This lecture will review the unique aspects of pediatric cataract and IOL implant surgery, emphasizing critical differences between pediatric and adult patients when it comes to surgical technique, intraocular lenses and postoperative management. Presentation will include a video demonstration of vitrector surgical technique for children under 5 years of age.
Lecturer: Dr. Daniel Neely
Technical Aspects of Pediatric Cataract 04/22/2016 from Cybersight on Vimeo
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DR DANIEL NEELY: Going to put up our first poll question. And I’d just like to get some feedback. Are you an ophthalmologist? Are you an ophthalmologist in training? A technician or perhaps a nurse, or even one of our Orbis staff members? We appreciate everyone’s time tonight, and I’ll show you who we all are. And by and large, we are mostly ophthalmologists, and certainly our discussion here, with surgical techniques, will be addressed towards that. We welcome anyone’s comments, though. I would like this, again, to be a discussion, and not simply just a lecture. Close this out. And we’ll move on here. As we go through this, we’re going to kind of work through this front to back. There are — we’re gonna talk about the anterior capsule. We’re gonna move on and talk about removal of the lens material. The lens placement. And then how do you handle the posterior capsule. The posterior capsule in particular is something that’s significant different, compared to adult surgery. But each one of these steps, you’ll see, has some very unique aspects to it. So starting with the anterior capsule, when you’re managing the anterior capsule, we really have a couple of options. You have the standard adult continuous curvilinear capsulorrhexis, performed with bent tip needle cystotome or forceps, or we have something that’s relatively particularly unique only to children, and that’s the vitrectorrhexis, performing the capsulotomy with the vitrector. And for me in particular, this decision is age-based, and we’ll discuss that. Before we get into what I like to do, let’s see what each of you likes to do. Our second poll question has to do with capsulotomy, anterior capsulotomy techniques. And what do you like to do? Do you like to do a manual tear with cystotome needle or forceps? Do you use a vitrector, or do you perhaps use some other instrument? Looks like most of you are coming in with the manual tear. Not surprisingly — I think that’s the one that most of us are comfortable with. And then a few of you are using the vitrector. And for me, that’s kind of a key teaching point. As I travel the globe with Orbis, sharing techniques for pediatric cataract surgery, this is usually what I’m working on, is how to manage the posterior capsule in particular. So I think it is just a prime thing for us to discuss tonight. But first, let’s start with the anterior capsule. Now, the traditional adult technique is tearing a circular capsule. Now, why do we do that? Well, when you tear in a circle, it’s strong, it’s uniform, there are no tags, and the downside to that, though, in children, though, is that it really has to do with the elasticity of the capsule. And the radial forces that are created by the positive pressure in the lens, in the vitreous behind the lens, wanting to push it forward and then extending things. When you do a traditional tear, as we see here on the left side of the screen, in an adult or teenager, you’re really tearing tangential. So you start that tear, and your direction of pull is tangential, right around that circle. And that just follows itself around, typically. However, in children, we really have to change our technique. We’re going for the same shape and the same size, but you can see the forceps — instead of going tangential around like this, the forceps are gonna be pulling in towards the middle. It’s almost like the technique you would use to rescue an adult capsulotomy, rather than just tearing it normally. Now, the anterior capsule in children — just like all the parts of children — it’s relatively elastic. You get these radial forces. The lens wants to push forward. The lens is disproportionately large in the eye. For this reason, I really like to push the lens back. I like to use a very high viscosity viscoelastic, such as Healon GV. And you can do that quite easily. It’s nice because it sticks together, and these cohesive viscoelastics will come out easily. Now, when you’re doing phaco, you’d like to have something that has some dispersive qualities, because you want to coat the endothelium to protect it from the phacoemulsification. But we are essentially never doing phaco in these kids. It’s just not necessary. We’re treating them mostly, by and large, just with simple aspiration. So, again, that pulling technique is going in towards the middle, rather than going radial here. And here you can see that technique in action. See our tears extending around here. And the direction of the forceps is always in towards the middle. So you’re not laying that over like a carpet and rolling it around like you do in an adult. Now, the anterior capsule vitrectorrhexis — this is my preferred technique essentially in all children under 5. Most of the time I will do this, for a reason that I’ll state later for you. But definitely in the very younger children, the infants. So children less than 2 years of age. I find this to be extremely helpful and help controlling the capsulorrhexis and keeping it from getting this run away rhexis. I’d like to point out that it’s also quite useful in older children and adults, when you have kind of a fibrotic anterior capsule or a white lens, where it’s really hard to see the edges. This can be a useful technique in these kind of traumatic or dense white cataracts. Now, when you use the vitrector, there are some — a few pointers here. I like to use a larger gauge vitrector, so this happens to be a 20. Some people use a 23. And I like to use an anterior chamber maintainer. So this is a self-retaining — and you can see the ridges on this — the self-retaining 20-gauge, the Lewicky anterior chamber maintainer. And I like that, because I can stick it in, it holds itself there, and then I can put either both hands on the vitrector handpiece, or I can have a forceps in my left hand and use the vitrector in my right hand. I mentioned that this is the 20-gauge Lewicky. And that is because this is a 20-gauge vitrector. You want these to be the same size. Not only for fluid flow dynamics, but also you want to switch them out and put the vitrector over in this port, put the infusion in this port, you can do that, if they are the same size. One thing you don’t wanna do, that I think we should point out, is try to do a larger incision up here and tear with something like Utrata forceps. If you make this incision larger than this — this is an MVR blade. A 20-gauge MVR made this — if you try to make a larger keratome, you’re going to get leakage around that vitrectomy handpiece. And that’s going to cause the chamber to shallow, it’s going to cause the lens to come forward, it’s going to exacerbate any radial extensions you have. So you really want this to be watertight. And therefore, if you’re going to do a manual tear, you want to use small incision capsulorrhexis forceps, or do it with a cystotome needle. Now, relative to the technique and the settings for the machine, it’s pretty basic. If you’re using one of the older vitrectomy machines, Alcon Accurus is one that I’ve used for a couple decades now, the settings are relatively fixed. So the cut rate is 250. The aspiration rate is 250. And I just leave it there. If you’re using one of the new variable machines, such as the Constellation, then you have the ability to adjust that, depending on the foot pedal position. And if you’re going to do that, I start with a high cut rate and a low aspiration. Then, as you press down on the foot pedal, the cut rate will drop down, and the aspiration will go up. So the reason these are inverse is, if you have a very high cut rate, it allows you to do a capsulotomy with very little suction on the capsule, so you’re not pulling up the lens and taking these big bites out of it, like you see in this photograph. And so it’s just really shading or trimming. But if the capsule won’t come forward, then you’re going to need more suction to pull it forward, as that cut rate slows down. The basic technique for this is just to use the minimum it takes to engage the capsule. And either start in the middle — where the light reflex is — or slightly down here to the edge. I kind of like to start here at the far edge and work my way back, towards this edge, and then just kind of round the whole thing out. The reason I like to do that is the cutting — remember, there’s a guillotine blade going back and forth inside here, and the cutting is at the distal end. And it seems like it’s easier to kind of feed the capsule edge into that, as you’re working back towards yourself. Now, we’ll look at that, as we get a little bit further along. But before — there’s a video here in a couple of slides — but before we do that, I want to stop and I want to see if we have any questions about anterior capsulotomy techniques. I don’t see any popping up here. So if there are no questions, I will move on to the management of the lens material. Before we do that, here’s a chance for another poll question. This is specific to young children. Older children — the technique is going to be like adults. So let’s focus on the young children. And so I’ve stated here less than 5 years of age. What do you use to remove the lens material in this population? In your current practice? There’s no right or wrong answer here. We’re simply trying to get a feel for what everyone does. So here’s our poll. What do you currently use to remove the lens material in children less than 5 years of age? Manual Simcoe? Automated I/A, phaco handpiece, cortical clean-up, do you use a vitrector, or do you use a phaco tip? It looks like our results are mostly in. And let’s share this with everybody. So we see that a lot of us are using a manual irrigation and aspiration. And that’s not surprising. And there’s actually nothing wrong with that. It works quite nicely. The one thing that I have concerns about with that is that we do need some mechanism for managing the posterior capsule. It gets a little more complicated when you’re doing it manual, but it removes the lens material just fine. Same with the automated I/A. The vitrector, again, in these younger children, as I’ll show you in a little bit, it’s kind of my preferred instrument for removing this material. I think the one challenge — you hear that I’m liking the vitrector quite a bet. I think that the one challenge that all of us face is that most of us, as pediatric ophthalmologists, are not trained in how to use a vitrector. So you do — it’s nice if you can have a mentor or someone to work with you the first time you do this. It’s quite simple, but you do need someone to show you kind of the basics of this. Now, in removing the lens material, you’re essentially going to aspirate it. The lens is never dense enough to really need any phaco power. So we’re simply aspirating. When you’re aspirating the lens material, it is helpful to have a large port size. These lenses are dense and gelatinous, and they have to be squeezed through that port, so that’s why I like to generally use the 20-gauge vitrector. Now, the 23 will work as well. If you are using an automated I/A handpiece or a Simcoe, either one of those — my one piece of advice there is: The port, the aspiration port, those openings come in different sizes. And it’s pretty standard that they’re around 0.3 millimeters. But these ports can be obtained for the Simcoe or the I/A handpiece that are up to 0.5 millimeters. And that gives you a much larger opening to aspirate this dense material. And so you want to investigate that, if that’s your chosen technique. Now, in the older children, it’s pretty much what I do. I just use a phaco handpiece. No phaco power. I’m just using a standard irrigation and aspiration automated handpiece. I do use the larger port size. This one, I believe, has a 0.5 opening on it. And it just makes it that much easier to aspirate out all this lens material. I do like to start in the subincisional area, up here underneath the wound. Because otherwise a lot of times you’re getting a lot of infusion out of the sleeve here, and you’ll start to lose your visibility here around the cornea. Also, it’s much easier to get this cortex up here at the top when you have all that lens material back here at the bottom, holding it back. So, see, I can easily aspirate this up here with the port facing straight down, because all this lens is down here in the bottom, and it’s keeping that posterior capsule back away from my port. Otherwise, you always want to work with the port facing upward. So you do see me using the port down here. But it’s only when it’s protected by the lens remnant. Once you start aspirating seriously, then you need to get that port facing up, pretty much all the time. Now, the vitrectorrhexis technique in the younger children — again, under age 5 — I do my two corneal entries with the 20-gauge MVR blade. Smaller, if you’re using a 23-gauge vitrector. There’s that self-retaining 20-gauge Lewicky anterior capsule maintainer. Now my hands are free to hold the instruments. There’s the vitrector. Port side up, right now. And now I flipped it over, and I’m down at the bottom edge of where I want my capsulotomy to be. And I’m slowly engaging it and pressing down on the foot pedal, until it starts to engage the capsule. And then just simply working around in a circle, until I get that circular size, that it’s about 4.5 millimeters or so. Now, the vitrector is taking bites out of the capsule. But what happens is all those bites are facing in. They’re all scalloped with the points going in. And so you don’t have points that are extending radial. And I’m gonna pause it right here, to, again, demonstrate this kind of need to do the subincisional cortex first. This is always the most difficult area to clean up. If you start off with it, again, you’ve got all this lens material back here that’s pushing the posterior capsule back, and you can just work straight down and aspirate it out. If you aren’t able to do that, and you end up with some retained lens material right here, what I suggest that you do — pull the instrument out. Take this anterior capsule maintainer. Plug it in up here. And now you can reach in through this incision, with the vitrector, and get access to this subincisional area quite easily. And this is much like cortical clean-up in an adult. You’re reaching out towards the equator. You’re engaging the lens, pulling it into the middle. If it won’t aspirate in with just suction alone, you’ll see I kick on the vitrector with the port facing up again, in a safe zone. It simply eats up the lens material and pulls it in. So even in teenagers, this simple aspiration technique is sufficient for removing the lens. Now, as you get down to the last little bit, of course, like any time, you have to be careful not to overaspirate. Again, we’re just using just enough of the foot pedal to pull that material in. And one thing I was starting to mention before was the scalloping. Let me see if I can roll back to the beginning of the video and explain what I mean by that. So the vitrector is taking bites out of the anterior capsule. Right here. The vitrector is taking bites out of the anterior capsule. And you can see it looks like a little Pacman came in here and took a bite there and there and there and there and so forth, all the way around. Well, look at the points. So it’s a bite out of there. It’s elliptical. But the point is in. Same thing here. Point is in. Point is in. Point is in. Because those points are facing in towards the center of the lens, and the center of the visual axis, they’re still strong. It’s just like a continuous tear. What happens then is that those points just roll over, and it looks very circular when you’re finished. But it has these small tags all the way around. Now, if the vitrector were to cut in a different way, to where the points were facing outward, that’s when you would get a radial tear, but they simply don’t do that. That’s why this is such a nice technique, and it ends up being virtually just as strong as a continuous tear. Now, some people — this slide is courtesy of Dr. Ed Wilson. Very famous pediatric cataract surgeon, and very skilled. He likes to use a bimanual technique. Here he has his anterior chamber maintainer, which is actually an infusion cannula. And in the other hand, he has his vitrector. So it’s got one hand on each instrument, and the nice thing about this is you can pop this one out and pop it over here. Pop this one out, pop it over there, and you can go back and forth like that, to do some of these tough areas up around the top. And it’s a very difficult cataract here. You can see it’s a PHPV with the stalk. Dragging of the ciliary processes. Nice to point out that this is the kind of eye that you probably don’t want to put an intraocular lens in, unless this eye is of sufficient size. But generally when you start to get a lot of this dragging of the ciliary processes, these are sometimes not the best candidates for IOLs. All right. So that brings us to the end of the removal of the lens material. We do have a couple questions here waiting. I’ll see what we have here. First question that we have is: How do you control the infusion pressure in the anterior chamber? The two vitrector-type machines, the Accurus, Alcon Accurus, and the Alcon Constellation, have — you can set the pressure. So it’s not a free flow. It’s not based on the bottle height, like it would be if you were doing a manual I/A. You can set it right to the pressure you want. So if you want the eye to be 30 millimeters of mercury, which is what I use, you set it there. The machine will keep it there. That’s the really nice thing about being able to use a vitrector, a modern vitrector, like that. If you don’t have a machine like that, then you simply have to adjust your bottle height until you see that it’s enough pressure to keep the lens back, and aspirate your lens. The next question here — we have a question — wouldn’t it be easier to make the limbal incisions at 3:00 and 9:00? Then the vitrector can be used in either hand, to eliminate problems with subincisional cortex. Yes. So if you — 3:00 and 9:00. If you’re coming straight in like this, then the only issue there is one of those instruments is going across the bridge of the nose. And I think that’s why most surgeons will shift one of them up to the top, and then put the other one temporal. But you do want them spaced out. It’s not so much that they’re at 3:00 and 9:00, but that you have them about 90 degrees apart, so that they are reaching complementary areas. This same person is also commenting that they like the bimanual irrigation and aspiration, and I do too. I have switched over to that, and I think it’s a lovely technique. I do think it takes a little more skill, but people who are used to using both hands during cataract surgery can pull that off quite well. But I think it gives you a lot of flexibility. We have another question here. How to aspirate the subincisional cortex with a vitrector? Well, that is the tricky part. And that is the point of being able to access from the side. Usually, though, I find that if I start — if I make the anterior capsulotomy large enough, then there’s not so much subincisional cortex hidden there. The rim of capsule remnant is thin enough that you can reach up there. The other trick that I would point out is, again, starting with the subincisional cortex first, and once you engage it, it tends to be very sticky, and that whole wedge will come out, and you’ll get it out of there first. So start with it first. And if that doesn’t work, then switch around to — just switch your instruments to the side port and go from there. All right. Going back to our lecture. We’re going to move on to talking about intraocular lenses. This is a complicated area. And I think it’s fair to say that there’s no right or wrong answer. You’ll see — we’ll talk about some basic concepts here, and some basic guidelines. But what you do in one country, for one person, is not easy to translate what you do for another person in another country, because there are a lot of factors here that have to do with access to follow-up, that have to do with a patient’s ability to get glasses or contact lenses, so there are a lot of factors here that go into that decision. We’ll touch on those. Before we get into the material, though, let’s see what everyone here does. I would like to know what people do with intraocular lenses. Now, we’re gonna make this a more difficult question. Don’t answer yet. Because I want to know what you do with infants. Let’s talk about the young kids, particularly under 1 year of age, because that’s where it gets really tricky. In the older kids, I think it’s pretty much a slam dunk. Anyone who’s age 2 and up, you’re pretty much gonna treat them like an adult, relative to whether or not you put a lens in. Now, maybe not what you target for your refractive outcome, but the decision of — yes, you’re gonna put a lens in — or no, you’re not gonna put a lens in — is very tricky when you’re talking about infants. And the younger they are, the more tricky that is. And I think you’ll see here, as I show you the results of the poll, your answers are going to reflect that trickiness. So here you see some people never put them in infants. I know some of us are doing it only in unilateral cases, and some are doing it in both unilateral and bilateral cases. And actually, I agree with all of these. I think that really it’s a case by case situation. And understanding what to do for a given patient is really more important than whether or not you do it. All right. So let’s talk about that a little bit more. Because I think that’s really an important point, and something we all need to understand. Now, the lens considerations. You know, any lens will work. Are some of them easier? Yes. I have a personal bias towards the — again, these Alcon lenses. Not pushing Alcon. Just happen to be what I use. I used to use this three-piece lens. Now I’ve transitioned over to the one-piece lenses. Keep in mind that these SN… Let me go to this next slide. Here’s the SA60 and the SN60. Now, these are nice. They’re one solid piece. They’re acrylic. They have squared-off edges. They work well, even if you flip them in upside down. They go through small incisions. They definitely go through 3.2-millimeter incisions, and now with the new injectors, these will go through incisions less than 3 millimeters. So it’s a really tiny incision. The nice thing about this lens, more than anything else, is that it unfolds slowly. It stays folded up. The legs, the haptics come out slowly. You can get it into position without stressing a small eye, without stressing a small capsulotomy, particularly a capsulotomy that might have some irregularities to it. So it really gives you a margin of safety, so you maneuver that lens into position. Some of these injectable lenses that you’ll see out there and that I’ve used — they almost explode open. And that really is not a pleasant experience to be going through. I’m gonna back up one slide here, because I want to point out the difference here. So this is the SN and SA60. The three-piece lens does have a role. You can put this in the bag. It’s also probably preferred in terms of putting it in the sulcus. These one-piece lenses, the haptics are quite thick, and you can get some iris chafing if that’s sitting in the sulcus. So if I have to put a sulcus lens in, I’ll use this one, the three-piece. If I’m putting it in the bag, then my preference is for this one-piece. But, again, we all have to use what we have and have access to. And some are easier. But a non-folding lens you can use. It’s all gonna work the same. It’s just a matter of incision size and safety. Multifocal intraocular lenses. We get this question a lot. If you’re talking about an adult or a teenager, whose eye is finished growing, probably nothing terribly wrong with a multifocal lens. Has some advantages, with the depth of focus. But multifocal lenses only work well when you can target emmetropia. All right? So you’re gonna have emmetropia, and then you’re gonna have a range of depth of focus with these multifocals. If the eye — if you have to target hyperopia, because the eye is gonna grow, there’s really zero advantage to this. Because the child is still gonna need glasses. It’s still going to be very difficult to refract through this. If you look through a retinoscope here, you’re gonna get images off the different rings, and the different powers, and it really is kind of tough. So in general, the consensus, by most pediatric cataract surgeons, at least in the US, is that we don’t place these in children. We reserve these for adults, or eyes that are not growing. And we’ll find people around the world, of course, who have different opinions. But I think you need to understand why it’s maybe not a good idea. Intraocular lens calculations in children. This is a real bugaboo that I don’t think we’ve gotten past yet. You need to have — if you’re going to do true pediatric cataract surgery, and do intraocular lens calculations on young children, you’re going to need a handheld keratometer. There aren’t many to choose from. This is the Nidek model, and there might be a couple others on the market. But there aren’t many to choose from. My experience with them is that the reproducibility is somewhat variable. But it’s kind of the best thing we have. Using standard averages, I guess it’s better than nothing, but it’s really not very reliable to take an average. These eyes are small. They’re not average. And some of these eyes are actually microphthalmic. So there’s really no average to go by here, in a lot of these eyes. Intraocular lens calculation formulas. We have a lot to choose from. I’ve looked at this in my pediatric population. And essentially the outcome in our paper was that there really was no difference between these. The SRK II, the SRK-T, the Hoffer Q, the Holladay I — why is there no difference? It has to do with — these formulas are designed for adult eyes and they’re designed for full-sized eyes, and they’re designed for outcomes that generally target emmetropia. Almost none of those apply to a young child. We have eyes that are changing. We have small eyes. We’re not targeting emmetropia. There’s so much static built into these measurements that the predictions are quite poor. Now, there have been some other studies which have shown that maybe the Holladay I is slightly better than the others, but the difference is really not that tremendous. I do tend to use the Holladay I. If you’re going to have to pick one, you might as well go with that one. Why not? Well, what do you do? Once you pick out the fact that you’re going to put a lens in — what do you target, then? Well… These eyes are still growing. So the younger the child is, the more you have to anticipate the growth. And this is like trying to buy shoes for a 1-year-old. How do you know what size shoes they’re going to need as an adult? You don’t. There are a lot of factors that go into that. The age that you’re doing the surgery. Whether or not they develop secondary glaucoma. The effects of hereditary — if they have myopic parents, you’re probably gonna get more of a myopic shift. And then there’s this phantom factor of emmetropization. Some of these eyes just change on their own, trying to neutralize the residual refractive error. It’s hard to account for all those things. So we do have guidelines. But these are not absolutes, and they are by no means perfect. These are some general guidelines that I think are quite reasonable. Here you can see that in a younger child, one year of age, we’re targeting a residual refractive error of +5. Well, why +5? Because this child is going to grow. And then by the time they’re a teenager or adult, that +5 is going to have melted away. If we were doing the surgery in a 10-year-old, there’s really not much growth left, so we’re gonna leave them very little hyperopia. So most surgeons in the United States will target leaving residual hyperopia, because they will correct the residual difference with glasses or contact lenses. Now, if that’s not an option for you, then maybe targeting more towards emmetropia in the younger ages, when they’re so sensitive towards amblyopia, might be a better idea. You can argue this both ways, and I can understand the argument either way. But if you have access to glasses, and you have potentially access to contact lenses, then leaving them a little bit hyperopic, so that you don’t have to change out the lens later on, you don’t have to do refractive surgery later on, you don’t have to issue strong glasses later on, is a nice way to go. Again, that assumes that you have access to follow-up and you have access to changing the glasses as the child grows. Questions about intraocular lenses in children? We’ll get to that. I think we should probably talk about the infant aphakia treatment study. I don’t have a specific slide on that. But the decision of whether or not to give someone an intraocular lens depends on all these factors that we’ve been discussing. Age of the patient. You though, there’s a big difference between a 6-month-old and a 6-year-old. Bilateral versus unilateral. Well, bilateral aphakic patients do great, with aphakic glasses or aphakic contact lenses. Size of the eye — if the eye is too small, less than 10 millimeters, then these intraocular lenses almost don’t fit in them. And you can see where the haptics actually come back onto the optics sometimes. Presence of dragging of the ciliary processes with persistent fetal vasculature. Again, usually in a small eye — it’s also an issue. And then of course parental resources and abilities. If the parents can’t afford glasses, if the parents can’t get access to contact lenses, then an intraocular lens might be a better choice. Now, I mentioned the infant aphakia treatment study. The infant aphakia treatment study has some important conclusions, but we need to keep in mind that they apply to infants less than 7 months of age, so this study involved 114 infants, which were age 4 weeks to 7 months, when they had surgery. And they were all unilateral cataracts. So these are not bilateral cataract patients. These patients were randomized to either getting a contact lens or an intraocular lens. The outcomes of those patients, the visual outcomes after 4.5 years, showed that the visual outcome was equal. Again, that’s assuming that you have resources, and assuming you have access to refractive correction. And unilateral cases. This does not apply to bilateral cases. Now, the visual acuity was the same after 4.5 years, but what was different was the rate of complications and the rate of reoperations. It was significantly higher in the intraocular lens group. So a lot of surgeons in the United States have backed off on infant IOLs in unilateral cases in particular. There seems to be a slight diminishing of enthusiasm for that, and a lot of people leave these aphakic, correct them with a contact lens, and then go back and do a secondary intraocular lens later. The infant aphakia treatment study also showed us an important thing about glaucoma. About 1/3 of the patients in both groups developed glaucoma, or were glaucoma suspects. So there does not appear to be any particular protective effect of an intraocular lens when it comes to aphakic, pseudophakic glaucoma. Now, this is — I’m sure there are gonna be people who have different opinions on this, but these are the facts as we know them right now, and you need to modify those facts, based on what is going on in your environment at home. We’re gonna go to the questions now. And see if we have any questions related to intraocular lenses. The first question has to do with anterior capsulotomy and posterior capsulotomy. The question is: What would be the ideal size of the anterior capsulotomy and posterior capsulotomy? Well, the ideal size for an anterior capsulotomy is that it be slightly smaller than the diameter of your intraocular lens optic. Generally it’s going to be about 4.5, 5 millimeters, in that ballpark. The posterior capsulotomy, if you do one — it should generally be either the exact same size, or perhaps slightly smaller. And I tend to leave it slightly smaller. Next question has to do with intraocular lenses. How about rigid IOLs used in pediatric cases? Absolutely. Many places — that’s the only resource they have, are these inexpensive rigid, non-folding IOLs. They work just fine. Why don’t we use them? Well, we don’t use them because it takes a big incision, which induces astigmatism, and we try not to use them, because they’re just big. They’re hard to get in. So it’s just a matter of ease and induced astigmatism, when it comes to what lens you’re using. But you use what you have, and they will work fine if you can get them in gently. All right. So we’ll go on to our next section, which is, again, the posterior capsule. This is the real big one here. Our next poll question has to do with that. I want to know what each of you is doing with the posterior capsule. In children — again, we’re gonna qualify this. This is children less than 5 years of age. How do you currently handle the posterior capsule in these kids? Do you… In a child less than 5 years of age, do you leave the anterior capsule intact? And do a YAG laser later? Do you open the posterior capsule manually with a cystotome needle or other instrument? Or do you open it with an automated vitrector? I’m sorry. I forgot to launch the poll. Here you go. Now you have the option to answer. Leave it intact, open it manually, with a cystotome, or open it with an automated vitrector? And I can tell you from experience that what you will do probably depends on what you have available. And here are the results. Leave it intact, YAG laser later — my only comment about this — if you leave it intact, it’s going to become opaque, and you need to know that you can somehow get that child in a YAG laser. That becomes a little bit complicated. Open it manually with a cystotome. I think if you aren’t going to use a vitrector, that’s probably the technique that I would recommend the most. Just tear an opening in the posterior capsule. This can be done quite elegantly. I don’t have a lot of personal experience with it. I know some of you do. I’ve seen some lovely videos of this being done. And I think if you’re not going to use a vitrector, this is something worth exploring, because you need to open that posterior capsule in a young child. Open it with an automated vitrector. Half of you are doing that. And that is my preferred technique. Well, let’s talk about this posterior capsule issue. Why open it? Why not just leave it intact? Well, the answer is because it’s going to become opaque. This graph is based on surgeries done in my home institution, at Indiana University. Here at the time of surgery, of course the capsules are crystal clear. They’re perfect. You almost can’t see them at all. You wonder if they’re there. But then, as time goes on, here we are, about 48 months. 4 years, right here, on the graph. Almost 100% of them are opaque. Why is that a problem? Look how many are opaque even here at 2 years. So if you’re gonna do a surgery on a 2-year-old here, and then 2 years later, they’re going to be 4, and they’re probably gonna have an opaque capsule. Or it’s an infant. You do a 1-year-old, and they’re gonna opacify quite quickly. Here they’re 2 or 3, and you’ve got an opaque capsule. Well, that’s just as amblyogenic as having a cataract. It’s almost like you wonder if you wasted your time even doing the cataract surgery. So you either need to open that surgically, or open it surgically with a laser. And they do have vertical YAGs, and my experience with them is that they don’t work very well, and that these capsules are really thick and tough to laser. So opening it up primarily at the time of surgery usually works best. If you go back and try and cut these things open later, they’re pretty dense, and it usually takes scissors in addition to a vitrector handpiece. What I do tends to be very age-based. So if the child is over 5, I think that capsule is gonna take a while to opacify, I’ll leave it intact. Because most of these kids, 5 and 6, 7, they can sit at a traditional YAG laser. The capsulotomies are hard. They’re very thick. Takes a lot of power, a lot of shots, but it can be done. Children under 5 — there’s no way you’re gonna get a child under 5 to sit at a YAG laser. So it needs to either be opened up with a vitrector or a tear. You can do that before the lens is in, after the lens is in, you can go from behind, you can reach around the lens — there are a lot of ways to do that. But you need to somehow get that opened up, and I’ll show you my preferred technique with that. My preferred technique is to use a vitrector. And I like to do it from a pars plana approach. I wasn’t trained as a retina surgeon, but I did learn to do this as a pediatric ophthalmologist. You can learn to do this. You may not be comfortable with it, but it’s not that difficult. And I think the safety margin’s actually relatively high. Unlike when you’re doing the lens material, you can use the smaller gauge vitrectors, when you do this. The reason to use the larger vitrector with the lens material is because you need more aspiration. Now, the vitrector — I usually will just use the 20-gauge and do it from the front. I do the anterior capsulotomy. I aspirate the lens material. And then do I the posterior capsulotomy. All with this same handpiece. And so I think choosing either the 20 or 23 is great, because you can just do the whole case, opening one pack, and using one handpiece. If you do the lens with this, and then you switch over to a smaller one for the posterior, I think you’re using a lot of resources. The settings are such that the cut rate needs to be high. You don’t want to be pulling on the vitreous. You want a very high cut rate. At least 500. So that’s why I use if it’s a fixed rate. If I have a variable rate, I go for really high cuts. You can go higher than this. You can go to 5,000. Whatever the machine will do. And then as you go down on the foot pedal and apply more aspiration, 0 to 300, you’re gonna start to engage, and you want that to slow down with the cutting. Now, the pars plana. This is the tricky part. You have to know where you’re going to do this incision. Pars plana in a child is not where the pars plana in an adult is. So the younger they are, the more anterior you have to go. It’s just like doing an Avastin injection for ROP. You’re actually going pretty close to the limbus here. So in an infant, less than 1 year of age, I will go about 1.5 millimeters back. So it’s gonna be right around up in here. If they are a little bit older, 2 years, going back 2 millimeters, and then the older kids, you’re getting back — here at 4 years, you’re going back about 3 millimeters. And that’s about as far back as I go. I like to open up the conjunctiva, so I can see the sclera. Go in with this MVR blade. You want to remember — you’re not going in with this angle that you see right here. You’re gonna stand that blade up towards the ceiling. You’re really gonna aim the tip of that blade towards the optic nerve. Keep in mind the lens is larger. It takes up more volume in the kids. And if you don’t direct it posteriorly enough, you’ll get into the edge of the capsule, but you do want to see that edge of the blade appear back here, behind the posterior capsule. You want to see that point and make sure you’re all the way through. Now, the nice thing about the smaller gauge vitrectors is you can do these entries with the trocar, and you have that — I think that’s an extra margin of safety, if you’re able to use those. So that’s the advantage of the smaller vitrectors, in my opinion. When I do this, we’re keeping the infusion here in the anterior chamber. Whether it’s bimanual or self-retaining anterior chamber maintainer. It stays in the anterior chamber. That makes it imperative that you try and increase the flow back to this handpiece in the posterior chamber as quickly as possible. So I like to get a cut right away in the middle of the capsule, so that that flow is going from front to back. You don’t want to be sitting back there, doing a vitrectomy with a closed posterior capsule, because then all the flow is gonna be going around the lens, and it can be pretty limited. So try and increase — get that capsulotomy going here first, so that you have flow around the lens and in the bag and outside the bag, and maintain that flow of the fluid. Here you can see I’m doing it to the pars plana. I could have gone through the corneal incision right here. And maybe tried to push the lens out of the way a little bit. And reach around it. And do that. If you do that, you have to be careful that you don’t drag vitreous out with you, when that comes out. The other way to do this is to do the posterior capsulotomy before you put the lens in. And that’s not a bad technique. The only thing that I don’t like about that is that when you have anterior capsule open and then the posterior capsule open, you just need to be careful with that posterior capsule, not apply a lot of pressure to it. You don’t want it to be blown out by inserting the lens. So… This is why I prefer the pars plana technique in particular. Now, in the 18 years that I’ve done this, have I ever seen retinal detachment doing this? Yes, I’ve seen it in a couple cases. Both of those were really small abnormal eyes. I have never seen a retinal detachment in a normal-sized pediatric cataract eye. So I do think that there’s a certain margin of safety here, despite how some of us may feel about this. We’re just trying to open this central area here. The presence of a posterior capsule, the presence of a posterior side of the lens, intraocular lens, those things provide scaffolding for the retained lens material to migrate across that visual axis. This looks crystal clear, when you’ve done the lensectomy. But out here in the equator, you can be guaranteed there are lens epithelial cells, and they’re going to enlarge and spread across that visual axis over time. So we need to kind of get away from the anterior vitreous here, and the capsule, so that there’s less of a scaffold for those cells to spread across. Here’s an example of how that looks with the bimanual technique. You can see left hand is still holding the anterior chamber infusion, and the right hand has the vitrector back through the pars plana incision. Again, this is courtesy of Dr. Ed Wilson. This is going to be injection of one of the slowly opening SN60 lenses. Followed by demonstrating the posterior capsulotomy technique through the pars plana. Now, you can see, once that’s injected, look how slowly those haptics are coming out. That really gives you a lot of time to get this lens in position. I will leave the anterior chamber maintainer in, kind of close up that corneal incision, and then again, you can do this through the conjunctiva. I like to open the conjunctiva and measure back from the limbus, and then go in with my MVR blade. A little cautery here, so we can see. And then there’s that same size 20-gauge MVR that I’m using, aiming back towards the back — now, look for the tip of that blade to appear right there. You want to see that. That’s what guarantees you that you’ve gone through the pars plana far enough that you’re not going to be engaging retina, when you go in with the vitrector handpiece here. So I mentioned trocars. These 20-gauge vitrector handpieces — the downside is that they’re big. They don’t go through protective self-penetrating trocars. The smaller vitrectors do have those. And I think that’s, again, probably one of their primary advantages. So first I’m cutting right where that posterior plaque is, trying to get a hole in that posterior capsule. You can see the edges of our anterior capsule out here. And the intraocular lens is in place. We’re simply gonna go around and make that posterior capsulotomy about the same size as the anterior capsulotomy. Just kind of finishing that off. I would say this one’s a little bit smaller. Maybe 4.5 millimeters in diameter. And then once we pull that out, we’re gonna make sure we don’t have any vitreous expelled from that wound, before we suture it closed. And the nice thing about that — the vitreous does follow the instrument that’s going to that sclerotomy. Versus if you’re from the front and the vitreous follows that instrument, it comes around the intraocular lens, it comes to the incision — that’s my main reason for not doing it through the anterior approach. Special considerations. I have a couple of things to touch on, before we go back to the final questions. Sutureless sclerotomies with the smaller vitrectors. You can do this. My only concern is that I think there’s an increased infection risk. I have seen a few cases myself. And the reason I think, for this, is that the sclera, much like the cornea and the anterior capsule in young children — it’s very elastic. These wounds tend to gape open a little bit. That is my preference for putting a suture in them. Using an anterior segment machine rather than a vitrector. It can be done. They work relatively well. I have some limited experience with this, using an Alcon Laureate. If you set it to IA cut, it will — the vitrectomy function, the anterior vitrectomy function seems to be adequate for doing a lensectomy in a child. Again, the cut rate is about the same. 250 for the anterior capsule and lens. 500 or so for the posterior capsule and vitreous. Vacuum settings are about the same. It’s this aspiration rate which is different, when you’re using an anterior segment machine. And I have a range here, because you kind of have to just play with this, and see how things are moving and behaving, and adjust that aspiration rate up and down. That’s the one thing I don’t like about these anterior segment machines, is that aspiration rate is kind of funny. Now, what about subluxated lenses? Let me pause this just for a second. Stop, stop, stop. Okay. What about subluxated lenses? So Marfan’s syndrome, idiopathic subluxation? These are tough. And it’s a nice way to use a vitrector, because you can take this lens out by virtually leaving the entire lens capsule intact. What I’ve done here is I’ve punctured it from the position of greatest displacement with an MVR blade. And then I’m gonna stick the vitrector in there, and aspirate all the lens material while the capsule is intact. That avoids any pulling on the vitreous. Because these patients are really at high risk for retinal detachment. You can also make this initial opening with the vitrector. Just cut a little hole and then stick the instrument in. But let’s let that roll and see how this technique works. All right. Now the vitrector is inside the lens capsule. And we’re just trying to aspirate all that lens material while leaving the capsule intact. And a little bit of cutting is being used here. In general, I try to avoid that as much as possible. Here you see we overaspirated a little bit there. The eye collapsed. We try to avoid that as well. Mostly once you get a little bit of room inside there, you can do this all with aspiration. And then once the lens is empty, which is just about now, then you can go strictly to cutting and just cut the empty capsule that’s there now. So you’re able to just have it cutting the whole time, so that you’re not pulling on the vitreous, once you get the lens material out first. All right. We’re going to go to the final questions here, and then we’re gonna wrap this up. Do you perform posterior capsulotomy before inserting a foldable IOL? My personal choice is to do that after, but you can do it either way. I think that is a matter of personal preference. Another question is the same topic. Do you do a posterior vitrectorrhexis before or after the IOL placement? Again, I do it afterward, because that way I avoid pulling vitreous anteriorly around the lens or to the wound. This same person is commenting that they’ve had some intraocular lenses open so fast that they extend the posterior opening. I agree. I don’t like the ones that open fast, and this is also why I don’t particularly like opening the posterior capsule before I put the lens in. Now, you can do it. And you have to be a relatively decent surgeon to pull this off, but it can be done. And again, it’s a matter of — how many are you doing? How comfortable are you with it? Final question is: Should we always remove the central vitreous, or can we leave it? If the anterior hyaloid is still intact? You can leave the anterior vitreous face intact. I think some people would argue that that might be better. I don’t know that we absolutely know the answer, but I know people that will tear the posterior capsule open and they’ll leave that anterior hyaloid intact. Certainly if you’re going to tear it open with a cystotome needle, I think it’s probably best that you leave that intact, because you don’t want to drag vitreous around. As we wrap this up, I want to point out to you that all of this material — first of all, this webinar today is being recorded, and we have this one as well as the time we presented this a couple weeks ago. Both of these are recorded and available on the Cybersight website. Also, if you go to Cybersight, all of the step-by-step instructions for doing a pediatric cataract are available either online or as a downloadable PDF, talking about each of these techniques, the settings, the instruments, step by step. And again, if you have questions that we haven’t answered, go to Cybersight consult, and general question, and send us your questions. Either myself or another pediatric cataract surgeon will answer you, and share tips or items that might be specific to a particular patient. Again, thank you for joining us tonight. We appreciate your time. And we look forward to our next webinar. Thank you.
April 22, 2016