Lecturer: Dr. Lisa Park
DR PARK: Okay. Good morning! I believe we’re on. Hi. I’m Dr. Park. Welcome to our Cybersight webinar. Good morning and welcome. I’m excited to be here. My name is Dr. Lisa park, and we’re here for a Cybersight webinar on phaco fundamentals. I’m very excited to be asked back, after doing a session on basics and introduction to phacoemulsification. Let’s see if I can see my slides here. Fantastic. I just want to say hello to everybody. Just to give you some information, I am a cataract surgeon. I have been on the faculty at the New York University School of Medicine for over ten years, practicing in New York, in Midtown Manhattan. My passion is surgical teaching, and I’ve been honored to be able to teach a number of residents through the years, and also too to participate in surgical teaching around the world. I know there are a number of you who logged on from Ethiopia, so I just wanted to say a quick hello to my colleagues that I’ve been working with, in Addis Ababa, and I also recently returned from Pondicherry, India, and I was excited to participate in the seminar put on by the eye hospital there.
So I would like to say hello to our Indian colleagues who are also joining us today. I would encourage you to look at a couple of surgical educational materials that I’ve been involved with. The VCSE series is revised every three years, and the Lens and Cataract Book has been updated as of this year. The cataract section has been markedly revised. I encourage you to take a look at it, if you haven’t read it in some time, and I encourage you to look at the ASCRS Center for Learning and particularly the Phaco Fundamentals Classroom. I hope that these are helpful to you. I just want to start by showing a video of — this is a typical case in a patient that doesn’t have — well, has I guess a fairly significant lens, and this is the type of surgery that I’m doing traditionally. And that is… When there’s not a lot of you staining with Trypan blue, doing a clear corneal incision, performing a continuous curvilinear capsulorrhexis, and this would be a traditional stop and chop case, so making a groove, and then using a horizontal and vertical chopper to break this lens into a number of pieces, and then bringing them up individually. These pie-shaped wedges. So you see that’s a horizontal chop, and using the fluidics of the phaco machine, in order to maximize efficiency. We’re going to talk about some techniques and strategies for being efficient and using as little energy in the fluidics as possible. And here this is injection of a one piece Acrosoft lens. Inserting it into the capsular bag, and removing viscoelastic with irrigation aspiration.
So I just wanted to show a very straightforward case. So we have a starting point to talk about and to work from. And I understand that having operated around the world, that there are… We’re all under various conditions. So technology is different in different places. The access to instruments and materials is different all over the world. And the main point is — as I’m showing you the videos that I have — the main point I want to stress is just because you’re driving a sports car doesn’t mean you’re a good driver. In other words, you can’t depend on your technology on achieving what you need to achieve. Many surgeons said of course if I had the machine you had, I would be able to do what you’re able to do. And I would say a really important understanding of the principles is more important than actually just having access to this technology. So I’ll just talk about — just to give an overview of the machinery and the equipment that I’m using. I operate with the Zeiss Lumera microscope. I also happen to like the Leica scopes very much, and the machine you’ll see in the videos is the Alcon Centurion machine. I’ve used the Alcon Infinity. There are of course a number of other very good phaco machines that are available to you. And I’ve operated with tabletop machines in the developing world. So I understand that there is a wide range. I operate through a temporal clear corneal incision, and the blade I use is either 2.4 or 2.2 millimeter incision. When I initially trained seven years ago, it came down from a 2.75 or 2.8 millimeter incision. The needle I like to use is a 45-degree balance tip, and in my previous talk, we talked a little bit about the choices that you have, regarding what your phaco tip looks like. You’ll modify your technique according to what machinery and instruments you’re using.
I perform a continuous capsulorrhexis using a 27 gauge cystotome. I tend not to use forceps, simply because one, it’s harder to do in a smaller incision, although the instruments have gotten smaller and smaller, so now it’s not so difficult, and number two, I happen to not like it, because very often, when you go especially to places where you don’t have access to your own instruments, that those forceps can become easily misaligned. If you have your own system and bend your own needle, you never have to worry about that. The chopper that I use is a horizontal and vertical chopper, and I like these, because they have generally rounded edges. On the distal aspect. To protect the bag. But of course, there are a number of other choppers that are available to you. The consumables I use — I like the intraocular lenses from Alcon. My go to lens is the Acrosoft one piece lens, I also use this three piece foldable lens. And then my viscoelastics that I tend to like to use include two categories — and we’re gonna talk about this in detail. I use Healon as my cohesive so today I’m going to be talking about a little bit of a variation on what I had announced.
I’ll talk about four topics today. The first is going to be phacodynamics. We’ll talk about viscoelastics and consumables and the importance of making certain choices, we’re gonna talk about the geometry of intraocular implants, and I’ll talk about the use of rings for the pupil and rings for the capsule. When we talk about phacodynamics, there are three main parameters that we discuss. The first is power. And the goal is to use enough power to be efficient but not more than needed. We’re gonna talk about irrigation, maintaining a stable anterior chamber, and vacuum. That is achieving purchase and grabbing onto your pieces and avoiding postocclusion surge. So the first is power. And the goal is: Use enough power to break up your lens, but don’t use more power than necessary. And why is that? We’re trying to prevent clouding of the cornea, and we’re trying to prevent the possibility of grabbing onto the capsular bag. Your choices include multiple ways of modifying your phacoemulsification in order to minimize the amount of energy that you use. One is — one category is direction of the needle. And the second category is timing. And we’ll talk about both.
When we talk about traditional longitudinal continuous phaco, what we’re talking about is this. A phaco tip that is being pushed forward and back. As we see in this video. So this is the traditional forward and back motion. We believe that this breaks up the lens using a physical jackhammer effect, as well as the formation of cavitation bubbles, which are then also using their energy in order to break up lens material. Let’s see if we can put this down here. This has been modified with various other modalities. So transversal ultrasound combines a longitudinal forward and backward motion, with a transverse elliptical motion, and these motions happen simultaneously. To show us this. And so this combination of forward with a transverse motion then provides additional physical energy to break up this lens, without converting into additional dissipated energy that affects the endothelium. And then we also have torsional ultrasound. And this is a movement of the phaco tip in a semi-circular fashion. And this allows, again, further breakup of the lens. Without causing energy that can affect the endothelium. And this is something that’s specific to the Alcon machines. And is very effective, and enables us to really break up this lens easily. You can see that there is advantage to using a beveled tip, a 45-degree tip, and an angled tip, in order to maximize the physical energy that is used. So that’s direction. And that will depend upon the machine that you’re using. The second aspect is timing, and that will depend upon the mode that you choose to program into your phaco machine. So there are two main categories, and that is pulse and burst. So if we think about continuous phaco, when you’re pressing down your foot pedal, the greater amount that you press, the more energy you will achieve. So that’s linear phaco. And that will be continuous, 100% of the time. If we talk about pulse, this is our ability to depress the pedal and then allow there to be an on and an off time that’s programmed automatically into the machine. The more you press, the greater your total phaco energy will be. But there will be some time where the phaco is off, and so you can minimize the amount of energy delivered. And you can see here that you can set the limits of your phaco power, and then the percentage of time that the phaco is on, or the pulses per second. We call this the duty cycle.
Phaco burst is another modality, in which the phaco power is actually set at a certain level, but the greater amount of pressure you put on the pedal and the further down you press the closer together those bursts of phaco will be, and if you were to press 100% of the way down, then you’ll just get continuous phaco. And so this shows you how many milliseconds between each of the bursts, the minimum and the maximum, and allows you to, again, adjust for the amount of time that the phaco is on. What this can be very helpful for is actually to grab onto a large chunk, to burst in, and then allow you to grab it — is very helpful, this phaco burst. So this is just a diagram to show you the differences in power modulation. So phaco continuous, versus pulse, versus burst. You can set these on various machines and on the Centurion, you can see here when you press this button, it allows you to change from continuous to pulse to burst. And you can see here that it’s separated out the longitudinal versus the torsional.
And so in most of my cases, I’ve eliminated longitudinal and I’ve gone simply to the semi-circular motion of torsional and I’ve found this to be very effective in these cases, and this can then limit the amount of dissipated energy that is then delivered to the endothelium. And let’s see here. And so you can see here… This is a 94-year-old gentleman with a relatively dense lens. Here’s the longitudinal setting here, which is zero. And torsional, which is linear, with a max of approximately 80. You can notice this is the dissipated energy over here, this is my aspiration and vacuum setting, and this is the level of intraocular pressure. This would be a traditional stop and chop, I cracked, and then I’m gonna go ahead and using higher vacuum, chop this lens. So we can see here, utilizing again, this chopper, to engage, and the vacuum is approximately… 475 would be the maximum, in order to bring these pieces up and out of the capsular bag, once it has been disassembled. So now this would be a horizontal chop, I brought the lens up using high vacuum, and then you can see here the amount of torsional energy that’s being used. And so this is linear. And I’m using chop to break up this lens into smaller and smaller pieces. And then utilizing the simply phacodynamics in the vacuum. This is bringing up the entire lens. As you can see here, our amount of dissipated energy is quite low. I think we’re gonna end up under 10 CBE. This is bimanual irrigation aspiration. I like the Katena handpieces. The key here is that your aspiration should be smaller than the irrigation, in order to achieve your stable anterior chamber. And you can see that I’ve maintained a pretty high IOP. And so this enables me to do this, without collapsing the anterior chamber. This is actually autoinsertion of the Acrosoft lens, and centration, and again, irrigation aspiration. The second principle is — in addition to minimizing the amount of energy, we want to minimize fluidics. Don’t use more irrigation than necessary.
The more we’re irrigating the cornea, the more you’re losing those endothelial cells. I will address a question — somebody had put in a question — what is your cutoff point to decide whether to do phaco along with a DSEK. The answer is I like to see a specular microscopy count greater than 2,000. Under than 2,000, it comes down to — what do the cells look like, how much polymorphism is there, but even with all that, let’s say I see a lot of gutta, I see a lot of cells, even then it doesn’t matter. You’re measuring what the function of the cells is, and I will counsel a patient, I’ll take pachymetry. If their pachymetry is normal, we’re gonna proceed in all cases with phaco first, and see how the cornea does. If the edema is unresolving, then we’ll proceed with a second procedure, such as a DSEK. But we don’t do that primarily, if possible. Unless it’s completely necessary. But in general, we do the phaco first, and we counsel according to the cell count and according to function. So now the technology exists where hanging the bottle has been replaced with bags that are actually in the machine, that are actively compressed, and so there are plates that will adjust and deliver the fluid, so that you can just adjust the IOP.
This is active fluidics. There’s a sensor which senses how much fluid is coming in, so this is the state of the art now. Of course, this is not wide, widespread. So adjusting the intraocular pressure by bottle height is very important. And so when one is operating, it’s very important to ascertain — if you’re not getting good anterior chamber stability, you have to ask yourself one of two things: Number one, is your wound leaking, and number two, is your bottle high enough, or is it empty? So these are important things to consider. What I like to do is bring the bottle down as low as is feasible, in order to maintain an anterior chamber, to prevent this turbulence inside the eye. And that’s my goal here also. If you can get a lower IOP, and still maintain the anterior chamber. That is more ideal, to save the endothelium. So let’s talk about the times when you would adjust your bottle height. One would be right here, and that is in the case of posterior capsular rupture. Here the case seems to be going fine, there’s some epinuclear material, however, as we notice — that there’s an opening in the posterior capsule, and we’re going to immediately drop our IOP. Actually, we don’t do it right here. So this is a little bit high.
And you can see that I’ve not taken out the phaco handpiece, but immediately put in a dispersive viscoelastic, with the intention, then, of trying to get out the pieces, while maintaining that aspect of the capsule. So here… Let’s see. So you’ll see — so I dropped it from 80 to 55. And so in doing so, I’m hoping not to hydrate the vitreous. I’m hoping to keep these pieces a little bit more stable. And you can see here… Not entirely successful. A little piece falls behind. However, we’re still able to place a lens into the posterior chamber. So, again, we’re adjusting the bottle height according to the situation. You can see this is the equivalent bottle height. This is the IOP in this particular case. And principle number three is don’t use more vacuum than necessary. It depends upon what aspect of the case you’re performing. When we talk about vacuum versus aspiration — aspiration is how quickly the pieces are going to be attracted to the tip when it’s not occluded, and vacuum is how tightly it’s going to be held to the tip when it is occluded. So the key here is you have to achieve total occlusion of the tip in order to get your maximum vacuum.
So oftentimes I’ll see people try to raise their vacuum, when they haven’t occluded the tip, and they’re thinking — how come I’m not grabbing these pieces? The answer is maybe you’re not completely occluding. So your physical movement of your handpiece to get the full occlusion is very important. And adjustment of choice of phaco tips. So sometimes I’ll have residents where we’ve gone to a 45-degree tip, they’re not getting full occlusion, so they’re trying to increase their vacuum, and my answer to them is — let’s change back to a 30-degree tip and make sure you have full occlusion before we go ahead and make that change. So let’s see here. And this is a case of… Phaco flip. So what I’m doing is I’m doing hydrodissection, and then actually trying to get this lens up a little bit into the anterior chamber. And in doing so, then, I will use high vacuum immediately, to grab this part of the lens. And tilt it up and out of the bag. You can see that it’s just completely flipped over. So I know I have full access. So I will not need to chop this lens. It’s not that dense a lens, and therefore I’m gonna use high vacuum to grab it and simply phacoemulsify it, and I’m in the anterior chamber in this particular case. The other question — where is the ideal space to do chopping of the lens? The ideal place is the posterior chamber.
It’s more ideal to save your phaco energy and get the lens broken up in the posterior chamber, if possible, but we use our chopping techniques in the anterior chamber, as you can see, in this particular case. Okay. And then again… This is the importance of high vacuum to perform a vertical chop. So you can see here — here is vacuum. We have to completely occlude, completely bury this tip, in order to be able to grab that lens and to perform that vertical chopping maneuver. And you can see here that the vacuum is linear. So, in other words, I’ve adjusted it so that when I press the pedal, the more I press, the more vacuum I get. In this particular case, you can see I’ve set my baseline setting at 100, and my maximum setting at 475. And in doing so, what I noticed here is that my pieces are a little bit too jumpy. I don’t like the way that this is acting here. You can see that the pieces are not coming so easily. So you have to ask yourself: Is it that there’s lack of full occlusion? Are the pieces not completely disassembled? Why am I not able to achieve what I need to achieve here? And sometimes what you’ll see is that maybe your parameters are too high. So, in other words, if I don’t have a smooth flow of the nuclear pieces, then I’m wondering if perhaps this is not — these are not the correct settings to use in this particular case.
You can see I’m eating directly through these pieces. They’re not coming very easily. And so what I’ve done in this particular case is I actually… Lowered my baseline vacuum. From 100 — I went down to zero. I said… You know, maybe we need to have a little bit more time for those pieces to be grabbed onto, before they’re phacoemulsified. This is a dense lens, so I’m using some longitudinal, and I’ve lowered the vacuum so that it starts at zero. And now you can see that the pieces are really — it just gives me an extra millisecond to be able to grab that piece adequately, and bring that up. So mild adjustments in the settings can be very helpful in these particular cases. And so you can see here — my aspiration maximum is at 32. And this is how quickly the pieces will come. And then the vacuum allows me to phacoemulsify and hold on and grab those pieces adequately. So my take-home points are: Your goal is to use only the power needed in order to phacoemulsify your lens, and not too much power. The second is: Use your irrigation to maintain anterior chamber stability, but lower it in cases where you need to make adjustments.
And so be aware of where your height is. And three, your aspiration — your goal is to achieve effective purchase, so use linear modalities to your advantage. So that’s phacodynamics. We’re gonna move now to… Two quick things. And that is use of viscoelastics. Okay. So what are viscoelastics? These have various viscous and elastic properties. They can be thick or thin. They’re elastic. They change shape under different shear forces. And they coat various tissues. Why are these important? We obviously are protecting the endothelium. We can create space. We can manipulate tissues. A survey of cataract surgeons in the US indicated that 68% of surgeons use only one OVD for routine cases, but the vast majority of us adjust the OVD in complex cases. And so I’m just gonna talk about those here. So I wanted to ask this question, because I know that these are consumables that are hard to obtain. So my question to you is: For for those that are operating regularly, do you have more than one OVD available during surgery? The answer is yes or no.
So everyone can submit their answers. Let’s see.Let’s take a look and see what our results are. So yes, two thirds of you do have more than one OVD available. So we’re gonna talk about the differences, and when we use them. A third have one — if you have one, you’ve got to use it.. Okay. What are these made of? They’re generally made of sodium hyaluronate and chondroitin sulfate. But you can’t determine how the OVD is going to act based on the fact that the sodium hyaluronate, which is the most common — it’s going to be the length of the molecular chain. You have to know which category they’re going to fall in, based on the length of the molecular chains. So the two categories include cohesives and dispersives. This video is going to show how they’re going to act. The cohesive is on the left, long molecular weight chains that bind together, and the dispersives are short molecular chains that are more viscous, and they tend to coat tissues better.
So here the long molecular weight chains and the short molecular weight chains… And this is a video that shows — why is this important? It also is important when we remove them from the eye. So this is a cohesive viscoelastic. You can see once you grab part of it and you aspirate, it’s gonna come up as a single long chain, versus your dispersive. So you can see here, when we take these out, these are gonna come out individually. And the importance of this is: Dispersives that are used need to be removed in their entirety. Because if you have viscoelastic that remains, this is the source of your intraocular pressure spike on postop day one. So these need to be removed carefully. These are categories of cohesives. Again, like ProVisc, Healon, these are used to create or maintain space. And so this is just the video, showing — I like to use cohesives in the cases of the floppy iris syndrome case. Where I use a ring to push the iris back, cohesive is nice to be able to put your lens in the bag very easily. And then maintain the space in the anterior chamber, in order to then go ahead and remove this ring easily.
And you can see here as we’re removing it, it comes out almost entirely with just irrigation. So again, this is a long molecular weight chain, so it almost burps out of the wound. So I like to use this at the end of the case, simply because I know that I can perform a very quick irrigation aspiration to remove the viscoelastic. The second category is dispersives, which are smooth. They like to coat. So this would be your Viscoat, Endocoat, OcuCoat, and these are used the majority of the time to protect the endothelium from the energy of phacoemulsification. And this is very important to prevent posterior capsular rupture. And so this is a dispersive OVD. So this is a case in which most of the nucleus is out. I’m actually performing a little bit of endonuclear removal, carefully. Which you can see here — I’m trying to remove this endonuclear shell, but I’m starting to wonder if there’s an opening there, in the posterior capsule. And so… As I’m doing this, I’m looking very carefully at that very bright red reflex, and I’m thinking to myself… That posterior capsule is open. So the thing to do is to inject a dispersive viscoelastic. And now I’m checking to see what’s going on there. And you can see in this particular case that it looks like there’s a central opening there, but I’ve walled it off. In order to carefully remove the material that’s on top of it. And I’m using those small molecular weight chains in order to fill this space.
And what’s nice about this is that it actually turns out there was no rupture in the back but I’ve actually filled with those small molecular chains, in order to protect that area, in order to perform the rest of the removal safely. There are dual viscoelastic systems that are sold, which combine both. And I like to use this Arshinoff shell technique, to really protect the endothelium. And this is a combination technique. So you can see here that we’re going to go ahead and inject — that’s the dispersive. And then a cohesive underneath, to really press up and protect the endothelium. And I like the way that the cohesive presses down on the anterior capsule, in order to perform the capsulorrhexis. And you can see here, during phacoemulsification, a lot of the viscoelastic is actually aspirated, but when you have a nice coating of the dispersive, that really protects your endothelium. I use a cohesive to then go ahead and inject the implant. And you can see here that many people go ahead and irrigate and aspirate underneath the implant, in order to make sure that everything is removed from the eye. And this is the technique that was popularized by Steve Arshinoff, and this is what I use very often, especially in cases where you’re worried about the endothelium. So again, in cases with low specular microscopy counts, low endothelial cell counts, that’s your dispersive. I’m gonna place the cohesive, coating the endothelium, this has really pressed down my anterior capsule, in order to perform the capsulorrhexis. There are some variations that try to do both, like Healon 5 or DiscoVisc, and these are long molecular chains that are very fragile, so they’ll change their behavior based on shear stress. And you can see here — you can see what it looks like outside the eye. So when do we modify? I modify based on challenging cases. So shallow anterior chamber, floppy iris, and pediatric cataracts.
I’ll just show a few examples. So this is a case for my friend Uday Devgan at UCLA. He likes to use this very heavy viscoelastic in a case of floppy iris syndrome where the pupil is not so large. And you can see he’s using this very dense cohesive in order to dilate this pupil and maintain it during the case. I like to use a very dense cohesive — you can see this is, again, a floppy iris syndrome case, trying to manipulate that iris, put that back inside the eye, and really weigh it down, in order to go ahead and perform this surgery in this particular case. This is a case of a pediatric cataract. This is video from my colleague and friend Marc Lustig. So in a pediatric case, the capsule is very rubbery, and acts in a very different manner. So you can see here that it can run out at any time. And so the use of a very dense cohesive viscoelastic can be very helpful in order to tamponade the capsule, to prevent it from running out during the capsulorrhexis. So in summary, your cohesive viscoelastics maintain space, and highly cohesive OVDs can be used in complex cases, such as pediatric cataracts and floppy iris syndrome.
The dispersives coat and protect the endothelium, and can be used in order to prevent corneal edema, and they can compartmentalize the capsule, in case of posterior rupture. So I highly encourage you to vary your use of OVDs in various types of cases. Okay. So we’re gonna move on to biometry. I know that the availability of intraocular lenses varies around the world. And my challenge to you is: In the United States, we have now become refractive cataract surgeons, where it’s not enough to just take out a cataract. We need to really be spot on, with the implant that we put in. And patients are expecting to not only see better but to see perfectly, without glasses. And for that, biometry is critical, and the availability of various lenses is critical. So I’d like to ask: And I know that know that we don’t always implant a lens. Depending upon your access. So what I would like to ask is: In what percentage of cases are you implanting an IOL? No access to IOLs? Less than 50%, greater than 50%, nearly 100%?
And I understand that also in many parts of the world that it depends upon the patient’s ability to pay. So the choice of implant will depend a lot on not just access, but cost. Let’s see let’s see. What percentage of cases do you implant IOL? The vast majority are placing an IO IOL in the vast majority majority of cases. And you choose it based on biometry? In other words, are you choosing the lens before the implant that you’re putting in? I know that in many places that we’re using an average length eye, in order to choose the most likely implant that will be helpful. Okay. So the vast majority are — so I’m very happy to hear that, because I’ve been to places wheres where that’s not the case. Excellent. I’m just gonna talk about… What are the advances in biometry? And advances for getting that perfect 20/20? Measuring the eye. We know that you can see here that there is a very… Wide variety of — obviously refractive error. Okay. I operate in Addis Ababa, a city hospital in the capital city. And you can see here over the last number of years they’ve documented exactly what IOL powers they’re putting in. The vast majority of them are right here. 20, 21, 21.5. But they vary widely, so I want to make the point that it’s very important to consider your implant your implant carefully. What is your target refraction? Do you implant for plano, mild myopia, or using standard IOLs for every case?
And this is something that I commonly see, is that — because… Difficulty accessing glasses after surgery, that many places are aiming for myopia, actually.. Okay. So yes, and I think that is a very common thing. Aiming for a little bit of myopia, versus plano. And we’ll talk about some of about some of those choices. Great. So obviously the two main measurements that we want are the axial length and the corneal curvature. And so ultrasound biometry is critical. Taking good measurements, looking for the appropriate spikes. This is immersion biometry, which is considered to be a little bit more accurate, simply because it eliminates observer error. So, in other words, if you’re pressing harder with your ultrasound probe, you’re going to get inaccurate measurements. And this is manual keratometry. So this is basically reflecting light off of the surface of the cornea. And then ascertaining through calculations of the reflection of those images what the corneal curvature, average corneal curvature is. And manual keratometry — this is about 3 millimeters away from the center of the eye. So what has evolved? We’ve evolved into now optical biometry, and that is the use of light, in order to take those measurements of the length of the eye. It’s infrared light that calculates the axial length, and it uses partial coherence interferometry.
You can see here this is the IOL master and this is the Alcon lens, and the number of spots will determine the accuracy of your measurements. What are the pros? This is non-contact. So, in other words, this really minimizes intraobserver variability, and it may be more accurate, simply because it gives you a refractive axial length rather than an anatomic axial length. The cons are that you can’t use it 100% of the time. It will not penetrate through corneal scars, dense cataracts, so you have to have access to your ultrasound. It also requires patient cooperation and fixation to look into the target, and there is also of course the issue of cost. When we talk about topography and measuring the cornea, there are three basic techniques now placido disc reflection, scanning slit elevation, and the Scheimpflug principle disc assessment. This is reflecting circles onto the eye. You can see here immediately if there’s some steepening or irregularity based on the concentric circles. And this would be a typical Zeiss atlas corneal topographer that gives you some indication of the regularity or irregularity of the cornea. Scanning slit elevation uses a projector and a camera to project these slits onto the eye and then to interpret their reflection back to the camera here. And this allows us to analyze both anterior and posterior aspects.
And this would be scans that you see such as the B&L Orbscan and it gives us indications of both anterior and posterior. And the last is the Scheimpflug principle, which basically tells us that if you were to reflect an object, that you can adjust the image plane, and calculate out this intersection, which gives us many, many points on the surface of the eye. And gives us images such as this. This is the OCULUS Pentacam. This is what I use, the Scheimpflug principle. Which gives us a lot of information about the anterior and posterior curvature. And now we’ve moved into intraoperative calculations on the table. This is the ORA intraoperative aberrometry. So we take the cataract out, we remove the aberration from the lens, and calculate what the contribution of the corneal curvature is directly. And this requires patient cooperation, intraoperatively, and then allows us to then actually even choose an implant and then, again, calculate out what the refractive error is going to be, right on the table, before the patient leaves the operating room. So these are the measurements and advances in measurements that have occurred. Number two, more predictable calculations. This is the traditional SRK formula, which shows that very simply, the calculated IOL power should be the A constant, minus the power of the cornea and the axial length of the eye.
We now know that there are other contributions to calculations, which include the effective lens position. And you can see here that the lens position varies quite a bit. And so this is important to consider. And we now know that there are many, many calculations that are available to us. And I will say just — there are many, many talks that are given, based on what we believe to be the best for not necessarily just the normal eyes, but for the eyes at the extremes. The short eyes and the long eyes. I will say I personally like to use the Holladay II for the long eyes and I use the Barrett for really quite a range. We know that refractive procedures are now causing us to have miscalculations of the corneal curvature, and so it’s very important to take this into consideration. In my hands, the Barrett calculator has been very helpful in this particular case. So this is what I spend the majority of my time now, in preparation for surgery, doing all of these IOL calculations, and making a comparison, choosing my best possible implant, in order to try to achieve the refractive outcome that’s desired.
This is a very good website, Warren Hill’s website, gives us a lot of information. And can be very good for those unusual cases. And also the Barrett calculator on the ASCRS website has become very popular in the last year or two. And then third is… Premium implants. So solving presbyopia — we have accommodating IOLs. I’m personally not the hugest fan of them. They don’t work over time. The multifocals, we have to be very careful, because of the problems with glare and haloes. I tend to use this implant for refractive error, and that’s the toric for astigmatism. This is a very good premium lens and has been very effective in a patient with over a diopter of astigmatism. And we now have just come out — new implants, such as the Symfony, which combine the toric implants with the multifocals, and they are touting an extended range of vision, in order to get a better presbyopic correction. The main point I want to make is that one size does not fit all. So measure and choose your IOL accordingly.
One of the things we don’t have time to talk about is that my choice, in the absence of a premium IOL, is to perform a lot of what I call monovision, and that is putting the implant into the dominant eye aimed at plano, and then going for a little mild myopia, in the non-dominant eye, and mild myopia — I would say I would go to about a -1, or in a patient who has had the experience of monovision previously, I will go up to a 2 diopter difference in the non-dominant eye, if the patient is able to tolerate that. What I feel that does is it gives us a range of vision. The patient is able to walk around without glasses, but I tell them with a mild monovision, they’ll be able to look at their watch, pick up a newspaper, go to a grocery store, pick up things off the shelves, without the need for reading glasses. And so this I think is… In the right patient, is a good option. I would say that 70% of patients will tolerate. About 30%, 25%, 30%, will not tolerate that difference. Even a very mild difference of a -1.
So it’s important to really assess preoperatively your patients. And I listen very carefully to what their optical needs are. So somebody like myself, a microsurgeon, I do not tolerate that difference at all. And so… Depending on a patient’s vocation, what they’re doing on a daily basis, I’ll make that decision and discuss with them whether that is a possibility. So that’s optical biometry. And the importance of choosing your IOLs. And the last thing we’ll talk about here is… Let’s talk about small pupils and use of rings. This is the ring from the movie and book Lord of the Rings. So I’m going to ask: What is your preferred method of handling a small pupil? Do you use scissors sphincterotomy, do you do stretching, iris hooks, or pupil expander rings? All of these are equally valid. It depends on what you have access to and what is available to you. And of course, the clinical situation at hand. So let’s see. Sphincterotomy versus stretching. A large number are using iris hooks, expander rings can be limited, sphincterotomy can be very helpful, especially in those scarred down cases of pseudoexfoliation. Even putting in rings is not rings is not necessarily going to be helpful. So I’m gonna talk a little bit just about the Malyugin ring.
This is my go-to pupil expander. There are many that are — many new ones that have come out. But I’ve used this the most. It comes in two sizes, 6.25 millimeter and a 7.0. In a case I know of floppy iris syndrome, I’ll put the larger ring in. It’s a little bit more difficult to maneuver. The 6.52 is most popular, and you need a greater than 2.2 millimeter incision in order to insert this ring. In order to place the ring, the Malyugin manipulator, which has this little knob on the end, is very helpful. You can do this with a Kuglen or Sinskey hook, but I found the manipulator is a very nice tool to have. This is a relatively small pupil, and we’re gonna go ahead — this is through a 2.4 millimeter wound, so this inserter fits in very nicely. We’re gonna engage the distal part of the iris and then we’ve got very lucky, and two other scrolls were also engaged. Let’s see here. The next video. And then this is the use of the manipulator, in order to engage and center this ring.
And this is the 6.25, I believe, in this particular case. So let’s just show a case of intraoperative floppy iris syndrome. These are some of the modifications I do in these particular cases. The use of Trypan blue — I like to make sure that we’re seeing what we need to see, especially if you anticipate the pupils coming down. I use the Arshinoff shell, as I mentioned previously, and in particular in a floppy iris syndrome case, I like to have that cohesive-dispersive, giving me just a little bit of extra measure here of assistance. So in this particular case, I know this patient is on a prostate drug. However, I proceeded, because the pupil didn’t seem too bad. You can see here I’ve grooved and cracked, and now as I’m starting to engage the lens, I am looking carefully, actually, at the pupil, and the activity of the pupillary margin.
I don’t like the way that this is bouncing down in this particular case. I’m not paying attention so much to the fact that I can’t engage the lens. But I’m looking up — that pupil is really starting to come down. I have epinephrine in my bottle at all times. I’ve used phenylephrine, Cyclogyl, and Mydriacyl, in order to dilate that pupil preoperatively, but that pupil is gonna come down. I’m now putting a cohesive viscoelastic in. And look at that pupil. That iris. We know that it’s going to prolapse out of the wound. And so I’m gonna go ahead and put a Malyugin ring in. The important thing here is that you don’t want to engage your capsulorrhexis. And so I’ve put it on top of the iris first. And then manipulated that into place. And you can see here now things have markedly changed. I don’t have to worry about the fluidics, and need be…
That a piece of the iris engaging into my phaco tip. So the case can proceed normally. The Malyugin ring has now come out in a thinner version, so you can see the polypropylene haptic-like material, and they’ve actually come out with — recently — with a more flexible, malleable, thinner version of this. But I feel that the traditional one has really done quite well for me. And as you can see here… I keep the ring in, in order to perform the cortical removal. And in this case, I’ve decided to keep it in, as I’m putting the lens in. You have to make the choice whether to keep the ring in, before you put the lens in. And sometimes I’ll remove it beforehand, if I think there’s gonna be difficulty. If that IOL expands before you are fully in place, you can engage that ring, and that can be a little bit difficult to then get that out. And in this particular case, because the iris is prolapsing through the wound, I put a stitch through the clear corneal incision, simply because I don’t want that to be a nidus of infection and possible endophthalmitis. So my question here my question here to all of you is: What do you do in a case with zonular dehiscence, now?
We’re moving away from problems with the iris and moving to capsular problems. Would you leave the patient aphakic, would you place an anterior chamber IOL, if you have that available, suture the lens to the iris, suture it to the sclera, use the capsular tension ring, and put IOL in the sulcus or the capsular bag, or do we just hope this doesn’t occur and avoid these cases altogether? So we’ve got a lot of choices here. I would say this is just in… Obviously we adjust according to the type of case. I’m gonna say… In the case I’m gonna show you… This is what I’m gonna do. Okay. So vast majority of people are using the capsular tension rings. So hopefully I have something interesting to show you, then. Okay. These are the capsular tension rings. They’re put out by various companies. This is the StabilEyes by AMO. It comes in two sizes, the larger is in the uncompressed state and the smaller is after it’s compressed.
This is the Morcher Ring by FCI Ophthalmics. It comes in multiple sizes, so you adjust according to the axial length of the eye. It’s a little confusing here, because the smallest one is 14 and the largest one is 14A. The largest one is this one, the 14C. And then you can put it in manually, or you can go ahead and inject it with an injector, if you have that available to you. So I’m just gonna show a case of zonular dehiscence with the CTR insertion. This case has gone well, I’m at the very, very end, I’m removing the cortex, and as I’m removing the cortex with the bimanual irrigation aspiration, it’s the very last piece here, I’m looking, seems to be home free, everything seems to have gone well, but as I’m grabbing this last piece, something is a little strange. It looks like there’s actually dehiscence right there. You can see it right there. So I’m gonna make the decision to put in a capsular tension ring. These work ideally in cases where there’s 3 clock hours or less of dehiscence. Once you get to 6 clock hours, this becomes a little bit more unlikely to be successful.
So again, it’s 3 clock hours or less is the most ideal to go ahead and put this in. And then you can see here… Once we put that in, things have been stabilized. And I’m gonna go ahead and put a one-piece into the bag. Some would argue that it might be better to put a three-piece, and I would say that’s equally valid, to get that sort of help from the haptics that are going to push out, there, to give yourself a little bit of extra measure of support. So I’m gonna be very careful in placing these haptics into the capsular bag. So that’s rings. So I rushed through a little bit, but I wanted to make sure we covered all these topics before the end of the hour. I think we have a number of questions. And so let’s see if I can see some of these. Yep. Somebody has asked: What about left-handed trainees? The answer is go ahead and use your left hand, your dominant hand. I actually — I’ve had multiple trainees who are left-handed, and all you need to do is rather than putting your wound at 12:00, just put it slightly to your left. I had an experience with a left-handed trainee and somebody tried to make them operate right-handed.
You don’t need to do that. Use your dominant hand as your phaco hand and move the wound to the left side and use your right hand with the secondary instrument. Do that accordingly. If you’re with a teacher who is right-handed, if they take over, they’re gonna adjust the scope accordingly, if they need to take over. But you should use your left hand. Okay. Let’s see. Okay. I have this question here. When do you… I’m gonna answer this question. Using longitudinal versus burst versus pulse. Okay. So I would say that… It’s okay to use complete longitudinal in cases where you don’t think you’re gonna lose a lot of energy. If it’s a very, very dense lens. I go ahead and I like to use pulse. So pulse — that will minimize the amount of energy that I am using. Ultimately. So burst is the kind of thing that you have to adjust if you’re going to be grabbing onto dense lenses. I think that that burst is helpful in those particular cases. Okay. Let’s take a look. Okay. I have somebody who is going to… Shift from Simcoe to bimanual… The shift is a bit scary. Yes. I love the Simcoe cannula.
So I would say in the case of going to bimanual I and A, the most important thing is to double check that your I and A handpiece — again, your irrigation has to be bigger than your aspiration. They can’t be the same size. If you’re worried, I would go with a 0.5 or 0.4 millimeter on the irrigation, and then your aspiration should be… 0.1 millimeter less. So if you have a 0.5, I would go to 0.4 aspiration. If you go 0.4, go to 0.3 aspiration. That’s the first thing. Make sure your irrigation is higher. And the second thing is: You can go very high with the bottle height. I would put that up at 100 or 105, and just be aware then as you’re pressing the foot pedal, you are again controlling the amount of aspiration linearly. So just be very light on your foot pedal, when you’re starting your bimanual irrigation and aspiration. Okay. If you have to place an IOL in the sulcus, what power do you use? So yes. Because you are placing a lens a little bit more anterior, many people will decrease your IOL power by 0.5.
So if you are 20, in the bag, a 19.5 in the sulcus. However, if you’re going to do an optic capture, so, in other words, you’re going to place a lens in the sulcus, and then push it back into your… To capture it in the capsulorrhexis, then you don’t need to adjust. So it’s just where the ultimate effective lens position is going to be. But I would say the vast majority of people probably adjust by decreasing your IOL by 0.5, if it’s the same A-constant. So again, you have to be sure that the A-constant of your IOL is the same. For those who are using the Alcon IOLs, it’s slightly different. So, again, you want to make your calculation according to the A-constant of your lens. Okay. Intraocular adrenaline on floppy iris syndrome. Many of us have tried it. Shugarcaine was popularized, a combination of epinephrine and lidocaine, which seemed to be quite effective. You can look it up. It was popularized by a surgeon by the last name Shugar. And that is something that some of us use. I find, though, if the pupil is gonna come down, it’s gonna come down. It’s not so much the dilation that’s problematic, as much as the floppiness and the prolapse through the wounds. So because of that I tend to like to use the rings, rather than just dilating with epinephrine. Good for dehiscence of three clock hours or less.
What do you use if dehiscence is more than that? There are a couple of options. Number one, you can put two capsular tension rings in. Number two, you have to ascertain — it’s not just a problem with the capsule. It’s going to be a problem with vitreous coming forward. So you have to make that decision as to whether you’re going to try to save that capsule or whether the vitreous has become to problematic that you’re not going to be able to save it. So then in those cases you have to determine whether you’re gonna take the entire capsule out and where you’re gonna put the lens, whether it’s anterior chamber lens, suturing the lens to the iris, suturing the lens to the sclera. So those are more advanced cases that you’re gonna have to consider. Okay. And there’s a question… Whether to put… Whoops. Where to put the tension ring. In the sulcus or the bag. I’m gonna say 100% of the time you have to put the tension ring in the bag. This is not a ring that’s going in the sulcus. The purpose of the ring is to redistribute the forces around the bag, and in order to expand that, in order to prop up that area, where there’s a dehiscence.
So there’s no use for it, if it’s in the sulcus. So be sure to put that capsular tension ring in the bag. And okay. What is — (inaudible) in the Centurion? When you have full occlusion at the end of… Vacuuming up a piece… What’ll happen is you’ll get a very — there can be some obstacle to the very last part of your piece. And so what intelligent phaco does, when it senses that complete occlusion at the end of a piece, meaning that the vacuum is not effective, it’ll actually give you a very tiny burst, in order to get through the end of that piece. And so — and then it’s a millisecond burst. So it prevents postocclusion surge. And so that’s the purpose of intelligent phaco. And you can turn it off by pushing that IP button on the machine. How high is the IOP that you recommend to be maintained? Okay. So this question has been asked: How high do you recommend the IOP to be maintained during phaco? Do you maintain that same IOP during surgery or do you adjust during different steps of surgery? And the answer is you have to make adjustments during different parts of the surgery.
So when you’re sculpting, you don’t have to have high IOP because you don’t have high vacuum. So really it’s a balance between the irrigation and the aspiration of fluid outside the eye. So when you have high vacuum, you want to have a higher bottle height. So we are equating IOP with bottle height with irrigation. And so all those three things you’ll have to adjust, according to what you’re doing in your particular case. How do you… Dilute epinephrine in the solution? Okay. So the dilution is usually… I use epinephrine in my bottle. And I’m using a 1:1000 vial, and then I dilute it again, 1:1000. So it’s 1:1,000,000 in your bottle. Okay. Let’s see. I’m gonna answer a few more questions here. Let’s see here. Intraoperatively, how do you manage a hazy cornea?
Okay. If you have a hazy cornea, intraoperatively, you have to determine what the reason for the hazy cornea is. Obviously if you have corneal scarring, there’s nothing you can do about that. You’re gonna just have to see around it, or make other arrangements. Replacing that cornea before surgery, if it’s truly a scar. If it’s haziness because of edema, you’re gonna have to make adjustments accordingly. You have to protect your endothelium with a dispersive, and you might have to scrape the epithelium, if that’s really the cause of the problem.
I think we might be concluded. So I want to say thank you, everybody. It’s really been a privilege. I really enjoyed very much this entire session. And I hope to be able to present to you again. Thanks very much, everybody.