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defined, this is a loss of function of the optic nerve with resulting
gliosis and a decrease or loss of capillaries and axonal tissue within the
nerve. The type of optic
atrophy depends on the pathogenetic factors involved; ascending damage
from within the eye (glaucoma, optic neuritis, papilledema, and many
primary lesions of the retina-choroid), descending from damage to the
optic nerve or brain (trauma, hydrocephalus, neoplasm, demyelinating
diseases), or due to congenital defect (Leber's optic atrophy).
Clinically, the atrophic disc appears white and pale diffusely.
Histologically, the myelin sheaths and axons degenerate, resulting
in loss of substance of the optic nerve, causing expansion of the
subarachnoid space (and causing the dura to appear redundant).
The pial septa thicken within the optic nerve due to proliferation
of the glial, meningeal, and connective tissue elements.
Gliosis is also seen randomly within the nerve parenchyma. Within the retina there is a corresponding loss of ganglion
cells and nerve fiber layer.
Other clues such as loss of the inner nuclear layer (central
retinal artery occulsion) or posterior bowing of the lamina cribrosa with
cupping (glaucoma) may give clues to the origin of the atrophic process.
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| Clinical
#22087 |
High
Power #22090 |
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| Med.
Power #22089 |
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