| Identifier |
cortical_visual_impairment_lee |
| Title |
Cortical Visual Impairment |
| Creator |
Andrew G. Lee, MD; Jae Eun Lee |
| Affiliation |
(AGL) Chairman, Department of Ophthalmology, The Methodist Hospital, Houston, Texas; Professor of Ophthalmology, Weill Cornell Medicine, New York City, New York; (JEL) Class of 2023, Baylor College of Medicine, Houston, Texas |
| Subject |
Cortical Visual Impairment; Occipital Cortex; Cerebral Visual Impairment |
| Description |
Summary: • Cortical Visual Impairment o Term preferred over cortical blindness as patient does not need to be blind o Impaired with vision due to problem in the occipital cortex o Any lesion behind the optic chiasm bodies > homonymous hemianopsia on the contralateral sides of the lesion. • Posterior reversible encephalopathy syndrome o Variety of causes > Hypertension > Pregnancy eclampsia > Medication o Visual acuity will be down in both eyes equally • Genuine cortical visual impairment o Pupil will be normal, and the rest of the eye exam may be normal o This however does not mean that the patient is faking > must include cortical visual impairment in the differential diagnosis |
| Transcript |
So today we're going to be talking about cortical visual impairment. I prefer this term over cortical blindness because the patient's don't have to actually be blind. They can just be visually impaired. So cortical visual impairment means they're impaired with their vision because of the problem in the occipital cortex. Now it can be that it's cerebral visual impairment because it could be through radiations it doesn't have to be the occipital cortex. But in general when you have lesions in your brain, because the crossing point is the chiasm, any lesion behind the optic chiasm bodies that have produced a homonymous hemianopsia on the contralateral sides of the lesion. So normally when you have a hemispheric lesion, for example, in this patient was a right homonymous hemianopia, you're going to have something that is damaged - either their retro chiasmal pathway, in the temporal lobe, parietal lobe, occipital lobe - and that's gonna be on the left side. And so when people have a homonymous hemianopsia they still have a normal acuity because they still have half a macula - the half on the left is still able to see 20/20 even though you've lost everything to the right. When people have cortical visual impairment they have a lesion that's on the left side, so this is like the MRI, and they have a new lesion on the right side. So when you have that happen you have a left homonymous hemianopsia from the right-sided lesion superimposed on the right homonymous hemianopsia from the left side of the lesion. So we have a cortical blindness you actually have bilateral lesions. So that can occur from bilateral simultaneous stroke or sequential stroke. You had a stroke and the left occipital cortex last year and now you have a new stroke and your right, and that juxtaposed homonymous creates cortical visual impairment. But sometimes it's not a stroke, it might even be reversible, and so one of those conditions is called the posterior reversible encephalopathy syndrome, usually from hypertension but also from pregnancy eclampsia, or meds and in those patients they have bilateral posterior cortical disease usually occipital and that white matter change and edema can be reversible if it's vasogenic edema rather than cytotoxic edema. So it can be a stroke, it can be press, it can be seizure, it could be a tumor, it could be metastatic lesions, so it really doesn't tell you what the cause is when you have cortical visual impairment, and the way to make the diagnosis is: the visual acuity is down and it'll be down in both eyes equally. They should both be affected the same. It can be 20/200, it could be hand motions, it could be no leg reception. But the pupil better be normal because a cortical retrochiasmal pathway does not contain the pupil pathway. And of course the rest of the exam in the eye is gonna be normal because it's not really an eye thing so the slit-lamp, the pressure, the motility, and the fundus exam all have to be normal. And that's what makes it dangerous - because you have patients who have loss of central vision, they have a juxtaposed to monomyth so you really can't do the field on them or if you did do a field it's a juxtaposed field and the rest of their eye exam is normal. And you might think this person is faking when they actually have cortical visual impairment. The reason you might think they're faking is because the their pupil is normal. And so you really should be thinking in the differential diagnosis of bilateral simultaneous loss of vision with the normal pupil and normal eye exam, but maybe the reason the eye exam is normal is because it's not an eye thing at all and it might be cortical visual impairment. |
| 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 |
| Rights Management |
Copyright 2019. For further information regarding the rights to this collection, please visit: https://NOVEL.utah.edu/about/copyright |
| ARK |
ark:/87278/s618944f |
| Setname |
ehsl_novel_lee |
| ID |
1680596 |
| Reference URL |
https://collections.lib.utah.edu/ark:/87278/s618944f |
