What’s New With Disc Drusen

Elizabeth Steele, OD, FAAO talks about what’s new with Disc Drusen.

Cara Moore: Hi everybody. Thanks for watching Optometry TV. I’m Cara Moore joined now by Dr. Elizabeth Steele. Thanks for being here.

Dr. Elizabeth Steele: Thank you.

Cara Moore: So we’re here to talk about Disc Drusen and let’s start off with some new technologies.

Dr. Elizabeth Steele: Right. So Disc Drusen is sort of an age old problem. We’ve known about Disc Drusen for decades, but probably the most common reason we discuss it or the thing that keeps us, our awareness heightened about Drusen is that it can often mimic Disc Edema. And so, you know, diagnostically anything we can do to have a more accurate picture of what’s really going on can actually can prevent stressful conversations with the patient. It can prevent invasive tests, you know, brain imaging, lumbar puncture, things like that. So what’s unique is that when we really look carefully at the recent literature, we can, we can be more confident using our OCT, our Spectral Domain OCT, the technology specifically, either a swept source type OCT where we were using longer wavelengths to get deeper penetration past the inner layers of the retina down into the sclera. But more commonly what, what optometrists have access to is called Enhanced Depth Imaging OCT. So what we’re doing is we are sending the signal, we’re focusing the signal deeper into the retina. We’re able to get a really good resolution of the sclera, of the globe and its shape. We can look if, we can, you know, if we’ve got a situation where there may be very subtle Disc Edema or Disc Elevation and we’re not really sure clinically if it’s Drusen or if it’s a crowded optic nerve or if it’s actually just subtle Disc Edema, we can use this enhanced depth imaging to get a very high resolution look at the shape of the globe. We can look for what’s called scleral flattening. In the case of elevated intracranial pressure, like we see with papilloma, which is what we hope it’s not. Ultimately when we’re sitting there talking to a patient or a parent of a young patient, in the case of an intracranial pressure that’s elevated what we’re going to see on this OCT scan with enhanced depth imaging, is a push forward and anterior push of the sclera and it’s going to look flat just like it would if we were to order an MRI. So it’s unique because we have it at our fingertips. It’s not invasive, it’s not expensive and it can prevent unnecessary testing and stressful conversations. So that’s really what I would focus on the most in terms of technology.

Cara Moore: What about some of the newly suggested associations for Disc Drusen?

Dr. Elizabeth Steele: So one of the things that is really published in 2016 so not entirely new, but something that should kind of heighten our awareness to is Disc Edema itself. So it’s kind of funny because we think of them as a, and we kind of clump them together clinically because they can appear as one another, Disc Drusen can look like Disc Edema. Disc Edema can actually be Drusen. And so we’re always trying to differentiate the two. But in 2016, a group of folks published a really nice study of 300 patients. They followed these patients over 25 years and that group of patients all had resolved papilledema, so they all had resolved, you know, Disc Edema on both eyes from intracranial pressure. And, in that group, what they found over that 25 year period is that about 19% of them actually had Drusen. And that’s about 10 times the normal population. So ruling out coincidences, which they did, what that tells us is that there’s a relationship between these things and it really kind of goes back to the mechanism of Drusen. There’s a problem with axonal metabolism and transport. The nerve fibers are just really struggling to do what they’re supposed to do. And so you get these deposits of calcium and things, and so it’s not clear if the association is, you get Drusen, so you’re predisposed to, you know, fluid in the retina or in the nerve or if it’s the other way around. But it’s just one of those things that we want to continue to look for, in addition to the vascular association they’ve seen.

Cara Moore: What do you say to clinicians who may be watching saying, well, what do we do? You know, because, you know.

Dr. Elizabeth Steele: And that really is the question. So, the tough thing with Drusen is that, you know, we think of it as a benign condition because it wasn’t papilledema. You know, we’ve ruled that out with our, with our testing, with our high definition OCT. But once we get the diagnosis of Drusen, it’s really important to realize that that is its own condition that needs to be followed, and it’s not relatively benign. It’s relatively benign compared to a brain tumor or intracranial pressure that’s increased, but it’s not benign in that it causes cell death of the axons of the optic nerve. And that means we’re going to get visual field defects. And so all we know to do, and there’s really not good evidence that for decades we’ve known that maybe we can reduce the intraocular pressure. Maybe we can put them on a drop or something that’s anecdotally neuroprotective and there’s really not good data there. But, there is some substantial, you know, relatively anecdotal but clinically relevant data that we should just reduce the IOP. So that’s what clinicians will typically do is put the patient on an IOP lowering drop. Even if the patient’s pressure is normal, we can do that. Just like if, if it were normal tension glaucoma, we would do the same. So again, there’s not a lot of data that we should be doing it, but the data that’s there says, Hey, this might help and it probably wouldn’t hurt as long as we’re not, you know, picking a drop that would otherwise cause an adverse event.

Cara Moore: All right, well, a lot of good information there. We appreciate you being here, Dr. Steele. Thanks so much.

Dr. Elizabeth Steele: You’re very welcome.

Cara Moore: And thanks for watching Optometry TV.

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