| Identifier |
yt1s_com_Light_near_dissociation_from_ciliary_ganglion_lesion_360p |
| Title |
Light Near Dissociation from Ciliary Ganglion Lesion |
| Creator |
Andrew G. Lee, MD; Akash Gupta |
| Affiliation |
(AGL) Chairman, Department of Ophthalmology, The Methodist Hospital, Houston, Texas; Professor of Ophthalmology, Weill Cornell Medicine, New York City, New York; (AG) Class of 2023, Baylor College of Medicine, Houston, Texas |
| Subject |
Light Near Dissociation; Aberrant Regeneration; Ciliary Ganglion |
| Description |
Dr. Lee lectures medical students on light near dissociation. |
| Transcript |
"So today we're going to talk about what the mechanism is for light near dissociation from a very specific cause which is a lesion in the ciliary ganglion. So if you have a lesion, any lesion in the ciliary ganglion, and you remember the whole pathway again - where we have the afferent limb, we have the pretectal nuclei to the dorsal midbrain, and we have the Edinger-Westphal nucleus to the ganglion which is the ciliary ganglion to the postganglionic nerve. This pathway is necessary for you to understand light near dissociation. So under normal conditions this fiber for making your pupil constrict is actually the same fiber that goes to the ciliary body as to the iris. However, when you have a ganglion damage the signal has been disrupted. And so this fiber has to grow back - this we call regeneration. And that regeneration has two ways it can regenerate - it can regenerate the normal way or the abnormal way; and the abnormal way we call aberrant regeneration. So this guy's trying to regrow and normally you have 30 times the number of fibers going to the ciliary body because that ciliary body is a way bigger muscle than the iris because you have to pull on the zonules and change the shape of the lens. So under normal conditions 30 times the number of fibers. But when you have regeneration that's aberrant some of the fibers that were supposed to go to the ciliary body, they got lost, and now they go to the iris. This we call aberrant regeneration. So now you're firing the light pathway, the light comes in: Edinger-Westphal nucleus, ciliary ganglion, but oh no the fiber to the iris has been damaged. So we get a poor light reaction; however, we can still make this pupil constrict - and that's the near response. So the supranuclear pathway to the Edinger-Westphal nucleus for near tells the Edinger-Westphal nucleus and the third nerve to fire. That signal still travels to the ganglion. But you think you're firing your ciliary body to accommodate the lens, but in reality the aberrant regenerating fiber is going to the iris. And so now we get a near reaction even though your brain thinks you're trying to fire the ciliary body and accommodate the lens. That light near dissociation occurred because after the ganglion the fibers got reversed. And that is the cause of light near dissociation in a ganglionopathy in the ciliary ganglion and it's from aberrant regeneration." |
| Date |
2022-03 |
| 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/s6awsa56 |
| Setname |
ehsl_novel_lee |
| ID |
1751104 |
| Reference URL |
https://collections.lib.utah.edu/ark:/87278/s6awsa56 |
