Visual Field Deficits Flashcards
What is arterio-venous Nicking?
Chronic hypertension stiffens and thickens arteries, leading to vein indentation and displacement
What are cotton wool spots?
Microinfarcts result in retinal ganglion axonal damage;l axoplasmic material builds up in the nerve fiber layer
What is retinal vein occlusion?
Arterial atheroschlerosis causes blockage of nearby retinal vein, resulting in hemorrhage and edema
What is central retinal artery occlusion?
Occlusion of the central retinal artery
Causes monocular vision loss with “cherry-red” spot at fovea
What is retinal detachment?
The neural retina separates from the retinal pigment endothelial layer
Results in sudden blindness in the part of the visual field where these two layers detached
Typically associated with blows to the head, cataract surgery, or shaken baby syndrome
What is Rhegmatogenous?
Most common form of retinal detachment
Hole or tear in the retina allows fluid to accumulate underneath
Risk increases with aging
What is tractional retinal detachment?
Scar tissue growing on the surface of the retina may prompt detachment; typically observed in poorly controlled diabetes
What is exudative retinal detachment?
Fluid accumulation beneath the retina without a hole or tear
Can be caused by age-related macular degeneration, eye injury, tumor, or inflammatory disorder
What is a Scotoma?
Abnormal blind spot in the visual field caused by focal lesions in the reitna
Typically unilateral
What is the difference between homonymous and heteronymous vision loss?
Homonymous - same side in both eyes
Heteronymous - Loss in either both temporal halves or nasal halves
What is macular sparing?
Center of the visual field is preserved due to redundant blood supply to the occipital pole by branches of the MCA and PCA
Why are homonymous hemianopia/quadrantanopia deficits called retrochiasmal lesions?
The lesions that cause these deficits occur after the crossing of the retinal ganglion fibers at the optic chiasm
What causes Binasal hemianopia?
Lesions of the uncrossed temporal retinal fibers
May result from congenital hydrocephalus
What causes bitemporal hemianopia?
Lesions of the crossed nasal retinal fibers
Can result from pituitary tumors, hypothalamic tumors, or berry aneurysms
What causes superior quadrantanopia?
Lesions of the inferior portion of the middle cerebral artery disrupt the lower division of the geniculocalcarine tract at Meyer’s loop
Results in loss of the upper half visual field contralaterally
