| Affiliation |
(AGL) Chairman, Department of Ophthalmology, The Methodist Hospital, Houston, Texas; Professor of Ophthalmology, Weill Cornell Medicine, New York City, New York; (PD) Class of 2021, Baylor College of Medicine, Houston, Texas |
| Transcript |
Today we're going to be talking about ophthalmic manifestations of Parkinson's Disease. As you know, Parkinson's Disease is a neurodegenerative disorder and it affects the basal ganglia, because it's dopamine depletion of the substantia nigra. And what that means is that the patients are going to have dysfunction in their motor system. And for us in Ophthalmology, what that means is that the patient's blink rate is going to be decreased, they're going to have a stare, they might even have lid retraction, and of course that will go with their masked facies. That decreased blink rate causes dry eye, which is common in other patients who are their age, worse; so dry eye is super common. In addition, the supranuclear control mechanisms for convergence are going to be decreased. So the most common cause that we see of the double vision in Parkinson's Disease is convergence insufficiency. So when you're looking at something and your eyes have to converge, then you have to diverge, and if you have an insufficiency of your convergence, you'll get binocular horizontal diplopia, but only at near, because it's an insufficiency of the convergence. So we should test for an exotropia at near that isn't present at distance; the ductions and versions will otherwise be full. They might also have decompensation of pre-existing phoria, so if they had a previous tendency for their eye to drift, the breaking of the fusion might cause that diplopia to come out. And finally because their eyes don't move properly, their saccades might be a little jerky, they're having a difficult time moving their eyes, we probably should use single-vision readers for those patients, so we don't want to use a bifocal or trifocal or a progressive in a Parkinson's Disease patient, because they already have problems such as orthostatic hypotension, some of their medicines might make them unsteady, and so they might suffer a fall. And so we really don't want to use a bifocal and trifocal in a Parkinson's patient because they're not going to be able to use the segment very well. In addition, they've got this stooped over posture so their glasses are constantly falling down their nose, and so it's probably better to use single-vision readers for those patients. The most important thing is to make sure they can look down. So patients who can't look down, as opposed to them looking up - a lot of older patients can't look up and it's supranuclear. In Parkinson's patients, that seems to be accentuated, they have an up-gaze paralysis that's supranuclear. But if they have a downgaze supranuclear palsy, then that's probably going to be Progressive Supranuclear Palsy. So instead of having Parkinson's Disease, they have parkinsonism, secondary to Progressive Supranuclear Palsy. So always test the downgaze in patients that have Parkinson's Disease, especially if they are unresponsive or poorly responsive to levodopa-carbidopa combinations. So in summary, Parkinson's Disease, a very common motor disease, and it comes to us as worsening dry eye, decreased blinking, or increased blinking (blepharospasms). And sometimes they have apraxias. So the apraxia, for example, might freeze their gait, so they get stuck with their walker, they can't get going, they can't get back to walking, they're just frozen. And the same thing can happen with eyelid opening, so they have eyes closed lightly like this. It's not really ptosis. And if they open them with their hands, or use some sensory trick, like touching their eyebrow, or doing some sensory trick, the eyes just open up. So apraxia of eyelid opening, and blepharospasm, are both seen in Parkinson's Disease patients and other movement disorder patients who have dystonias. And then dry eye, super common. And convergence insufficiency, please don't give them a bifocal or a progressive of a trifocal to a Parkinson's patient because they might fall. |
