| Identifier |
retrograde_anterograde_optic_atrophy_lee |
| Title |
Retrograde and Anterograde Optic Atrophy |
| Creator |
Andrew G. Lee, MD; Alicia Chen |
| Affiliation |
(AGL) Chairman, Department of Ophthalmology, The Methodist Hospital, Houston, Texas; Professor of Ophthalmology, Weill Cornell Medicine, New York City, New York; (AC) Class of 2023, Baylor College of Medicine, Houston, Texas |
| Subject |
Optic Atrophy; Anterograde; Retrograde; Wallerian Degeneration; CRAO; BRAO |
| Description |
Summary: • Optic atrophy represents damage to nerve's axon or cell body o Can happen in the anterograde/orthograde or retrograde direction o Ophthalmoscopic finding of optic atrophy is due to Wallerian degeneration of the optic nerve axon o Results in a pale nerve • Causes of optic atrophy o Anterograde > Retinal disorders • Central retinal artery occlusion: diffuse optic atrophy • Branch retinal artery occlusion: sector optic atrophy o Retrograde > Optic neuritis > Tumor pressing on optic chiasm (e.g. pituitary adenoma) > Chiasmal lesion (bitemporal hemianopsia) • Bilateral band atrophy > Optic tract lesion (incongruous homonymous hemianopsia) • Band atrophy • Lesion in radiations or cortex normally does not produce optic atrophy o Can be seen in trans-synaptic degeneration though o Clinically, only defects before the lateral geniculate body will produce optic atrophy |
| Transcript |
So today we're going to be talking about optic atrophy but I want to show it to you in a little bit different way which is the difference between anterograde or orthograde, and retrograde optic atrophy. And the reason this is important is it truly is our super power. Our super power in neuro-ophth is we get to look in someone's eye and we can see that something's in their brain or something's in their body. And the reason we're able to see that in terms of optic neuropathies is we can see the nerve turn pale or that the nerve is swollen. So when the nerve is swollen we can see papilledema, we can see giant cell arteritis, and today we're just going to be talking about optic atrophy. And this optic atrophy represents the damage to the axon or its cell body. And so in pathology, you remember that you have the cell body and then you have the axon and then you're going downstream to the synapse. So anything that disrupts the nerve will cause dying back of this nerve and it can go die this way which is in the orthograde anterograde, or can die this way which is retrograde. And the reason that's important is that is what's producing the ophthalmoscopic finding of optic atrophy, it's the thing we see and that is Wallerian degeneration in the axon and for the optic nerve what that means is when we're looking at the afferent pathway, the retina is the starting point and so diseases of the retina that affect the retinal ganglion cell will damage that retinal ganglion cell and that is connected to the axon of the optic nerve and that means some retinal disorders are going to produce optic atrophy in the anterograde or orthograde direction, and the prototype for that is central retinal artery occlusion or branch retinal artery occlusion. So if you have a central retinal artery occlusion or a branch retinal artery occlusion, you are losing the inner retina because the blood supply of the retinal arteries to the inner retina and that means you're going to knock out the ganglion cell and the axon and that's gonna die and then we'll see the nerve is pale. So a year after a CRAO we'll have diffuse optic atrophy. A year after a BRAO we'll have sector optic atrophy in the sector of the retinal artery that was occluded. And that means retinal disease can produce optic atrophy because the nerve then travels backwards to the chiasm and ultimately to its synapse and that cell body is in the lateral geniculate body. And so the dying back could occur in the retrograde direction. So that is retrograde Wallerian degeneration and what that means is if you have a nerve lesion here like optic neuritis, you'll get a pale nerve. If you have a tumor pressing on your optic chiasm, you'll get a pale nerve like a pituitary adenoma. If you have optic tract lesion, you'll get optic atrophy. But if you get a lesion in the radiations or the cortex, that normally does not produce optic atrophy because it cannot jump this synapse here. Now there is such a thing as trans-synaptic degeneration where it does jump the synapse but from a clinical standpoint, an occipital stroke or a radiation lesion from the temporal lobe or the parietal lobe really should not produce ophthalmoscopically visible optic atrophy because the line is at the geniculate body and anything in front of the geniculate body will produce optic atrophy. If it's a tract, that's a special kind of optic atrophy called band atrophy and so when you have an optic tract lesion you usually have an incongruous homonymous hemianopsia and the eye with the temporal field defect is gonna have nasal loss and that's called band atrophy and there's a whole video devoted just to that. And if you have a chiasmal lesion where you have a bitemporal hemianopsia, that will produce bilateral band atrophy. So the key take home point is optic atrophy is a sign, not a diagnosis. It doesn't tell you where the lesion is. The lesion could be in the retina, in the retinal ganglion cell or its axon, in the optic nerve, in the optic chiasm, in the optic radiations and the optic tract -- I mean in the optic tract but not the optic radiations. And so you need to know that optic atrophy means we are in front of the geniculate body all the way to the retina and that could be either retrograde or anterograde optic atrophy. |
| Date |
2021-04 |
| Language |
eng |
| Format |
video/mp4 |
| Type |
Image/MovingImage |
| Collection |
Neuro-Ophthalmology Virtual Education Library: Andrew G. Lee Collection: https://novel.utah.edu/Lee/ |
| Publisher |
North American Neuro-Ophthalmology Society |
| Holding Institution |
Spencer S. Eccles Health Sciences Library, University of Utah, 10 N 1900 E SLC, UT 84112-5890 |
| Rights Management |
Copyright 2019. For further information regarding the rights to this collection, please visit: https://NOVEL.utah.edu/about/copyright |
| ARK |
ark:/87278/s6ns6rjw |
| Setname |
ehsl_novel_lee |
| ID |
1680622 |
| Reference URL |
https://collections.lib.utah.edu/ark:/87278/s6ns6rjw |
