Lecture: MIGS: Initiation to Gonioscopic Surgery

In this lecture, Dr. Johnson goes through all the important considerations to be made while performing a minimally invasive glaucoma surgery. She explains the concepts, the importance of patient selection and her current preferences.

Lecture Location: on-board the Orbis Flying Eye Hospital, Kingston, Jamaica
Lecturer: Dr. Sandra Johnson, University of South Florida, USA



DR JOHNSON: Today I thought we’d talk a little bit about small incision MIGS, where we go through these corneal wounds, and try to take care of patients with perhaps moderate glaucoma, not the severe ones that need trabs or the ones that we need to put tubes in. So which tool must be available to do most of the minimally invasive glaucoma surgeries? All right. So about 60%, the favorite answer is intraocular gonioscopy. Nobody wants a nasal lid speculum. I think that’s reasonable. Because I would say you don’t need that for most of the surgeries. So we’ll go through, and at the end we’ll see how our learning has progressed, and where we stand on these issues. Okay. Which of the following is for a goniotomy surgery in adults? And yeah, 82% would use a Kahook dual blade, and I think that is pretty good. Pretty up to date. And we’ll go through this again near the end. All right. And here’s another one. Which one of these microinvasive glaucoma procedures enhances outflow to the subconjunctival space? And a little bit split. So definitely in favor of the Xen gelatin implant, and as you’ll go along, you’ll see if this half of the classroom is on the money. Okay. So let’s talk a little bit about gonioscopic surgery. That’s a pretty common way that these surgeries for more moderate glaucoma are done. Many of them are done in conjunction with cataracts, because, as I said, a MIG is really a microinvasive, as I said. We’re not cutting conj. We’re just using a clear cornea incision or a paracentesis-type incision through the cornea, like small incision cataract surgery. So everything is going small incision, and now we have these small incision glaucoma surgeries. So gonioscopic surgery has long been used for pediatric surgery. If a baby has — or a small child has pretty clear cornea, then the preferred surgery is a goniotomy. And it has a high success rate in this group, and usually they can have two goniotomies done, if one is not enough. If you look at older literature, goniotomy didn’t really work for adults. You can look at studies maybe from India, different places, where they tried goniotomies and trabeculotomies in adults, and there was no long lasting effect. Because the adult sclera is thicker and more rigid than a baby’s sclera. So when we cut open a baby angle, it’s easy for it to splay open, and there’s something about that pliability that this surgery works very well. When we go ahead and incise and make a lot of little tags and things, and rip open, an adult TM — it scars shut. Right? Because it doesn’t splay open. It’s not a supple sclera. It’s got different characteristics. And so what we do on babies doesn’t work on adults. But now we have this approach that we use for babies, for different adult surgeries. So we found ways that you may get lowering, when you work on the angle, but curtailed and directed for adults. So again, what is a MIG? It’s glaucoma surgery that is microinvasive. To me, it’s the ones that are done through a cataract surgery incision. The oldest MIGS, if you think about it, was goniosynechialysis. Right? Doctors, for many years — it was described by Dr. Dave Campbell, who was a prominent glaucoma specialist in the United States for a while. He described this, where you go in, you look with a gonioscope, you use either like — maybe a sweep, and you gently sweep the iris off the trabecular meshwork, or you can use these special forceps that have since been designed to go in and gently pull the iris out of the angle, and open up an angle, so that patients can have better pressure control, post-cataract surgery. So they have their cataract taken out, they have their little residual synechiae broken, and then the viscoelastic is removed from the eye. So if you think about it, when we look at what’s the definition of a MIG, goniosynechialysis was actually a MIG. Then we had this endocyclophotocoagulation that came in. You know, Martin Uram in New York did a lot of these, and some cataract surgeons embraced it, and they would go ahead and do their cataract surgery, and through the cataract wound, put a lot of viscoelastic between the IOL and the iris, and go in, and laser ablate the ciliary processes to leave the patient with lower pressure. So if you think about it, that is a MIG. They were just going right through that incision, and not doing anything, cutting down conj, and this and that, and doing some type of procedure for the glaucoma, coupled at the time of cataract surgery. And this being a cycloablation, they do have extra inflammation, and things to deal with, when the patient has this done. And it’s still done today. Both of these procedures. Even though they’re older. So now we have these more recent microinvasive surgeries. And going through that corneal wound, you can put iStents in. So iStents are really for the mild glaucoma patients, and these are giving those little tube things, little snorkels that you put into the meshwork, and the fluid can bypass the sick TM, and go right into Schlemm’s canal, and then go on through the aqueous veins. So those are indicated in the United States at the time of cataract surgery for mild glaucoma. You know, you’ll get the patient off an extra med. Things like that. It does have some — I just saw a man who had a beautifully placed iStent. The eye that has the iStents on four meds, with a pressure of 17, and the eye that doesn’t have the iStent is on four meds with a pressure of 21, and he’s doing a little better in his iStent eye. He probably could have used something a little more aggressive. Some doctors are doing this ABIC. I’m not really sure what I think about it. That is when they use this… They go in, make a small incision in the cornea, make a nick in the trabecular meshwork, and they thread a cannula into Schlemm’s canal, and then as they back out the cannula, they inject viscoelastic and vasodilate that system, but to my mind, I don’t know if that’s really gonna work, because we’re not taking care of the sick trabecular meshwork. Now you get a dilated outflow system, but can the fluid get through the TM to the outflow system? I’m not sure. But that is the concept of that procedure, which I haven’t really decided. We have this Hydrus implant, which I’ll show you, which I’m very hopeful about, that does what the iStent does, and creates a little hole, where the fluid can get into Schlemm’s canal. It’s a bigger lumen than the iStent. But it also does some dilation to the canal. So it does a little bit of what ABIC does. No viscoelastic in there, but it does dilate the canal for several clock hours, so you’re getting a dilation of the canal of Schlemm, if it’s collapsed, and you’re getting more inflow, past the sick trabecular meshwork. We have the Kahook dual blade, which is nice, because you can do it with and without cataract surgery in the United States, because goniotomy is a well established, old procedure, but this gives us some hope that it can be successful in adults. Because of the way the blade is designed. And I’ll show you that. And then we have the Xen, which you inject from in to out, which creates a bleb. It’s kind of like a mini-trab, but it’s done with injecting a little stent through the clear cornea. And again, you can do it with and without cataract surgery in my country that has a lot of rules about these things. So when we do some of these procedures, you do need requirements. Right? So this is the machine that we use with ECP. We put that probe in, and we can see on the screen the little ciliary processes, and then you can paint them and shrink them and ablate them. But it’s an expensive machine. It’s not for everybody, because you have to buy this equipment, and then you’ve got to buy a probe every 20 cases, and so forth. So there’s an equipment investment. Same thing if you do trabectome, which is a way to do goniotomy. That requires you buying the — you’ve got to make that initial equipment investment, and then you have a per-case cost, like with almost all of these. You’ve got to buy a special blade or a little implant to do it. With trabectome, you’ve got to buy the little handpiece for each case. So there is some cost to these procedures. Essentials. So if you’re gonna do this type of surgery, you’ve got to be used to looking at the angle. You have to know what a normal angle looks like and what your structures are, okay? You don’t want to be like a lady I saw who had trabectome. She had a beautiful goniotomy done to her ciliary body by a prominent place, and now she has hypotony, she’s got a cleft, and then she had a bunch of things done to close the cleft and undo it, but if you looked at her, she was a high myope with very pale trabecular meshwork. So the surgeon got confused when she was in the OR, and then you’ve got viscoelastic and that angle is nice and deep, and he mistook the ciliary body band for the TM. So you really have to be making a mental note and be conscious. Because sometimes your angle doesn’t look exactly the same as it does in the clinic. It’s gonna be a little deeper or shallower. So you have to be able to identify your landmarks to have a successful case. If you do it with topical, if you put topical drops on the eye, like tetracaine pre-op, and then you inject some, say, preservative-free — no preservatives, but preservative-free — anesthetic into the chamber, you can numb up the meshwork for a short procedure like this. The patients can be quite comfortable. It’s surprising, but they’re not long procedures, and the numbing lasts long enough to get a good comfortable procedure done. You’ve got to tilt the head away from you to get down and looking in the angle. You’ve got to tilt the microscope. So you’re looking down into the angle. Right? You can use a direct or indirect lens. So if you’re using an indirect, if you’ve got a Sussman-type lens on the eye, then your brain has to convert the image, because you’re upside down and backwards. What you’re looking at — your hand is kind of like the endoscope, where you’re looking at the screen, but your hand is doing stuff. On this, you’re looking in one mirror, and your hand is somewhere else. And it’s a little weird when you start, and you do something like that. The direct views — if you’re going right nasal, it’s really wonderful to have the Swan-Jacobs, or something reusable and reautoclavable, that gives you a nice view into the angle, with a little bit of magnification. So you can have a lens that you sterilize and reuse, and now they’re starting to sell cheaper disposable lenses. And so you do your equation for your hospital, what’s gonna be the most cost effective for you, to buy boxes of these little disposable lenses, or to have one that you make an initial high investment, but you can use it over and over again. And then the lid speculum. Sometimes you do need a nasal lid speculum for, say, something like the Xen, where you’re going in at a little bit of an odd angle, and you don’t want to be hitting the lid speculum, so some people use, say, a nasal lid speculum, for a procedure like that. So that could be a consideration. Critical. When you first learn a new surgery like this, you want to pick people with beautiful, perfect angles. We did a Kahook dual blade with our trainee earlier this week, and the woman had a perfect angle. Nice, pigmented, easy to see trabecular meshwork. No doubt of where we were aiming for. So the surgeon didn’t have to worry, when they’re learning a new thing — is that really the TM or not? Am I cutting in the right place? That takes that out of the equation, if you pick someone with perfect anatomy, and they’ve just got a nice classic-looking angle, and so you know you’re putting the implant or the blade in the right place, and you don’t have to have that part to worry about, as you’re building your skill set. And then of course you’ve got to pick which procedure for which patient. You know, I have a handful of MIGS that I like the most. They make sense to me, and the kind of patients I see — like I said, I don’t do iStents, because I don’t really have mild glaucomas. Those people don’t come see me. They’re in a general ophthalmology clinic somewhere. They’re not coming to see the glaucoma specialist and worrying about going blind. They’re just getting a little quality of life — oh, I’ll take you off one extra medicine. We’ve got your ALT, SLT, and then a little stent. Maybe you’ll be on less meds. It’s for the mild patients. So you’re gonna pick different procedures for different patient groups, depending on who comes to see you, what you feel comfortable about, what you have available, and so forth. Of course, you’ve got to have a good view to the angle. I stressed that already. Comfortable with your instruments. You know, it’s nice if you can practice ahead of time. Feel the injectors. If you go to a meeting, go to the dry/wet labs. Have somebody come and sit with you, so you get comfortable with the instrumentation. Because that makes life easier, when you go to do it in the operating room. And we’re cutting open an angle, right? What’s beyond Schlemm’s canal? The aqueous veins. When you lower pressure, when you open up something, you’re gonna have reflux. Most of these — all these angle ones bleed. You’re gonna see some blood. It’s not gonna be bloodless. And so we have to get used to a little microhyphema and seeing a little blood. And there’s just an example, from this place I found, Abilita.com. Look at all those blood vessels around the angle, right? The angle is a vascular place. So if you’re doing a Xen, you’ve got conjunctival vessels. If you’re working — like if you do your trabeculectomy wrong, and you cut the ciliary body, you think you’re cutting iris, but you cut ciliary body, it bleeds like crazy, if you get into the circle of the iris, it bleeds. It’s a lot of vessels in the angle. Right? So we’re gonna be dealing with the ones that are the aqueous veins, which we can see here. So we’ve got Schlemm’s canal. And then it goes into veins. And veins will backflow, when you lower the pressure. It’s just like plumbing. So we’re dealing in an area where you do glaucoma surgery that does have blood vessels. Little tiny ones, but they can bleed. All right. So I say start with angles that you can see. Watch some videos. Go on gonioscopy.org. Go on the website of the product and pick someone who you know is a good surgeon, and watch them on EyeNet or YouTube. Okay? And then always look at the angle at the beginning of surgery. I look first, before I have them open my stuff. I put on my lens. I make sure my patient’s head position’s good, I make sure I can see the angle well. It looks like what I expected it to look like. I can see where the structures are, where the trabecular meshwork is, and then I say: Okay. We’re good to proceed. You know, it just takes you a couple minutes, and then you know you’re good to go, and you don’t jump in there and go… Ooh! It doesn’t look the same. What’s happening here? Because then you know: Do you need a little extra Provisc or something? Are you getting corneal fold with your gonio? Do you have to push the iris back a little bit? You know, whatever. You just verify in your head you know where you’re gonna go and your view is good and you really are set up. This is the Swan-Jacob type of lens. And these are the types. You hold it with your non-dominant hand. So we’re doing two-hand surgery, but most of us know how to do that. And use something through a side port, or use our left hand, if we’re right-handed, for something. And when your residents learn, make them do stuff with both hands. The brain doesn’t know any better. It’s not like we’ve been writing since we’re two years old and eating since we’re two years old. We’re learning a new skill, and there’s a little bit of plasticity in our brain. Our brain doesn’t know, when we’re in the OR, that we’re left and right-handed. And you can teach your non-dominant hand to do stuff. So throw a suture with it sometimes. Don’t be afraid to have house staff, when it looks like they’re struggling with their dominant hand, and they’re to their left side, say, when they’re right-handed, make them use their left hand. And then you get a little bit of facility. It’s easier to hold something like a gonio lens. Whatever. You develop a little bit of skill. Because your brain is learning a lot of new stuff. So it doesn’t know whether you’re left-handed or right-handed for this. So you can kind of teach yourself to use your non-dominant hand, and make it a little more useful. Okay. This is a beautiful view. Right? These are those classic gonio pictures you see. It’s probably somebody with pigmentary glaucoma. But there’s no doubt here that this is trabecular meshwork. Right? You know that’s your TM. And like when I do my first cases with something new, I pick angles that look like this. They may not be 4+ pigmented. Maybe they’re 2+. But I know the TM is there, and I’ll have no difficulty isolating it, that’s not what I have to worry about in surgery. And then as I get facile with something, I can take more patchy pigment and go in between PAS, and get fancier. But to start, you just take a classic angle. Okay. Sterile handles are nice. So if you have sterile handles, you can have them on there. You can be twisting the scope as much as you want. Or you have an assistant who can jump in there and help you with the scope. Like I said, if your patient’s under topical, you can tell them: You know, if you want them to look towards their nose or whatever, you say — hey, look over there. And they help you. Look down and to your left. Look up and to your right. You can have your patient helping you, if you numb them up with some preservative-free lidocaine. It just depends on the patient. Some patients aren’t very cooperative. You’re better off just blocking them and taking them out of the equation. So you decide on that. And sometimes, because it’s a new procedure, you like them blocked. Because you are not ready to have the patient help you. You just want to take them out of the equation. You just block them. So you have to kind of know thyself, and figure out what’s gonna make it easier for you. Okay. So the goniotomy kind of procedures — okay. We had the trabectome first. This was developed by George Baerveldt, who developed the Baerveldt glaucoma implant, way back when, and he worked on this, and this idea was that: Okay, if we’re gonna rip open an adult angle, we have to do something with those little leaflets and things that meet each other and scar after. So he came up with this idea, as you’re cutting open the TM, you have a little cautery there. So you cauterize the edges, so you don’t end up with little rough tissue edges that are gonna bind together and scar it down, as time goes by. And so they call it, for some reason, a trabeculotomy, but to me, it’s a goniotomy, because we’re going from the inside. Somehow he named it trabeculotomy, but I think it’s kind of a goniotomy. And that one, you did have to buy a machine, and it came with irrigation, kind of like when you do an I/A. You had some infusion coming in the eye to keep your chamber. So you didn’t necessarily have to use any viscoelastic, really. You just put the thing in, and it inflates the chamber, and then you do your cutting. The KDB was another type of thing. You know, Dr. Kahook, who is a glaucoma specialist right now in Colorado — he does trabecular meshwork research. So he wanted nice sections of trabecular meshwork to study in the lab. So he came up with this design of this blade that’s tiny. It’s like the width of the trabecular meshwork. Very sharp edges. And almost like a little scoop. And so he would go along and cut these nice sections of trabecular meshwork for the lab. And then somebody got the eureka that — oh, maybe this will work in people! Right? We can do a nice smooth goniotomy, and the edges are so smooth. It won’t scar down. We won’t have those little tissue leaflets, and we can get a goniotomy to work in adults. So thus came the KDB into our marketplace, right? Oh, this came out blurry. This is a slide — it’s supposed to be showing you how you see the instrument near the angle. Right? So when I do these, I have my wound, I put my gonioscopic lens on the eye, after I have my instrument, my trabectome, my Kahook blade, close to the angle. I do the same thing in babies. Then I put on my gonio lens and finish going all the way to the TM and so forth. But this came out blurrier than I thought it would. All right. Here’s kind of a schematic of what’s going on when you do, say, a trabectome. Right? So you’re going along, and the trabecular meshwork is to the right of the slide, and to the left is where the doctor would have unroofed Schlemm’s canal by taking off the trabecular meshwork. So they’re just going along and cutting, and you really do see these little collector channels. It’s very, very cool. Like, you’ll unroof Schlemm’s canal, and you’ll see these little red pinpoints, and they’re not all spread out evenly across the Schlemm’s canal. There may be a couple together, and then a few clock hours of none, and then another. So you can see how the iStent can miss these. You put the iStent in, and if there’s a septa there in the canal, it may not be near the collector channel. You can see how they’re a little bit randomly distributed. But you see them. You literally can see them as you take off the trabecular meshwork. It’s very, very cool anatomy. So this one cuts with this little fine tip, kind of like the Kahook, but it’s leaving behind that little bit of cautery. Okay. The Kahook dual blade. This is what it looks like, when it comes out of the package, like on the bottom of the slide. And then on the top is a diagram showing you how you incise the meshwork, and you’re just scooping that trabecular meshwork. It’s got that little — almost like a little shovel on it. And it’s just stripping the meshwork, as your hand moves along. And again, you see those little tiny red dot collector channels, and they start to ooze, because you’ve made a good communication with the aqueous veins. And it’s supposed to leave you that nice smooth edge, like in this schematic. And not leave a lot of leaflets to scar. The pros and cons — I already said the trabectome, to me, is a little more expensive, because you’ve got to buy a unit and all that. The KDB, you’ve got to buy your blade per case. So that’s the cost of that. But if you’re buying a trabectome, you’re buying a kit per case. So I don’t know if you do the initial investment of the machine, and then buy your kit per case. Is that — you know, gonna be less than buying a blade per case? I think the blades are less than the kits. But both of them lower pressure and the medication burden of patients. Both can be done independent of cataract surgery, so you can take a pseudophake or someone and do it, and there’s some head to head comparisons starting to come out. I know of one that’s gonna be presented at AARVO, where someone did a chart review on small people. On kids, really. But looking at the two different procedures, to see: Is there a difference between the two? But my suspicion is not. It’s very — at least in my assessment of doing both, they’re pretty similar. Just go back here a minute. These procedures — one thing about them: They seem to get more steroid response than, say, if you put an iStent in, or you put in a Hydrus. Because we’ve just unroofed so much, and the steroids get in there. So you don’t really know if they work for about a month, as you taper the patient off the steroids. And patients have about — if it’s a 20/20 eye, they’re about 20/30 blurry the next day. They’ve got some red blood cells floating around, and they seem to disappear pretty quick. I leave these people — just like I do with babies, I leave them on pilocarpine twice a day for a little while. Right? Because there’s a lot of flow at first. You don’t want the iris flowing with the aqueous and giving you PAS and ruining your cleft. So you want to put them on a little miotic, and I do twice a day, because that’s more livable than more, and try to keep them from having obstruction of that cleft I made. The iStent Inject, which I don’t use much, puts these two little — literally injects those through the TM into Schlemm’s canal. After surgery for cataract. And they do lower the pressure a little bit. And it’s been around a while. It’s very safe. It’s hard to injure a patient. And I see them all over the place. I see patients come in, and they’re beautifully positioned in the scleral spur. They don’t always get them where they think they’re getting them. It’s kind of interesting. But a lot of people who do a lot of cataracts and take care of mild glaucoma like to do this. And then if it doesn’t work, well, it didn’t work. But if it works, great. And there’s not a lot of morbidity. This is the one I like. This is the Hydrus. This is just new in the United States. It’s just kind of rolling out now, and I started to put some in. And this has a much larger lumen. If you look to the left of the slide, where that little metal thing — it kind of comes from the technology of heart stents. It’s nitinol, which they use for the cardiac stents, and the body reacts — doesn’t react to it, basically. So it’s a very kind of nice… It’s titanium, coated with nitinol, and people with nickel allergies don’t react to it, apparently. So it goes right into the canal, but you’ve got this little lumen on the left side, where the fluid can go in, and that is bigger… More surface area for aqueous flow into the system than two iStents. So it’s a nice-sized lumen, and it threads right into Schlemm’s canal. And then it scaffolds the canal. So like when I talked about the people who like to do, say, ABIC and viscodilate the canal, well, this sits in the canal and it stretches it open for the clock hours that it’s in there. And you can see it’s quite a few clock hours. You know? So you’ve got this thing in there, and it’s scaffolding and holding that canal open, and then it’s not continuous medicine. I mean, excuse me — not continuous metal. They’ve got windows in it. Because then where it’s stretched open, the concept is that more aqueous can get through where the windows are, where the trabecular meshwork is just kind of sitting over the stretched Schlemm’s canal, and even that is stretched open a little, and you get more direct flow into the TM in those areas. So this is kind of what it looks like, when it’s just there. That’s the injector on the right. There’s like a little wheel. You have to prick the TM at a certain angle, about 15 degrees. Just like you do in a KDB. And then you go parallel. And like in a KDB, you would cut. And in this, you just start pushing the little roller, and it loads it right into the canal. And then it does these different things. And they know — they think the stretch and the open window part is functional, because they have seen patients where the inlet gets clogged, and yet they’re still getting their pressure control. So they think the dilation and the windows concept does help. And this is made by a company — I think it’s called Ivantis. This is the only thing that it sells. It’s like a new biotech whatever — startup. But I kind of like the concept. And this is replacing, for me, the CyPass, that went off the market. Because I had some great pressures with the CyPass, but, you know, they’re worried about the cornea. This is far away from the cornea. We don’t think they’re gonna have cornea problems. And all their data so far they’ve collected — they’re not seeing any changes in the cornea. And so it’s likely good to go with that. And they did a big study. I think they’re doing a head to head now with the iStent Inject. I’m sure they’ll be better. So this is a nice — I think this shows a lot of promise for something that’s a moderate. And they’re also doing studies, I think, in Chile, looking at: Can you put it in alone, in a pseudophake? So, you know, for our country, the FDA will have to say we can do that. Right now, we can’t. In other countries, it may be different. I don’t know how that works. But maybe people could have it… Say you travel a lot, you leave far away, whatever. But you need more than I can give you with lasers and medicines. Let me stent your canal and see how you do. So if we can do it as a standalone, it might be a nice adjunct, before going to the trabeculectomy and the bigger procedures. The Xen. The Xen started as AquaSys, and now Allergan owns it. It was a biotech startup. It’s a technology that came out of Australia. It was a Dr. Daoyi, who did a whole bunch of these little collagen stents in monkeys, showing that it lowers pressure, and working on his technology. Then that now — a biotech venture capitalist, whatever — took his technology and said: Well, let’s see if we can bring it to market for humans. And millions and millions went into this. It’s crazy, when you look at all that. But they made a permanently crosslinked collagen tubule, and that’s gonna be — it’s kind of like a little doll’s piece of spaghetti. A little ziti or something, and you inject it from inside to outside. It goes through a 27-gauge needle, and you kind of pierce the TM, and you thread it through the TM, up and pop it out from the sclera, and leave part of it in the subconj space, part of it in the sclera, part of it in the anterior chamber. And you get a bleb right away. And these blebs, though, sometimes have to be needled. You don’t do suture lysis, but you have to do needlings. And it’s a different kind of needling. It’s mainly sweeping, because Tenon’s sometimes gets in these lumens. And they recommend doing mitomycin C. Like a one-time subconj injection. I personally use 0.1CCs of 2 milligrams per milliliter, way up in the fornix, under thick Tenon’s, away from where the tube is, because I don’t want any in the eye. Oh, came out a little blurry. But this part here you can see. So that’s on someone’s finger, the little tubule. You can see in the lower middle, that’s a schematic of the tube. So you’ve got a tail. Oh, no, actually, that’s a CyPass. I don’t know why that’s there. The other one shows you it. It goes up through the sclera. But they don’t show you a good coming out underneath. Let me see the next picture. Okay. This is someone putting one in. This is a little better. So you have this hook that a Dr. Vera designed, that you put into your second port. So you can stabilize the eye. It’s got this little ball on the inside, and it helps to hold the eye in place, because when you’re injecting, the eye wants to roll, right? So you want to keep your eye stable, so you can see what you’re doing. And this one’s a little bit nasal, but you try to put it towards 12, because we always like blebs underneath the lid. You know, we don’t like to have filtration in the fissure, where this is a little tube — you don’t want them blinking and rubbing on that every day with their lid. But you mark 3 millimeters from the limbus, and then you put on your gonio lens. I do a gonio-assisted. Some people don’t. But I like to put the gonio lens in, and just like I said with the Kahook, I put the needle, the injector, across the anterior chamber, almost to the angle, and I have — then I put on my gonio lens. I see the injector go up. I kiss the angle with the needle tips. Right? You get something on a thing you can roll, on the injector. And you start pushing it. And so you see the needle come out, and you impale your TM. And then you direct it so that it comes up, the needle pops up, and you think you’re gonna poke through the conj, but you don’t. You want to see it right under the conj. You want to pop through Tenon’s. And there’s a potential space there. There’s a space waiting for this. And then you inject it, so that you’re gonna have an intrascleral portion, a portion under the conj, and a portion inside the eye. And then before you leave the table, you go… Wow. Look at that. They’re making a bleb. It’s really cool. Takes less time than a trab. And this is what it looks like. They come back, and they’ve got a very low-lying bleb. It’s not like a bleb like we see. We don’t do the mitomycin the same. They don’t get ischemic blebs, really, and it’s less elevated than a traditional beautiful trab bleb. And you get this little thing there that the fluid’s coming through. But sometimes you can imagine how you have to go in with a little 30-gauge needle and sweep it if it stops working. You know, so that you get any little Tenon’s that plugs it. Because it made the lumen kind of small. I think it’s 40 microns. So here’s a case. Here’s someone I used the MIGS for. Okay? This guy is 48 years old, with bad glaucoma. He’s got glaucoma in his family. He’s got a thin central cornea. He’s been progressing. He’s had laser in his left eye. He’s got a prostaglandin. He comes in with 21 and 27. He’s not in control. His visual field looks worse. He hasn’t been here in a few years. The reason he comes in? He’s getting cataracts. I don’t see so well. Right? But he’s not taking care of his glaucoma. Right? And he’s a high myope. He’s like a -10 or something. So he’s kind of a mess. He’s only 48. His visual field looks worse. He doesn’t come in for checkups. He’s only there because he’s got a cataract. Right? And then we have no idea if he’s taking his medicines or not. Because you don’t come in years. Who is writing your prescription, right? Where are you getting your drops from? You know? I mean, God bless it. I had a lady the other day, she wanted to know if she could still use her bottle of Trusopt. No kidding — it was eight years old. I’m like… Oh my God. Are you… Do you take your drops? This is eight years old! I think we need to throw it away! So I have no idea where he’s getting his Latanoprost, if at all. So in this case, we had the CyPass at the time. Okay? So we did SLT. You can do that over ALT. So we said… Okay. We’ve got him here. Let’s laser him. Okay? Before we do his cataract. So we lasered the temporal TM, because we were gonna do a MIGS in the nasal. Okay? And then we put in the CyPass. And then guess what? Two months. He’s 20/25. No more -10. But the best part? His pressure is 10. He’s just got his little CyPass working like crazy, and his SLT, and we got him tuned up for a while. Though we tried to talk him into coming a little more often. Don’t come every five years. Whatever. But you can do well, when you get somebody not compliant. If they’re gonna have a cataract, you’ve got a chance to do a little something extra, if you have it, and try to keep them lower. Okay? And I had another man similar. Won’t take his drops. Oh my pressure is 30 all the time, Dr. Johnson. But I don’t like any of those drops. And I’m like… Oh, okay. Your pressure is 32. That’s gonna wipe out your nerve, eventually. Well, I’m here for my cataract. I go… Okay. Guess what? He got the same thing as this Howard guy. I said — okay. Well, before I touch your cataract, we’re doing a little laser, and we’re gonna do something at the time of cataract. And I gave him also a CyPass. And you know what? Instead of being 30 all the time, he was 18 and 19 all the time. Which was fine. He only had a little bit of field loss. And he was stable for, like, two years. I followed him for a while afterwards. So that was my chance to, like, oh, you’re gonna work with me a little. I’m gonna do a little laser first, and then we’re gonna take out your cataract, and oh, I’m going to do a little something else. It only adds three minutes, five minutes, to your cataract surgery. We’re gonna work on your glaucoma. And you get them to do it. So anyway, that was Howard. And that was another… A few other patients like that. So I personally like the Hydrus. So a person I just did a Hydrus in has a big nasal step, he’s got a pressure of 18 to 20 on three or four meds. He was allergic to the Trusopt. He was on Combigan and Latanoprost. And his pressure — I’m not happy with it. So you know what? He has a cataract. So we go to the OR. We do a cataract. We put in the Hydrus. His pressure is 14 now, and he only takes timolol. Right? So I got him on a dirt cheap drug. I tell him to do a once a day in the morning. And I got his pressure cut down a number of points. And I’ve done that with several patients. I’ve been doing the controlled eyes, and putting in a Hydrus, and then that helps me get their medicines down. And that guy had already had lasers. So that had been exhausted on him. I do KDB, I get great results in people with things like zoster uveitis. They got delights. They’re on chronic little steroid, not to let the pressure go up. You go in — like, I had a woman who had barely controlled pressure on aqueous suppressants. You couldn’t give her prostaglandin. She would get her uveitis right back. So she was on Cosopt and brimonidine. And pressure was running 20, 21. Not really a candidate to do SLT, because she’s uveitic. And she didn’t want a trab or a tube. She was emphatic about that. So she got trabectome. I did a trabectome and a cataract surgery, and then she was pressures of 15 and 16 on only her Cosopt. I got rid of her brimonidine, and I got her pressure down 5 points. So she was happy. She’s got less drops, I’m happy, the pressure is better, and then her vision, which was 20/200, was amazingly better. She waited a long time. We were a little afraid to operate, so she waited until she couldn’t see. So those kinds of eyes, with junk in the TM, you go in, and you unroof it, they do really well. And then I’m also thinking it’s gonna be good for my JOAG. I had one lady, two failed trabs, pressure of 32, won’t take many medicines, she got a trabectome, and her pressure was 14 for like 3 years. It worked like a charm on her, and she was a juvenile open-angle. So I feel like Kahook may be good for that population, and I’m using it. Xen — I like to do it in my little old White ladies. Or people with thin Tenon’s. Because then I don’t have to worry too much about the sweeping. And so I’ve been using it on those. But there are doctors experimenting with doing the Xen from outside in. So they sit — it’s a little different technique. I haven’t tried it. But they put that thing through the conj, through the sclera, into the chamber. And to me, that may be the way to do it in people with thick Tenon’s. Then you’re sure the lumen of the tube is up above that Tenon’s. You know, like, we operated on someone this week, like tons of Tenon’s. I don’t think a Xen could ever work in a patient like that. But if you went from out to in, you would have a better chance of having the lumen of your little gelatin tube being above Tenon’s. So maybe that will work for them in the future. Well, the patient that I did SLT and then the surgery with a MIGS is because if the pressure’s 30, for example, in the one man, I know if I do a laser, it’s gonna go down about 20%. So then I say: Okay. With the laser, you’re gonna have a pressure around 24. I need to do something else to get you down. Because the cataract surgery, we know, lasts about a year or so. He had wide open angles. So I’m not gonna get a big drop from taking out the cataract that’s permanent. So then I say: Okay. If I get you around 24 with laser, if I do a little something in the OR, like the CyPass, I’m gonna get you down some more points. You know? And this is someone that tolerates no medicines. So it depends where their pressure’s at. If they’re like 18, like the other one on a lot of meds, I just do one thing, and just go in, and do that. But if they’re kind of high, around 30, if I think if they haven’t had laser, and they don’t like meds, doing a laser first and then the MIG in the other angle helps them. All right. Quick on the quiz. Which one of these do you need to have available for most surgeries? Look at you guys. So attentive. The few outliers that were gonna do something else all know — intraoperative gonioscopy is very critical to all these surgeries. Excellent. Okay. Which of the following is for the goniotomies in adults? Oh, we still have a little learning to do. Okay? Because a goniotomy is when you unroof the TM, right? So you’re not unroofing the TM when you put in a Hydrus. Right? You’re just bypassing the sick TM and stretching the canal. And then the CyPass is actually off the market, but that went into the suprachoroidal space. So no goniotomy there. Right? So the goniotomy is when we use the dual blade or trabectome. Unroofing the sick TM is the goniotomy. All right. Which of the following gives you outflow to the subconj space? Which of these microinvasive things? Hydrus, CyPass, iStent, Xen, or trabectome? Oh, pretty high. Some people still want to throw those CyPasses in, but CyPass goes to the suprachoroidal space. It’s the Xen that goes up under the conj. So somebody wanted to put a CyPass there, but it wouldn’t fit. Okay? So CyPass was something that was into the suprachoroidal space. A little tube. But it’s the Xen I talked about, that we inject through the meshwork, and come out up underneath the conj, to form like a bleb. Okay? All right. Thank you. You’re a great audience.

April 06, 2019

Last Updated: October 31, 2022

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