Resource Speaker: Dr. David Richardson
When: Friday, October 23, 2016
Where: Embassy Suites 211 E Huntington Dr, Arcadia, CA 91006, United States
Event: Joint University of Southern California (USC) – San Gabriel Valley Optometric Society (SGVOS) Annual CE Symposium.
Femtosecond Laser Assisted Cataract Surgery
How Do The Marketing Promises Compare To Reality?
So today’s topic is going to be on Femtosecond Laser Cataract Surgery also known as FLACS. In particular, we’re going to be discussing whether or not the literature supports the marketing. First of all, can I have a show of hands how many are familiar with FLACS? Ok, very good. How many of you have been to a presentation on it already? Ok, so just a few.
David D. Richardson, MD
So, first, just a couple statements about me; So you’ll understand a little bit about me and my practice. As well as why I’m here talking about this particular conversation or topic… Cataract surgery is actually one of the focuses of (not only my practice but) my career and not just in terms of performing it but also in terms of educating those [patients] about it.
- Author, So, You’ve Got a Cataract – For example, I wrote a book about cataracts surgery. It was focused specifically for patients addressing their needs, their concerns, and helping them to choose among the numerous options that are now available. Because it’s not like it used to be decades ago, as we know, where you just have a cataract, put in your lens, you’re done! He gets new glasses. Now, we know we have a lot of different lens options. And now, there’s this type of surgery option available: Laser-Assisted Cataract Surgery (we’ll talk about that).
- Medical Director, San Marino Eye – As a doctor who’s in private practice, I also spend, on average, between 45 and 60 minutes with my new cataract surgery consultations. And that’s because, I think, it’s really important to actually communicate all of these very, very confusing topics to patients and that just cannot be done in a short period of time.
- Adjunct Assistant Professor of Clinical Ophthalmologys, USC Roski Eye Institue, Keck School of Medicine – And finally, as Adjunct Assistant Professor of Clinical Ophthalmology of USC [University of Southern California]. My primary role there is teaching residents how to communicate these things to their patients in the clinic as well as developing the skill sets they need in the operating room.
Confict of Interest
I have no conflicts of interest. This is important to be aware of. With each presentation that you get on something that’s going to cost your patients hard-earned money. This will not be your typical industry-sponsored dinner talk which just glosses over the side effects and counts all of the benefits. I want you to have a clear understanding of what the literature states.
What Is Laser Cataract Surgery?
What is laser cataract surgery? Well that’s a misnomer and we do not perform cataract surgery with a laser. It’s not been done and it’s still not. What it is, in fact, is Femto Laser Cataract Surgery also known as FLACS.
Femto Laser-Assisted Cataract Surgery
The “Femto” is short for “Femtosecond”. This is the same laser that’s used very successfully with lasik. Instead of using the microkeratome, you use a laser. It cuts to clear tissues such as the cornea very, very well; and very precisely. And that particular term is one that you will be exposed to (if you’ve not already been exposed to)
Precision. One of the things that the marketing pushes about the femto laser-assisted cataract surgery (I’m just going to call it FLACS from now on) is that it’s more precise than manual or the traditional, ultrasound-only phacoemulsification. Precision is a term that, you have to recognize, comes with a lot of assumed promises. And we’re going to discuss whether or not assumed promises are actually born out.
Can I just get an idea, when you hear the word, “precise” when discussing cataract surgery, what are some of the things that you think that might be describing? Any ideas? Capsulorhexis – precision in creating the Capsulorhexis. What other things do we look for with precision? What the patients’ ultimately want after surgery? Better vision – closer to 20/20; closer to 20/20 uncorrected. So, if we can get something that could accurately get somebody there that would be very desirable. So precision is being used very loosely in marketing and advertising to make us feel like we’re going to get our patients closer to 20/20. That’s the assumed promise. So let’s see whether or not that’s actually the case.
Other marketing terms you’ll hear: Safer. When you hear, “safer” what do you think? What do your patients think when they hear “safer”? Less side effects. Less risks. Let’s see whether that’s the case.
The other thing you’re going to see: Gentler. “Laser is gentler than ultrasound”. Again, “gentler”, one would think, is safer. Fewer risks.
What Does the Laser Do?
So let’s take a look. Just briefly for those who aren’t aware. What does this laser do?
- Create Corneal Incisions – It makes incisions. Corneal incisions – the side port incision, the main incision. You can also make arcuate incisions. So limbal relaxing incisions to correct for astigmatism. Now, traditionally we do these with metal or diamond keratomes but they can be done with a laser now.
- Create an opening in the Capsular Bag – You mentioned creation of the capsulorhexis. The laser can create a perfectly round capsulorhexis and it is beautiful. When you watch this laser performing capsulorhexis, it is perfectly round. The question is, “does it matter?” Now, traditionally we perform the capsulorhexis with either forceps or *** bent needle cystotome.
- Soften the Cataract – The other thing you can do is soften the cataract. Well softening the cataract makes sense because you can soften the cataract before using ultrasound energy. You’ll use less ultrasound energy. Less ultrasound energy should protect the corneal endothelium, should result in less inflammation, faster healing and just generally a gentler procedure. So this is where the term, “gentler” comes from. Now, you can also soften the cataract using certain phacoemulsification techniques, such as “chopping”, which is a newer technique; it’s more challenging technique but it’s one that most surgeons should be capable of performing and chopping essentially does the same thing as the laser softening.
So, what does the laser do? The summary is, “nothing that can’t be done already hasn’t been done already”. So, the real question is, “is using a laser to perform these things truly superior to the ultrasound only” And the marketing tells you that it is. And indeed (if I was to present the industry supported marketing) it looks pretty slick. But, we only have about 20 minutes today so rather than show you all of that, which you can find very easily and I personally don’t believe it because it’s industry-supported (he who pays the piper chooses the song /chooses the outcome of what’s going to be published). I find that literature to be very questionable. So, I’ve chosen instead to present to you the literature that you’re not going to get presented at any industry-supported evening dinner show; the peer-reviewed large studies that were performed by non-industry-supported groups.
This is an expression of my disappointment (as well as others disappointments) when we realized that, “Wow! There’s really nothing that the laser does that we can’t do already. It just does it in a way that sounds a lot cooler.”
FLACS ESCRS Study
So let’s take a look here. This is a Peter Barry, MD ( 2016) who presented the preliminary results of a study performed by the European Society of Cataract and Refractive Surgery. And I’d like to thank my colleague Dr. Steven Safran in New Jersey who brought many of these studies to my attention as I was investigating whether or not this was something that I wanted to provide to my patients.
So this study was not a small study there are 16 centers in 10 European countries throughout Europe. This involved almost 3,000 patients.
So what were the results?
- Worse post-operative visual acuity – Unfortunately, the visual acuity, which we were hoping precision would result in better acuity, (it) turns out that in this study those who had FLACS actually ended up with worse visual acuity on average than those who had phacoemulsification only. Now it was small but still it was worse and whole point is we believe the marketing that it should be better but it was not.
- More post-operative complications – It gets gets worse. there were more postoperative complications among those who underwent FLACS than those who underwent standard phacoemulsification.
- Were more likely to have post-op visual acuity worse than pre-op – Take a look at this. This requires that we spend a moment and think about it. Those who underwent FLACS were more likely to have post-op visual acuity that was worse than pre-op. Why do we submit our patients to the risk of surgery? To make their vision better. Any new technique or technology has to, at the very least, not make patients worse more often than the gold standard. So FLACS fails there.
A Closer Look
Let’s take a closer look and because these these results are really unintuitive right?
Post-Operative Biometry Prediction Error
So let’s first take a look at the idea of accuracy. Again, what is being loosely referred to with the marketing term, “precision”. One would think that if you’re targeting plano refractive error or minus one-half (whatever it is you’re targeting), that this more advanced technology is going to get you closer to your target. Well, indeed, that’s not the case. At least not based on the preliminary results of this very, very large study.
Postoperative Surgical Complications
I think it’s important to look at the types of complications that are more common.
Corneal Edema, Posterior Capsule Opacification, and uveitis (so anterior chamber reaction) ***. These are not small differences. In fact, corneal edema is five times more likely among those who had FLACS; Posterior Capsule Opacification, six times more likely.
Now you may say, “Okay that’s not a big deal. We take them back to the the yag laser. Good to go!” The yag laser is not without risk. Specially in high myopes. Three times the risk of anterior chamber reaction. “Ok”, you say “but that’s just one study”. Albeit a very large study – almost 3,000 patients. Well it’s not the only study.
There’s another study that looked at almost 2,000 patients enrolled and what this one found and I’ll read the conclusions because it’s a little difficult for you see,
“femtosecond laser cataract surgery did not demonstrate clinically, meaningful improvement in visual outcomes over conventional phacoemulsification cataract surgery.”
If you look up a little bit higher it gets even more concerning.
“Phacoemulsification cataract surgery cases had more letters gained compared with laser cataract surgery.”
[Reference: Ewe S, Abell R, Oakley C, Lim C, Allen P, McPherson Z, Rao A, Davies P, Vote B. A Comparative Cohort Study of Visual Outcomes in Femtosecond Laser-Assisted versus Phacoemulsification Cataract Surgery. Ophthalmology. 2016;123(1):178-182.]
So conventional, actually, did better. And why that might have been the case? Well let’s look again at risks and complications.
Perioperative Complications – laser cataract surgery and phacoemulsification only. If you take a look at those ring in the red you’ll see that there are some significant differences but not just your usual, just barely, less than P (P-Value) or P is less than 0.05 these are really statistically significant. But more important than statistically significant they are clinically significant. Ocular hypertension, cystoid macular edema – these are things that can result in loss of vision. It should be noted that these are not the first studies to show this cystoid macular edema is an increased risk in FLACS.
Cystoid Macular Edema
This study is from 2014 and showed an increased risk of cystoid macular edema in cataract surgery patients who underwent FLACS. So why might this be? What could be going on during the laser portion of FLACS that results in (more likely) corneal edema, increased anterior chamber reaction, iop elevation, cystoid macular edema and posterior capsule opacification.
[Reference: Ewe S, Oakley C, Abell R, Allen P, Vote B. Cystoid macular edema after femtosecond laserassisted versus phacoemulsification cataract surgery. Journal of Cataract & Refractive Surgery. 2015;41(11):2373-2378. ]
What could be the the unifying factor here?
Well, let’s take a look at some of the studies that have actually looked at the changes that occur during and after the femto laser portion of the cataract surgery.
Corneal Edema – So with corneal edema, what could be going on? Well it turns out that the bubbles that occur (the cavitation bubbles that occur) from the femtosecond laser change the pH in the aqueous. It shifts it to more acidic aqueous. And we know that the corneal endothelium is exceptionally sensitive to changes in pH.
[Reference: Rossi M, Di Censo F, Di Censo M, Al Oum M. Changes in Aqueous Humor pH After Femtosecond Laser-Assisted Cataract Surgery. Journal of Refractive Surgery. 2015;31(7):462-465.]
Anterior Chamber Reaction – Prostaglandins have been shown to rise immediately after femtosecond laser treatment. Prostaglandins are part of the pro-inflammatory cascade. But that’s not it. It’s not just the prostaglandins. There are, in addition, other inflammatary mediators that have been shown to increase after the femto portion of the cataract surgery (Increase inflammatory Cytokines after Femto treatment).
[Reference: Schultz T, Joachim S, Kuehn M, Dick H. Changes in Prostaglandin Levels in Patients Undergoing Femtosecond Laser-Assisted Cataract Surgery. Journal of Refractive Surgery. 2013;29(11):742-747.]
Posterior Capsular Opacification (PCO) – How about Posterior Capsular Opacification? Well, It turns out that femto is association with a higher concentration of fibroblast growth factor (FGF-2) as well as other pro fibrotic factors.
The conclusion from that particular paper was
“femtosecond laser pretreatment in cataract surgery significantly induces altered levels of pro-fibrotic intraocular cytokines which are involved in the development PCO…Increased levels of these cytokines and growth factors in aqueous humor in the early phase after cataract surgery could induce lens epithelial cell proliferation, migration and transdifferentiation.”
So this is a a posited mechanism by which Posterior Capsule Opacification (PCO) could actually be more likely after Femto. It’s a reasonable hypothesis.
[Reference: Chen H, Lin H, Zheng D, Liu Y, Chen W, Liu Y. Expression of Cytokines, Chmokines and Growth Factors in Patients Undergoing Cataract Surgery with Femtosecond Laser Pretreatment. PLOS ONE. 2015;10(9):e0137227.]
So Where Does That Leave Us?
So then where does this leave us with regard to FLACS versus traditional, ultrasound-only phacoemulsification? Well, first of all, let’s take a look at the benefits. I mean, the marketing benefits don’t seem to have a lot of support in the literature. At least not in the non-industry supported, large-scale population studies.
Benefits of FLACS
You have to admit it’s cool. I mean, it is a really cool technology. Anytime you have laser and you put it with anything it just makes things cooler. And this is very much true with patients they hear laser cataract surgery and they want it.
It’s fun for the surgeon
And it is a lot of fun for the surgeon. Okay, Ophthalmologists, in general, are kind of geeky. We like our Star Wars and most of us have seen Logan’s Run and there’s something about doing surgery with a laser – it just…it feels cool. And I will say – having performed FLACS, it is fun. There’s just something about watching that video screen…it turns surgery into a video game. And so from the surgeons perspective, it’s a lot of fun.
Bragging Rights for the patient
It does give bragging rights to the patient. The patients get to tell their friends at the golf course/at cocktail parties that they had laser cataract surgery. Right? And that really does sound impressive. Even more so when you find out that in general we have to pay extra for it. So, it’s kind of like “anything that have to pay extra for – whether it be a nice bag or a really nice car, whatever it is, you get bragging rights for it
To date there’s no strong evidence from (this is key to recognize) independent (non-industry supported), peer-reviewed (published and represented in major conferences). So, no strong evidence from independent, peer-reviewed studies, supporting an objective benefit. Not just a cool sounding marketing term benefit, like “precision”, which basically means “nothing clinically”. But, an objective benefit to patients of FLACS over conventional phacoemulsification.
But it gets worse. FLACS appears to actually be associated with greater pro-inflammatory changes in the aqueous humor that can lead to increased risks of vision-threatening postoperative complications including:
- corneal edema,
- anterior chamber reaction,
- cystoid macular edema,
- posterior capsule opacification, and
- intraocular pressure elevation.
And I’ve not spoken about any of the other risks that were common in the early studies of Femto; such as capsular tags, increased risk of posterior capsule rupture, and things that were largely associated with learning curves of the surgeon or with improvements in technology. We’ve not talked about those because, I think that for the most part, those were related to learning curves and technology issues that have, for the most part, been solved. So, what I wanted to focus on today was just what (objectively) appears to be going on when you look at a large number of patients who’ve had surgery by experienced surgeons with the modern equipment that’s available. All of the FLACS have been modern, but [I mean] the most recent.
Still despite everything that I said today, FLACS is very much in its infancy. There’s a very, very good possibility that with tweaks to the technology – perhaps the hardware, perhaps the software, or perhaps changes in the way we treat patients pharmacologically (so either with with drops or injections before or during surgery), that it may be possible (we may be able to) reduce or even eliminate the rise inflammatory mediators and with that the added risks of FLACS. So that FLACS could potentially – not only be “equivalent” to ultrasound-only phacoemulsification, but “better than”.
To summarize, at the moment…
- FLACS is not all it’s stouted to be. Not by any objective criteria
- At the moment there is no strong evidence that FLACS is superior to conventional phacoemulsification, and may actually be a step back at least with regard to intraocular inflammation and its associated risks and complications.
- But (I do think that there’s the real possibility that) with advances in technology, it may have the potential to make good on at least some of its promises. That’s just not the case yet.
My argument is that until that’s the case it’s very very difficult for me, as a surgeon, to justify strongly recommending FLACS to my patients over traditional phacoemulsification-only surgery because I don’t think that the coolness factor and that the bragging rights really justifies the risks that I just went over.
Anyway, that’s my view. You will definitely hear alternative views but I want to thank you for attending this and then now it’s off to lunch. Any questions that anyone has?
All right, thank you.