Daniel Rubenstein, MD, Oculofacial Plastic & Reconstructive Surgeon at UNC School of Medicine in Chapel Hill, NC talks about a new treatment for NK to restore blinking.
Interview conducted by Ivanhoe Broadcast News in 2024.
What is NK?
Rubinstein: NK stands for neurotrophic keratopathy or neurotrophic keratitis. And it describes a condition in which the nerves that provide sensation to the surface of the eye and specifically the cornea, are damaged in some way and not working properly. That damage can occur due to any one of a number of reasons can lead to a whole host of problems with the eye and specifically the cornea.
So we have a patient who has this condition. What are the first signs of the eye which may be seen?
Rubinstein: Well, neurotrophic keratopathy tends to occur after an infection and episode of inflammation of some sort, or having had some more major medical problem having to do with the head and neck, taken care of whether that’s a tumor that was removed by surgery, radiation, some trauma that cause nerve damage in some way. So sometimes there’s some facial numbness that comes along with that. Sometimes the damage is localized to the surface of the eye. Generally, what happens is the eye starts to turn red, it may tearsome, and the vision becomes blurry. Those are frequently the first signs of trouble.
Do people mistake this for something else? And what could that be?
Rubinstein: Sometimes people with this problem are diagnosed with dry eye. I mean, that can happen at the same time. It’s part of the same problem. The major difference between one of the mild dry eye and neurotrophic keratopathy or neurotrophic keratitis is the underlying nerve damage that contributes to neurotrophic keratopathy. Whereas patients with dry eye don’t frequently have that nerve damage associated.
So, specifically, what happens to a person’s eyesight in the different variance?
Rubinstein: Sure. Well, what happens in the process is the sensation to the cornea, which is the clear window in the front of the eye that lets all of the light into the eye and helps to focus that light on the critical structures in the back of the eye. The sensation to that structure is diminished. And that does two things. One is it diminishes the natural reflex that everybody has for blinking, which helps to moisturize, lubricate, and clean the surface of the eye. So with less blinking, there’s less tear production, and the eye does in fact dry out. And that can lead to defects on the surface of the cornea, irregularities, infections, and scarring. The other part of the process is that the nerves which provide sensation to the surface of the eye and the cornea release important proteins that help to in and of themselves maintain the health of the surface of the eye. So when those proteins are no longer being created by the damaged nerves, any damage that does occur on the surface of the cornea, let’s say from that dryness, is very difficult for the eye to repair. So the cornea tends to break down. And again become infected, get ulcers and scars which causes very cloudy and blurry vision.
So is there any pain from it or is the pain only come from the side effects of it?
Rubinstein: Well, people can have different degrees of loss of sensation and somebody who has completely lost sensation. The whole process may be 100% painless because those nerves just don’t function at all. Most patients are somewhere on a gradient where they have some sensation but not quite as much as they should. And the they may feel some irritation or pain, but it’s not really as much as you would expect given how severe the damage can be.
What is the standard of care?
Rubinstein: Currently, or I would say previously, the standard of care has been supportive for neurotrophic keratopathy. That would be topical eye drops to help lubricate and moisturize the eye to prevent damage. Consciously trying to think about blinking, even though it may not be reflexive anymore for patients that require surgery due to progressive damage to the surface of the eye that includes surgical procedures to help to permanently close a portion of the eye to help protect it and keep it moist. There also have been some eye drops that have been brought to market recently that aim to replace some of those important proteins that help to maintain the health of the surface of the eye. All of those are supportive and none of them really get at the underlying problem, which is the nerve damage itself.
What is corneal neutralization?
Rubinstein: Corneal neurotization is a surgical procedure, and it’s really the first surgical procedure, I would say, that aims to correct the underlying cause of neurotrophic keratopathy. And it basically describes a procedure where healthy nerve tissue is brought back to the cornea. A healthy nerve is coapted, or a graft is used to bring healthy nerve tissue from a nerve elsewhere in the face to the surface of the damaged eye that has damaged sensory nerves in it. And those nerves actually grow back into the damaged cornea and replace the nerves that are no longer functioning. And it helps to restore sensation, restore the blink reflex. And those nerves also start to release some of those important proteins that we had discussed that maintain the health of the surface of the eye.
How does this work?
Rubinstein: So we had discussed a number of possible underlying causes for neurotrophic keratopathy in the first place. If the damage is very local, just on the surface of the eye and in the cornea, there are often nerves either right under the eyebrow or at the top of the cheek on the affected- even on the affected side that are functioning properly. And those nerves can either be directly mobilized and brought down onto the surface of the eye and sewn in place. Or a graft can be used to tap into those healthy nerves and then tunneled onto the surface of the eye and attached there so that the nerves can actually grow into the cornea itself. In cases where the damage is due to removal of a tumor, trauma, or there’s more extensive damage to multiple nerves on that side of the face, it may be necessary to bring nerve tissue from the other side of the face, in fact, and use a long graft in order to do so.
Is it all minimally-invasive?
Rubinstein: I would say it’s fairly minimally-invasive. The incisions are usually pretty small for this procedure. In some cases, it can even be done without a visible skin incision. In other cases where skin incision is necessary, they’re often fairly small and can be placed in locations where they hide quite well. If a nerve graft needs to be taken, it’s often taken from the leg. There’s a specific nerve called the sural nerve that most surgeons use for these nerve grafts. That incision usually is a bit larger and it’s down by the ankle. But as far as scars that are left on the face, I would consider this to be pretty minimally invasive.
So can it stop visual loss but can’t reverse it?
Rubinstein: In some cases, yes, interestingly. So vision loss from neurotrophic keratopathy occurs due to ulceration and scarring of the cornea. In severe cases that can actually cause the wall of the eye to lose its integrity and for the eye to perforate. In those cases, vision- restoration of vision may not be possible. But where a scar has formed due to a previous infection or ulcer, the- those proteins that the nerve release can help to decrease the degree of inflammation on the surface of the eye and helps to remodel that scar to clear it up a bit and help restore some vision.
And how much can be restored – 10%, 20%?
Rubinstein: That’s a good question and it’s very situationally dependent. In general, research and studies have shown that younger patients who have this procedure done for neurotrophic keratopathy tend to have more vision restored than older patients and tend to have some more success on that front. But a lot of it depends on the severity of the damage at the time of surgery. So one interesting direction that current research is pushing with us is to encourage surgeons to consider this procedure, which was until recently considered very experimental, to consider doing it for patients with more mild changes to help reverse those changes before they become more severe and irreversible.
This can be life-changing, right?
Rubinstein: It could be. For somebody who’s had their eyes sown shut with a procedure called the tarsorrhaphy, not able to see out of it, potentially, for years with severe damage and recurrent infections. Having the prospect of reversing that damage and at least mitigating those infections really can make a big difference.
Is there anything we’re missing that you want to add about this?
Rubinstein: I definitely would like to acknowledge the team that I worked with here to accomplish this surgery. I worked with an excellent ENT, facial plastic surgeon named Dr. Matthew Miller, who works here at UNC as well. And my colleague in the ophthalmology department, cornea surgeon, Dr. Hussain Bana. The three of us work together on our neurotization team here. And I think our teamwork really has helped us to pool our expertise and accomplish this. I’d also like to acknowledge the work of everyone who came before me and working on and really refining this procedure, because we’re certainly not the first to do it. But I think we’ve been successful in bringing this procedure to our population here in North Carolina.
END OF INTERVIEW
This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc. or any medical professional interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult your physician on medical matters.
If you would like more information, please contact:
Kendall Daniels
Kendall.daniels@unchealth.unc.edu
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