Lecture: Cyclophotocoagulation: Technology and Patient Selection

Trans-Scleral Cyclophotocoagulation (TS-CPC) is a commonly used laser treatment for glaucomatous eyes suffering from severe to end stage disease. The endocscopic form, known as endocyclophotocoagulation (ECP), is commonly used for earlier stage glaucoma and is often coupled with cataract surgery. This talk will focus on the basics of both transcleral as well as endocsopic CPC including patient vignettes and pearls for practice.

Lecturer: Dr. Malik Y. Kahook, Professor of Ophthalmology – University of Colorado, USA


DR KAHOOK: Hello, everybody. I am going to put up my screen here, so that you can see my slide deck that we’re gonna go over. As you can see, the title here is cyclophotocoagulation: Technology and patient selection. My name is Malik Kahook. I am professor of ophthalmology at the University of Colorado, and I’m currently sitting in an airport lounge. So I’m going to keep my voice to this level, and hopefully there won’t be too much surrounding noise during this. I’m gonna try to get this done with enough time for question and answer afterwards. You know where the question tab is, so please take a look at that and send in your questions, so that Lawrence can tabulate the questions and we can go over them with as much time as we have left. These are my financial disclosures, none of which are relevant to this talk. And here’s a simple outline. We’re gonna talk about cyclophotocoagulation in the traditional sense. That is transscleral. But also covering endoscopic, because more and more we’re doing this treatment endoscopically. I’ll go over a case-based teaching approach throughout the talk, and at the end, I’ll cover some of the basic thought process as to selecting ECP, versus CPC. And then of course we’ll do the question and answer. So I’m gonna start off with a patient case here. Mr. JC is a 73-year-old phakic Latino male with 25-year history of primary open-angle glaucoma, he has advanced disease with advanced cupping and visual field loss in both eyes, he has failed trabeculectomy and GDD in both eyes, pressure is 26 in the right and 24 on the left, on maximal tolerated medical therapy, and the goal is in the low teens. So you should be thinking: What is the next step, keeping in mind that we’re talking about laser therapeutics today. And I’ll come back to that case towards the end. From a historical perspective, I was surprised when I saw this list. The range of treatments that have been done to the ciliary body and ciliary processes throughout history is extremely long. You can see this list is two columns. The focus of this talk is going to be the diode laser-based therapy, transscleral, but also like I said, more recently, getting into the endoscopic route. From a transscleral cyclophotocoagulation standpoint, the indications for use include failed prior filtration surgery, and in particular these are patients where you don’t want to do further conjunctiva-based surgery because of the high risk for failure. Poor prognosis for filtration surgery. These are patients like neovascular glaucoma, postpenetrating keratoplasty, and postscleral buckling patients. Poor vision, and the focus is really comfort care in these patients. We try to avoid incisional surgery and CPC is a good option. And primary therapy in patients who are poor incisional surgical candidates for physical or social reasons. This is what the box typically looks like. I actually haven’t seen a transscleral diode traditional box that looks different than this. They might be available in other places around the world, but this is the one that we typically use. From an energy standpoint, 1.75 to 2.5 watts. Typically around 2 seconds is what you see in textbooks and I’ll go over what we do here in a little bit. And 24 spots over 360 degrees. The way that the treatment is done is the probe itself, which I’ll go over in the next couple of slides, is placed at the limbus, with the center of the fiber optic, the quartz tip will actually be at 1.2 millimeters posterior to the limbus when you place the edge of the G probe on the limbus. And the edge of the probe is placed in the center of the previous spot, after each exposure. So that way you’re kind of getting these overlapping spots, but the quartz tip is actually a full distance away from the initial quartz tip. And we do this for 24 spots. Typically avoiding 3 and 9 o’clock. What I would like to emphasize, if you don’t remember anything else about the treatment parameters, remember low and slow. What I typically like to do is set the time at 3,000 milliseconds, and from a watt standpoint, 1500 milliwatts. This allows the slow treatment of the tissue without that first full burst of energy that can cause the popping noises that you can hear from time to time with these treatments. That slow simmering burn on the tissue tends to do really well. And also minimizes inflammation, in my experience. Now, this is the G probe. You can see the quartz tip, which is on this bulbous extension at the bottom of the G probe. This extends about 0.75 millimeters from the flat surface of the bottom of the foot plate. And again, it’s located 1.2 millimeters away from the limbus, when you place the edge on the limbal margin. So this allows you to target the ciliary processes, to know that you’re at the appropriate distance away from the limbus to target the tissue, and in cases of normal anatomy, this does quite well. Now, in cases of congenital glaucoma or high myopia, where the tissue might be slightly different, as far as the relationship between the limbus and the ciliary processes, something to keep in mind and one of the reasons why we’re doing more and more ECP. This is what typical treatment looks like. I tend to use a lid speculum to keep the lids out of the way. You can see from this textbook photo, Chandler and Grant Glaucoma, the surgeon is lifting the lid. I find this to be awkward and just take that variable out of the equation. And I mentioned avoiding 3 and 9:00. Very important. If we have trainees on the phone here who are just starting to do CPC, avoiding 3 and 9:00 allows you to avoid the postciliary nerves and vessels, minimizing discomfort and inflammation postoperatively. Very important point. So keep that in mind when you’re doing your therapies. And in the corner you can see the overlapping spots. You have one on top of the other when you put the edge of the G probe where the previous quartz tip was, you’re doing a full distance away of the quartz tip to allow you to do 24 spots for 360 degrees. What do you do preoperatively from an anesthesia standpoint? We typically use retrobulbar anesthesia. 2% lidocaine, 0.75% bupivacaine, plus or minus hyaluronidase if that’s available to you. In many areas it’s not, but if it is, we like to use it, just to disperse the anesthetic better. Atkinson, a retrobulbar needle, is the safest to use, 5 to 10 milliliter syringe with an alcohol swab to prep the area prior to injection and always have a gauze pack that helps you massage the eye afterwards with the patient being comfortable with the gauze laying over the eye. This is essentially a non-sterile procedure, which can be done in a procedure room or in low resource settings, which is why it’s valuable in many areas around the world. Postoperatively, we use prednisolone acetate four times a day. The inflammation dictates the dose. You can do it higher or for an extended period of time depending on what the inflammation is telling you. Atropine BID or QID. I usually use QID. Continue all preoperative glaucoma medications except miotics. The miotics can actually increase the synechiae that occur between the iris and the anterior capsule. You can resume the miotics when the inflammation subsides. Check pressure, one day, one week, one month, three months later. In some cases, surgeons choose not to do the one hour postoperative IOP check, but if you can do that, it’s good to do before sending the patient home, and you can retreat if desired, if the IOP dictates that. We have people from Nigeria here. This is a study that came out in 2018 from Nigeria. I want to make a couple of important points from this study, which was very well done. You can see the CPC G probe on newly diagnosed patients. The two things to highlight here is that the pressure started at around 39 and decreased at month 12 to 19. Very good IOP lowering with CPC, but you can see there was a loss of patient follow-up. And one of the great points made in this paper is that something like CPC might be a safe and effective option, especially in areas where follow-up might not be as good. Follow-up is less critical with CPC versus the incisional surgeries. This might be a very good option, and you can see the low complication in the bottom right hand corner, whether uveitis or hypotony. Another point I want to make about this study — and you can go back to the video — but one point I highlighted and underlined here is they did the study in patients who had very good visual acuity to begin with. A lot of times we think of CPC as something we don’t want to do in patients who have good visual acuity. In this case, traditional transscleral cyclophotocoagulation, they noticed that there was a significant decrease in 30% of patients — their visual acuity. That’s one reason why we’re looking for a better way to do cyclophotocoagulation. And this is where micropulse enters into the picture. This is a relatively recent addition to the method for doing cyclophotocoagulation. From the transscleral route. It’s called cyclo G6, using a slightly different probe. And we’re gonna go over some of these basics just so you’re aware of some of these other technologies. The main difference — one simple way to think about this, if you’re thinking about traditional transscleral versus the micropulse form, continuous with the traditional transscleral mode, versus a micropulse, which is very similar to how we think of SLT versus ALT. There is a relaxation period in between delivery of energy. So that the tissue has time to reduce that thermal buildup that happens. So micropulse in theory should be easier on the tissue with less inflammation, less complications, potentially, than the traditional transscleral. And this is something that we’re still studying and trying to find out more and more about. I got a couple of slides here from Nate Radcliffe, who practices in New York and has done many of these procedures. He typically titrates laser power between 2,000 to 2500 milliwatts, but keeps the time at 100. If there’s any factor he alters, it’s the power, not the time. The laser is titrated by several factors. Iris color. Darker irides will get less pressure if you’re seeing a patient or treating a patient with higher pressure, you’re using more power. Higher power for more severe cases, more severe disease. Visual acuity, you’re using lower power for patients with 20/20 vision, good visual acuity. And repeatability. Lower power if the patient is willing to come back for more procedures. You can hedge your bet on the amount of power and go low, and retreat as needed. From an anesthesia standpoint, retrobulbar block, propofol plus or minus, speculum, lubricant. Some surgeons like to use lubricant because it helps with the movement of the probe, which is different from the G probe. And you can use a Q-Tip or cotton tip swab for control of the eye. Here’s what the probe looks like for micropulse. Very different and very important to know the differences between the two. In the case of the G probe, you have the quartz tip that is sitting 1.2 millimeters away from the flat tip. And the curve of the G probe teaches you where to put it on the eye. In the case of micropulse, it’s a little bit more difficult to tell which side goes against the limbus, and you can see here the notch on the probe is the part that should go against the limbus. If there’s confusion, you’re not gonna have the energy delivered to the right spot. So if you’re using this type of therapy, make sure you read the instructions, and look at the package insert that comes with the device, so you know exactly how to use it. And I’ll show you a video of that here. So you can see there’s a side to side movement that happens. This is again Nate Radcliffe doing the procedure, not using a speculum, which is something I like to do, but in his case he doesn’t do that. And there’s a side to side motion that’s happening. Using a coupling agent like Goniosol or a lubricant, artificial tear, will allow you to smoothly go back and forth. And this is a sampling of patient scenarios where this might be used in clinic. Patients who prefer laser over incisional surgery — and we’re getting more and more of those patients in our clinic — primary surgery for elderly patients, who might not tolerate some of the more invasive incisional surgery, choroidal hemorrhage in the fellow eye, if they had surgery and had complications, it’s something to keep in mind. Failed tube, poor vision, severe blepharitis, if you don’t want them to have an incisional surgery that could potentially get infected, and some other scenarios where we use micropulse. Frankly, the low and slow of transscleral traditional CPC could also apply to all of these cases that I have listed here. We don’t have a lot of studies looking at micropulse. We’re just now starting to see some of the publications. This is one that came from Nate Radcliffe and colleagues, looking at a pressure of 25 going down to a pressure of 17, but only short follow-up at three months. We need to see longer term follow-up in these procedures. There’s also a significant reduction in medication, from 3.3 to 2.4. Here’s a study comparing micropulse to traditional CPC. 24 patients, smaller study, as you can see listed here, but one of the take-homes is that they had greater success in the micropulse arm compared to traditional CPC, and they didn’t have prolonged hypotony cases, as opposed to the traditional CPC, which had 5 cases. So it might be safer. Still too soon to tell. We’ll keep following and learning from the studies that are being published. Postoperatively, Dr. Radcliffe likes to use dexamethasone, but everything else looks very similar to what we discussed. And you can do retreatment at one month, as I mentioned, as well. The expectations here is that the eye will be quiet at day one and following day one, they’ll have treatment and that’s one of the main benefits. If you titrate the energy and use micropulse, you might get less inflammation. Don’t expect to have the ultimate IOP lowering until about a month or two months postoperatively. And in the experience of surgeons who have done a lot of micropulse, about 10% of the cases require a retreatment. To give that sustained effect of IOP lowering post two or three months. So some CPC conclusions. Traditional CPC, meaning non-endoscopic, low and slow, if you don’t remember anything else about the treatment, please remember that part. I think it’ll serve your patients well. And complications are real, but might be safer than incisional surgery. Micropulse CPC might be appropriate for earlier disease, because of the lower complication rate. But that’s still to be determined. We need longer term and head to head studies to really know that for sure. Still associated with complications. Still laser, still glaucoma surgery. So just keep that in mind, that it’s not an easy fix to what we do. It requires a lot of thinking, and the art of medicine is still involved here. So is there a better way to target the ciliary processes? Endoscopic cyclophotocoagulation is something that I’ve been involved with for over 15 years now. So we’ve done a lot of work looking at the utility of doing endoscopic CPC. Either combined or standalone, combined with cataract surgery or standalone. The probe itself has a light and camera component as well as a diode laser, and that’s an important point here. ECP uses the same laser technology, a diode laser with wavelength of 110, exactly the same as what CPC does. Typically we dilate the pupil, we put a cohesive viscoelastic under the iris to take it away from the anterior capsule and ciliary processes, and we treat as many of the ciliary processes as we have accessible, and I’ll go over the treatment modality a little bit more here with a video. I’m not gonna go through all of the points here on the EndoOptiks E2 box, but I wanted to put it into this discussion so you can go back to the video later on and pause it on the slide and read 1 through 10 to see what all the components are. The important ones are 7 and 10. I always set it at 2.5 watts. I don’t alter the power. I alter the distance between the ciliary processes and the probe instead of increasing the power, and the aiming beam, 20 to 30 is what we’re looking for, so it’s not washed out by the illumination of the light source. I’ll show you a video of this, with these settings being used. There are many choices for the probes. We use a small gauge curved probe, which allows you to go in and treat a lot of the ciliary processes that are away from your direct clear temporal incision. A lot of times we couple this with cataract and go through that incision. The curved allows us to treat a lot more of the ciliary processes compared to the straight, but they’re both effective and you can use either one. You should see equal effect on the tissue. We did early light microscopy and electromicroscopy studies to make sure there is a difference between the endoscopic and the transscleral route. These are ciliary processes that we’re seeing with the arrows pointing at the ciliary processes. This is what normal looks like. You can see the iris on the right hand side, and the pars plana on the left hand side. This is post-ECP, where you see a blunting. If this is what the ciliary process looks like, post-ECP, it looks like this. It blunts and shrinks, as opposed to CPC transscleral, where the arrow is pointing towards a cavitation area of destruction that happens with the pop in the ciliary processes. With light microscopy, this is what normal ciliary processes should look like. You see this lacy pattern of the tissue. Post-ECP, you don’t lose the architecture of the ciliary processes, but you get this blunting of the laciness of the tissue. As opposed to CPC, where you see full destruction and disruption of the tissue and the surrounding areas. So from our study, looking at the endoscopic route, versus the transscleral route, there are definite differences from a histologic — both electromicroscopy and light microscopy, to show that ECP has a lower tendency to disrupt tissue, and you would then extrapolate and say: There’s probably a lower chance for complications and inflammation. There aren’t a lot of studies comparing ECP to traditional CPC, but I can tell you in my experience that we do see lower inflammation, lower complications. And that makes sense. Because we’re targeting the tissue directly. We’re not going through the sclera through the ciliary body, trying to get to the ciliary processes. What we’re doing is directly targeting the tissue from the inside and not going through all of those layers that we really aren’t targeting anyway. We aren’t worried about them. But you can see all that destruction histologically, that augments the belief that from an endoscopic standpoint, we’re doing something good. And that’s really what the results were, that there are clear differences, and that has driven us towards doing more and more endoscopic therapies. From a patient selection standpoint, I use this as replacement for medical therapy. So if I’m in there doing cataract surgery already, then I’ll combine that with ECP. Especially if the patient is on two or three medications. I can often get them off one or two of their medications, and lower their burden of treatment. Post-trabeculectomy failure or glaucoma drainage device failure. If I’m in there doing cataract surgery in particular, combining that with ECP tends to do very well. Poor bleb candidates. These are patients who are, for one reason or another, would not tolerate a bleb-based procedure, whether it’s increased risk of infection, physical limitations, social reasons where follow-up might not be possible. ECP is going to be a better treatment in those patients. Any indication where transscleral cyclophotocoagulation might have been a prior approach, ECP would be appropriate. Corneal transplant or Kpro patients, these are patients who are going in, often combined with our cornea specialists, where we can do it at the same time of the corneal transplant or Kpro. And that way you can keep them away from tube surgery, which might alter the outcome of their cornea-based procedure. Congenital glaucoma, we’ve used this extensively. There’s a ton of literature out there on pediatric cases where it shows very great efficacy, without having to put hardware on the eye like a glaucoma drainage device. And then in aphakic vitrectomized eyes, where you’re trying to keep it open without a bleb or a fistulizing procedure, using ECP tends to be safer. From a pre-op regimen, it’s gonna look very similar to cataract surgery alone. Phenylephrine, cyclogyl, an NSAID, whatever antibiotic is available, lidocaine gel, and when you’re first starting out, it would be good to do a peribulbar block, typically an infranasal cut down, and put a cannula in and inject lidocaine and bupivacaine. As you advance in your treatment, you become better at doing ECP, you can inject lidocaine intracamerally, especially if you have good anesthesia service with you, so you have a trained anesthesiologist or anesthesia specialist who can give propofol or keep the patient comfortable while you’re doing the procedure, in which case you can take away the retrobulbar, peribulbar block, and save some time and potentially some discomfort for the patient later on. From a treatment step standpoint, I wanted to emphasize some points here. That we use a temporal clear corneal incision. Typically 2.2 or 2.4 millimeters. With topical cases, we use the 1% intracameral lidocaine, preservative-free. We inflate the iris off of the anterior capsule, to expose the ciliary processes, and we typically do this with a cohesive viscoelastic. In the US, we typically use Healon GV, but you can use anything that’s cohesive, that will really maintain that space. If the patient is aphakic, or in pediatric cases, use an anterior chamber maintainer. You don’t have to keep putting in viscoelastic and have viscoelastic go into the posterior chamber. If you use an anterior chamber maintainer, the lens isn’t in the way, so you can get in with the probe and its not as important for the iris to be far away, because you have a lot of space to work with, and plus or minus superior clear corneal incision. I’ll go over that with one of the studies I cover. With the modes, we typically set it on 0.25 watts, continuous mode, adjust illumination to visualize the aiming beam, prior to entering with the probe into the eye, so you get something with writing on it, you take the probe which is curved, put it up against the writing to make sure you’re oriented correctly, and you can adjust the illumination and the aiming beam to make sure that before you go into the eye you’re set to go. The nurse or the technician is always going to have to be there to alter the camera. One of the unfortunate aspects of ECP is that the surgeon doesn’t have complete control of rotating the camera when you’re using a curved probe, in order to reorient the image. And in some cases, you might need help with focusing, which is best done on the box, and you can’t do that during a sterile procedure, so an assistant always has to help you with that part. The endpoint is whitening and shrinkage. So that’s what we’re looking for. And we’re using a painting motion. We keep our foot down on the pedal and we’re painting over the ciliary processes. We’re not doing step on the pedal, treat one, stop, treat one, stop. We’re actually doing this painting motion. And that allows you, as the ciliary processes are shrinking, to get the cells that are on the sides of the ciliary processes. So you’re not just doing this. You’re basically doing this. Shrinking and getting the sides of it. And that allows you to treat maximum amount of the cells that you’re targeting. You don’t want to get a pop. If you’re getting a pop during ECP, you’re basically taking away the benefit of doing an endoscopic treatment. Right? So we’re trying to take that away from what traditional CPC is. We’re just trying to do the painting motion and doing everything possible to avoid overtreatment. One of the tricks that we investigated over a decade ago, which is really funny to think about — this is almost 12 years ago that this was published — we were looking at: Is there a visual clue to tell you when you’re appropriate, when you have a distance appropriate from the ciliary processes? Like I said initially, I don’t alter the power. I keep it at 0.25 watts. And what I do is I alter the distance away from the ciliary processes to get the treatment effect. We found that the ideal distance from the ciliary processes with the probe was 2 millimeters, and a way to indicate that during surgery is if you can count six ciliary processes in your view, you’re about two millimeters away from the targeted tissue. I always tell the trainees when they’re doing their first few cases, try to count six ciliary processes as you’re going through, and that should give you the appropriate distance away from the targeted tissue. Here’s a video showing everything that we just talked about. You see the probe between the iris and the anterior capsule, and there’s a very targeted and slow methodical approach to treating the ciliary processes. We keep our foot depressed on the pedal so we’re not starting and stopping. And once we get to the extreme of our treatment, we then flip the probe, flip the camera view, and go around the other way with the curved probe. And you can typically get about 300 degrees with the curved probe through a single incision. And if you get that, then I would consider that — you can see here the haptic abutting the equator of the lens capsule. Which isn’t really getting in the way. But you can imagine if this patient were phakic, then this treatment would not be the best possible thing that you could do, because the lens, the natural lens, really does get in the way. But one of the points here that I wanted to make when I was mentioning the curved probe is that no matter what you’re not going to be able to get 360 degrees, even with the curved probe, because you’re not getting your subincisional ciliary processes. And that’s an important point to keep in mind, and I’ll show a couple of studies, where we went through how to overcome that. Postprocedure, thorough viscoelastic removal. You’re using a cohesive viscoelastic, so if you don’t completely take it out of the eye, you’re going to have significant pressure spikes. Prednisolone QID for four weeks or so, non-steroidal QID until finished is typically what we do in our practice. And then a fluoroquinolone, fourth generation, is what we use, but you can use any antibiotic that’s standard of care in your area. And then of course if you’re blocking the patient, then patch the eye. ECP, postfollow-up, in the postoperative period, glaucoma meds are restarted. Typically if the patient has a pressure of 15 or higher, postoperatively, I’ll put them back on all of their medications. If their pressure is lower, 10 to 12, I’ll just put them back on one medication and ride it out until they’re done with their steroids. The pressure will not drop immediately after surgery. It’s not like a trab or a tube where you might see an instantaneous decrease. In this case, it might take a few weeks to actually get to the ultimate pressure that the ECP is gonna take you to. So you want to follow these patients, and then once they’re off their steroids and they have a few weeks behind them, then you can start to wean them off the glaucoma medications and see where they end up. Here’s the point of 300 degrees versus 360 degrees. The only way to do 360 degrees with either the straight or the curved probe is to make a second incision. So if you’re doing a temporal clear corneal incision, you can then go superonasal and get the subincisional ciliary processes. We did a study on this, as you can see here. And we found a significant improvement with pressure outcomes of 360 degrees versus 270 to 300 degrees. So when possible, especially in the patients where the target is very low, we try to do a superonasal incision after we’re done with the initial 300 degrees, and treat the remaining subincisional 60 degrees to get a significant reduction in pressure as well as in their dependence on medications. Does ECP work as standalone? This was a big question, and because of the lack of many studies that are looking at this question, we ended up doing this study in our own clinic, and we found that both combined ECP with cataract, as well as standalone ECP, significantly decreased pressure as well as medications used. But as you imagine, when you’re combining it with phacoemulsification or cataract extraction, you’re going to get a bigger combined effect. But you’re still getting significant benefit from doing standalone ECP. Now, we don’t have a ton of time to go over all the studies, but I wanted to put this link on there. And you can go back to the video. Or do a screenshot of this, if possible. And then go to the EndoOptiks website, and they have a PDF with all the studies to a certain date. It’s not updated to 2020 with the couple of studies that have just come out, but it allows you to go and see what the studies were, how many patients, what the outcome might have been, and it’s a good resource if you’re starting to look at ECP as a potential option in your area. Now, here are some considerations to keep if mind. Always do it after cataract surgery if you’re going to do it combined, because you don’t have enough room in a phakic eye to do the treatment. Use enough viscoelastic. Do not skimp on the viscoelastic. You want to make sure the iris is far away from the ciliary processes. You don’t want it to get in your way. There have been complications where the iris gets connected to the endoscope and it’s pulled out when you pull out the endoscope. You don’t want that to happen, so be careful with the viscoelastic and inflating the iris away from the probe. Take time with painting. Second clear corneal incision for 360 degrees, take time in removing viscoelastic. Very important. And then the final pressure is going to be in the mid to high teens. Really in our experience with 360 degrees, we’re getting somewhere between 13 and 16 with our pressure. Depending on the state of disease. ECP can be effective with proper patient selection. It’s not for all patients, but certainly in the scenarios that we discussed, it does very well. Proper technique is a must. We say that about all of the surgeries, but in this case, what I’m really emphasizing here is to avoid the popping of the ciliary processes, because you’re taking away the benefit if you’re getting a lot of popping ciliary processes. Two site surgery leads to lower IOP, so if you have the capability to do a superonasal incision and treat the subincisional processes, that’s the way to go. A couple of studies here. 2020, this just came out. Looking at phacoemulsification combined with either ECP or phacoemulsification with traditional transscleral CPC. 46 eyes underwent ECP and 34 underwent phaco with traditional transscleral CPC, looking at success and complication outcomes between the two. This is kind of study that we’ve been waiting for, to see what the advantage is of doing endoscopic treatment. And they found — I think these findings are interesting. The pressure was lower in the phaco-TCP, traditional CPC, they both lowered pressure significantly from baseline, but a lower pressure was obtained with the transscleral route. And this would have been unpredictable to me, but what they showed is that the adverse event profile between the two treatments was very similar, and the conclusion here at the bottom — phaco with traditional transscleral CPC could be considered as a simple and economical alternative treatment for patients with medically uncontrolled glaucoma, particularly where access to other ECP or angle procedures might be limited. So we shouldn’t think of traditional CPC as something that’s relegated to the corner of the operating room if you have an ECP machine. There are particular patients where if you’re combining it with phaco it makes a lot of sense to do endoscopic treatment, but if what you have access to is a traditional or micropulse CPC, in those cases. The patients tend to do very well, and the study I showed in Nigeria, populations where the return rate might not be 100%, as we want it to be, this might be a good option, because there are no incisions that are done on the eye with standalone CPC. Of course in this case it was combined with phaco. Let’s get back to the patient case here. We went through some patient scenarios throughout, to go over when you might want to consider doing these procedures. This is our phakic patient with advanced POAG, pressure goal in the low teens, and in this case, if available to you, cataract surgery with ECP is an excellent option. You’re going to improve the vision by the cataract surgery, you’re going to decrease the pressure with ECP, and doing all of this while minimizing the likelihood of inflammatory complications. If the patient is already pseudophakic, consider stand alone ECP, and if you want to lower pressure significantly beyond what the ciliary processes can do, I often combine it with goniotomy, and the two together will give me the best chance of getting to a lower pressure. Now, if all you have available to you is a CPC or micropulse device and you don’t have the endoscopic probe available to you, what we’ve seen from the studies and from my experience is that CPC when done appropriately, especially that slow and low or low and slow treatment, can give you quite effective IOP lowering and should be considered. From a global standpoint, if I had the capability to do one thing, in operating rooms around the world for the treatment of glaucoma, it would be to put a CPC box and probes in every operating room so that everybody has access to it. CPC can do a lot of good around the world, and lower the burden of glaucomatous disease, compared to what is required for trabeculectomy and glaucoma drainage device. The skill set is different. The follow-up is different. There could be major advantages to having better access to CPC. I wanted to put this in here, because we’re in an era now where we can treat the entire gamut of disease from mild glaucoma all the way to end stage with laser therapy. We can do SLT for mild beginning to moderate glaucoma, ECP when it’s combined with phaco on mild to moderate or moderate to severe if we’re doing standalone with 360 degrees, and from moderate all the way to end stage we have the option of using micropulse and traditional diode transscleral CPC. So this is to me a slide that really is impactful. We have the capability to do things with laser that we didn’t just a couple of decades ago. So we’re making some progress. Further reading — I wanted to point you to some websites. KEOGT is an EyeWiki that we’re continuously modifying. It has a lot of information on surgical procedures, we’re starting to populate with medication and diagnostics, but the main focus has been on surgical procedures. There’s a way to ask questions and email into the website, and give advice on what needs to be covered, and what needs to be updated. There’s some updating that’s being done to the content. But this is free access for all. So if you have residents or fellows or medical students, or you’re trying to learn new procedures, this is a good place to go. And Sidra Tree Foundation is a foundation that I’m involved with, that I would encourage you to visit, because they do give grants for underserved areas for different parts of the world. So if you’re doing mission work or if you yourself are in an underserved area, Sidra Tree Foundation might be a good place to go to and look for some support. I wanted to thank you and open it up to questions. I think Lawrence can help with putting up some questions here, and I’ll answer as many as I can over the next 15 minutes or so, and then I have to catch a flight to leave. As you can see up here, those are the planes that are leaving from the airport. So keep an eye if you see my flight blinking there. Lawrence, any questions? >> Thank you. You can stop your screen share. So far, there are two live questions. If you open up the Q and A. DR KAHOOK: What type of anesthesia to use in CPC? So we covered this for both CPC, as well as the micropulse approach. Typically what we do is a retrobulbar anesthetic, using an Atkinson or retrobulbar needle with lidocaine and bupivacaine. Lidocaine 2%, bupivacaine 7.5%, plus or minus hyaluronidase to allow for more diffusion of the anesthesia. I wouldn’t try any topical approach to transscleral CPC. It’s just too uncomfortable for the patient. Question number two. Is there risk of major hypotony? Can such a procedure lead to phthisis? The answer is there is a risk for hypotony. It’s not a major risk, when you’re doing a low and slow treatment. It tends to occur more in patients who have had multiple repeated cyclophotocoagulation. And it also tends to happen more in patients who have diseases like inflammatory or neovascular glaucoma. In those patients, I would say be a little bit more careful. Do maybe a partial treatment instead of 24 spots. Maybe you can do 12 spots and come back and revisit. Now, with ECP, I’ve found a much lower — I’ve actually never had hypotony from using ECP. Because you’re never treating 100% of the ciliary processes. Because you’re coming from an anterior approach, you’re not really able to treat the entire ciliary process. You’re basically treating about 50% of it, max. So we’re not seeing the phthisis or the hypotony with ECP versus CPC. Next question. If the pupil doesn’t dilate well, can you go ahead with ECP? Assuming that the patient is a standalone pseudophakic, and you can elevate the iris off of the anterior capsule, there’s no problem with getting the iris off of the probe and doing the treatment. Of course, if the pupil is small and you’re combining with cataract surgery, oftentimes in those patients we use iris hooks or we use some type of an expansion ring. And in those cases, post-removal of cataract with the IOL going in, we keep that ring in place or we can remove it at the end of the cataract surgery and inflate the iris up off of the ciliary processes. No problem in doing it with a pupil that is poorly dilated. With all of the precautions that we know about for cataract surgery, of course. What is the risk rate of sympathetic ophthalmia? Sympathetic ophthalmia has been reported in CPC cases, so we know that there is a real risk of sympathetic when you’re doing one eye. With the transscleral route. There might be reports on ECP. With sympathetic ophthalmia. I cannot recall one. So theoretically, though, it’s surgery, it’s similar with the treatment that’s being done with TCP. It’s invasive, of course. And you could theoretically get sympathetic ophthalmia. So it’s something to keep in mind. You should always be of course aware of that, when you’re doing surgery on patients, and keep that in the back of your mind as a possibility, if you’re seeing something that just doesn’t quite fit the picture. Do we have to move the probe sliding or we can put it, then move to side, move again. So I think what this question is asking is: Do we have to slide the micropulse, or can we actually move it from one side to another like we do with traditional CPC? With traditional CPC, you do want to treat, move, treat. And there are those overlapping spots that I talked about. With micropulse, really, to get the major benefit of it, you do need to slide it back and forth. Otherwise you’re basically doing a transscleral traditional CPC. So keep that in mind when you’re doing the therapy. With the micropulse box, that is available, you can use both a G probe, as well as an MB3 micropulse probe. So you do have the capability to go back and forth between the two. Next question. In early glaucoma, do you advise SLT in all patients, or if you find anterior chamber is narrow? Let me see if I can answer at least the first part. What we do know now, and more so with more studies that are coming out, is that SLT is a very safe and effective treatment, even in patients who are new to the diagnosis. Who have never been treated with drops. You can take a look at the light study that came out of Moorfields, to see more information about earlier treatment with SLT. I’m certainly using SLT more frequently as primary therapy, and early therapy. Now, with a narrow or an anterior chamber that is narrow — if I’m understanding the question correctly — if you can’t see the anatomical targets, then you’re of course not going to do the SLT. If you can barely see when you’re doing the treatment, you can barely see the anatomical targets, I think another type of therapy is probably called for. In which case, I’m very quick to do phacoemulsification, to deepen the angle, and then combine it with something like an ECP. So SLT — I’m a big fan. I think it has a big role. I’m using it more. I’m trying to really think about how I’m explaining it to the patient. If I’m going to start a PGA, like a Latanoprost, versus saying do you want SLT instead, I’m trying to explain it to them, to give them a choice, and I’m thinking more about and hopefully doing more SLT, to give the patient the benefit of not having to put drops in every day. Any other questions? All right. So… It looks like we’re done with questions. I did want to thank you. I know Cybersight will have this video online. There’s one question here. So I’ll answer this, and then we can close it off. Some of the patients had mild reduction in IOP. When do we need to retreat? Great question, and you get to dictate that. It really is based on what your goal pressure is. If you have not achieved your goal pressure, and you don’t want to start the patient back on their drops, or you’ve started them back on their drops and they’re not at their goal pressure, by definition you have to do more. Because you haven’t achieved the success that you were looking for with the initial treatment. So with ECP, you can always go back in and do a retreatment. You can choose a different type of therapy. You can go to incisional surgery like a trab or a tube. With CPC or micropulse, you can always go back in and do a second or a third. In my experience, with both micropulse as well as traditional CPC, it’s not uncommon to do a second. For me, it’s very uncommon to do a third. So typically, with two, we get the treatment maximally. We get it with — I would say with one treatment, most of the time, almost all of the time with the second treatment, and then rarely do we have to do a third treatment. But always keep that in mind. You’re going after your target pressure that you set before the procedure. If you don’t get there, think about other ways to get there. Keeping in mind all of the other factors, like patient compliance, any complications that might have occurred, what the vision is in the other eye, things like that. All right. So again, I want to thank you. I’m doing this in an airport lounge, like I said, so thank you for putting up with the lighting and the background here, as well as maybe some of the ambient noise in the background. If you have any need to ask me further questions, you can always email me. It’s [email protected]. It’s just the university that I work at. I’m also on Cybersight, so if you have questions, I encourage you to visit Cybersight with all the educational material they have on there. I visit frequently. I want to thank you and we’ll be back on in a couple of months with a couple of speakers, Husam Ansari and Pradeep Ramulu. So we’re presenting cases and going back and forth and I hope you can join us for that. Thank you very much.

Download Slides


January 9, 2020

Last Updated: October 31, 2022

Leave a Comment