| Affiliation |
(AGL) Chairman, Department of Ophthalmology, The Methodist Hospital, Houston, Texas; Professor of Ophthalmology, Weill Cornell Medicine, New York City, New York; (HW) Class of 2023, Baylor College of Medicine, Houston, Texas |
| Description |
Summary: • Monocular diplopia: each eye alone o Monocular problem: horizontal or vertical misalignment, neuron o Split between unilateral vs bilateral > Differentiation: Does the diplopia go away with covering either eye? o Unilateral problems: double vision goes away with covering either eye because it's intraocular > Causes: dry eye, refractive error, cataract, corneal disease, retinal disease > Image description: ghost image superimposed on clearer second image o Bilateral: persists if you cover either eye because it's cerebral > Image description: Separation between the two clear images • Can be two images or palinopsia (multiple repeat images) > Causes of field defect: cortical lesion of homonymous hemianopsia, stroke, seizure • Occipital seizures o Normal effect: positive visual phenomenon (small colored circle, formed hallucinations) o Cerebral polyopia • Occipital stroke • Myelination tumor • Binocular diplopia: eyes together o Could be neuron o Can identify cause with cover test and deviation measurement. |
| Transcript |
So today we're gonna be talking about an unusual thing which is cerebral polyopia. "Opia" means "the eye", and "poly" means "many", so we're seeing many of the same image, and so normally when we're dealing with a multiple image, we're talking about diplopia and patients who have double vision. The major branch point is whether it is binocular, meaning using the two eyes together, or monocular, which is each eye alone, and in the "Monocular Diplopia" video you can watch how we kind of work through that. Monocular diplopia can be unilateral or bilateral, so the question we want to ask to differentiate these two is does the double vision go away if you cover either eye, and if it does go away with covering either eye. If it does go away with covering either eye, that suggests that the problem is monocular, and that can be horizontal or vertical misalignment, and that can be neuron. So the binocular diplopia people, they're kind of an easy one because we can measure them, do the cover test, measure their deviation and figure out what actually the problem is in terms of the binocular diplopia. The monocular is actually a little bit harder because the unilateral monocular, that's like problem in your eye, usually dry eye or refractive error, cataract, corneal disease, retinal disease. This is intraocular that causes monocular unilateral. The dangerous one, and the one we want to talk about today is cerebral polyopsia. So when we have bilateral but monocular diplopia, that could still be central nervous system, that could still be occipital in origin, so even though it seems like a monocular diplopia can't possibly be neuron and that is intraocular, it's only the unilateral monocular that we can say that about. The bilateral monocular from cerebral polyopia will persist even if you cover either eye because it's a cerebral event. So to differentiate these two we want to kind of get an idea of what they're seeing. So in patients with the monocular diplopia unilateral or bilateral from an intraocular cause, they often describe the second image as a ghost image superimposed on a clearer second image. In contrast patients with binocular diplopia usually have some sort of separation between the two images, and the images are clear. And in cerebral polyopia, they see the same image, it's kind of repeated over and over again, and so that repeating process could be palinopsia, they see the same image over and over again, and that's why it sometimes can be described as triple-opia, or four images, or five images, or ten images, but sometimes it really is only two images and really is diplopia, two images. And so we'd like to get a handle on "is it two equally clear images", and so the thing we're going to be looking for is a field defect, a cortical lesion of homonymous hemianopsia, but also things that could cause cerebral polyopia, a stroke or a seizure. So what we're looking for in the stem is that "I see double", it's bilateral but monocular, the images are separated and equally clear, or there's three of the images or four or more of the images, and they have some risk factor for intracranial disease, and the thing we're worried about is seizure. So normally occipital seizure produces positive visual phenomenon lasting seconds at a time, usually small colored circle, formed hallucinations, but sometimes the seizure produces cerebral polyopia where they see two of the same thing or ten of the same thing and that can be a form of polyopia, and other things in the brain obviously could do this: an occipital lobe stroke, the myelination tumor. It doesn't tell you what the cause is, it just tells you that it's a cerebral thing in the association cortex or in the visual cortex. So even though, in general, diplopia can be divided to monocular and binocular, binocular being "could be neuron", unilateral monocular "not neuron". The one you need to know about is bilateral monocular, especially if the two images are equally clear and there's some intracranial risk factor (stroke, seizure, or tumor) that could be producing cerebral polyopia. |
