occipitotemporal cortex (OTC) but has a right bias
role in face recognition and perception
lesion to the FFA
lead to prosopagnosia.. the inability to identify faces visually
Akinetopsia
conscious loss of visual motion perception
can be traumatic, vascular, degenerative
human visual motion area occupies the lateral cortex at the occipital/parietal/temporal junction
optic nerve lesion
monocular blindness
could be due to optic neuritis
optic chiasm lesion
Bitemporal hemianopia (one half visual field lost both eyes)
may be due to pituitary tumor
optic tract lesion
Homonymous hemianopia (only see on side of visual field)
may be due to temporal lobe tumor
Temporal radiation (Meyer-Archambault loop)
Homonymous superior quadrantanopia (loss of vision in upper 1/4
may be due to temporal lobe tumor
Parietal radiation
Homonymous inferior quadrantanopia (loss of vision in lower 1/4)
may be due to parietal lobe tumor
primary visual cortex lesion
Homonymous hemianopia (person will only see one side of visual field)
could be due to PCA infraction
