| Identifier |
Prisms_in_Neuro-Ophthalmology |
| Title |
Prisms in Neuro-Ophthalmology |
| Creator |
Andrew G. Lee, MD; Junru Yan |
| Affiliation |
(AGL) Chairman, Department of Ophthalmology, The Methodist Hospital, Houston, Texas; Professor of Ophthalmology, Weill Cornell Medicine, New York City, New York; (JY) Class of 2021, Baylor College of Medicine, Houston, Texas |
| Subject |
Prisms; Neuro-Ophthalmology; Device |
| Description |
Dr. Lee lectures medical students on prisms in neuro-ophthalmology. |
| Transcript |
We're going to be talking a little bit about prisms and how we use them in neuro-ophthalmology. As you know, a prism is an optical device but it's different than the lens. A prism bends the image and if your eyeball is here, the eyeball will see the image displaced because the image was displaced. That amount of power of this prism to displace at 100 centimeters in centimeters is the power of that prism, and the power we record as prism diopters. So, a 5-prism diopter prism displaces 5 centimeters vertically at 1 meter. We can use these prisms to both measure and to displace images for clinical purposes. If a patient has an esotropia and their eyes turned in, we would put the prism with the apex facing the deviation, and we would do the cover, uncover tests and the alternate cover tests until the eyes cease to move. When the eyes don't move anymore, we know that that particular power of prism was enough to neutralize the deviation and then we record this esotropia, eyes turned in, so we're going to record this number as 45-prism diopter esotropia. The same can be done with exotropia, we would put the base in and apex out, and hypertropia [apex] towards the higher eye. So, when we're recording deviations, we want to do a prism cover test, a prism alternate cover test. This will measure, in prism diopters, the deviation, and it's an optical devise that displaces the image towards the base, and therefore the image appears to be in a different location, and the power is measured by the amount of displacement that occurs at 1 meter, a prism diopter. |
| Date |
2020-05-27 |
| 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/s64n4jmh |
| Setname |
ehsl_novel_lee |
| ID |
1561522 |
| Reference URL |
https://collections.lib.utah.edu/ark:/87278/s64n4jmh |
