VLOG: NeuroOp Guru: Multiple Sclerosis associated with reduced choroidal vascularity indicating uveal component to MS

Andrew Lee, MD, and Andrew Carey, MD, sit down on another episode of the NeuroOp Guru to discuss Multiple Sclerosis and its association with reduced choroidal vascularity.

Video Transcript

Editor's note - This transcript has been edited for clarity.

Andy Lee, MD:

Hello and welcome to another edition of the NeuroOp Guru. I'm here with my good friend Drew Carey from Johns Hopkins. Hi. Drew.

Drew Carey, MD:

Hi Andy.

Andy Lee, MD:

And today we're going to be talking about Multiple Sclerosis and its possible association with reduced choroidal vascularity that could indicate uveal component to MS. And Drew, why is this even important to us?

Drew Carey, MD:

Well, we know patients with multiple sclerosis often have visual manifestations. We talked recently about a good paper looking into that, and we know about half of patients are going to have optic neuritis during the course, and even maybe 25 to a third of patients, that's their first symptom. And those patients with optic neuritis definitely have thinning of their inner retina and the nerve fiber layer in ganglion cell. And some studies have looked at patients with MS who've never had optic neuritis, and they do show thinning in those layers compared to healthy controls. And patients with progressive MS, even if they've never had a clinical visual event, do show progressive thinning there. And so we know we can use those tools to help monitor patients and their disease course. But as we've developed better imaging techniques and ability to look at retinal perfusion and choroidal perfusion, we wonder, could there be an impact in other layers and other vascular areas in the retina? We do know that patients with multiple sclerosis can develop a retinal vasculitis, and perhaps some of their CNS manifestation is actually retinal vascular–not a retinal vasculitis, but a CNS microvasculitis. And so these authors wanted to look and see, because the choroid is a highly vascular layer. Can we see changes in MS patients compared to healthy controls in their choroid

Andy Lee, MD:

What did they find in this study?

Drew Carey, MD:

Yeah, so this was a cross sectional study at a single institution in China, and they took 37 patients with MS who've never had optic neuritis and don't have any other significant eye diseases, no retinal pathology, no glaucoma. They did not have high myopia. And they took 74 age matched healthy controls with similar requirements, and they did swept source OCT imaging and OCTA. And the advantage to the swept source is the wavelength of the the scanning laser is a little bit different, and so it penetrates better through the RPE into the choroid. And it's a much faster technology, so you can get very wide views of imaging and repeat them, because you have to repeat them for OCTA to see if there's changes in the blood cells as they move through the vessels. And what they found is they did see in MS patients, compared to the healthy controls, that there was reduced vessel density in the choriocapillaris, which is the most inner very fine layer of the choroid that really delivers nutrients to the RPE and through diffusion to the photoreceptors outer segments and cell bodies. Because those are not perfused by retinal vasculature. And they also showed that the percent of blood vessels making up the choroidal volume, term the choroidal vascular index, was reduced in the MS patients compared to the healthy controls. What was really of interest–structurally, they did not see any changes. So the outer retinal thickness was the same in MS patients and healthy controls, and the choroidal thickness was the same in the MS patients and healthy controls. So we know that something is happening to the choroidal vasculature and the proportion of how much of the choroid is made up by blood vessels versus other tissues in these MS patients. We don't know, is it chicken or egg, although we don't have a good reason to think that they would be preexistingly different and predisposed to MS from that reason.

Andy Lee, MD:

What do you think the take home messages for our audience is from this work?

Drew Carey, MD:

I think the take home message is, this is an interesting research finding, and it may be that the ophthalmologist is going to play a stronger and stronger role in the diagnosis and monitoring of patients with multiple sclerosis as this technology becomes more widely available. Or that the neurologists are going to be using this instrument in their clinics to screen the patients, and they may be finding other incidental abnormalities that they're going to need the ophthalmologist to then evaluate the patients for. So either way, I think it means that we're going to be busier.

Andy Lee, MD:

Well as always, fascinating insights into this interesting study. And this concludes another edition of the NeuroOp guru. Thanks Drew!

Drew Carey, MD:

Thanks Andy!