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On July 10, 2020, Glaucoma Research Foundation presented an Innovations in Glaucoma Webinar, “Glaucoma Surgery and Laser Treatments.”
Watch the recorded webinar:
"The discussion convinced me that my doctor is providing appropriate treatment. It made me feel confident I am on track to control this disease."
- Paul Altieri
"Dedicated glaucoma surgeons provide educational information to assist in understanding benefits of successful surgery."
- Ron Ponichter
The recorded webinar features a presentation on current and new glaucoma surgery and laser treatment options by glaucoma specialists Davinder Grover, MD, MPH and Oluwatosin Smith, MD, moderated by President and CEO of the Glaucoma Research Foundation, Thomas Brunner.
Davinder Grover, MD, MPH
Glaucoma Specialist at Glaucoma Associates of Texas
Oluwatosin “Tosin” Smith, MD
Glaucoma Specialist at Glaucoma Associates of Texas
Tom Brunner: Good afternoon. My name is Tom Brunner and I'm the president and CEO of Glaucoma Research Foundation. Welcome to our webinar, Glaucoma Surgery and Laser Treatments. Today, we will learn about current and new surgical and laser options to treat your glaucoma. Doctors Davinder Grover and Tosin Smith have very kindly agreed to join me today to talk about glaucoma surgery and laser treatment options. And we'll try to answer as many of your questions as possible. Dr. Grover specializes in medical and surgical management of complex glaucoma at Glaucoma Associates of Texas. He received his medical degree from Johns Hopkins University in Baltimore. He then went on to do his ophthalmology residency at the Wilmer Eye Institute at Johns Hopkins Hospital and the glaucoma fellowship at Bascom Palmer Eye Institute in Miami, Florida.
Dr. Smith specializes in medical and surgical treatments of glaucoma and manages the Cure Glaucoma Foundation at Glaucoma Associates of Texas. She graduated from University of Ibadan School of Medicine in Nigeria and then went on to do her ophthalmology residency at Howard University in Washington, DC, and the glaucoma fellowship at Wills Eye Hospital in Philadelphia. And they are both Ambassadors of Glaucoma Research Foundation. It is an honor to welcome Dr. Davinder Grover and Dr. Tosin Smith.
Davinder Grover, MD, MPH: Thank you, Tom. Thank you for the kind introduction and thank you also to Glaucoma Research Foundation for putting this together. This is such a challenging time for all of us. And it just speaks to, I think, the resilience of human nature that we can take these opportunities to still have a collegial interaction and a positive experience despite all the challenges we're facing. I think this pandemic has given us all a new sense of appreciation for life and gratitude for what we have. And one thing that I definitely do with my family is when we sit down at the dinner table, we talk about just one thing that we're so grateful for. So I hope you guys are all doing well. And I'm so grateful that we're here and we're having this opportunity. And I appreciate Tom and the Glaucoma Research Foundation for putting this together and I'm looking forward to a wonderful discussion and experience today that's hopefully very interactive.
I'm going to start off; we're going to both talk about glaucoma surgery and lasers. I'm going to start off just with some introductory stuff about opening up your own outflow system and I'll turn it over to my partner and colleague Dr. Smith to talk about some of the more invasive surgeries. We're going to talk first with a background on ‘what is glaucoma?’ What do we basically do? I often describe myself as a ‘fancy plumber of the eye.’ And so we're going to talk about the plumbing of the eye. And then we'll go onto some surgical and laser managements, either opening up a patient's own outflow system or having to create a new drain. But just as a background, the eye is no different than a drain and a faucet. It makes water and it drains water.
So you can see here these are various descriptions of how water, we call it aqueous, a fancy way of saying water, is made right here in this area called the ciliary body. And then it goes in between your lens and your iris. And it drains over here. This is the trabecular meshwork. We call that the angle. Because that's what it looks like. It's the drainage angle. And this is just another depiction. We're dealing with the fluid in the front of the eye. This is not on the outside of the eye. This is all within the eye and it's within the eye and the front of the eye. So water is made right here. Aqueous is made right here. And then it goes in between your lens and your iris and drains in this drainage structure.
And this is the nerve, the optic nerve that connects the eye to the brain. And that's really what gets damaged in glaucoma. And there are two broad categories [of glaucoma] and it's well beyond the scope of what we're talking about here but there's an open angle or a closed angle. So we already talked about what that angle is, it's the drainage system of the eye. Aqueous goes around and goes into that angle and there's an outflow pathway. When that angle closes, we call it narrow or closed angle glaucoma. And that also is its own entity that you can get a lot of information on about on the Glaucoma Research Foundation website (www.glaucoma.org).
This is one of my favorite pictures because it shows what's happening in front of the eye, where water is made and then it goes and it drains in the angle. And then how the pressure over here, this is the optic nerve. It's a cross section of the optic nerve, the nerve that connects the out of the brain. And when the pressure builds up, it's like if someone pushes their thumb through that optic nerve and it gets damaged or it gets ‘cupped,’ is the nomenclature you may have heard.
This is my surgical algorithm. This is how I think about patients and glaucoma surgery. I'm either going to open up their own outflow system or create a new drain. And then when I can't do that, then there's also the option of turning down the faucet, which Dr. Smith will talk about. What I'm going to focus on here is evaluating whether they have an intact outflow pathway and whether we can do surgeries to open up their own outflow pathway, such as GATT or the KDB or trabeculectomies and all these things we'll talking about. Or do they have an atrophic collector system that can't be opened up and they need a new drain. And that's also what Dr. Smith will talk about.
So let's talk about this outflow pathway. And before we get on there, there's surgical management and then there's laser surgeries we can do. And let's talk about the laser surgery because they really enhance the patient's outflow pathway. There are two different types of laser procedures. There's ALT and SLT. And I can give a whole lecture on the differences and why one is better than the other. But in general, we're talking about just doing some type of laser to the drainage system. And really what's exciting is there was a trial, a really landmark trial that just came out recently that actually showed as a first line treatment, laser can be a more cost effective intervention with an equal amount of success. But when they looked at the people that got the laser compared to the ones that were treated initially with medication, the laser group actually had a lower rate of cataract progression and cataract surgery and a lower rate of needing more surgery for glaucoma.
So it really has changed, I think, a lot of our practice patterns and made us all lean more closely to considering laser as an initial treatment. One thing I always do as a physician when I'm taking care of patients is I always ask myself what I would want if I had glaucoma or what my family would want. Because I treat my patients the way I'd want my family to be treated. And in truth, if I were ever diagnosed with glaucoma, I would have a very low threshold for having a laser trabeculoplasty [SLT] on myself. But let's talk about this next category of MIGS —Micro-Invasive Glaucoma Surgery — which is another term you might've read about or heard about when you're discussing this with your doctor. And most of these surgeries are surgeries that help open up a patient's outflow system.
So we mentioned this slide, I talked about the aqueous water being made and then going into the drain. Then what happens after it goes into the drain? The drainage system is like a donut around the eye and it's called Schlemm's canal. And then there are little outflow pathways that are little openings called collector channels. And then they lead to this whole drainage pathway which we can't really visualize. But think of the heart and an angiogram of the heart. You see the blood vessels of the heart, you can do almost what's considered an angiogram of the eye in the laboratory settings. And this is from 1978 where someone injected dye into the outflow system so you can see, this is Schlemm's canal and then it's going down to the vasculature.
This patient has an intact outflow pathway (almost like they did an angiogram of the heart and you see all the blood vessels of the heart are intact). But look over here, this is really one of my favorite slides — here you have a patient and their Schlemm's canal is all destroyed and atrophic. This is advanced glaucoma. And then their outflow pathway, you can do any stent. You can do any kind of MIGS surgery or you can stent it, open it, you can put something made of gold in there. It's not going to work because their outfall pathway is destroyed. So those patients need a new drainage system. So the question is: do your doctors know how to evaluate your drainage system?
And we don't have a way to do it pre-operatively yet. But one of my other partners, Dr. Fellman and I described this back in 2012 of evaluating, we call it the Episcleral Venous Fluid Wave or ‘the wave.’ And you can evaluate in the operating room after you've done some type of surgery to open up the patient's meshwork or their outflow pathway to see if that would work. And so you can see right here in A, with these dark arrows, this large vessel that blood is coming into the eye and then I can irrigate fluid in the eye and that whole vessel disappears or it doesn't disappear, the blood is being diluted and now it's full of clear fluid. And so that's proof that this patient has an intact outflow system. and that's almost like an enviable or a real-time angiogram of the eye.
And you can see patterns of outflow which are just so exciting where you can see this large vessel disappear. And then you can see this plexus of vessels. There's a couple of different ways that fluid can leave the eye once you remove the trabecular meshwork, that mesh over the drain, and you can see in real time. And the question really is, does it matter? Do these patients behave differently? So you have a patient here on the left side that has, we thought, an amazing ‘wave.’ If you see that blanching, it was just tremendous evidence that the patient has an intact outflow system compared to here on the right side, where maybe this blood vessel disappears just a little bit. I would call this a very mild or poor ‘wave.’
And what's crazy is we've actually done studies that have shown that patients with an amazing wave do extremely well after MIGS surgeries where you open up the drain. And if a patient has a very poor wave, there's about a one third chance they're going to need another incisional glaucoma surgery. So before I do any of these kinds of surgeries on my patients, I have them go to my YouTube channel. I have them watch these videos. And I'll even have patients ask me on the table, "Doctor Grover, did you see the wave?" And I'm like, "Please don't talk about it right now. We'll talk about it after the surgery."
But that really allows me to give my patients real time advice and evidence. So I see them right in the recovery room. And I say, "You know what Ms. Jones? You had the most amazing wave. I'm very optimistic that your surgery is going to work." Or sir, "This wave, wasn't that impressive. There's about a one third chance we may have to go back in." And so they get real time data just like I do in the operating room or right after the operating room. And that allows me to maintain that trust and that relationship with my patients to know what I'm doing and why I'm doing it. And what I know about their eye.
So let's talk about some of these surgeries that open up the drain. I think aside from one of the more traditional surgeries, Trabectome is electrocautery where they remove the drainage system, that mesh, through electrocautery. And this is probably one of the oldest available surgeries that was kind of the first kid on the block in terms of this new phase of MIGS. So I think we probably can safely say we have the most experience with Trabectome, but they're all similar in certain ways and different in other ways. So something that's somewhat similar is the Kahook Dual Blade goniotomy, instead of using electrocautery just makes an incision where you can remove that strip of trabecular tissue to have direct access to the downstream pipes.
And then what I use for my very mild cases are things like an iStent and this is the original iStent, the G1 [first generation], which actually I don't think is being used that much anymore in the United States. But it's a little snorkel that we kind of sneak in to the meshwork and it allows fluid to shunt and bypass the meshwork and allows fluid to go straight through the drain. This is a G2, this is the second generation. It's called an iStent Inject. And there are actually two of them that can be put in the drainage angle and help enhance outflow system bypassing the meshwork.
And the meshwork, the reason why we care about that is the vast majority of studies on regular primary open-angle glaucoma and even some other types of glaucomas, saw that the meshwork is the problem. And if you can remove that mesh, usually you can remove a lot of the resistance to drainage system. And there's some other things out there. This is a Hydrus Microstent. It's a nitinol stent that goes into the eye and helps open the outflow system. And how each of these are used and why each of these are used, there's not a right answer and there's not really a lot of studies comparing each one to each other. And so really when you talk to your doctor and your surgeon, a lot of people have kind of just chosen one or two that's in their wheelhouse that they really liked that works best in their hands.
I don't think, especially for the more than mild stuff, like the Hydrus or the iStent, there's really a right answer on which one is better yet. We're still working on that. So more important, I would say, to see what your own surgeon prefers. And this surgery is a surgery that we actually developed. It's called the GATT surgery. And it's being used worldwide in over 25 countries as far as we know. It's a modification of a surgery that's been around for about 70 years. Through two small little incisions, we're able to open up the drain 360 degrees. And the most exciting thing about this, in addition to the fact that it is a safe and effective surgery, is that it can be done with a $4 suture, which it has tremendous implications worldwide for cost-effective delivery of care. And we use it on a regular basis to treat patients that have significant glaucoma.
So that is how we can open up a patient's own drainage system. Now it's my pleasure and honor to introduce a close friend of mine and a colleague, Dr. Smith, who I have so much respect for. Every time she talks, I make sure I listen very closely because she has tremendous insight into this disease process. So it's such an honor to have doctor Smith take over and share with you surgeries that help create a new drain.
Tosin Smith, MD: Thank you very much Dr. Grover and Tom for the very kind introduction. I'm taking over from this point and I will be talking about outflow surgery. And this is surgery that bypasses the natural drain that Dr. Grover just talked about. We'll briefly look at subconjunctival flow, which is surgery that diverts fluid under the skin of the eye, we'll mention briefly suprachoroidal flow, which is flow into that layer that lies between the wall of the eye and the choroid which are the layers or vessels that sit on top of the retina in the back of the eye. And just talk about a new option that's available for people. It's a bridge between surgery and medical therapy that is also available now to patients.
So the first thing we're going to talk about is trabeculectomies. The trabeculectomy has been around for many years. Essentially, there is a small little ‘trapdoor’ as can be seen right here in this right hand corner of the slide, where a ‘trapdoor’ is created in the wall of the eye, a small hole is made under that trapdoor, and then sutures are used to hold the trapdoor down. And then the skin of the eye, which is that conjunctiva I mentioned before, is then closed over the trapdoor. This then allows the formation or egress of fluid from the inside of the eye, under the skin of the eye, and there's formation of what we call a bleb.
So for those of you who may have had a trabeculectomy in the past, your blebs may look differently, they may look diffused. There may be an area where there's no blood vessels. But trabeculectomies lead to flow of fluid under the skin of the eye. And if I had to say something about trabeculectomies, they're able to get [intraocular] pressures to really low levels. So if you were somebody who needed a pressure in the single digit level, a trabeculectomy is more likely to get you there. The one thing I would say though is that with trabeculectomies, there's potential for long-term, not just short term, related to surgery complications, but there are long-term complications that could occur with trabeculectomies. So we have to be very watchful after trabeculectomy surgery.
The Ex-Press shunt allows you to achieve the same goal as a trabeculectomy. So let's say that trapdoor was created, the flap was lifted, the Ex-Press shunt is a tiny little metal shunt that's then placed under the trapdoor without having to make a hole. The trapdoor is then put over it. It allows fluid to find its way out of the eye, under the skin of the eye where it's absorbed. So the same thing [as a trabeculectomy] but just with a device that helps you achieve that goal.
Many of you may have heard of glaucoma drainage devices or as they're more commonly called tube shunts. If you've had a tube shunt for instance, I would say this, there are various types of tube shunts out there. There are implants that are bigger, they're shaped differently. But the biggest difference between the different types of tube shunts is whether they have a valve or whether they don't have a valve. The valved implants are those ones that have a valve mechanism that prevents your pressure from dropping below a certain level. So if the pressure is higher than this level, the valve mechanism opens and allow fluids leave the eye. But the non-valved ones at the time that they are put in may be tied off for a little bit. So you may have higher pressures for a short time.
Now who gets a glaucoma drainage device? Previously we would say drainage devices were for people who were not ideal candidates for trabeculectomies or people who may have had a trabeculectomy in the past that has failed. But more recently there are studies that have been done that show that tube shunts compared to trabeculectomies are just as effective. You may require a few more drops or supplemental eyedrops to get your pressure as low as a trabeculectomy if you pick the tube shunt option for surgery.
Now, what else can give a subconjunctival flow? The XEN-45 Gel Stent is available on the market. It's a device that is about six millimeters long. It's like a tiny little noodle. It can be placed from the inside of the eye or from the outside of the eye. It's less invasive, way less invasive than doing a trabeculectomy. The implant is put under the skin of the eye, connects those two chambers. But unlike the trabeculectomy, it doesn't have a big wide plate attached to it. So it's able to cause fluid to move from one chamber, which is the inside of the eye to the area under the skin of the eye, keeping pressure maintained between those two spaces.
The CyPass system is a suprachoroidal shunt. It was available on the market for a short time. And what that did as you can see in that picture right there, it's a device that's kind of like a noodle as well, but the problem is instead of passing it under the skin of the eye, it was placed inside the eye into an area called a suprachoroidal space. So it allowed fluid to flow from the inside of the eye, through the little opening into that space where it subsequently drained out of the eye.
One option we'll discuss here also is the sustained release medication delivery platforms. Recently Durysta which is the Lumigan or Bimatoprost SR that has been approved by the FDA. And what we do here is that the medication in the form of a pellet is placed in the front side of the eye where it slowly releases medication over a four to six month period. So four to six months, the medication is released over time. And it results in lowering of intraocular pressure. So that is an option that is a bridge between both medical therapy and surgery but it releases medicine inside the eye, taking away that responsibility of putting eye drops inside the eye from the patient.
So we've talked a little bit about outflow surgery. It's now a time to look at the other thing. How do we turn down the faucet in patients who have glaucoma? There's certain types of lasers that help us do this. Cyclophotocoagulation has been available for a long time as an option for surgery. And you can either go inside the eye to deliver the laser, or you do it from the outside of the eye. The difference between a continuous wave or standard, what we refer to as CPC laser and a MicroPulse laser is that the CPC laser has a continuous wave of energy being delivered while the MicroPulse is pulsed laser. It delivers for a time and then the laser goes off for a time as the laser energy is being delivered.
So we'll start here talking about the MicroPulse laser. The MicroPulse laser is being delivered here in this case with the laser hand piece, it's done in an outpatient setting usually with the patient laying down with a speculum in the eye. And it's delivered right there. Usually you're awake when this is going on but the eye is numb. And it gently delivers that laser through the wall of the eye to that ciliary body that Dr. Grover talked about. They're like little florets right there sitting behind the iris that are responsible for making fluid inside the eye.
So, what else is delivered this way? There is a endocyclophotocoagulation which is also a type of laser that's delivered inside the eye. In that case, it's done inside the operating room where the laser is delivered straight to the ciliary processes directly in the operating room after you've had cataract surgery. So if you had to do a glaucoma and a laser procedure, that would probably be one that can happen at the same time in the operating room. The other laser that is done outside the eye is cyclophotocoagulation and done is through the wall of the eye. But the probe that's used for that laser is a little different from that which is used from the MicroPulse which is the one that is not a continuous wave laser.
So having talked about this, what we do essentially is all in a day's work of ‘plumbing.’ Whether we are inside the eye turning down fluid production by doing lasers or we go to the trabecular meshwork, which is that membrane that covers Schlemm's canal that's responsible for collecting the fluid and passing it out through the collector channels which I would liken to the sieve that covers your kitchen sink. Or the problem is further along in the sink and the drain that comes under the sink that goes onto the public drainage system, that will be a Schlemm's canal problem or public drainage which would be a collector system problem. Whether the problem lies in any of those places, our job is to find a way to address your glaucoma by either turning down faucet or improving the drain or coming in there and putting in a completely new drainage system. So I thank you all very much for listening. And we're open to taking your questions.
Tom Brunner: Well, thank you so much Davinder and Tosin for a very, very informative presentation. And now we do have time for some questions. And the first question, what can I do to increase my odds of a successful eye surgery?
Tosin Smith, MD: I'll start answering that question. So in having successful eye surgery, there are several factors that may be helpful in making sure that surgery is successful. But first I would say the type of surgery is really important. For some surgeries like outflow surgery, trabeculectomies or surgeries that lead to subconjunctival outflow, having the skin of the eye not being inflamed or red prior to surgery is helpful to the success of that surgery. Making sure you follow your post-op instructions if you've been asked to use steroids after surgery. That is a big part of success after glaucoma surgery.
The other thing is timing. Sometimes people get a little worried about having glaucoma surgery and they decide to put it off too long. We know with glaucoma, lowering pressure leads to a situation where you're more likely to preserve vision. So timing of your surgery is another important thing. Don't wait too long because you're afraid. Because the more damage that's been done then the likelihood of losing vision at the time of glaucoma surgery is higher. So those are some of the things I would say. I say, let's time your surgery. Don't be too scared. Certainly surgeries require an eye that is more quiet. That is not so red or irritated for their success. And be compliant with postoperative instructions are another way of ensuring that your surgery is successful. Davinder do you have anything to add to that?
Davinder Grover, MD: No. I think you summed it up really nicely. And I actually think that the next question leads into this one as well — what should I look for when selecting an eye surgeon? So it's important to remember, and I tell my patients this all the time, this is a lifelong battle. It's not like a broken bone that you're fixing and you can move on. This is a lifelong battle. Whether we win or whether we lose, this is a path that you and I are going to go on together. And so it's a long game, it's a marathon. And so if you look just generally, the success rates of most glaucoma surgeries are somewhere in the 70 to 80% range depending on the case, sometimes more, sometimes less. But every glaucoma surgery over time has a slightly higher risk of failing.
So you still need to be monitored and followed. When it comes time to selecting your eye surgeon, the most important thing is finding someone that you have that relationship with, you have that trust with, and that you're going to go down this path together with. Because one thing is, especially what doctor Smith said, to increase your odds of success is really having that faith. Because the problem as we all know is with glaucoma, there are very rarely symptoms. And so every day I see patients, I'm telling them, "You know what sir? You need surgery. Your pressure's too high. We're seeing loss of nerve tissue. I'm not seeing a visual field defect yet but I know where we're going to go." And the problem with glaucoma (and don't hold me to these numbers, but) you could lose a vast majority of your nerve tissue without having any overt visual field changes.
So here I am every day telling patients that are feeling fine and seeing fine that they have a blinding condition and I need to do a surgery on them. And unfortunately it happens still despite my best efforts, patients will not listen to me, not listen, not understand, not understand. And I'm not going to pretend it's easy because it's not fun. It's very scary to have the idea that you're going to have surgery on your eye. But you have to pick a surgeon that you trust that you want to go on this path with, you have that relationship with, you're going down that path together. And it's a leap of faith that you have to trust the person that's taking care of you to know that the intervention early is going to prevent you from losing vision.
And prevention is not sexy. Prevention is not easy. It's not fun to say, "Hey, look, I prevented you from going blind." Because you will never appreciate that. But the problem is when patients start to notice their vision loss, then we're at this point where the vision just starts to rapidly fall. And then they come to me and say, "Hey, Dr. Grover. Okay. Now I'm ready." And I'm like, "Well, we can do it. And we are going to do it. But now we're on this curve where we're very at high risk of losing more nutrition, then it's going to start effecting your vision. I wish we would have acted here before we even came close to the cliff." So it's so important to have that understanding and pick that one surgeon that you have a relationship with and the trust with because it's a leap of faith. Tom, what's the next question?
Tom Brunner: We have another question here. ‘If my glaucoma is well managed with eyedrops, what are the advantages of having surgery despite the risks?’ And I think you kind of have just answered that. But maybe you want to make additional comment.
Davinder Grover, MD: Yeah. I can talk to that and then I'm sure Tosin will add to this as well. I tell my patients this, "I don't care how we get there. I just need to lower your pressure." Okay. That's the only modifiable risk factor is [eye] pressure lowering. So I don't care how we get there. We can get there with medication. We can get there with surgery. But just like… I know, I floss. My dad's a dentist. My sister's a dentist. I floss a week before I go to the dentist and a week after I go to the dentist and then it falls off. And so using eyedrops is not easy. And they're very easy to forget. They also can cause surface irritation and dryness and can change the appearance of your eye. So my goal, if I'm going into a patient's eye to do cataract surgery or to do something, I think it's a very great opportunity to do some type of safe surgical intervention to decrease their dependence on glaucoma drops.
But I also have a frank discussion with my patient. Let's talk about the costs of the drops. Let's talk about the irritation. It's a full time job to use multiple drops. And if you're doing it, we don't need to touch you. But be real to yourself and be real to your surgeon and your physician that's taking care of you that if it's something that you find yourself consistently forgetting once or twice a week, which is very common and is human nature for all of us to not be 100% all the time, then have a long-term game plan of, "Do I see myself doing these drops for the next 10, 20, 30 years?" when there are now safer surgical interventions that have lowered our threshold for surgery.
Back in the day when we just had ‘trabs’ and tubes, our threshold for surgery was so much higher because these are very invasive surgeries. Now we have a lot of safer surgeries that have pretty good success, that have lowered our bar because of the safety to do a surgical intervention, to get patients off drops. Dr. Smith, what do you think?
Tosin Smith, MD: That's a great answer. The issue of risk of surgery, we're at a different place with that now. We had those options of trabeculectomy and tube shunts which have higher risks than the mixed procedures which are available now. So if I had to give an example, even in patients who come in and who have managed well on an eye drop, if they were going in for cataract surgery for instance, that would be a good time to try and reduce their medication burden and do a mixed procedure in which case, which is a minimally invasive glaucoma surgery, which has a different risk profile than a trabeculectomy. And what that would do is reduce the medication burden in that particular patient who may have been stabling their eyedrops but the benefit of having that done comes with cataract surgery which they were going to get in the first place. So that's a thought. That's an example of times when it will be beneficial to get something done for your glaucoma even when your eyedrops seem to be working.
Tom Brunner: Are there special considerations involved with cataract surgery for glaucoma patients?
Tosin Smith, MD: There definitely are. And the biggest category is that one which I just mentioned, which is doing minimally invasive glaucoma surgery at the time of cataract surgery. We have patients who either have pressures that are not controlled or pressures that are doing okay on their current medication who need cataract surgery. In that particular scenario, doing a procedure to control pressure is a big option for patients. But there are also those people who have sort of more advanced disease or who need a lower pressure and doing a combination of cataract surgery.
And glaucoma surgery is something that gives you the opportunity for the surgeon to go in at one time and take care of those two disease entities at the same time whether it's anything from a glaucoma laser with cataract surgery or a mixed procedure, or even the traditional trabeculectomies and tube shunts, we would have to look at the individual patient, look at where are their diseases, look how much pressure lowering they've had, look to see what other procedures they've had done in the past and making the best decision as to where to go or which of those procedures to do. Davinder, what do you think?
Davinder Grover, MD: Yeah. What's interesting is in addition to many great things Glaucoma Research Foundation does is they have this newsletter, this Gleams newsletter. And a couple of years ago, I wrote an article specifically about this, about special considerations for cataract surgery in glaucoma patients. But I wholeheartedly agree with everything Tosin just said. I think it's a great opportunity to address patients that don't have controlled glaucoma or have controlled glaucoma and you want to decrease their dependence on drops.
There are other things you can consider. I talked about the narrow-angle glaucoma. Sometimes cataract surgery alone can be an amazing treatment for just narrow-angle glaucoma. But the other thing you need to understand is that when you have both cataracts and glaucoma, there are also some certain special considerations you need to take into account in the operating room. Patients with glaucoma have a higher likelihood of complications during cataract surgery, have a higher risk of a pressure spike after a cataract surgery.
So I always insist that when you have a patient that has real disease, real glaucoma, and they need cataract surgery, I would say number one, it would be a disservice not to address both at the same time. And number two, glaucoma specialists, that's all we eat, live and breathe. And we're used to managing patients with small pupils or are at a high risk of having some weird complications during the operating room that needs a special tricks. That's all we do.
And so those eyes are a little different than your neighbor that had cataract surgery in the same 2020 and was out playing golf the next day. Glaucoma eyes don't always follow the rules and they always try to trick us and do weird things to us in the operating room. And we come to the operating room every day prepared for those tricks to really optimize success. So they're a little bit more challenging but again as a glaucoma specialist, it's like breathing.
Tom Brunner: So what about the success rates of some of these different surgeries? I think you may have touched on that a little bit before. But just generally speaking, there are different levels of ‘risk-reward’ between the different procedures that you do. Can you comment on that?
Davinder Grover, MD: Sure. Let me start with that. And then I'll let Tosin complement what I'm saying. Yeah. I think it's all a matter of tailoring the surgery to the patient and the stage of disease. And so that again goes to picking the best surgery for the patient — which ones are best to be combined for cataract surgery, which ones are not. But in general, if I were to give you a statement, I would say, the average success rate is 70%. But I think that's in some ways a meaningless number because what matters is the patient that's sitting in my chair and my exam lane and I'm talking to.
There are certain types of glaucoma, pseudoexfoliation glaucoma. I know there are some questions about that with laser and different surgeries. Pseudoexfoliation is one of these things where the meshwork is almost always the problem. And surgeries where you can open up the drain, do so much better in patients with pseudoexfoliation like GATT surgery. Patients that develop glaucoma at an early age that have some, we call them juvenile open-angle glaucoma. You got glaucoma when you were in your 20s or 30s or 40s or 50s. Again the meshwork is almost always the problem.
So it's hard to give a general number of 70%. That's really meaningless when it comes to what happens. When I'm the patient, what are my chances of success? But if you have mild disease, Tom like you pointed to, then you can go with surgeries that are a little bit less invasive. If you have more advanced disease than you need to go with procedures that a little bit more invasive to get more bang for your buck. But it's that discussion of which surgery is best for your specific case, your specific disease and that specific patient. And their activity level and what they do. Scuba divers should have special considerations as opposed to construction workers, as opposed to an 85 year old that's retired and plays bridge and watches Wheel of Fortune. So it's a matter of what they do on a daily basis.
Tosin Smith, MD: I couldn't agree more, which brings us to the issue of target pressures. It's always about where your surgeon is trying to get. And looking at what you've had before and what can help you get where you're trying to go. So many glaucoma specialists are aware of what's the efficacy of the different surgeries are. And what we try to do is take you as an individual, look to see all of these things that I have spoken about and try to match you off depending on your stage of disease with that place where he's trying to get your pressure in terms of your target.
Tom Brunner: Another question is about scar tissue and does that prohibit other surgeries? And part of that question also is why do surgeries sometimes need to be repeated over the years?
Tosin Smith, MD: That's a good question. I talked about some of the outflow surgeries, something like the trabeculectomy, the XEN Gel Stent. Those are surgeries that lead to flow of fluid outside the eye, under the skin of the eye. And there tends to be scarring with that. And what we try to do to prevent scarring, because the natural thing for your body to do, if you have some kind of injury so to speak, and whether it's surgery or it's a laser, it is trauma to tissue. And the natural response is for you to heal. So with those surgeries, what we do is we actually use medication that prevents scarring.
An example is mytomycin or 5-fluorouracil. Those are medicines we use at the time of surgery, incisional surgery to prevent scarring. Now with lasers for instance, there are certain laser procedures that you could do to the drain of the eye, the SLT for instance. The SLT causes less scarring in the drain of the eye, but the ALT which is the Argon Laser Trabeculoplasty tended to cause a little bit more scarring.
Scarring does occur. If you have scarring in the drain of the eye that actually causes closure of the drain of the eye, where you can't see it, a laser procedure to the drain of the eye may not be the best option for you. And that's we as physicians have to look at. But over time, what happens is you scar after you've had a procedure or you might do well for several years. And over time, your body starts to recognize that this fluid flowing into this area shouldn't be doing that. And gradually your trabeculectomy may fail. Your body gradually causes a healing of that reservoir where the fluid flows to.
When that happens, we either have to go in there and reopen that and give you some more anti-scarring medicine or do an alternate procedure if that becomes your best option. Like old chronic disease conditions, sometimes it's a matter of just progression of disease. You may have a trabeculectomy that's working and maybe your drain is still working partially. But as time goes on, that drain degenerates and the trabeculectomy is only able to control or whatever surgical procedure is able to control pressure to a certain extent. And so what then happens is you need further treatment of some sort, whether it's another procedure further down the line to try and catch up and cope with that pressure elevation that occurs over time as disease does progress.
Tom Brunner: Davinder, you talked a little bit about the ‘LiGHT study’ with SLT and commented on a very interesting finding that I think it was 11 patients in the medications group went on to needing a trabeculectomy. And in the SLT group, zero patients went on. Can you comment a little more about why progression may have been worse in the medication group?
Davinder Grover, MD: Yeah. The LiGHT study again, and you can read about this online, was actually a really well-designed trial that took patients that were initially diagnosed with glaucoma and randomized them to either laser trabeculoplasty SLT or medication. And what it showed over time is that even though the pressure lowering was about the same in both groups, in the medicine group, more patients went on to need cataract surgery and trabeculectomy as Tom mentioned. We don't know why. There was an association and we're trying to figure out why.
One of the other questions was the medication use. And this is something that is still very poorly understood. But I can tell you based on my experience of treating patients around the world, in the United States and a lot of developed economy health systems, patients are on drops for a very long period of time for exactly the problem that I have discussed. I meet a patient for the first time. It's so much easier for me to say, "Miss Jones, I'm going to put you on a drop. Come back and see me in a couple of months." Versus, “and you know what? Miss Jones you don't know me at all. You just met me. But let me go and laser you.” It's hard to do that. Or “let me go do a surgery.” It's so much safer to just start them on a drop.
And so what happens is patients get put on drops, and they get in that routine. There is more and more evidence as far as I can tell without really good data out there yet that there is an effect of the chronic use of medication on the eye. These are chemicals that you're putting in your eye. And we have to again weigh the risks and the benefits. What's the benefit of drops over having an incisional surgery. And what's the risk of putting a patient on a drop versus taking them to the operating or doing a laser. But what was exciting about this study is it showed that actually the laser intervention group tended to do better. Not only did they do better, but it was actually more cost effective which is great from our health systems’ perspective.
So in other countries where glaucoma is such a big problem in more developing countries that don't have the infrastructure of a developed health system, patients usually present with advanced glaucoma. But their eyes haven't been bathed in glaucoma drops for 20 years. And when I operate on those eyes, they behave differently than eyes that have the same stage of advanced glaucoma but have been bathed in drops for 20 years. And this is revolutionary. I mean, you ask all glaucoma specialists around the country right now, and they're going to say, "Don't listen to Davinder. He's crazy." But you can see the way the tissue behaves in patients that have been on drops for several years, decades even.
So I think what the LiGHT study, and this is just postulating, is that it's showing that there are some unnoticed effects of the chronic use of drops. Now is that chronic use of drops better or worse than taking a patient to get a trabeculectomy? That's a discussion between you and your surgeon. And it's probably still much safer to put you on a drop than it is to cut your eye open. But in a procedure like trabeculoplasty, which is actually very well tolerated than safe, it gives me the confidence more so that trabeculoplasty may be an appropriate intervention. And again, like I said in my talk, I treat my patients the way I'd want my family to be treated or the way I want to be treated.
And the fun thing I love to do is sit around a room of glaucoma specialists and say, "Hey, if you had glaucoma, what would you have? If you had, what would you have?" And if I had glaucoma, I would want Dr. Smith to do an SLT on me. Because of that observation that I had personally in operating on eyes and developing countries that have not been abused by drops versus eyes that have been on drops for decades.
Tom Brunner: Well, unfortunately that's all the time we have for questions. But perhaps we'll be able to answer some of your questions in a future webinar. You can also visit our website, www.glaucoma.org for more answers and for the latest information about glaucoma and our research. And please remember to use the search box in the upper right hand corner there to put in your question or a key word or a phrase. There is a huge amount of information on our website about glaucoma, about the latest treatments, about the things you heard about today in the webinar and the research we fund. And so I encourage you to search for it and find the answers to your questions. Now the other thing I want to mention is that you also can follow us on Instagram (@glaucomaresearch) where we post glaucoma-related videos and articles and updates.
And once again, I want to thank both Davinder and Tosin for making the time for us today and for their dedication to helping glaucoma patients maintain their vision and stay informed. And I want you to know that at Glaucoma Research Foundation, we remain as committed as ever to helping glaucoma patients especially in these very extraordinary times. Our office has partially reopened as we continue to work hard to advance our mission to cure glaucoma and restore vision through innovative research and provide information and education about the glaucoma. Please take your vision seriously and your health seriously. And work with your doctors to help maintain your vision. We want to thank Aerie Pharmaceuticals for sponsoring this webinar series and their support of all glaucoma patients. And thank you again for your ongoing support for the Glaucoma Research Foundation.
Last reviewed on July 30, 2020