Dr. Katz: I'm actually gonna talk about something that’s very familiar to all of you and that’s laser trabeculoplasty. But, suggesting that maybe me put it into a novel position for many of you. Just a quick poll, how many of you routinely suggest, to at least some of the patients, laser trabeculoplasty as an initial therapy before medication. How many of you?
So, a few already do that. Now, what if you had glaucoma yourself, how many of you would consider laser trabeculoplasty as an initial intervention? So, maybe even a few more there.
My disclosure, I have received grants and I've spoken for Lumenis, the company that makes the laser technology. Now, I'm not being political this morning, but I do miss George W. Bush because he would come up with--inadvertently come up with words that were new. And one of the things he said, you know, I was driving home one day and he said that the press had misunderestimated him. And I thought well, that was kind of neat word, you know? And it really works when you talk about laser trabeculoplasty for me because we really kind of misunderstood its role in many ways and, therefore, underestimated the value it may have.
Traditionally, what we've been taught is to maximize medical therapy for a typical open angled glaucoma patient and then move on to laser trabeculoplasty and then towards incisional surgery, traditionally have been filtering surgery in the past. And the question is that kind of approach really what we should offer to each and every patient or can we change it up depending on the circumstances?
Laser trabeculoplasty has been investigated in many different ways. I'm only gonna talk to you this morning about primary therapy, that’s really what I'm gonna talk about. And, again, the role that we've laser trabeculoplasty in, meaning you failed medical therapy, the patients not doing well, it’s not too surprising that laser doesn't pretty--doesn't work very well in that setting. And that led many of us to be discouraged about laser trabeculoplasty.
Well, as first line therapy, you're gonna have really kind of standalone, not influenced by being on multiple medications, not influenced by somebody who is doing poorly with everything. Let's see how it stands alone against medical therapy, so, as first line therapy. And there are four ways you can look it. You can look at the efficacy, the pressure reduction, compliance issues, which hound us with medical therapy, safety, side effects and then, finally, as a society, we're looking at the cost issues as well.
So, let's start with efficacy. One of the first National Eye Institute trials, multicenter trials in glaucoma, was the glaucoma laser trial. And I thought this was really a good study. I was a fellow involved in this study years ago as a lasering physician. And I thought it was a good trial, but it failed miserably to change anything that we did in our clinical practice. But, what they did was they randomized patients who had newly diagnosed open-end glaucoma. One eye received medication Timolol and the other one--eye received argon laser trabeculoplasty. And they follow patients. And there are two papers published on pressure reduction, the two year and the seven-year data. And you can see by very tight definitions of control, laser trabeculoplasty faired very well, both in the two year and the seven year papers compared to Timolol, which was our first line medication at the time. But this study was widely criticized for a lot of reasons by thought leaders. And it really changed what we did in clinical practice. But, I always remembered it really looked fairly good against Timolol.
Now, fast forward today, selective laser trabeculoplasty has been introduced by Mark Latina [sp] the developer and we won't go into why it's kind of called hole [sp], but it seems to be a kinder, gentler laser with similar efficacy to Argon laser trabeculoplasty.
And AchukaMalamid [sp] in Israel deserves credit for kind of bringing back to our attention the possibility of laser trabeculoplasty as an initial therapy. So, he did a pilot series in 40 eyes and it showed that there was actually a very dramatic drop in pressure in this pilot series of patients. There was no comparison to medicines, but there was about a 30 percent reduction in trabecular pressure.
And when you think about that, that’s very similar to what we would expect to see with, for example, a prostaglandin, that we're currently using today as our initial therapy for most of our patients.
This led to several comparative trials looking at SLT versus medical therapy, a trial in the UK with Dr. Nagar, Dr. Hutnick in Canada and also the U.S. Canadian trial that we performed.
In the UK trial, as well as the Canadian trial, they really saw similar results with SLT compared to a prostaglandin, so kind of a similar in trabecular pressure drop. You can see here in the UK study there's actually kind of a dose response curve, meaning if you did 90 degree treatment versus 180 versus 360, the 360 degree treatment had the best intraocular pressure drop that was sustained going out to about a year, very similar to what was seen with using Lataniprost [sp] with a 90 percent success rate, meaning a 20 percent drop below the baseline in trabecular pressure.
In the U.S. and Canadian SLT med trial, which was published recently, we did something similar to what was done in the old glaucoma laser trial with the argon laser. With the SLT we randomized the patients, but not the eyes. Meaning we did SLT in both eyes in the SLT arm and we did medication in both eyes of other patients randomized to the medication arm. And the reason was that we didn't want to have a crossover effect of the medications, with some of the medications like Timolol for example.
And these are some of my colleagues who participated in the trial here. So, again, the patients were randomized to SLT both eyes or to medication in both eyes. And we try to keep the populations pure, meaning not using medication in the laser arm unless we really needed to and not switching to laser in the medication arm unless we really have to. We used as our target pressure, a formula borrowed from the collaborative initial glaucoma treatment study. That was another large multi-centered trial comparing trabeculectomy against medication as the initial therapy. And this target pressure is calculated based on the starting intraocular pressure and the severity of the visual field loss. And it gives you a number. So, this is an objective, we think a fairly objective way of coming up with the number for each eye of the patient. So, the same patient can have two different target pressures for the right and left eye.
When we looked at the intraocular pressure drop in the SLT med trial, there was a very similar drop, whether it was SLT or medication, but there appeared to be more stepping in the medication arm, meaning going beyond prostaglandin, going to, yet, another medication. Whereas in the SLT arm, they had one SLT and there were fewer steps, meaning going to a second round of SLT.
Well, what about safety when we talk about looking at laser versus medication? Well, with laser trabeculoplasty the biggest thing that we worry about has been the intraocular pressure spike. And usually that’s transient and once it drops it usually will stay down. But, there are some situations where you have to be very careful with heavily pigmented angles where you can have a sustained pressure elevation. But these other complications that I've noted for you are fairly rare, whether it's Uveitis, Hyphema, hyperopic shift, corneal haze. Those are things that are very rare, but occasionally you'll run into.
What about--and here is one paper talking about the heavily pigmented eyes in Canada? They had several patients of pigmentary dispersion syndrome that has sustained elevations after SLT, requiring emergent filtration surgery in several of the cases. So, again, pigmentary glaucoma [unintelligible], we have to be more careful. Well, what about side effects with medications? Well, we have the cosmetic issues, for example, with hyperemia, with prostaglandins. We have the bluffer [sp] congentavitis that you see sometimes with rumadine [sp]. And, of course, there are sometimes systemic concerns with a drug like Timolol that have led to serious problems, hospitalizations, for cardio pulmonary related issues.
So, we know that these side effects are out there with medications. What about adherence? Well, there are a lot of great studies looking at compliance persistence in use of medication. I'm only gonna show you two here. One was the old study with Michael Kass [sp] where the electronic monitor showed that patients, even though they tell you they're taking the medications, they're really not. And then in the--there's a study from Willmar [sp], which try to tackle the issue of well, if you're one medication and we provide it for free, does that help in terms of compliance? Well, about the half the patients, even though the medication was given free, only uses a prostaglandin about half the patients used the medication less than 75 percent of the time. So, our best guess is that maybe 50 to 75 percent of our patients are truly compliant.
Well, obviously, with laser you have 100 percent compliance. Lastly, cost issues, and you know as a physician we're uncomfortable in getting into these discussions. We want to do what's best for our patient. But, society has to look at the cost issues as well with all the rising costs in healthcare. And there are several modeling analysis that have been done in Canada, the United States and Australia in the past, all concluding that laser trabeculoplasty is probably more cost effective than using medication initially.
Two recent papers from archives this past year by Dr. Sider [sp] and Dr. Stien [sp], two separate papers. Even with generic prostaglandins out there, factor in the cost and the compliance that you have with medication, they both concluded that laser trabeculoplasty may be a more cost effective initial option.
So, in conclusion, what I want to leave you with is just the idea that using initial SLT is a reasonable choice for certain patients, certainly not for every patient with open end glaucoma because there is a comparable IOP drop compared to our best medications out there as mylo-therapy with Timolol or a prostaglandin. When you look at safety, compliance and cost, it may tip in the favor of laser trabeculoplasty. So, that old treatment paradigm of only using laser trabeculoplasty when you failed medical therapy may be outdated. And at least think of the option and have kind of an informed decision-making discussion with your patients about maybe using laser trabeculoplasty first. And some of the patients may opt for that. Thank you.
This Glaucoma 360 educational program is brought to you through a partnership between the Glaucoma Research Foundation, OphthalmologyWeb and Lumenis, Inc.