Dr. Jonathan Solomon

We're gonna discuss our experience with the CALLISTO guidance system as it relates to our surgical cataract refractive patients and in a pursuit of achieving zero refractive cylinder.  We did a pilot study and we're very grateful to be able to work with ZEISS.  And what more can you ask for if you're gonna attach a guidance system to what is certainly, in my experience, the finest scope on the market.  As part of our due diligence, we've looked at a lot of the technology and admittedly we work with a lot of different companies in our efforts to offer the best outcomes for our patients.

And that also can be said in our pursuit for the correction of astigmatism.  So, first and foremost, I have no financial interest in the discussion here, the obligatory slide.  And we'll move on to actually the nuts and bolts of this discussion, which, in essence, as I mentioned earlier, is really a pursuit for astigmatic neutrality in the course of cataract or lens based refractive surgery.

We did a pilot study looking at 15 patients using the CALLISTO system for guidance with Toric implants.  And it ran across the spectrum with regard to which impact we were using.  It included an Alcom [sp] product and included the BNL product.  It included the Abbot product.  And, as many of you already know, when it comes to I'll say aligning a Toric implant the orientation of that lens is crucial or paramount in the pursuit of residual refractive cylinder or in the opposite trying to achieve a spherical outcome. 

With this in mind, for each degree of error you're gonna lose about 3.3 percent of the value.  And that certainly will climb as we are using implants now that are capable of correcting upwards of four diopters of astigmatism and then depending on how you want to move beyond that with the advent of overlaying arcuian [sp] incisions with the use of femtosecond technology orientation is gonna be critical.  And you're gonna hear that over and over again in this discussion.  Orientation and access alignment is critical. 

So, in case there's anybody out there that doesn't believe it, I'll invite you into the office for patients that we sometimes see usually as a second opinion because it doesn't happen to me directly, particularly with regard to the CALLISTO system where a patient is expecting what we call a 20 happy [sp] outcome.  And we all know that it doesn't necessarily mean that you have to be planisphere to achieve that, but you're certainly going to stack the deck in your favor if you are able to go in that direction. 

The slide here, again, is a little bit of a glare off this, it's really meant to demonstrate our ability to achieve less than a half diopter which is considered to be the gold standard here for astigmatic correction.  We can look at this in the context to say multifocal implants and combinations with arcuate incisions.  And it used to be said that you have to achieve outcomes that are less than three quarters of a diopter in order to achieve happy patients with regard to multifocal implants.  I think that number is going to drop.  I think with the advent of the technology it's probably safer to say that if you have a happy patient with less than three quarters of diopter you're probably gonna have an even happier patient if you're down and around a quarter to a third of a diopter.

And so, when we did our study 100 percent of our patients actually were less than a diopter post operatively.  But, the overwhelming majority of them were actually less than a half diopter of residual cylindrical power.  So, we're talking about if we're gonna compare different technologies, as I said, we implement--we've implemented in our practice preoperative measurements that include different topography systems.  We have intraoperative aberrometry as well.  But, we also, and have had for a long time and rely heavily on the non-contact biometry in the form of the iOL Master. 

Well, let's shift gears here a little bit and discuss as it relates to efficiency.  If you're able to collect information from your patients by sitting in one chair, gather your axial measurements, your anterior chamber depth measurements, your keratometry measurements, that in and of itself will allow your practice to operate more efficiently.  It means that you'll have a happier patient, happier staff and ultimately a happier surgeon because that’s really what it's all about, right?

And so, gathering this information, implementing it, placing it across a digital platform to your operating scope, which then offers guidance.  And I hope everybody here has had an opportunity to look at the CALLISTO system, it's unbelievably accurate.  And I say that because in some respects there's a little bit of a surprise to us with regard to our outcomes.  And if we're able to discuss this a little further, I know that the next generation is likely to also include a capture system that will allow us to reference the eye as it relates to natural landmark sclera or limbal or otherwise. 

And so, when you try and determine the value of your astigmatism correction there are three things that you're gonna look at.  One would be your reference error, which in essence means, how accurately did you identify the horizontal meridian?  Then there's the access error, which means how accurately did you identify the steep access of the corneal astigmatism or where did you feel you want to align the implant?  And then, finally, how good a surgeon are you at aligning the implant to your predetermined axis?

And so, if we consider the publication a couple years ago looking at those three things, we performed 50 percent better in every respect, with the exception, of course, of reference marking.  And the only reason I say that is because we didn't measure it as it related to this study.  And on top of it, it's really gonna be irrelevant when we're able to get a registration platform, which we know is coming down the line.  But, that’s likely the discussion we'll have next year.

So, if you consider the standard to be roughly about 5 degrees of error for Toric iOL alignment, we were able to reduce that number simply by applying the CALLISTO software.  And it's hard to believe that we're gonna have this discussion and talk about intraoperative aberrometry as our gold standard.  But, if we're gonna consider the data that has been published, it's certainly quite compelling and it has also mirrored what we were able to appreciate in our office, which is aligning that lens accurately based on these aberrometry measurements are important.  But, again, it's another scale and another step that is required in order to achieve your goals.

So, getting back, let's just come full circle.  If you're able to use measurements that are already being acquired in an office usually, at least in our case, by a technician, yes, granted they have to be scaled and understand the subtle nuances of the technology, but if you're able to capture that information in your office, import it into your surgical suite and then deliver it in an efficient manner, again, patients ultimately are happy because of better outcomes, surgeons happy and the practice is going to thrive.

And what have we asked our staff to do differently in the process, really as it relates to the CALLISTO system, nothing, nothing different.  They're capturing the information, importing it into a computer software system and achieving a goal that will lead to a much happier patient.  So, let's put this, again, in this context that from the standpoint of aberrometry we are getting what we would consider to be perfect measurements.  Now, I use that term loosely because in large part there are things that we have to take into consideration because it's an imperfect eye.  We've got to talk about effective lens position.  We've got to talk about pressurizing the eye.  We got to talk about the ocular surface and as it relates to things like making sure that it's well lubricated with, in our case, a balanced sale solution in the midst of the intraoperative process and making sure that there aren't any unnecessary variables like the lid speculum.  Turn that around and we consider what we call to be an imperfect measurement on a relatively perfect eye, meaning prior to walking into the operating room, we assume that the eye is in its nature normal physiologic state.  You haven't done too much in the way of adulterating the corneal surface.  You haven't done anything to change the pressure, which in essence is gonna have an impact on the relationship of what we assume to be the effective lens position to the corneal surface. 

The one thing that we weren't able to do in the course of our study was get information with regard to the posterior cornea.  I say that to you because what it does require is a little bit of a nomogram adjustment and that’s well known.  The baler [sp] Doug Coake Nomogram [sp] really in essence gives us a fairly easy reproducible and efficient way of in addition looking at the anterior surface, adding the value of the negative mirror on the back of the cornea and then determining what the true corneal power is for this deep access. 

And it's remarkable just how reliable those results were.  And I hope somewhere in here we're gonna look at our outcome.  But, what we did in essence, and this is just really a summary of what I already mentioned earlier, which was regard to reference and access and alignment error.  We compared it to two months' worth of patients or premium patients and measured with the intraoperative aberrometer [sp].  And this is a fairly good image demonstrating what it is you're gonna see through the oculars of your Lumera microscope in the process of performing cataract surgery.

And so, the last thing you want to do, if your goal is to achieve a good surgical outcome with your cataract patients is add to the surgical time.  And so, this is the overlay that you are gonna see through your scope in the process of three and a half minutes, four minutes or five minutes if you're on a bad day, six minutes of cataract time.  And so, what have we done differently?

Once again, I'll say to tell you, nothing.  This is exactly what we're already doing.  It just gives us an overlay through the scope in order to align the Toric implant or also could be applied to limbal relaxing incisions or if there are cases where we're doing manual capsulatomy or capsulorhexis you can also get an overlay of whatever predetermined casulatomy [sp] size you would like to see. 

So, there's a wealth of information being collected and delivered to you in a very, very short matter of time.  Well, we're gonna refer back to some data I had mentioned earlier with regard to the Visur study and also make some comparisons to our ora data.  And without question you can see that we are achieving residual refractive error below a half diopter.  So, it really does take it to a new level here. 

If the standard assumption is that three quarters of a diopter is good, well then I would certainly argue that less than half a diopter is better.  Well, let's take it a step further, with the calculations that we describe, how close were you to your intended outcome?  As we know, not every Toric lens scenario is gonna allow you to achieve a spherical outcome or a theoretical outcome of zero.

So, we wanted to know based on which implant it was determined how close we were to our actual outcome.  And, again, you can see we were just a little over a quarter diopter away on average.  And I can tell you if we were to look at the number of patients we were certainly within a half diopter for every patient.  And that’s truly remarkable in and of itself.

Well, let's compare it to our intraoperative aberrometry.  And you can see that it is certainly quite comparable to our aberrometry data.  You're still right there at about a half diopter.  So, you put this in the context once again.  You're looking at imperfect measurements on a perfect eye.  Well, we've kind of already demonstrated that that’s probably not the case as long as you're doing your due diligence and make some fairly straightforward simple tomogram adjustments by adding the baler calculation with regard to post year a cornea and you're doing it in a very controlled environment in your office with a patient that already is able to cooperate hopefully in a much better way than they would on the operating table whether it be through respiratory variation or, as I mentioned earlier, with a little bit of squeezing that’s gonna impact your outcomes.  And it's all being done by your staff, which is something that they're already very comfortable doing. 

And so, the theoretical bests published by Warren Hill [sp], you know, you're approaching levels of residual refractive error that is very I guess we could say aggressive.  You can afford to be aggressive in your pursuits of cylindrical neutrality, and certainly up there with the new iteration of intraoperative aberrometry.  And looking at this once again, 100 percent of the patients were within one diopter, 93 percent of our patients, as I said, were within three quarters.  And the overwhelming majority approaching 90 percent were below a half diopter.  So, that certainly is very, very impressive.  And you apply that, again, what we call the defocus equivalent.  It's not just the spherical equivalent, but you have to add that component.  We all agree that someone who comes in with plus or quarter minus 50 is gonna have a very different outcome to someone who comes in with plus 150 minus three.  And so, this pursuit certainly has significant merit.  And I'll say it once more; I didn't do anything very different from what I was already doing in my practice.  And if you're not gonna upset the natural flow of the practice like, once again, you're gonna have a happy patient, happy staff, happy physician. 

So, in summary, the utilization of the CALLISTO system certainly is comparable to what is considered to be the gold standard.  I chuckle there under my breath when I say that in comparison to the intraoperative aberrometer and certainly the most up to date version of that being to verify this was actually compared to the generation prior to that.  But, it certainly does, I think, drive the point home.  we expect in the future to also be able to address what I think to be a major player in what was the residual astigmatism, which is our error with regard to reference, the point or the diameter of that ink pen that we were forced to use in this particular instance does play a role.  So, the finer that mark will be the less stackable error you're gonna have, which leads to a better alignment and orientation.

So, as things are moving forward this is a technology that certainly is going to hopefully play a role.  It certainly will in my practice, but certainly those of you who are already using the Lumera or the Ziscope [sp] it's fairly straightforward adjustment to in an effort to incorporate this technology.

So, I thank you if there aren't any questions.  We can put that subject to bed then, astigmatism, zero, thank you.