During this live webinar, we will discuss the spectrum of neonatal and pediatric corneal opacities and their effects on childhood visual development. We will also highlight the importance and key differences between adult and pediatric corneal transplants and review alternatives to corneal transplant surgery in high risk pediatric patients.
Lecturer: Dr. Shazia Ali, Ophthalmologist, Texas, USA
Hello, everyone. My name is Dr. Shazia Ali, and I am extremely honored to be able to present this very important topic, which I think is typically overlooked due to just how few specialists are able to treat this type of disease.
Today I’ll be speaking about pediatric corneal opacities and with special emphasis on corneal transplant surgery. I’m truly honored to be able to speak to such an international audience and I do realize that many people have a very different background coming to this talk today, so I’m gonna go over the basics today and we can delve more into details as we move forward. I did receive a number of questions, which I hope to have addressed during the talk today, but at the end there will be a question and answer session in case there are any remaining burning questions on your mind. I’ll also leave my contact information at the end. That way you can contact me directly.
So looking at pediatric corneal transplants, there’s a lot we need to cover today, corneal disease accounts for over ten percent of worldwide blindness So today, we will be looking at preoperative considerations, which patients we should be taking to the operative room, which types of surgeries are good for pediatric patients.
Interoperative considerations, post operative considerations, as well as long term prognosis, and how to really improve the outcomes of our pediatric patients.
Now, points to consider pediatric patients and pediatric surgery is not the same as adult surgery, So it is really important to make sure that you are prepared as well as preparing the family for what they’re going to need. Not every corneal’s opacity requires corneal transplant surgery and we’ll talk about other intraocular options during the course of the talk today. Now a clear graph it does not always equal clear vision.
Unfortunately, unlike adult patients who tend to have excellent outcomes after Corneal transplant surgery, pediatric patients are so dependent on amblyopia and the development of their ocular dominance columns that They may not even have clear or good vision after an excellent clear graft surgery.
It is extremely extremely important to maintain an excellent and lifelong relation with the patient as family because you will be taking care of these patients for many years.
Now we should be screening for any sort of social circumstances whether the patient lives really far away, whether they’re able to afford or not afford any of their postoperative drops, and that could preclude proper post operative care, and that may want us and lead us to doing surgeries that may not be transplant surgeries, but other options in order to get the best outcome for these patients. Postoperatively, we absolutely need to have a plan in place with a pediatric ophthalmologist in order to perform amblyopia treatment as well as low vision treatment.
I’m currently a pediatric trained as well as a corneal specialist trained ophthalmologist in the US. So, therefore, I feel like I do have the unique ability to be able to manage not only their corneal disease, but as well as their amblyopia treatment.
What is success? Now success for pediatric patients is very different from success for adult patients. What we are looking at is developmental vision. It’s more important than corneal clarity.
Some of these patients will come in with a very dense capacities and they’re able to function much more than you’re able than than you would have expected for them. What we’re looking for is their global milestone development within a normal range? Are they able to walk on their own? Do they have ambulatory vision?
Are they able to see colors, contrasts, Those types of things are more important than a number on the Snellen chart. Now central visual acuity is one component of visual function, but children are really able to adapt well using peripheral cues. They can use contrast sensitivity and their spatial temporal relationships develop until about age eight. So we do need to make sure that we set expectations for our family for surgical success.
These patients and parents may be looking online looking at outcomes for adult formula transplant surgery and expecting certain outcomes. It’s really important to sit down and have a long discussion with them that their pediatric corneal transplant, their kids are going to have a different outcome and will require lifelong treatment and therapy in order to have maybe even a modest or very even low improvement in visual quality, but given that they are developing normally, they can have a quote unquote normal lifestyle.
Now, when we look at preoperative considerations, what should we be thinking about when we are dealing with these patients.
What we need to really determine is the diagnosis. And that is one of the most important parts for pediatric corneal transplant. Every scar, every opacity is not the same, This is the commonly taught really old school method of learning, congenital corneal opacities, this mnemonic known as stumped. But this doesn’t really look at the etiology or the cause for why this patient was born with a corneal opacity.
Old terms like sclerocornea, Peter’s anomaly, are really not even used anymore. What we need to be actually looking at is the etiology of where this corneal opacity is coming from. Now I stole this slide from Ken Nischal in Pittsburgh, one of his videos that I was listening to recently. I hope that’s okay with him.
But I think it does a really good job of looking at pediatric corneal opacities and dividing it into a developmental anomaly of the cornea versus an choir corneal disease. If you look at the column on the left, all of the diseases that are highlighted in green are really amenable to having a corneal transplant surgery, and we’ll talk about the types of surgeries. So these are the corneal dystrophy, Chad, PPMD, CHSD, x linked endothelial dystrophies as well as corneal structural defects due to dermoids, either isolated or part of Golden Har syndrome, If there’s a SIPB1 path cytopathology, so looking at things like congenital glaucoma, as well as development anomalies of the anterior segment.
So the term Peter’s anomaly that people have been talking about for many years has now been re termed to keridoid lenticular dysgenesis or Kild, so basically there is an abnormal separation between the anterior streg segment structures. If there are aridoclonal adhesions only between the iris and cornea, these patients tend to do very well with the corneal transplant surgery. Whereas if the lens fails to separate from the cornea or it fails to separate but fails to form or it fails to form at all like a primary aphasia, patients in red on that left column tend to do very poorly with any type of corneal transplant surgery.
So really determining what the etiology of the corneal lopacity is will depend and give you an idea of what the prognosis will be. Looking at the other side if there is a acquired corneal disease, these patients tend to do typically a little bit better, and that’s really because their vision may have developed normally within the first few years of life. These are patients that present to you in their you know, five, eight, ten teens after trauma, after infection, and that can really tell you what type of vision you are expecting, which can typically be much better, especially in patients with keratoconus or keratoglobus.
Now, in order to really determine what the pathology is, and where the diagnosis needs to come from. We need to do two types of biomycros skipping.
The first step is always getting a patient history when did the opacity start? How has the vision been developing? Were there any congenital or issues during delivery, during the prenatal period. Once the patient is born, in the neonatal period, we can do things like high frequency ultrasound or UBM, which is shown on the top.
This is similar machine to what you may be familiar with using a BScan, but it does use a high frequency probe, and that allows you to really focus on the structure of the anterior segment to a high detail. You can see in the top screen, if you look at those top two images, you may say this is a central corneal opacity, what could be the cause? But if you’re able to get a UBM, and you can usually use a BC scan, a normal B scan that’s used in the operating room, now the quality may not be as good as a UBM Pro, but you’re able to really determine if there are iridocorneal opacities, or if the lens is involved, and we know as we’ve discussed, that if the lens is involved, that does pretend a much poorer prognosis.
A higher in-depth imaging that we could consider as an anterior segment OCT. Now this is a little bit harder to come across It’s a little bit more expensive and not as readily available, but it does give you better quality cuts through the cornea, can really localize the pathology and determine if it’s full thickness, partial thickness, or how deep the corneal opacity does extend into the eye. And that can tell you what type of corneal transplant you may need for these patients.
Looking at one of my patients that I recently took to the operating room, This is a baby that was born with bilateral, corneal opacities, and we took him to the operating room for a UBM. Now his right eye looks like this image in the top left, you can see there are significant erdo corneal opacities, mostly peripherally, which does show that wanted to do a transplant on this eye, we would be okay, whereas in the other eye there’s much more significant irritable corneal touch, which may portend a worse prognosis And if there was any lens involvement, that would also decrease the chance of having surgical success for a corneal transplant surgery.
One excellent review article that I have run across recently was published in India with the group listed below, now most of what I will be going over for the rest of the talk really can be found in this in this publication.
It does go through all of the etiologies pediatric corneal disease and keratoplasty, so I really do want to kind of share this as a resource for anyone that is interested in getting an excellent background review on pediatric corneal diseases, as well as pediatric surgery, and we’ll go over some of these moving forward.
Now, as I mentioned before, kids are not just little adults.
They have different developmental needs. They have different outcomes with their corneal transplant surgery, so it’s extremely important to not treat the parents, the family, the patients, the surgery, or the post operative outcome. As though you are treating a young adult. Now the age of the patient does present an increased risk with corneal transplant surgery, we’ll go over what ages we can do types of surgery with, as well as the risk of amblyopia. If these kids are born with a central corneal they are gonna have a much denser amblyopia than if this corneal opacity developed later in life where they have already moved past the amblyogenic phase of their vision development. The timing of surgery is also extremely important for kids.
If you do kid if you do surgery at a younger age, there will be certain risk associated with that as opposed to waiting, there will also be different risks associated with that, which we will shortly discuss. The indications for surgery are also extremely different in adults who are doing penetrating keratoplasty, dissect demEC for things like fuchs dystrophy, pseudo phacic bliss keratopathy, mostly keratoconus, corneal lacerations, scars from infections, whereas in kids we’re looking at congenital diseases, so the indications are quite different, and that does make the outcomes very different.
These patients need an extremely close post operative monitoring, and that’s why you need to have an excellent relationship with the family because the eye drops, as well as any anti inflammatory regimen that these kids will be placed on will have an increasingly important impact on their post operative outcome. There is an extremely high risk of complications, with this type of surgery, and it is extremely important for the patient to have a strong social support network in order to ensure success and proper vision development.
Now, if we look at the indications and alternatives to surgery, it really depends on characteristics of the pathology when this corneal opacity popped up? Is it in one eye? Is it in both eyes? Or are there any alternatives you’ll be doing anything other than surgery for these kids.
So if we look at these three images, you can see a photo of a infotemporal corneal dermoid, as well as two central pornial opacity. So as you can see, the visual access is going to be completely obscured with some of these, and dense or the opacity, the more dense the amblyopia, whereas the patient with the infotemporal dermoid may only have irregular astigmatism which is causing a refractive ambly Opia. So the characteristics that we should be looking at is is this central opacity I’m sorry, is this corneal opacity peripheral versus central, and that can really tell you as to the timing as well as the type of surgery that the patient may need.
Is it localized? Is it only in the infra temporal, moderate, or is it fusely over the entire cornea, is this a mild opacity that can be treated with things like glasses or is it a dense opacity that needs surgery? And then finally, is this an isolated corneal issue, or are there systemic issues that we need to be concerned about? Patients with systemic disease tend to have a worse prognosis, as well as higher risk of anesthesia complications.
If we look at the age of onset, as we’ve talked about neonatal affordable opacities tend to be congenital in nature and have some torp type of genetic association.
The juvenile onset patients will do a little bit better because they past that ambiogenic age range. If there’s trauma that can also affect to what type of surgery and when to do it, And then later on in life, these pediatric patients can develop keratoconus and that does typically have a different set of associated surgeries that we could consider.
Now unilateral versus bilateral is extremely contentious. There is no consensus. I know some corneal specialists that that will not operate on a unilateral coronary opacity. If the fellow eye is normal with normal vision, they do not want to risk having any type of complications associated.
Whereas I think it does depend on the status of the fellow eye Some corneal specialists as well as pediatric specialists do want to do surgery on a unilateral eye because it does improve a chance of binocular vision through development of stereo.
Now it is extremely important to realize that even if you did corneal surgery on the second eye, the chance of the vision in that second eye being as good as the first eye is very, very low. So in that case it could be considered to be a, spare eye because the vision in one eye is still significantly worse the patients typically consider it monocular and functionally, and can be considered functionally blind, that does increase the chance of them having trauma in that second eye and that does potentially open the risk of having vision loss in the good eye. Even with bilateral corneal opacities, there is no consensus as to what to do for these patients?
Should we operate on the better potential eye? Should we operate on both eyes? Should we operate on the worst potential eye? A lot of corneal specialists will want to initially operate on the worst potential eye.
That way you are saving the better potential eye from any type of untoward complications that may pop up. Now in the future, if the initially worse eye that’s had the corneal transplant becomes the better eye with amblyopia treatment and therapy, then you could consider operating on the initially better eye in order to improve their binocularity.
Typically for surgery, the outcomes tend to be better after two to four months of age. So when these kids are born with corneal opacities, we do tend to want to wait until about to eight weeks before doing any type of surgery for bilateral patients.
Now the alternatives are always no surgery, We can treat amblyopia progression through things like occlusion therapy, atropine penalization, as well as treating any type of strabismic or refractive amblyopia has developed. We always love to have patients and glasses regardless of whether they have surgery or not. Scleral contact lenses, rigid contact lenses are very good for the irregular astigmatism that typically happens with these corneal opacities. And we can also delve into a septoral aerodectomy, also known as an optical aerodectomy, which we typically prefer not to have it in the superior or the temporal quadrant.
The types of surgery depends on the optimal timing.
Now, as we discussed the early visual rehabilitation, it must be weighed against increased risk of surgical complications in children.
Even though these kids may have dense corneal haze and a really poor red reflex, sometimes you’ll be really surprised at how well these patients are able to see They may not be able to read on the Snellen chart, but they may be able to function very well independently walking through their home. I had a patient with a complete that was able to identify colors in which we were extremely shocked at. He was an extraordinarily intelligent patient. So it’s things to think about should we be doing surgeries in these patients despite all the surgical complications that can develop. Things that I always look at are fixation, one eye or both eyes. How are the eyes aligned? Is there a sex sensory exotropia, sensory esotropia?
Is there any component of nystagmus? If all of these are quote unquote normal, I tend to wait on the surgery if I can. However, if the fixation is poor, if there is a significant strabismus, if there is a sensory nystagmus, those would be reasons to do surgery earlier rather than later.
So looking at the timing for surgery, when we’re looking at doing surgery early for patients, the real benefits of doing it is that we can have improved amblyopia management, and that is because we are able to early to early early intervene to have a rehabilitation of the clear visual access. These patients will be able to see through a clear cornea However, when these patients are young, the risk of multiple anesthesia episodes is higher and the risk of neurological consequences from anesthesia also goes higher. However, younger kids can sometimes get the eye drops in easier if they are infants. Parents are able to successfully put them in without having to fight them and that can be a real benefit of doing early surgery. When patients are older, we typically do want to do the surgery soon after any type of trauma and not really weight.
And if there is an infant that has an initial PKP, which typically we like to do within the first two to three months of life, the second PKP we like to do within two to four weeks of possible, However, on the other end of the spectrum, if the first eye is doing well, some corneal specialist will want to delay that and do the second eye much later. Now the benefits of doing late surgery would be there is typically an improved graft survival.
I typically tell parents that the highest risk of rejection as well as failure of grafts happens when kids are younger than five years of age. However, it is very dependent on the indication for surgery.
Typically, there isn’t an easier post operative course because you’re able to examine the patients with a portable or an actual slit lamp. Plus or minus easier adherence, some older patients will really fight you for the eye drops, especially in that toddler age, and it’s really difficult to get the appropriate anti inflammatory regimen in, so something to consider about the timing of surgery. It is very important though for congenital glaucoma, If you are going to do a corneal transplant, you need to achieve excellent IOP control in order to ensure that the endothelial cells are able to function well of the corneal transplant surgery has been completed.
Now, what are the surgical options, as we talked about pediatric transplants, they don’t always go well. So sometimes we do want to do something and sometimes we really just don’t want to do anything. Looking at thickness and the layers of the cornea were all familiar with the epithelial layer, bowman’s layer, stromal, The decimate’s member as well as the endothelium, and there are a multiple different corneal transplant options that we could consider for our patient The first is a penetrating kerdiplasty, as you can see here, red to red, you do a full thickness graph and put in at least sixteen up to twenty four plus Sutures in order to close this corneal lesion. The dalk graft is a deep anterior lamellar keratoplasty, so as you see here, In the image, you are removing the entire epithelial bowman’s layer as well as the stroma. Typically down to descemet’s as close as you can get to descemet’s membrane.
The DSAEK graft is an endothelial keratoplasty where you are using a little bit of stroma to bolster the thickness of this tissue, which is typically about forty to sixty microns of tissue. And it also includes a decimate’s membrane, as well as the epithelium, I’m sorry, endothelium.
in And finally, the DMEK graft, which is technically very challenging especially pediatric patients. This is a four to ten micron thick layer of tissue that only includes the decimate’s membrane, as well as the endothelium, and there’s no stroma associated with this.
If we look at alternatives to corneal transplant surgery, One of the common options is an optical iridectomy.
So this option will allow you to create a peripheral hole in the cornea, and I’ll go over the pros and cons in just a bit, but you can see here how we pull out part of the iris and create an opening, so the central corneal opacity in figure A is able to be bypassed without requiring a full thickness or even a partial thickness corneal transplant.
Now the benefits for this is that the peripheral light rays that will enter through this peripheral area through the iris can develop central visual acuity up to two thousand and forty. You’ll be really impressed by how well these kids are able to see with a peripheral opening in their visual access.
There will be a significant improvement with ambulatory vision. These kids are not able to see much more than light and that eye may actually be able to have useful vision develop and you can also use this as a temporizing measure in order to give yourself some time before you need to do a corneal transplant in these patients. We tend to avoid the superior half of the cornea or anterior segment, and that’s really because the eyelid will cover any type of optical opening. The same goes with a temporal cornea.
It can be a little bit difficult if there is eyelid covering that as well. So typically the inferior and the nasal quadrants are what we like to do this type of surgery on. There are two ways to do this type of surgery. One is using a vitrector, so it’s a vitrector assisted optical iridectomy.
You would want to go in peripherally and you can really customize how large or how small you want this opening to be using of a tractor. Now this does have a higher risk of cataract formation because you are entering an eye that still has a natural lens in. So you should weigh the risks and benefits of doing this type of procedure.
The alternative would be a four steps assisted, which is the image that I had just shown on the screen below, which is where you create a per opening in the peripheral cornea, and you will pull out the peripheral iris and create a large snip. Now you cannot control how large you can.
However, I think that it’s a little bit less predictable as to the opening size, and since you are creating More inflammation in the eye, there can be a large persistent hyphena, which is what we want to avoid in children. This incision also requires a suture And if you want us to close this with the tenor bike world, you will develop a cornea opacity in the area of the clear cornea, which is a reason some patients some some practitioners choose to avoid this option. The cons of this is that patient will have eccentric viewing. They may have some glare photophobia, there may be an unacceptable cause mises result. So this is a patient that you see over here on the on the top right where colleague of mine has created an infronasal sectoral optical aerodectomy, and we’ll move on and discuss this patient a little bit more in-depth in just a few minutes.
The other option, which is not as commonly used in the pediatric population, is the Boston keratoprosthesis.
It comes with a front plate, a back plate, a corneal graft, and a locking ring. So if we look at our animated corneat is a full thickness intervention and it does come in two types. Type one is full thickness to the cornea and type two does require a full tarcorophy and the implant goes through the lid. Now very, very few practitioners would recommend doing this type of surgery. Type two is not even indicated in any pediatric patient. Type one you could consider in pediatric patient, but there’s such a high risk of glaucoma development, as well as retricornial membrane and endophthalmitis.
It’s very difficult to monitor the progression and health of the eyes in these patients. So really in bilaterally blind patients, I think very few patients surgeons would even recommend this, and most of the outcomes do lead to very poor surgical prognosis and visual prognosis.
Now, looking at the indications for the different types of surgeries, if we look at penetrating kerdiplasty, which is a full thickness corneal transplant, In developed nations, we are typically seeing this type of surgery for congenital developmental disorders, as well as acquired non traumatic disorders. In developing nations, The sequelae of nutritional deficiency typically vitamin A is where we’re seeing these type of surgeries, as well as post traumatic scars.
Dulp, which is the anterior lamellar kerdiplac we can see and use with superficial corneal scars, lumbold dermoid, postherpetic scars, keloid, or even advanced keratoconus.
An endothelial procedure like DEC or DMac, we could consider for patients that have CHED, PPMD, pseudofocus pseudophakic, blisscare topathy, x linked endothelial dystrophy, post birth trauma decimate break, boiled corneal transplants as well. And the last two that we had just discussed, the sexual aerodectomy, as well as the Boston Capro you can see are used for very small indications.
Now the first surgical technique that we’ll talk about is the penetrating keratoplasty. As you can see here, it’s a full thickness corneal surgery.
On our animated cornea over here, it does require general anesthesia.
Now there are risks associated with the retrobulbar block, some people to do this in addition, I would not recommend it due to high posterior pressure, and these kids already have a higher posterior pressure due to their dense vitreous, which is still consolidated age. You could consider using a honan balloon as well as IV Manital to lower the posterior pressure, but make sure you do give it as an infusion over fifteen minutes and not as a bowl us. We should be positioning these patients trendelenburg in order to lower the posterior pressure, and we do typically tend to do a trephonation procedure, which is similar to the adults.
Most surgeons will perform a peripheral iridotomy. These patients due to a high risk of fibrin and inflammation in the anterior chamber are likely to go into angle closure, and a peripheral aerodotomy can help prevent the development of glaucoma from a secondary mechanism.
We do like to do initially a very small graft. These kids are at a much higher risk of needing an additional corneal transplant and if you’re able to increase the size and the diameter the trephonation moving forward, a smaller graph initially will allow you to do that. So this is again a staged procedure where you’re thinking about the long term excess of the eye health and not just one surgery.
Typically, these patients will receive ten oh nylon sutures in an interrupted manner only, running contraindicated in very young children for a PKP. However, for keratoconus, you could consider a running suture technique.
Now, looking at the intraoperative considerations, these patients tend to have very low scleral rigidity, especially the younger you are. If you’re operating in the neonatal age range, this scleral rigidity is very, very thin. We always recommend Fluring a rings or a double Flurring a ring, Another option would be McNeil Goldman’s Glittle fixation ring. However, when you are suturing to the sclera to fixate with these rings, there is a scleral preparation risk, which is much higher than adults due to the due to this scleral thinness, so something to consider when you’re trying to pass sutures for these kids. They have a very small intrapal pupils space, so you always want to use a smaller sized donor tissue and you always want to consider the fact that these kids have a very narrow anterior chamber depth. When you’re trephonating, it’s very easy if you’re going full thickness with your tree find to actually hit iris. Which will cause a significant hyphena and AC reaction.
Now this higher posterior pressure that we were talking about, it can cause the iris to prolapse forward during the surgery, and we’ll talk about ways to combat that. The lens can also be extruded, and in very, very unfortunate cases, you could have a suprachoroidal hemorrhage, Over here on the right, you’ll see some options of flooring the ring for these pediatric patients, especially neonatal corneal opacities, you need to choose the absolute smallest size. Flour ring or ring that is available, or you could also consider the scleral fixation ring, the McNeilgoldenin that you can see below.
Now, for these PKP donor graphs, we typically wanna use a very small sized graph five point five to seven millimeters, Some surgeons will oversize by point five. I tend to like to oversize by one millimeter to give myself some more space to operate. And in terms of the graph tissue that is available, we do like to age matches as much as possible.
Some surgeons will limit their patients from four years to nineteen, I typically like to get the tissue as close to age to match the patient’s age as possible, but the most important thing is that the endothelial cell count is greater than three thousand cells per millimeter squared. And if you’re in a bind and you do have older tissue, as long as the end of count is within that range, you could potentially consider it. If we look at the average cell density by age range, you can see how the endothelial cell count decreases as we get older, which is why it’s extremely important to age match this tissue. If you are able to get a specular microscopy on the tissue before, you want to see things like the normal endothelium on the bottom left Now if there is a low density of endothelium, polymegasism, or goutet, you do not want to accept that tissue for your patient.
There were some questions about corneal tissue harvesting. In the US, we’re fortunate to have the IBank Association of America, which makes the process extremely easy for us. This is a website that you can go through. They’re really integral in ensuring retrieval, storage, tissue evaluation, donor eligibility, assessment processing and distribution is done up to extremely high standards, so we’re able to get the best tissue available.
When I get the tissue, from the IBank Association, it comes as three sheets. This is what I look at, the donor age, the death preservation time, as well as the storage media, why the patient died, what the expiration date is, as well as what the approved usages are for that tissue.
On the second page, I think it’s extremely important to look in the top left hand corner, you’ll see the endothelial cell density. Again, you want it above three thousand. You can also look at the slit lamp exam what they found to be very important for the epithelium, the stroma, if there’s any scars, how is the decimate’s membrane, and most importantly how is endothelium, they also tend to show a specular microscopy photograph for every for every patient that’s sent and you can really assess the quality of the endothelium before you implant this tissue in your patient.
It’s also extremely important to ensure that the serologies are all negative and to make sure that there is no infectious pathology that you are implanting into your own patient.
Looking at the surgical techniques for a penetrating keratoplasty neonatal patient, this is an excellent review article that I found online that goes over the sandwich technique. Now this is an extremely important technique for pediatric patients.
Usually within the first few years of life, if I’m doing a corneal transplant, what you typically want to do is remove a quadrant of the patient of the patient’s host cornea and sutrate back on itself as shown as figure A. Once you completely remove the host cornea and sutrate it back to itself, you can then place the donor cornea on top, suture that as shown in 1C in a completely different quadrant, at twelve o’clock, six o’clock, and nine o’clock, and actually looking at figure 1D, you can slip out the host tissue. This really prevents iris prolapse, lens extrusion, and the difficulties of high posterior pressure for pediatric patients. So I do highly encourage everyone that’s interested in pediatric keratoplasty to go over this sandwich technique.
Now this is a pediatric patient who came to me when he was neonate, he was born in our hospital. He ended up having a bilateral corneal transplants within the first few months of his life. As you can see, even with very successful corneal transplant. He still has a large sensory esotropia of that second eye, but he does have ambulatory vision and overall I think a very good surgical outcome Moving on to another patient, now this is an older patient, a ten year old patient who presented to me after a CAT scratch very severe infection.
To his left eye, he ended up having a full thickness cordial transplant very soon after. We tried multiple antibiotics, antifungals, antiprotozoa, nothing responded.
He ended up having a full thickness coronal transplant. And these kids as well as adults, if you do a corneal transplant in a hot inflamed eye, it’s most likely going to fail. So although his initial transplant looked great, he did require a second transplant, and now he’s seeing two thousand and seventy without any correction, and we are looking to get him hopefully into a contact lens sometime soon.
Looking at other types of corneal transplant, if we think about a DSAEK which is an endothelial keratoplasty, if we look at our corneal image on the top right, you can see that the inner lining of the cornea is removed and replaced. So doing things like, Chad, PPMD removing the inner lining of the cornea and replacing it with an endothelial transplant, you can have excellent outcomes and also decrease the risk of all the suture and wound related astigmatism. So the pros are it does eliminate the risks of open sky procedures with the PK. You can have rapid visual rehabilitation and early amblyopia treatment, you do decrease weakness astigmatism, so you can have better refractive stability, very low astigmatism for these patients, and also decrease the Sutra related complications.
Now it is very difficult to identify descemet’s membrane, especially if you don’t have an intraoperative OCT. These patients do have a shallow AC, which makes it difficult to get in and out of the eye as well as to get the tissue in the eye. These kids do not have much scleral rigidity, They do have a high posterior pressure, and you can have a high risk of iris prolapse again. Some surgeons do advocate the use of a sheet slide to get the tissue in and out of the eye.
Now post operative positioning is very hard. If you’re able to do this in a young patient that is not ambulatory, they may be able to do their operative care at home. Otherwise, you may need to admit them to the hospital in order to ensure proper positioning for the first three to five days after surgery.
Another really difficult thing is that re bubbling does require anesthesia for these patients, so we do need to look at the risk of anesthesia and multiple anesthesia episodes for these nations. We should always use postoperative shields to prevent inadvertent trauma, which can lead to graft dislodging in the immediate postoperative period.
The next procedure that we’re going to talk about is DME, very low number of indications for patients in the pediatric population, and that’s because there is no stromal tissue implanted, as you can see in the corneal anime, animation to the top right. This is just a descemet’s membrane and endothelial keratoplasty.
There is a very rapid visual recovery, less risk of rejection because there is no foreign stroma than the DSAEK procedure, which we covered, but it is a much more demanding surgical technique in both adults and pediatric patients. This does have a higher rate of endothelial cell loss about thirty three-fifty percent in comparison to the dissect procedure.
There’s also a higher risk of re bubbling and we just talked about how rebugly does require multiple trips to the operating room, so something to consider if we did want to do this type of procedure in a pediatric population.
The next procedure we’re gonna talk about is a l k, which is an anterior lamellocaridoplasty versus a deep anterior lamellocaridoplasty, as you can see here on the corneal animation, You’re removing the anterior part of the corneal stroma, as well as bowman’s membrane and the epithelium. There is a significantly lower risk of graph rejection and failure, up to about twenty percent it can be much higher when the endothelium is involved. There’s a decreased risk of wound dehiscence, decreased post operative astigmatism, but there are several suture related complications. However, sutures can be removed much earlier than a penetrating keratoplasty.
There are good visual outcomes with amblyopia treatment, more than eighty percent of patients can have excellent vision.
An intraoperative OCT can guide your surgical technique in order to get as far and close down to DesMA’s membrane as you can. Now there is a high risk of conversion to PKP and it can be as high as percent so it’s important to have backup tissue available for you. Big BubbleDalk, which is proposed by Enwar and his team. It is preferred in the pediatric Aconus population in these patients can have better than twenty forty vision at about fifty percent of patients.
If we look back at this patient that had this sectoral airdEC to me that I had discussed earlier. As you can see here, we have the anterior segment OCT which can highlight the level of pathology in this eye. It’s restricted to the anterior less than fifty percent of the stroma, which does allow us with the ASOC guided imaging to really know how deep to go with the surgery. So I was able to perform a successful AOK procedure for this patient as you can see in the top right. And he’s had some excellent post operative outcome, as you can see here, you’re able to really see into the eye. We were able to see the lens, able to see that the retina was normal, and his vision initially improved because of his peripheral aridectomy and now with amblyopia treatment, we’re really hoping that he’ll have excellent vision.
Initially, his surgery was done around five years of age. This was just performed a few months ago, and we’re looking forward to how much his vision can improve as he gets older.
This is another patient with an ALK procedure.
This patient has an infotemporal dermoid. As you can see here, it does completely obscure the visual access and extends through to the superior and the nasal cornea. He had an anterior lill melocaridoplasty procedure done here, which is why he has interrupted and running sutures, which I can perform. And he has an excellent post operative result. Now unfortunately, this eye has such high cylinder compared to the other eye.
He’s only able to tolerate glasses at this young age, but I’m hoping that once we’re able to get him into contact lenses, we can get him to have really excellent vision, but you can really compare the pre op to the post op and see how much clearer the visual axis is. Now not all dermoids or anterior chronial opacities require a lamellar care toplasty. You can just do a superficial care tectomy for very superficial dermoids. So the top two images shows a pre op and post op dermoid that I removed with amniotic membrane and the patient has healed very nicely. As you can see here on the bottom, there can be some residual corneal scarring, but this is easily treated with a glasses prescription.
Another option that we could consider in some patients is an ipsilateral rotational auto care toplasty, where we typically are looking at patients that are not candidates for PKP. There’s corneal opacity has to be less than four millimeters in the central cornea and they have to have a peripheral clear cornea. You want to do a trephonation size of eight to nine millimeters and decentrate the tree fine, so the peripheral edge of the cornea is close to the limbus. Now the central edge has to be three millimeters from the visual axis, and you want to rotate the opacity under the upper lid.
If you look here, I’ve included a citation of of a article that you can look at to really go through the surgical steps in order to provide this service to your patients. Now it may not provide good best corrected visual acuity is penetrating keratoplasty because there is a higher amount of post operative astigmatism, and that’s due to inadequate opposition of the central and the peripheral cornea. There’s a higher risk of wound leak, and if you combine it with the pupiloplasty, you may be able to really improve the amount of visual stimulus entering the eye. The benefits include retaining the host endothelium, and the stability of the endothelial cell population.
There is a reduced need of compliance of postoperative drops, as well as a decreased risk of cataract, glaucoma infection, and you can remove these sutures much earlier than a penetrating kerdiplasty.
Now let’s move to the last section, which is post operative considerations.
In these patients, what we should be thinking about is very post operative exams, we need to be seeing these patients at least once a week if not two to three times a week to ensure that their exams are doing well until early suture removal. Pediatric patients have a stronger inflammatory response due to increased fibrin So they are at a higher risk of iris corneal adhesions that can lead to devastating glaucoma.
Now they do have a much quicker healing time between the host and the door cornea. This leads to a contraction of corneal tissue and loosening of corneal sutures. Now these sutures can also form abscesses with corneal neovascularization, which will quickly within twenty four hours could lead to corneal rejection.
So it’s really important to get parents involved to be examining their kids daily with a Penlight. The parents are the primary caregivers seeing their kids every day and are the ultimate decision makers about what type of surgery as well as when to bring these kids in. So it’s very important to give parents red flags of when to return. They also need very frequent steroid drop administrations because there is a high risk of rejection. The parent should be counseled to do daily penlight exams, for redness, loose sutures, white spots, or photophobia.
The anti inflammatory regimen, I typically like to give my patient’s IV Methyl prednisone, one milligram per kilogram during the surgery, hourly eye drops the first few weeks with a very slow taper. You could consider prednisolone acetate, but for any regraft of a PKP in a pediatric patient, I like to do Durozol. I also like to add restasis or cyclosporin, You could consider tacrolimus, but it’s very poorly tolerated due to irritation profile. So I would hesitate to give it to a pediatric patient and you could consider a short course of oral steroids especially if you’re doing a combination cataract retina or glaucoma surgery.
Now these families do need to be counted on the risk of cataracts and glaucoma due to a chronic steroid use in their patients eyes.
Looking at long term considerations and outcomes, kids will have poor cooperation post operative exams and care. So going into this, everyone needs to be aware of this and counseled about that. It is very difficult to administer frequent eye drops in kids. Kids can rub their eyes, this can lead to woundy ascents, loose sutures, and frequent exams under anesthesia are required.
Make sure to start and initiate early and aggressive amblyopia treatment with glasses, contact lenses, and patching in combination with your pediatric ophthalmologist.
Looking at suture removal, it does require sedation in the OR. Any loose suture or neoniovascularization requires immediate removal. Desex sutures can be removed as early as two weeks after surgery, but it is age dependent. So infants you can start at two to three weeks after PKP and complete it by six to twelve weeks, one to two year olds, you can do six to eight weeks and so on.
Looking at the infection risk, there is a high risk of graph rejection after an early infection. And this can be due to loose sutures, wound dehiscence, persistent epithelial defects, as well as the fact that they are on high dose steroids, so we do typically tend to recommend topical antibiotics for a longer period of time. This is a patient who came in with a Mukio polysaccharideosis associated penetrating keratoplasty, as you can see here, really severe infection She had a choroidal that we had to drain and eventually did end up losing the eye. So this is a very significant risk that we can have associated with corneal transplants.
Now, the prognosis is guarded. There are lower rates of success in adult I would say less than fifty percent of kids end up having really excellent vision. There’s a higher rate of graph rejection failure up to fifty percent to eighty percent and the high risk of vision loss is from amblyopia even with a clear visual axis.
Now if you look at repeat corneal transplant, it is a cause common cause of graft failure, and it can influence the outcome of subsequent grafts. If you’re doing a repeat corneal transplant for a scar, you can have graft rejection and infection occur because of that scar. It’s better to wait more than six months from rejection episode, and even with the repeat transplant, there’s a high risk of complications like immune rejection, epithelial defects, and glaucoma. As you can see here, the graph survival time just decreases significantly as the patients get older and any type of irreversible immune rejection always causes a regrass failure.
So there are controversies.
Should we be doing immunizations after a graph rejection episode? Some people like to wait two weeks up to three months, and some people even say no immunizations for up to one year. And that’s because the immunizations could potentiate a graph rejection episode. I do recommend increasing topical steroids four weeks before the immunizations, and the best post operative anti inflammatory regimen is still unknown.
So I’d like to just wrap things up. Let’s go back to things that we should consider when doing these transplants, not every corneal opacity requires corneal transplant surgery. We need to redefine what success is for patients. It’s not a clear grasp because clear graphs do not always equal clear vision. It is very dependent on the diagnosis, as well as the amblyopia treatment.
We should, as a community come together to research and optimize outcomes in order to have the best surgical results for our patients, and I always like to provide support groups for my patients in order to allow them to connect to people around the globe that are undergoing some of the same things that they are. So I really want to thank CyberSite for the opportunity to discuss this topic with you And I do have my contact information here. I’m gonna pull up the question and answer and just try to go through as many as we can for the next ten minutes. And of course you are welcome to contact me. My information is at the bottom, and I’m happy to connect collaborate over anything.
Now I do see a few questions, which I’m gonna go over shortly.
Mr. Fard asked what is the most common corneal graft in children, PKP, DMEECRadalk.
I think internationally, as well as in the U. S. PKP is the most common, and that’s really because it’s the most technically easy to do this type of surgery. We’re doing a full thickness trephonation, we don’t need to worry about intraoperative OCT, which is typically not even available widely.
DEC and DemEC are very difficult, very challenging for the pediatric population because of the posterior pressure as well as the shallow interior chambers. And I think in my hands and I’m sure most surgical practitioners internationally, the penetrating keratoplasty is most likely the most common corneal surgery that we get.
The next question is what is the minimum age of donor and recipient for corneal graft in children. So the minimum age for the recipient, as I mentioned, for patients that are born with neonatal corneal opacities, so they’re born with these congenital opacities.
There is there probably are some practitioners that would argue to take these kids to the OR earlier. However, I like to follow the maxim that we do for pediatric cataracts, which have been going on for much longer, which is if it’s unilateral, we typically like to clear the visual axis by six weeks of age if it’s bilateral eight to ten weeks. So I tend to not want to take these kids to the operating room younger than two months of age. And I think most people around the US at least do the same, and that’s really because of the risks of anesthesia in the first few months as well as the eye and cornea does need to develop some rigidity to suture too.
The minimum age of donor tissue is typically around four years of age, so there is a mismatch in the donor as well as the recipient. But again, if the endothelial cell count is good, we typically do like to match these in order to get the best possible outcome. Now if you wanted to do surgery for a younger patient younger than two months of age, I think it’d be very difficult to get tissue at younger than four years of age, I’m not even sure I’ve seen tissue for younger than four years, and that may be just due to, again, the lack of rigidity and the difficulty harvesting in getting this tissue for these patients.
When do you remove corneal sutures in children post PKP or Dalk?
Again, for post PKP or Dalk patients, it depends on the age. I had a slide you, sorry, I had a slide a few ago, which goes over based off the age. The earliest you can start removing them are two weeks after.
Post PKP, I would say the most important thing to remember for PKP and Dulk is that we do need take these patients to the operating room in order to remove their sutures.
So unlike adults where we like to do a topography guided or astigmatism minimizing suture removal. When I take these kids to the operating room to remove their sutures, I am removing all of them at once. I’ve only had one case where the patient did actually dehisk while removing the sutures, and I had to just replace the sutures while I was there and bring them back within another few months. But the earliest I would do was two weeks, and then as, and that’s really because the younger patients, their cornea heals so much earlier than older patients. As the kids get into two, three, four, five, six, seven, and older, you can follow more of an adult regimen.
Do you remember Do you recommend the scleral flaringering during corneal transplantation? Absolutely. For every patient, I will do flaring a ring. I like either the single flaring a ring or the double flaring a ring. I would suture using either Viprole, eight zero role or a nylon suture in all four quadrants to the sclera, ensuring that there is no scleral perforation because if sclera is thinner, and you can actually use this to hang the sclera by putting some tension on those sutures and attaching it to the drape, and that can really provide a lot of counter traction as well as support during the surgical removal, as well as prevent collapse, which is very possible in these patients that have very thin sclera’s.
How many times would you consider repeating a quantograph after failure?
Personally, I think it really depends on the status of the fellow eye if the patient is monocular, if this is the only eye that they are using to see, and if they were developing good vision, you could consider repeating corneal transplants multiple times. It also depends on the social support as well as family support, if the family is very with it, if they are really willing to help, if they’re very motivated, if they’re able to get the drops in, would be more likely to do a repeat corneal transplant.
I recently had a patient. It’s a down syndrome patient who had what I believe initially was a neurotrophic d with a corneal ulceration. He’s had seven transplants already, and he may be eighteen years of age. And now he has developed a dometasteal in that eye. Now since his fellow eye has relatively good vision, I think we’re going to go with the corneal patch graft instead of a full thickness penetrating keratoplasty.
Because usually, once the cornea has been neovascularized, to that certain extent, anything more than one or two clock hour of quadrants of new vascularization, the risk of rejection goes really high.
Personally, I probably wouldn’t do more than about three to four, but if the family is is really motivated, I could be convinced to do more. In these patients, I really do like to use Durozol restasis or cyclosporine, as well as considering really strict perioperative steroids in order to prevent any future episodes of rejection and and having them to come back monthly for up to a year in order to ensure graph survival and success.
Do you remember, do you recommend keratoplasty if the patient has developed sensory and nystagmus? Absolutely.
Typically, if the patient is younger, we are able to get rid of the sensory in the stigmas if we’re able to rehabilitate the visual access. Now if the patient is older, for example, if there are eight plus I think the risk of nystagmus resolution goes down even if you were able to clear the visual access.
But as I mentioned before, there could still be beneficial outcomes in terms of spatial temporal visual development, binocularity and just really vision that we’re not able to quantify based off our typical smell and charts. So I would recommend doing it in a sensory nystagmus. Now again, it also depends on the on the fellow eye if the patient has a good second eye. It’s possible that you may not want to do that very high risk surgical procedure in a second eye and just monitor the sensory nystagmus.
The next question is do you recommend kerdiplaceli in a ticycle eye? I wouldn’t. Even if it’s an adult or a child, I would never do caretoplasty in the ticycle eye. It really depends on what the indications are for wanting this type of surgery, I’m much more likely to do a Gunderson flap, which is a conjunctival flap that covers the visual axis if there is significant ocular surface related pain a non healing epithelial defect. If there’s an infection, you want to get the infection controlled first.
And usually, entice eyes, the customization is not great to begin with. So doing a penetrating keratoplasty, which is a high likelihood of failure I’m not very enthused about that. I typically will like to either do a Gunderson flap or refer to an oculoplastic’s colleague to consider doing things like a nucleation and then placing a prosthetic eye in there with a scleral shell that has a much better cosmetic result than doing a penetrating kertoplasty in the ticycle eye, typically because the sclera and the size of the eye is not normal as well.
How long do you give topical steroids? I give topical steroids for life, so these patients are getting them hourly for the first few weeks. I give them antibiotic drops until Sutra removal at four times a day dose. And once the Sutra’s are removed, that’s the only time I to decrease it. And I usually decrease by one drop every three months, and you should see the patient before decreasing any type of steroid. The lowest dose I will ever keep a patient on is one drop of day of prednisolone acetate one percent There is some consideration for patients have keratoconus or other corneal ectatic disorders, which are less likely to reject to consider doing Lotimax. But I think that gets into more of an adult type of PDF sorry, adult type of corneal transplant, but you could consider doing low to max.
Patients that have ALK procedures are sometimes taken off their steroids, I don’t like to in the pediatric population just because it’s such a high risk. But if I am dealing with a pediatric pop pediatric patient that has transitioned to adult, we could definitely decrease risk of steroid complications by switching it to low to max or even off drops. When I’m seeing adults in my clinic as well, I feel very anxious to keep them off any type of steroid drop, and that just may be due to my own patient population demographics here. But even in adults, I like to keep them on steroids.
Do you prefer for Chad, I would recommend, so the question is for Chad, do you recommend PKP or DMac? If DMac you remove the host cornea.
So for Chad, I think it really depends on the extent of the disease. As we know there is CED one and CED two. It depends on how much corneal clarity there is. If there’s enough clarity to be able to score decimate’s membrane, as well as remove the endothelium, I would do a desect procedure if you’re able to get a measurement of the anterior chamber depth before as well, that may help.
And I would do a d sec procedure. DMEck, I am very hesitant to do in kids because of the high re bubble rate.
Now if the cornea is very opacified, then I would not be able to see and endothelial tissue being implanted into the anterior chamber, then I would opt for a penetrating keroplasty.
I think we have time for just maybe two more questions.
One question is can we use a smile lenticule in thin corneas or corneal ectasia as an alternative for adults? I I am not too familiar with using the smile lenticule for corneal ectasia.
I know that here in the United States, there are very few practitioners that use smile and it’s typically for treating different degrees of of myopia. I haven’t really been been familiar with the use of it for corneal ectasia, but it could, you know, definitely be something that we could look into.
Painful vascularized corneas, how do you manage that? It’s difficult. I think the vascularization isn’t typically what causes the pain. It’s accordial rejection, as well as failure, and then the secondary bolus care topography that causes the pain in these patients.
In kids, I tend to put them on neuro for any type of corneal edema that does develop.
I do switch them from a prednis loan rotate to Durozole, which is a much stronger steroid, and Durozole every hour is an extremely potent steroid. You do want to make sure to monitor their intraocular pressure very closely, but I think that does tend to calm down the inflammation.
You could always consider admitting the patients for IV steroids as well. And you could do a short course of oral steroids. I have reversed early immune rejection episodes of oral steroids with a medrol dose pack or solu medrol and younger kids, and some of these patients have done very well with that.
And last question, if a child having bilateral corneal opacities involving the visual access, do you go for bilateral optical aridectomy or just in one eye, if not going for a keratoplasty? That’s an excellent question. I think it depends on how large the corneal opacities are. If there is the old terminology of Peter’s anomaly that people like to consider You could do a bilateral optical aridectomy if the corneal opacity is limited to the central cornea, and the peripheral cornea is really clear. It would be really important to determine if there’s a better potential eye than the other and you could consider doing an optical aridectomy in both eyes initially to buy yourself some time to allow the visual stimulus to get into the eye for the vision to develop and do a stage procedure where you do a penetrating keroplasty later.
You could — I think I would initially do optical irredectomies in both eyes in order to optimize the vision development so that if you are planning for any type of stage procedure, you are more likely to have success with the kerdiplasty, as opposed to if the vision didn’t develop and you do a kerdiplasty when the kid is five, six years of age, you’re gonna have a much lower chance of any visual rehabilitation than if you had initially done bilateral optical aridectomy just to open up the visual access and allow the vision to clear.
I think that’s about it, and we are our time. So again, I do want to thank CyberSite for this opportunity and thank all of you that have joined from around the world. It’s very humbling and an honor to be able to discuss this topic with you. Please feel free to contact me with any questions, and I look forward to meeting a lot of you in person.