| Identifier |
retinal_hemifield_slide_phenomenon |
| Title |
Retinal Hemifield Slide Phenomenon |
| Creator |
Andrew G. Lee, MD; Sowmya Yennam |
| Affiliation |
(AGL) Chairman, Department of Ophthalmology, The Methodist Hospital, Houston, Texas; Professor of Ophthalmology, Weill Cornell Medicine, New York City, New York; (SY) Class of 2021, Baylor College of Medicine, Houston, Texas |
| Subject |
Retinal; Chiasmal; Tumor; Hemianopsia |
| Description |
Summary: Retinal Hemifield Slide Phenomenon • Problem: Two visual fields slide because the hemifields do not align, causing diplopia • Patient: Non-overlapping visual field defects with remaining field juxtaposition 1. Bitemporal hemianopsia (2/2 pituitary adenoma, for example) 2. Super-altitudinal OD, Inferior-altitudinal OS or vice-versa • Mechanism: 1. Typically, there is overlap between your OD temporal field and OS nasal field (and vice versa) 2. In bitemporal hemianopsia, you have two juxtaposed nasal fields because the temporal fields are knocked out 3. These juxtaposed nasal fields can slide -Vertical slide -hypertropia -Horizontal slide -esotropia or exotropia 4. This sliding breaks the fusional mechanism, causing a non-paretic diplopia (aka no weakness) |
| Transcript |
Today we are going to be talking about a very unusual thing called the retinal hemifield slide phenomenon. Basically, the retinal hemifield slide phenomenon is when the two visual fields slide because the hemifields don't align. The prototype for the retinal hemifield slide phenomenon is a patient who has a chiasmal tumor, like a pituitary adenoma, who has a bitemporal hemianopic field defect. What that means is that normally, the two fields overlap. You have overlap between your right visual field temporally in the right eye and the left side nasal field. When you have a bitemporal hemianopsia, you have two temporal fields that do not overlap with the nasal fields and so what you have is two juxtaposed nasal fields because your temporal field has been knocked out. So, when you have these two nasal hemifields juxtaposed to one another, they can slide. When the slide occurs, you'll have a breakdown of your fusional mechanism. Basically, what that means is your peripheral field in one eye overlaps with the other eye. If you don't have that overlap, it's going to be very hard to take the two images and fuse them into one. And so, in a patient who has a bitemporal hemianopsia, they have two juxtaposed nasal fields and those two juxtaposed nasal fields don't overlap. Therefore, the field can slide vertically, and it can cause a hypertropia or can slide horizontally producing an exotropia or esotropia. And so, it's a non-paretic form of diplopia. And by that we mean there is no actual weakness. It is breakdown of the fusional ability producing a non-paretic diplopia because the two hemifields slide over one another. Even though the bitemporal hemianopsia is the prototype, any two field defects that don't overlap - so if you have a field that looks like this, a super-altitudinal and inferior-altitudinal in the fellow eye, then these two fields are no longer able to fuse. The hemifield slide phenomenon can occur in any patient who has bilateral visual field loss where the two visual fields are juxtaposed to one another and are not overlapping. And that non-overlapping in the field allows the slide to occur and a non-paretic diplopia, which we call the retinal hemifield slide phenomenon. |
| Date |
2019-10 |
| 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 |
| Rights Management |
Copyright 2019. For further information regarding the rights to this collection, please visit: https://NOVEL.utah.edu/about/copyright |
| ARK |
ark:/87278/s6xw9991 |
| Setname |
ehsl_novel_lee |
| ID |
1469323 |
| Reference URL |
https://collections.lib.utah.edu/ark:/87278/s6xw9991 |
