This lecture will introduce you to the topic of evaluation and management of paediatric glaucoma. Dr. Neely goes through the steps of evaluation, diagnosis, and medical/surgical management of pediatric glaucoma.
Lecturer: Dr. Daniel Neely
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DR DANIEL NEELY: Well, good morning. Welcome to our continuing Orbis webinar series. I’m Dr. Daniel Neely, long time Orbis volunteer faculty member, and a professor of ophthalmology at the Indiana University School of Medicine. Today we’ll be discussing the technical aspects when evaluating and managing pediatric glaucoma. This is our fourth topic in our series. We’ve covered cataracts and strabismus in several other series. And now we’ll continue on with this. This is our fifth global webinar, and I say global, because today you are joined by 269 other participants, representing over 75 countries. And throughout today’s discussion, we’ll be again inviting your questions. We have a couple popping up already, that I see waiting for us. And I’ll periodically take breaks to address those. And we’ll also be launching some questions. We want to get some feedback from you. As much as telling you what I do, I’d like to hear some of the things that you do. Because I think we can always learn from each other, and there are some great things to be gained. I’m going to launch us into our screen sharing at this point. All right. With our music. So, again, this is the evaluation and management of pediatric glaucoma. And we’ll go into our first poll question, right off the bat. I’d like to get a feel for what you do in your practice. Regarding pediatric glaucoma surgery, which of the following applies to you? I’ll read through these, and then we’ll launch the poll. One, I never perform pediatric glaucoma surgery, and I never will. Or I do not currently perform it, but I would like to, or three, I perform it occasionally, but would like to improve my technique, and four, I already perform it on a regular basis and I’m rather comfortable with it. So launching our first poll question here. And again, what do you do? One, I never perform this procedure and I never will. Two, I currently do not perform, but I would like to. And three I perform occasionally but would like to improve. Or four, I’m pretty much already an expert, and I’m just here to make sure that Dr. Neely is telling everyone else the right thing. All right. Very good. Most of us are in more or less the same category here. And I’ll share these results with you. Most of us are interested in being able to perform pediatric glaucoma surgeries, and some of us already occasionally do. Some of us never will. And a couple of us are already pretty comfortable with it. But this is really important, because as I’ve traveled the globe, pediatric glaucoma is maybe the most neglected devastatingly blinding disorder that there is. And I think by the time we finish with this webinar and provide you with a little bit more material, you can become adept at performing simple procedures like trabeculotomy, which truly avoid blindness for hundreds and thousands of children, if we all know how to do it. So moving on to our lecture, when we talk about glaucoma in children, most of us think of this. Primary congenital glaucoma, where we have a dysplasia of the chamber angle. But fact is, that’s less than 25% of what we see. These are children who have that sole dysplasia and no other abnormalities. Well, here’s a typical primary congenital glaucoma. You can see that this angle is anteriorly inserted. It has this very irregular scalloped outline. And at times, you can see a wispy fibrous membrane, anterior to that. What is classically termed a Barkan membrane. However, probably most of the glaucoma that we see in our practices is this. Secondary glaucomas. And these are glaucomas that are from cataracts, aniridia, uveitis, Sturge-Weber syndrome, anterior segment dysgenesis. So there are other disorders of the eye that we’re dealing with. Now, the classic triad is tearing, light sensitivity, and blepharospasm. Most of us know this. Keep in mind you need to remind pediatricians and primary care physicians that nasal aqueduct obstruction should not cause photophobia. So that’s a cause for referral. Before we pop into the surgical procedures, we’re gonna talk very briefly about the examination under anesthesia. Because this is critical to not only making the diagnosis, but being able to monitor these children over time. We need to look for Haab’s striae with the slit lamp, or even just holding up an indirect 20-diopter lens, you can get magnification. And then we want to measure the corneal diameter with calipers. And we want to do that horizontally, because it’s the most reproducible. Why do we measure the corneal diameter? Because children have very soft sclera, and it’s distensible. Normal newborns should be 9.5 to 10.5 millimeters. If the cornea is larger than that, you need to be very suspicious of glaucoma. Adults in comparison are 12 to 12.5. Some of these children that we see come in with very advanced glaucoma, and they can be 14 millimeters or larger. And that’s easy to tell, when it’s unilateral, as in this child. You can tell one eye compared to the other. But when it’s both eyes, it does get to be a little more difficult to tell, because you lose that frame of reference. Now, the Haab’s striae, once you stretch that corneal diameter more than about 13 millimeters, we get these splits, and that’s simply the endothelium giving way. It cannot stretch anymore. That’s when you get fluid in the cornea and that’s when you get the opacifications. The corneal enlargement, again, becomes corneal edema. And once we get this kind of edema, it’s very difficult to get reversal and significant improvement in the vision. Now, one of the nice things — we talked about this distensible sclera that causes corneal enlargement. One thing it also does is it protects the optic nerve. The scleral ring around the nerve is able to expand, and the eye inflates, and this protects the nerve from some damage. So we can see that the cup in younger children — less than 5 years, definitely less than 3 years — you can see that this is reversible. So you can have a very large cup like this, bring the pressure down, and that cup becomes smaller. Here is one of my examples. This is a hazy pre-op view. It’s hazy because the cornea is still hazy, and the child is untreated. Cup to disc ratio is around 6. 0.6. And then after the surgery, you get the pressure down. Cornea clears up. We have a better view. And now the cup to disc ratio has come down to about 3 or 4. So that doesn’t tell you if you’ve lost axons, but you can see that the cup size is definitely reversible, and that is something worth following photographically, with ret cam or other device, if possible. Talk about intraocular pressure — this is only one of several factors that we’re looking at. And sometimes this is the least important factor, when you’re deciding whether or not to do surgery. Pressures can be dramatically elevated, 40 or more, but keep in mind that normal for an infant can be in the low teens. So there are times when we’re operating on an eye, and the pressure might be 20. However, if you look at the other eye, the pressure is 10. So the relative difference is significant. So symmetry is important, when you have unilateral cases. Keep that in mind. Tonometry — lots of great devices these days. Makes it much easier. And from what I’ve seen, most of us now have access to one of these handheld tonometers. The Tono-Pen is the classic handheld tonometer. More recently, we’ve had the iCare. Some models of this can only be used vertically. There is a model that can be used horizontally. And you need to keep that in mind when you’re looking at this. Now, one of the issues that comes up is: Are these devices accurate? We’ve looked at this. We compared iCare, Tono-Pen, and then the gold standard, Goldmann tonometry. So we looked at about 59 children. Average age was 10. And we did this on both normal and abnormal eyes. And very simply, what we found was that — here’s Goldmann on the far right. This is right eye, left eye. Gold standard. And then in the middle column, we have Tono-Pen. Very similar. Not much difference between the Tono-Pen and Goldman, and then in the third column, we have the iCare tonometer. What do you see with the iCare? On average, it was running about 3 millimeters of mercury higher. Now, that’s not really enough to change what you’re going to do with someone, but it is something to be aware of. A lot of times in our clinic, because the iCare is easier to use, and doesn’t require anesthesia, topically, we’ll use this to screen people, but if I get a high pressure, I’ll reconfirm it with the Tono-Pen. So just keep that in mind. All right. So before we go on to medical and surgical management, I will take a brief look at our questions here. First question is: What precautions should one take while doing a lensectomy to avoid aphakic glaucoma? So one of our secondary glaucomas. Well, other than just doing a nice job cleaning up the retained lens cortex, I don’t know that there’s a lot you can do. I think the risk of glaucoma in children really depends on the size of the eye. Smaller eyes, certainly PHPV, those eyes are much more likely to get glaucoma, compared to a normal sized eye. The infant aphakia treatment study found that there was really no difference in infants, if they got a lens implant, versus were left aphakic. So there does not appear to be a protective aspect to having a lens in there. I think it’s simply the size of the eye which dictates whether or not they’re going to have glaucoma or be a glaucoma suspect. And that occurred, again, in about 1/3 of all patients from both groups. We have another question. Should all congenital glaucoma cases be evaluated under general anesthesia? Well, clearly it’s helpful. You don’t have to do it that way. But typically what I’ll do is I’ll see the patient in the clinic, have a pretty good idea what’s going on. Schedule it for surgery, not for examination under anesthesia. I’ll book time, an hour or so, to do a surgery, and then we do a brief examination before we move into the operative procedure in the operating room. So it’s kind of all done at the same time. Same thing with follow-ups. We tend to give a little bit of extra time to these, because you never know when an exam is going to turn into a surgical procedure. And it’s better just to have that buffer, just to expect that you’re going to be doing a surgery. All right. Back to our lecture here. Treatment options. Well, this has really changed. In general, though, medications — at least for primary congenital glaucoma — tend to be supplementary. With the secondary glaucomas, the medications can be the only line of therapy that you need. When I was in training, we mostly had beta blockers, pilocarpine, and Diamox. Maybe some iopidine. Over the last two decades, we’ve seen a great increase in the number of options we have. Now we have brimonidine, we have topical acetazolamide, the dorzolamide, we have the prostaglandin agents, and then we have all these combinations. So there are really some great options out there now. But there are a couple things to keep in mind. One: These infants, when you’re treating an infant, 10-pound infant is getting the same dose as a 200 or 300-pound adult. So when possible, go with the lowest concentration that there is. If it’s available. For instance, a beta blocker. Betoptic, betaxolol, comes in 0.25%. So use that instead of 0.5%. Also, especially in babies, you might consider punctal occlusion. Put the drop in. Have them occlude the puncta for about 5 minutes, also wiping away any excess, and you can avoid some systemic absorption. The big one to be cautious about, in my experience, is brimonidine. So it’s marketed as Alphagan in the States. Brimonidine is fantastic. However, brimonidine and perhaps to a lesser extent iopidine — these can really cause some problems with somnolence in particular. As well as hypotension, apnea — I’ve had some parents call me. 2-year-old, they get their Alphagan, and then they can’t wake them up for several hours. So I always avoid it in ages 2 and under, and I try to avoid it pretty much in all children 5 or under, or just those that might be small for their age. So those are my two big cautions there. Oral Diamox — I do use that. I tend to use it as a temporizing measure, until I can get surgery done. But there are times when you can keep it going for a sustained run. All right. So let’s get on to the fun stuff. Let’s talk about the surgery for glaucoma. Because this is really how we cure patients. The great thing about treating pediatric glaucoma: A lot of times you can do one surgery in a newborn, and that child is cured of glaucoma for the rest of their life. And that is a very rewarding experience. Because otherwise these children are doomed to blindness. And it doesn’t take much to avoid that. It’s very simple surgery. You just need to know how to do it, and you need some very basic supplies. So let’s try to get into that. We’re gonna talk about goniotomy, trabeculotomy, a couple forms of that, briefly about trabeculectomy, although I’m not a big fan of this for children, touch on tube-shunt implants, and cyclodestructive procedures. Now, congenital glaucoma. If you are born with a dysplasia of the chamber angle, where the aqueous flows out, it makes perfect sense to fix that. Goniotomy and trabeculotomy are the mainstays for those reasons. They’re interchangeable. Some research would suggest they’re equally effective, but it’s very difficult to compare. You cannot do goniotomy and trabeculotomy on the same population. Why is that? We’ll touch on that in just a second. But they’re both directed at opening that angle, taking care of that dysplastic angle, and restoring normal flow. The problem is, historically, each time you do this, you can open about 1/3 — I doubt 1/2 — but 1/3 of the angle. So it may take up to three surgical procedures with goniotomy and trabeculotomy to get the entire angle open. Before we start talking about that, though, we’re gonna launch back into our next poll question. And let me go ahead and open it up while we talk about it. All right. And I’ll open it up for you here. If you currently perform surgery for congenital glaucoma, what do you usually do? One, do you do only goniotomy? Two, do you do only trabeculotomy? Not trabeculectomy, but trabeculotomy. Or three, do you do either, depending on what the patient needs? Or four, pretty much do an adult-style trabeculectomy, or five, you do a tube shunt? All of these can work. There’s no right or wrong answer. But here’s what your peers are doing. A small contingent doing only goniotomy. So only trabeculotomies, and then we have the either/or, a little bit more there, and then not too surprising, we have a very large segment doing trabeculectomy. Why does that not surprise me? Because that’s something that we do in adults, and a lot of us have some reasonable comfort level with that, for that matter. Tube shunts. The reason this is probably low, I’m sure, is because of availability. And we will talk about that in just a little bit. And again, there are the results. Goniotomy, trabeculotomy, pretty equal. Goniotomy and trabeculotomy, depending, and then only trabeculectomy, or a small percentage doing tube shunts. So most of us are kind of in the same boat on this, I would say. Always reassuring to know that you’re not alone out there. Because none of us are. We all face the same challenges, the same difficulties, and we can always learn from each other. The goniotomy — the beauty of this is direct incision of that trabecular meshwork. Nice and clean. You can do these very quickly. It’s a matter of 5, 10 minutes to do a goniotomy. Can be just that simple. But you need to have a clear cornea. If the cornea is even the least bit hazy, once you get this lens on there, it becomes really hazy under the microscope. It’s just really hard to see. So you need a clear cornea. That’s why comparing it to trabeculotomy — maybe not fair. Most of the patients that we all receive, particularly in the countries where most of you are located, they don’t come in clear like this. So goniotomy might be more frequently a follow-up procedure, rather than a primary procedure. But the advantage is it leaves that conjunctiva completely intact. So if you need to go back and do trabeculectomy or tube shunt later, as a secondary procedure, you’ve got nice, healthy, undisturbed conjunctiva. That’s a nice plus. When we do this, it’s basically using either a specified goniotomy knife — some of these are irrigating. Others, you just take — what I do now — I used to use this irrigating goniotomy blade. And have the assistant push the fluid in. Now I pretty much keep it simple. Do it all on my own with a 25-gauge needle. Needs to be a little bit longer. Of course, it has to reach across the anterior chamber, to incise the trabecular meshwork. And then I have that on a viscoelastic cannula. And I don’t automatically put viscoelastic in, but I have it available in case the chamber shallows. And I’ll demonstrate that to you. I like to have some locking forceps on the eye, so the assistant can help rotate. Trying to spread out this angle we incise as much as possible. Because it’s difficult to reach across the nose, usually we’re doing this from 12:00 at the head of the bed, and then temporal. You can do it across the nose sometimes, but these are the easiest places to access, and therefore we’re usually incising inferior or nasal angles. Makes it very tough to get superotemporal with the goniotomy. As you hold that lens, we’re trying to incise right in front of where the blood vessels loop up from the iris root. And we’re maintaining our anterior chamber depth. We need to avoid the lens. So you do not want the pupil dilated. That’s one downside of going from an EUA to a goniotomy in the same anesthetic. You need to bring that pupil down, and in general, I try not to have these patients dilated. Because if you contact the lens capsule with this needle or knife, obviously that is not going to work out well, and you’re going to get a cataract. So let’s look at the video. Here’s the 25-gauge needle technique. Again, this is what I use now. And we have the Swan-Ganz lens, which I’m coming left and right modes — and now we can see that scalloped iris, now that the lens is on. Getting across that first third is kind of tough. You can see I direct it out around where the iris was. I didn’t go here over the pupil. I think that’s a smart thing. Reach peripheral. Once you get there, we’re making these little sweeping motions. Just anterior to where that iris inserts. You don’t want to cut the root of the iris. It’ll bleed. Sometimes there’s a little bit of bleeding. But this is why we want to cut just anterior. And you’ll see that as you cut, this whole thing is dropping back a little bit. I usually start in the middle. Sweep to the right. And then going as far as I can, you start to lose your visualization. There’s only so far you can go. And eventually it gets to be not safe to go any further. You can’t see. So then I’ll come back across, and we’ll start over here. But you can see how all this has opened up so far. Dropped back. There should be very little resistance when you do this. If you feel the needle grating against the sclera, you’re probably too deep. The depth on the bevel is usually about 1/2 of the bevel width. Maybe 2/3. Very little resistance. And here — so my chamber has shallowed. I’ve taken the lens off, and I’m going to inject that viscoelastic. You’ll see the iris moving now. So I’ve had to put viscoelastic in the eye, even though I started with none. Try to put the least amount that you can in there, because you’re gonna leave it in there. It’s very difficult to get it washed out at the end of the surgery. So I tend to leave it in there and just keep sweeping across. And then the last important point is… When you pull this needle out… Almost to the end here… Try to do this in a relatively swift manner, and staying over the iris. Again, avoiding that pupil area. And we’ve got viscoelastic in here, so it’s not going to collapse like it will, but there — once you get out — it does. So stay away from the pupil. Very simple, very elegant technique. And I think relatively easy for people to learn. But look what a clear cornea we’re using here. If you’re going to learn one procedure, it should be this. Traditional trabeculotomy. You can do this on any eye. They can be clear, they can be cloudy. It takes — similar to a goniotomy, it takes almost no instrumentation. These trabeculotomes come left and right. They probably cost less than $300 US. They’ll last forever. And you can treat any kid with congenital glaucoma, with this instrument. So if you’re gonna learn one thing, learn this. This video will be kind of stop motion, but just like a trabeculectomy, making a half — roughly half depth scleral flap. Based in the limbus. And then about a 2 millimeter radial incision that should be right across this blue-white junction. That’s the landmark we’re looking for here. This blue to white transition zone. That’s one reason why I do this under a flap. I think it’s easier to find this landmark if you’ve dissected partial thickness. And now we’re going down radially. Just one small shallow cut at a time. Because we’re looking for this. We’re looking for it to kind of open up, just anterior to this junction. That is Schlemm’s canal. We’re gonna identify that with this 6-0 prolene. And it’s been blunted on the end. It’s not sharp. You’re gonna thread that in, and you can strum it, and you can feed it in up to about here, and it lets you confirm that you’re actually in Schlemm’s, and that you’re not in the anterior chamber. Because you can be in front of the trabecular meshwork, sometimes. I like to have these in there, because when you get halfway through the trabeculotomy, sometimes the chamber collapses, and this helps you find the second side. I typically start with the trabeculotome going to the left. Going as far as you can, following the curve, and then you slowly rotate into the anterior chamber. There should be not too much resistance. If there’s resistance, you might be into the iris, or you might be into the cornea. The top bar is simply just to tell you where the bottom bar is. It’s merely a point of reference. It doesn’t do anything other than guide you and reference it. There should be a little bit of hemorrhage after that happens. But not a lot. Now we have that prolene in place, so we know right where the right side is. And, again, this one is curved to the right. They come right and they come left. Thread it in. If you go in too far and it won’t rotate, just back out a little bit. I find that that’s frequently necessary, particularly on the second side. You can’t quite bury this to the hilt and rotate it in. Second side, the chamber starts to shallow. Sometimes I will irrigate it with some VSS in there, to get it open. Other times you can do it without reinflating the eye. And then withdraw. And you’ve now done from about here to here, more than 120 degrees, probably. You can either leave this radial incision open or closed. I tend to close it. And then I tend to put one more suture across the triangle. And then I’ll just tack down the conjunctiva. Some people combine these two. Trabeculectomy, combined with trabeculotomy. That’s great for getting the pressure down short-term. Probably doesn’t stay too patent, long-term. So let’s go on. After I talk about 360-degree trabeculotomy, then I’ll pause and take your questions about these two techniques. Well, about 20 years ago, even longer than that now — 30 years ago — it was described using that same prolene, just threaded around Schlemm’s canal, either halfway and retrieve it, or all the way around, and have it come back out here. And then pull the ends, and you effectively use that suture to cheese wire Schlemm’s canal all the way around. Well, that’s great, and it can be very effective. And when I was first starting this procedure, I was pretty excited about it. And I used it for a while. But then I had a few false passages, which bothered me. It’s very difficult to monitor the position of that suture, when you thread it in. If there’s resistance, you know you’re in the wrong place. But if there’s no resistance, it can be difficult. You can try to monitor it with a goniotomy lens. Koeppe or other lens. But it can be very difficult to see that prolene in the canal. Here’s an example of one of my patients. I did an exam, pre-op. And you can see it looks normal other than some cupping. Attempted a 360-degree trabeculotomy. It didn’t work out. I couldn’t — I kept feeding in the prolene, and got to the point where I thought it should be coming back out, and it wasn’t. So I pulled it out. And I did a traditional trabeculotomy. And when I went back for a follow-up EUA about 3 months later, this is what I found. I looked in, and there was a subretinal scar, pretty much headed right towards the fovea. So that prolene had left Schlemm’s canal, traveled in the choroidal space, and now was in the choroid, scraping off the RPD, and you have to wonder if that also means scraping off photoreceptors, as it’s traveling down here. So once I saw that, I said — okay. Clearly I can’t tell where this is going. And just mathematically, that suture can get to the fovea before it’s gone around the circumference of the limbus. So… I stopped doing it for that reason. If you choose to do it, just be very careful and try to monitor that. Because this is a potential complication. You can also see it appear in the vitreous. I’ve seen sutures coiled up behind the lens. But… About a decade ago or so, they came out with this microcatheter system, which I think has really revolutionized the 360-degree trabeculotomy. This catheter is disposable. Supposed to be disposable. It has optical fibers. One of them illuminates. And it’s got this channel, so you can inject viscoelastic. And basically this tip is blunted. You can see it’s rounded off, so it’s less likely to leave Schlemm’s canal. And it lights up. So here’s the iCath lighted catheter. So now — look. It’s got this great flashing light. I know exactly where this thing is going. And it’s roughly the diameter of that 6-0 prolene suture. Hardly any larger. This is used for adult viscocanalostomy, but great adaptation, to use it for pediatric glaucoma. I just love the fact that you turn down the microscope light, see exactly where this thing is, and not every time, but more than half the time this is what happens. It just slides right around, and you retrieve it back at the beginning. And then the hardest part is just getting it out of the Schlemm’s canal, once you get it back around. But one of the best things that I like to use now, that I’ve found from one of my partners, Kathryn Haider, is using a Sinskey hook, just to hook under that other end. So we’ll retrieve this out of this now. So we have this microcatheter going all the way around. And now we’re fishing it back out from our original incision. And once we fish it out, we’re gonna grab the two ends here. So now I’ve got the other end. And as we put tension on these two ends of the suture, it’s gonna tighten up, and there it is. It’s coming across the anterior chamber right now. It’s already pulled out of this angle. Here’s the microcatheter. And we’ve done about half the angle here. We still have to tear out this remaining half. You have to watch that — it does drag on the iris, because you see it’s shallowed here. But it tends to come out real easily. And right here is where you might get hung on the iris. And if you get hung up too much, just let go of one end, and it will slide out. And that’s it. You’ve now opened 360 degrees. I think this is a fantastic procedure. And there’s a still shot of that microcatheter traveling across the anterior chamber. That is fantastic. Does it make a difference? We’ve looked at this, and we’ve got a smaller number. So here we looked at traditional 360-degree trabeculotomies, using trabeculotomes. The metal trabeculotomes. We’ve got about 78 patients there, and then a smaller number we were able to do the 360 on. What did we find? Well, here’s baseline. Both groups were similar. This is traditional trabeculotomy in the blue. This is 360 in the red. Baseline pressures were high, just what you would expect. 30s. And then at one month, the 360 group is a fair amount lower than the smaller angle, 120 degrees, that you can do with the metal trabeculotome. And that was sustained. Here’s 3 to 4 months later. So you can see it went from 30, traditional trabeculotomes went down to 20, the 360s went down to 13. So that’s a pretty big difference. So I think this is worth doing. Not only does it get the pressure down lower with one procedure, but there’s no secondary procedure to do now. You don’t need to go back and do more angle and more angle. This either works or it doesn’t work. So you’re not having that same child go back for follow-up anesthesias, for more surgery. You’ve got the whole angle open now. If this doesn’t work, you need to go on to something else. Things that we’re gonna talk about next. So if you can get these, it’s fantastic. If you can’t get these, try the prolene suture, but just be very cautious with it. Blunt the end. And only do it on eyes that have not had surgery before. If they’ve had angle surgery before, the angle will be scarred, and that will cause the suture to misdirect. So it’s a primary procedure only. The other thing is that prolene tip — if you use a prolene suture — maybe take a cautery, heat it up, and let it cool down just a little bit, and then touch it to the end. And that will blunt it up. All right. So let’s take some questions now. I’m opening up to questions. Scroll back here. Okay. We have a question about trabeculotomy. And tube shunt after failure. Well, absolutely. I would always, in a primary congenital glaucoma case, I would always start with trabeculotomy or goniotomy. Then I move on to tube shunts. Now, the only time not to do it in that order would be if you just don’t know how to do a trabeculotomy or goniotomy, or you don’t have the instruments. But in those cases, I think tube shunt as a primary procedure might be a reasonable alternative. And we’ll talk about that. So that’s potentially one way to go. Next question: When attempting trabeculotomy, do you ever encounter Schlemm’s canal dysgenesis, absence, especially in very large eyes? Absolutely. This can be frustrating. When I first was in practice, I preferred goniotomies, because I thought they were easier, and there were a lot of times where I would be cutting down on Schlemm’s canal for a trabeculotomy, and I couldn’t find it. As time went on, and I got better at it, trabeculotomies became easier. But you still encounter times when the eye is so stretched out and dysplastic or Schlemm’s canal is not there, or it’s abnormal, that you can’t get into it. And in those cases, you can try in a different location. A lot of times, I’ll make the trabeculotomy flap wider. So instead of doing a small triangle, I’ll do a wider rectangle. That way, if I cut down over here and it doesn’t work, I just go further over in the triangle flap and I do it there. So that gives you a little bit of flexibility to go to two locations. I have a question about — would you perform 360 trabeculotomy on both eyes the same day? The answer is yes, I would. In my hospital, do I? No. Not unless the child has a high anesthesia risk. But in areas where pediatric anesthesia is limited or you’re worried you may not get the child back for a second surgery… I think doing both eyes is quite reasonable. And you have to make this decision on a case by case basis. But I think because these procedures are so critical, and they have to be done in young children, that it is a reasonable choice to do bilateral surgery. But I would make sure that you do it as two complete surgeries. You do one eye. And then you reprep, you re-drape, you have a second set of instruments, so it’s completely limiting the risk of bilateral endophthalmitis. We have a question about microscope angulation in goniotomy. And that’s a good question, because when you do goniotomy, we are tilting the head, so the head is not straight up like this. We’re trying to visualize the angle. So we’re tilting the head sideways, and when you do that, you also want to crank the tilt on the microscope. So the microscope, instead of being straight up and down, is going to be angled like this, so it’s looking where the angle is. And you have to play with that. But you can find that that is useful. Good question there. Next question is: What do you do if goniotomy fails? Do you move on to trabeculotomy afterwards? Actually, maybe the other way around. If goniotomy — my first procedure, a lot of times, because the corneas are hazy, is probably trabeculotomy. And then maybe it works partway, but I need the pressure lower. But the cornea is clearer now. So you can do a goniotomy. But they are — you can move from one to another. And let me show you how that works. Let’s go to new share, and… Lovely whiteboard. Let’s bring this up. So doing these… How are these complementary? Well… Let’s take a look at this. Too much stuff in the way here. All right. One eye. Two eyes. And… So our nose is right here. If you’re doing… Let’s say you start off doing… Let’s just say you start off with what you’re asking. I’m gonna go goniotomy first. So goniotomy, I can come in here, and I can come from above there. But once I’ve done that, what have I opened? Okay. Well, I’ve opened… If I’m lucky, I’ve opened this part of the angle. This one. And then the goniotomy blade here opens that part of the angle. Very tough to get over here, though. So then I say… Okay. Well… I’ve got 2/3 of the angle. Now I’m gonna do a trabeculotomy. So I’m gonna go and I’m gonna make a trabeculotomy incision right here. Under a little flap. And that’s gonna let me open this part of the angle. All right? So now from here, I can do that. And I can do that. And even if, once you’ve done all that, sometimes — and I still need the pressure lower — I’ll go back and I’ll reexamine, with the gonioscopy lens, and if it looks like it’s not open, you can redo areas. So three is kind of the minimum to get the angle open, but if you go back and it still looks closed, do something else. Do another trabeculotomy. Do another goniotomy. Get that angle all the way open. Especially if that’s the only tool you have. All right. All right. Let’s move on a little bit here. Close out these questions for now. Trabeculectomy. I mentioned I’m not a big, big fan of this, because my experience has been kind of dismal. You might have experience that’s been positive, and if you have, I’d love to hear if. But trabeculectomy, we’re basically — as you know, we’re cutting out part of the trabecular meshwork to give access directly to Schlemm’s canal, and subconjunctival spaces that way. Peripheral iridotomy here. And we’re letting fluid get out of the eye by that. Blebs can be avascular and cystic, or they can be very large and vascular and perfuse. But… My real question for you is: Antimetabolites. My experience hasn’t been that great. It hasn’t been the best, rather. But what about you? Have you had success with antimetabolites? So launching our poll questions here. Do you currently perform trabeculectomy with antimetabolites? One, no, I never do. Or two, no, I used to, but I stopped because of complications. That would be me. Three, yes, but I do not think it works very well in children. Or four, yes, I use it all the time. I think it works great in children. And I just need to do it a certain way. And if you have a certain way that it does work for you, I’d love for you to share that with us. Here are the results. We have… No, I never use them. None of us. Stopped using them. That would be one, me. I would be there. Some of us do, but they’re not real impressed. And some think it works very well. So we have kind of a mixed crowd here on this. And any time you get that many answers, it tells you — there’s no perfect answer. Who knows? All right. Back to our slides. This is what happens to me. This is what I’m afraid of. I use so much antimetabolite that I get this very thin, avascular bleb. They leak. You can see the fluorescein leakage. And they start leaking, and then you have this lifetime risk of endophthalmitis. And for me, people can easily get back to see me, but it’s still a problem. If you’re in a remote area, and you’ve got some kid walking around a day’s drive away with a bleb like this, that is a setup for disaster, in terms of endophthalmitis. And so I really have kind of stopped doing these, over the years. Thin, leaking blebs. In the literature, about 1/3 to 2/3 after 18 months are having this same kind of problem. So it’s a pretty common problem. All right. Before we go on to tube shunts, let me just look at — see if we have any magical advice on trabeculectomy, of what to do with antimetabolites. I do have someone commenting on combining trabeculotomy and trabeculectomy together. Absolutely. I think that is a reasonable thing to do. I think that the trabeculectomy gets the cornea cleared up, and even if your trabeculotomy didn’t work, maybe now your cornea is clear, and you can come back and do a goniotomy or other trabeculotomy later. What is my opinion about that? That’s one of the other questions. I think it’s fine. One of my partners tends to like that procedure very well. I don’t routinely combine trabeculectomy and trabeculotomy. When do I do it? I do it on cases where I get in there and maybe I get half a trabeculectomy, or half a trabeculotomy. I only get it to one way and not the other, or I can’t find Schlemm’s canal, or things seem funny. So if I have a non-standard effort, giving that trabeculotomy, then I will convert it to a trabeculotomy/trabeculectomy. For me, that’s when I use it. All right. Rolling on. And we’ll go… Oh, let me pop back a second here. Tube shunts. This is an important topic, because I think they’re great. And I think they can be a really useful tool. And here comes our fourth poll. Get this launched so you can see it. Tube shunts. Regarding tube shunts in children. One, you are unable to get them, so you’re not even gonna be able to do one, as it is right now. Or two, I can get them occasionally. But access is limited. Or three, I can get them easily, but they’re too expensive. Most of my patients cannot afford them. Only a few can afford them. Four, I can get them easily and expense is not a problem. Okay. For me, that’s the situation. They’re easy to come by. I can use them if I want. And so I have a lot of leeway with this. Here’s what all of you have said. All right. This is what I’ve seen around the world. A lot of places you just can’t get them, or it’s sporadic to get them. So it’s a great tool, but it’s expensive. Here, that was the number one answer. Expensive. And they are expensive. I can get them easily, and expense is not a problem. Some people are fortunate. So let’s talk a little bit about tube shunts. You know, they are difficult. For me, if a child with primary congenital glaucoma — if that child fails angle surgery, and I’ve gone all the way around and opened the angle, this is step two for me. I use these in aphakic and pseudophakic glaucomas. Either this or endo laser that we’ll chat about. I think it’s great for that. Inflammatory glaucomas. Good for that. Because the angles tend to close up. Around the rest of the world, you know, I again — I think if you aren’t able or comfortable performing goniotomy or trabeculotomy, this is a reasonable thing to do. Most of us as anterior segment surgeons can get these things implanted in the eye. I like the Ahmed valve, because of the pressure control valve that closes when the pressure is less than around 6. To me, I like avoiding hypotony, and that’s why I use it. Some people argue that that valve and the plate area with Ahmed are less than what you might get with Baerveldt, and that the long-term results of the Baerveldt are better. That’s true. If I use a Baerveldt, I tie it off. So you kind of have to decide things about timing. Do you tie it off, not tie it off, because hypotony in a kid — the problem with hypotony in a kid is that kid’s got to go back to the operating room to reform the chamber, if it doesn’t reinflate with some pressure patching over a couple days. And that’s different than adults. Adults, you can reform their chamber at the slit lamp. So there’s a trade-off here. From a surgical technique standpoint, you want this front edge of the plate about 8 millimeters away from the limbus. If this gets too close, it causes problems. I usually go in about a millimeter or 2 behind the limbus with my 23-gauge needle. You want to keep that flat. You want to keep the tube tip about 2 to 3 millimeters in length. You don’t want it to go past the iris edge. You don’t want it too anterior, so it’s touching the cornea. So you’ve really got to enter parallel to the iris plane. This is a big bugaboo here. The patch. I always put a patch of pericardium over the anterior tube. I used to use sclera. Sclera is thicker. It makes a little more bulk up in this area. If you can’t get that, because I find a lot of people cannot get sclera or pericardium, you can do this by a partial depth tunneling scleral tunnel technique, and so if you’re comfortable doing that, that’s an option. But erosion in this area is always a problem. Complications in general are a problem. The advantage: These things are simple. Right? The disadvantage — if it touches the cornea, you get a cloudy cornea. If it touches the lens, you get a cataract. If the kid rubs his eye or wrestles with his brother, you’re gonna get a dislodged tube shunt. Sometimes they migrate forward, sometimes they migrate backwards, and a lot of stuff can go on with these. They work. We’ve gone back and looked at our own results. They work pretty well. We did a study, looking at 36 kids. They were about 7 years of age, most of them. This was a secondary procedure for them. Most of them had had two or three procedures before. This was a division of aphakic and congenital glaucoma. But what I want to show you is: A, success. So baseline pressures were about 35. And the pressures dropped down about 20 points. So we went from 35 down to a mean at the last visit of 15. That’s tremendous. I really like that this can get the pressure down. But does it stay down over time? Well… Here’s baseline. 35. Here’s one year. Two years. Four years. Six years. Start to get a little creeping up over time. And this is that long-term question. Is the pressure gonna stay down long-term? This end — these are pretty much all Ahmed valves. This end of the curve, years down the road, this is where some people argue in favor of non-valved larger plate tube shunts. Baerveldt, et cetera. Complications that we found were about like this. About 25% of our patients had complications. Flat chambers, tube migration, hypotony, retinal detachment, implant exposure, choroidal effusion. Things happen. This is tough to control, once they’re in there. All right? So the overall success rate was high. 75% got the pressure down. But we’ve got about a 25% complication rate. And I’m gonna keep this rolling. Let’s take some questions before we get on to cyclodestruction. Questions we have… Do you experience retraction of the tube shunt back into the sub-Tenon’s space? Yeah. I actually see this go both ways. You would think that as the eye is growing that that tube would retract, and sometimes they do. And you see it — you can’t find it in the anterior chamber anymore. Usually it’s right there at the angle. When that happens, I have one of the tube extender kits, and I don’t replace the plate. I simply lengthen the tube with this tube extender to get it back in there. Sometimes I see the opposite problem, though. The tube goes forward, and now, instead of having 2 or 3 millimeters in the eye, you’ve got 4 or 5 millimeters of tube in the eye, and it’s up against the cornea. And I have to go in and trim it or reposition things. I tend — if the tube shunt fails, I tend not to try and put a new tube shunt in the same quadrant. I usually will go on to another quadrant. So I usually do superotemporal. If that doesn’t work, it fits pretty fine superonasal. I don’t have any problems getting it up superonasal. And then you can always go inferotemporal. Here’s a nice question about tube size, size of the plate, rather, in different age groups. And this is a great question, because, when they came out with pediatric sizes, I said — great. I’m gonna try those. Almost universally, I found that they’re too small. The plates are… I don’t know. They’re like, what, a third of the adult size, and I find that they don’t work. Even in an infant, especially once you’ve gone through angle surgery, there is enough room in the orbit to get an adult-sized tube shunt in. So I don’t remember the last time that I put in a pediatric-sized tube shunt. I pretty much always use the adult-sized tube shunts. And I’m just looking here — someone has a nice question about the ExPRESS shunt. The mini-shunts, the ExPRESS shunt. And it’s a great question. I haven’t personally tried those. But I bet a lot of you out there have, and if you’ve had a good experience with that, that would be good to know. Seems like it would make sense. But I think you run into the same issue of failure. If you’re just bypassing Schlemm’s canal, it seems like it could work. If Schlemm’s canal is abnormal, it’s not gonna get you anywhere. So… All right. Back into our — let’s get into cyclodestruction. Because we have a limited time left, and I want to show you a couple procedures. Cyclodestruction. We’re going to destroy part of the ciliary body. Fluids made back here. Pigmented epithelium with the ciliary processes — we want to slow that down. So this is analogous to turning the bathwater off, versus letting the bathwater out faster. Cyclodestruction — it’s quick, it’s easy, but there’s a lot of what I would call collateral damage. Look at this eye. This eye has had cryotherapy. It’s got a cataract. It’s got — the iris is stuck to the lens. A lot of inflammation when you do these things with cryotherapy in general. Also, you take out too much pigmented epithelium, and now you’ve got hypotony. You’ve gone from too high to too low. Sometimes it’s tough to titrate. So in general, I try to avoid cryotherapy. But if you do it, you should do the inferior. Put in about 6 spots down there with the cryo probe. Keep it off the cornea. 2 or 3 millimeters away. And get it down to -70 and hold it there for 30 seconds or so. I’ll use this on some end-stage eyes, occasionally. But not really my go-to. If you have access to this, this is kind of a nicer way to do it externally. This is the G-Probe. The G-Probe has a custom fitted handpiece that spaces you out the right distance from the limbus. It uses the 810-nanometer wavelength. Diode laser. The diode laser doesn’t do anything until it hits pigment, so it goes right through the sclera, and then it hits the pigmented ciliary body, ciliary processes, and it heats up down here. And so nothing happens to the sclera. The heat is all in here. Well, the only downside to this is that our eyes that we’re seeing — a lot of times, they’re stretched out. Who knows that you’re actually on top of where you need to be? In these buphthalmic eyes — because this handpiece is designed for an adult, normal-sized eye. But I do use that. I think it’s nice and controlled. And some would say that the results are similar to this, which is my favorite. I’ve done a lot of work on this over the last 15 years. 20 years. This is cyclodestruction using the endo-cyclo-photoablation handpiece. So, again, it’s a diode laser. You’ve got this really awesome handpiece that goes in, and you can see on a video monitor the ciliary processes, and you can laser them, and just take out the ones you want. I usually do about 270 degrees. And that will work about 50% of the time. Give me the pressure I need. But it’s controlled. So it’s a controlled way, and it’s through the cornea. Most of us are comfortable doing that. Just reaching through the iris. This is a pseudophakic patient. Phakic patients — I’d like to point out that I don’t like to do this in phakic patients. Because the lens is here. The handpiece is here. Sometimes these edges are a little bit rough. And I have torn open anterior capsules before. Even using viscoelastic. So I pretty much now reserve this for aphakic and pseudophakic patients. I’m gonna show you a quick video, and then we’re gonna spend the rest of our time taking your questions. Here’s a view inside, through the camera. These have already been ablated. This is the aiming beam. This is the ciliary process. This is our victim right here. Start at the top. And hold that laser on there for 2 to 3 seconds, ’til it shrinks up. You don’t get hypotony, because you’re leaving all this other pigmented ciliary epithelium. That’s an air bubble from the viscoelastic. And just one by one, you go around and do about 180 degrees to 270 degrees of the ciliary processes. And I love this, either before or after tube shunts, for aphakic or pseudophakic glaucoma. This is pretty much my go-to for that type of patient. All right. All right. Exit out of that. And I’m going to scroll through the rest of these, because this is just the results. My personal results with that procedure. That’s all published information. And I’m going to take some questions from everyone, but while we talk about the questions, I want to point out this resource, which is on Cybersight. cybersight.org. If you go to this link, you’ll find this manual. This manual was written by myself and a couple other — three other fantastic experts on pediatric glaucoma. Dr. Gordon Douglas, Dr. Alex Levin, and David Walton. These people have tons of experience with pediatric glaucoma. This book mostly focuses on those surgical techniques that we have just talked about. And it tells you pretty much step by step how to replicate these techniques. So if you want to — if you’re not comfortable with what you’re doing, or you want to learn, read this. You can read it online, or you can download it as a PDF, either with or without illustrations. And you’ll see all the other wonderful resources that are on cybersight.org. So check that out. I think anyone can learn to do goniotomy and trabeculotomy. You just need to go for it and do a little bit of practice ahead of time. Going back to our questions, as we come to the end of our session, we have a question here about: Do you find sympathetic ophthalmia in the fellow eye after cyclodestruction? I haven’t encountered that, but certainly that is one of the concerns. That has been reported. And it can happen. So, again, probably more likely to happen in the very inflammatory ones, like cryotherapy. Next question: When I use the Ahmed valve, I find the most common complication is plate encapsulation, needing repeated excision of the capsule to control the intraocular pressure. How do you avoid this? This person also mentions that they’ve tried mitomycin C. I haven’t tried that, but I have seen that some people like that, and they’ve had good results with that. In general, if I get encapsulation, I’ll go in one time and try to surgically revise it. If that doesn’t work, then I simply go in and I put in either a second or a third tube shunt. Again, they fit everywhere. Here’s a question about trans-scleral cyclo-photocoagulation. Can it be titrated to get the desired result? Yes. You don’t treat all the way around. Again, you’re treating either 180 degrees, probably as an initial procedure. The power you titrate — start off with about 200 milliwatts, 200 milliseconds, and if I hear popping, that’s probably too hot. So I’ll turn the laser down. And do a shorter duration. Next question is about endo laser. Is endo-cyclo-photocoagulation a viable primary procedure for congenital glaucoma? My answer to that is no. I think it’s a great secondary procedure, if you’ve worked on the angle already. My attitude towards primary congenital glaucoma is that — look, you have an abnormal angle. The drains are abnormal. You want to fix that, you need to cut those drains open or tear them open or bypass them with a tube shunt. So go where the problem is. And that’s gonna be your best solution. All right. These have been wonderful questions. And I appreciate everyone’s time and interest today. This will be available online, if you want to go back and look at the slides, listen to the webinar. If you have any further questions, please feel free to send them to me at Cybersight. Also, don’t forget you can ask pediatric glaucoma consults at cybersight.org, through the consult system. And you can also ask general questions through that. Simply select general question, rather than patient consult. And your question will come to me or another expert, and we can give you tips on techniques, just as we’ve discussed with our questions today. Thank you. And I hope everyone has a good day, and I will end the meeting at this time.
May 31, 2016
2 thoughts on “Lecture: Evaluation and Management of Pediatric Glaucoma”
How to select the site of inner window in advanced buphthalmos for trabeculectomy?
Trabeculotomy is definitely more challenging in advanced cases of buphthalmos and sometimes is almost impossible because of scleral thinning and displacement of Schlemm’s canal. I generally look slightly more posterior and if the sclera is thin I avoid doing a scleral flap and just make the radial cut over Schlemm’s canal directly from the scleral surface. Some of these cases may be better suited for tube-shunt implantation.