 Now we have Dr. Maylon Xu who's been one of our cornea fellows this year. She's currently negotiating with a group in Ashland, Oregon, and we've been glad to have her. So today I'd like to present kind of this year a lot of the work I've done with Dr. Moschbauer and Dr. Mifflin on our D6. So I'll start with an introduction and then two projects that we worked on were one on using a double pass technique to prepare ultra thin graphs and then looking at doing the same with the femtosecond laser and then our outcomes in different D6 scenarios. In addition to working on a lot of projects I also was fortunate to travel around southern Utah as well which has been pretty amazing so I have a few photos in there as well. That is Zion's at the top of Angel's Landing. So for some of the medical students endothelial keratoplasty is a surgery where instead of replacing the entire cornea we're replacing only the posterior disease endothelial cells. And so the methods we're going to talk about today is DSEC and that's where we strip and remove the disease patients endothelium and decimase and then we prepare tissue that has a little bit of stroma and we attach that with an air bubble technique. The other way described is DMEC where instead of having the donor tissue stroma you're just translating the decimase membrane. So there's obvious advantages of endothelial keratoplasty over PK. This is an open globe that I had with Bryce where it was a bar fight patient, young guy who had keratoconus and a previous corneal transplant. He's always going to be at risk to trauma and so most of his eye contents were extruded. So both intraoperative and postoperative complications are higher in PK and then the recovery is much longer with PK with months of suture management to manage astigmatism and there's always a risk of suturapsis and infection. So DSEC has really replaced full thickness penetrating keratoplasty. Some of the limitations are you do get this hyperopic shift after a DSEC tissue is placed so we usually aim about minus one when we combine it with cataract surgery. And then also it has been noted that some patients just really never get to 20-20 even if their graph looks really, really clear. Possibly it's due to a stromal interface problem but as Dr. Misslin and I have brought in a lot of our patients really kind of looking at their astigmatism trying to get a really good refraction. We get pretty close but there's still some patients we can't really explain why they're not 20-20. And so if you look at, this is the DSEC graph, this is at one month, three months and four months you see that the graph continually gets thinner and thinner. And at one month we still have the edges of the graph which don't have decimays quite maybe covering it so these edges kind of swell up and then it does become thinner and the vision continues to improve months after surgery. So with DMEC it's thought you could avoid having this extra tissue. However DMEC still is very surgically challenging and studies are still being done to see if with all the surgical manipulation if endothelial cell loss is higher and then you also have more dislocation re-leveling rates. So what we looked at is can possibly a thinner DSEC graph that's more planar produce less hyper-opic shifts and possibly even refractively neutral outcomes. So we looked at two techniques in preparing these ultra-thin DSEC graphs and so this was the narrows that we hiked and my parents came so that was really fun. Okay so we're really lucky here at the Marin and that as fellows we prepare all the DSEC tissue ourselves and we either our options currently are we use a 300 or 350 micron keratome head. When you use higher thicker heads there's higher rates of perforation and really the only way you can really limit how thin your graph is going to be is either you can do a slower pass for thinner graphs or maybe go a little faster. But Shamima Sikter the previous fellow she worked on this as well but the new change this year was that Moria the company made a disposable artificial anterior chamber with a rotating guide ring and there's multiple heads so you have more options. And so you do one pass and then this rotating guide ring allows you to do another pass 180 degrees away. So this is an interesting patient I had who had Ched she was from Thailand had probably narrow angles in retrospect but it was really hard to evaluate her because her cornea was a thousand microns very adept but we went ahead and did a DSEC on her. And that day the tissue was just very thick we got like a 700 micron graft we cut it with a 350 micron head and the graft was measured with pychometry to be 400 microns. But we went ahead and did the DSEC and the next day she looked great the air bubble was like 10% and then on post op day three she comes into the ER with a pressure of 50 and she had the 360 degrees of IK touch. And this was her anterior segment so she had this thick graft so I think she had some kind of odd mechanism of pupillary block perhaps this graft kind of shallowed the passage of aqueous. And an LPI was done but the next day her angle started closing again so we went back and just had to open up the angle. But the graft amazingly you can see here this is post op week one it was 940 microns and the graft was 400 microns thick. And then in one month it's already half in size and then at six months her cornea was a lot thinner almost 600 microns but then the graft was about 200. So perhaps having a thinner graft in her would have really helped her avoid those complications. This is a video showing the technique that we of this double pass technique. So this is the artificial anterior chamber and this is optosol and this is the cornea button. So there's just two the first fixation is doesn't really move when you do the second pass and then you'll see the guide ring here. And this is all hooked up with two lines one to control the optosol and another one is linked up to an IV pole that's raised the ceiling to keep the pressure about 90 millimeters mercury. And so we check four different areas peripherally and we record those and wherever the thickest picometry reading is is where we start the first pass with the microphone. And then we check the thickness and based on that we decide which head which size had to use. So here we're going to start where the the chemistry reading was the thickest and this is the extra locking device so that you can rotate it the next time. And the first pass is relatively normal 46 seconds and then we rechecked the chemistry to decide what what size had we used for the second one. And so here is the nice thing about the device is that you can rotate it and now you're going to start 180 degrees away from where you initially started to prevent the risk of perforation. And here we're just making sure that the IV tubing is allowing slowly to recalibrate the pressure. And then the second pass is all at controller. When we say ultra thin we're really trying to aim under 100 microns of thickness and so there is the second pass. And we'd put the we didn't we'd put this cap on top before we take the tissue off. We do but with our ultrasound picometer it only under 100 microns most of the time you can't get a reading. So that's another problem. But I think we're getting a new one that reads up to 50 microns. And in this part we just have to be very cautious not to allow the chamber to collapse. And so we just kind of flip it over and because it was under such high pressure we have to release some of the adhesions and then and then we would put this in the in the punch a separate tree find punch to when we for the graph. Well the kind of it's not an exact you can't just subtract it out mathematically that you have to give a little bit of room. But this is kind of the no gram deciding what kind of head but the first pass you want to estimate to try to have about 220 microns left. And then the second pass depending on what your pre-chemistry reading is you decide what head. And if it's really thin you can always put a little bit of BSS with a Wex cell to make this the cornea a little bit thicker. So here's some anterior segment OCT images of the first pass and then the second pass creating a nice less than 100 micron graph. And there's one that turned out really well. So some things to consider one the second pass can create a small diameter cut so you want to make sure you can kind of see the edge. So your tree find or you do a donor punch with the same with the right size. And then the thinner tissue is a lot it's not as bad as DMIC tissue of course but it's going to be a lot more harder to manipulate. So the boost and glide works really really well if you were going to try to do like a folding technique that would be I think more difficult. And they have also a new boost and glide where the platform is a little bit larger so that you can insert it a little easier. So then we also tried to do some studies with the femtosecond laser and cutting donor tissue. So femtosecond lasers are what we use for Lasik and there have been studies looking at desect graft preparation with femtosecond lasers. The problem is that the cornea in the posterior the collagens are a lot loose are different structure made structurally differently in that they're more looser. So it's not as smooth of a cut and it's not as predictable. But here's using a 30 kilohertz and 60 kilohertz. There's been reports kind of looking at the smoothness. This is with the microkeratome. It looks relatively smooth. Whereas the femtosecond laser you have a lot more stucco like irregularities. So we looked at this and so we have an IFS 150 kilohertz laser. So it's much higher frequency and looking at different settings using a tighter spot line separation or lower energy. We wanted to see if you can make predictable desect tissue. So we had some donor tissue from the iBank that was going to be discarded. And we were all trying to target them less than 100 microns. So here's a video of this. So this is also mounted on the anterior chamber and hooked up to an IV pole to maintain the pressure. And so it looks different than a Lasik flap because it's going a lot deeper. Yes. And now it's going to make the side cuts. You'll see the rim are being cut now. So just using a lot of different variety of settings. None of them were really that smooth. Some of them were a lot harder to lift. There was definitely strong adhesions. But this one actually turned out okay. But usually there would be like a little tag of tissue that was not cut very well. So after we cut each one we imaged it with the anterior segment OCT and then we had a mass grader kind of rate them as one, two or three. So this is a micro-caratome cup really smooth. This one was actually a pretty good one from a femtosecond laser. And then this was kind of moderate. And then there were some really bad rough bronze where you probably wouldn't want to use that for tissue. So the energy ranged from trials of 0.4 milliliters to all the way up to two or three. Several of them perforated. And overall when we looked at it, tried to analyze it. When we used lower energy levels versus higher ones we had smoother tissue. You know we had a lot of variability and a lot of it could be explained by it. Kind of better quality tissue that wasn't as thick in this range as well. So the results are basically that it wasn't very predictable and I wouldn't really use it for destect tissue. The micro-caratome still created the smoothest surface when we compared all of these different settings and all these different trials. So possibly these can be better. The settings can be further modified. There has been other reports looking at this as well. And then all the measurements are the depth reference from the anterior surface, not the posterior. So you still won't get a very planar cut. And then of course the main thing is does all this ultra thin tissue really affect outcomes? Are you really going to give you faster recovery and better visual acuity? And that's all being studied right now. And then the other thing is how can you really measure the graph thickness if we can't even measure the thickness with the chemistry? This is one of the ultra things we actually did in a patient. And he had a little fluid cleft the very first day and the tissue looked really, really thin and really good. But it's 300 microns here on the very first day. I re-bubbled him and then the very next day I just was curious and it already decreased 110 microns. But people who are looking at this are saying well you shouldn't really give a graph thickness until use it on the anterior segment OCT like at one month. But it's very, very variable so it's going to be hard to kind of know what thickness the tissue is and when is the appropriate time to call its official thickness. Okay, so that's kind of those studies. I'm going to move over to kind of our clinical outcomes if anyone has any questions on those. Okay, so this of course is at Arches which is really amazing. So DSEC there's been tons published but we wanted to look at our outcomes and especially in those more complicated surgeries. One of the main indications for DSEC is pseudophagic bull's keratopathy. So we get a lot of patients who have PBK with ACIOLs, they're a phagic or they have a dislocated IOL and they need an ILO exchange. So we looked at 109 consecutive cases that Dr. Mifflin did of just uncomplicated DSEC. So these were, they didn't have a tube or a trap, they didn't have a penetrating keratoplasty. But 53 of them were just combined FACO DSECs. And then we looked at all the complicated DSECs that have been done but both Dr. Mosch, Dr. Mifflin and compiled these cases. So four of them were a phagic and two were left a phagic, two had a secondary IOL exchange done at the time of surgery. 14 had an IOL exchange at the same time of DSEC. Ten of these were iris-fixated IOLs, three scleral-fixated and one was just a sulcus lens. One had a varicice lens removed followed by a FACO IOL and then three of them had it staged where they did the IOL exchange first and then the DSEC. And then two had a dislocated, well, FACO pseudophagodinesis but not a dislocated lens. And then later developed a dislocated lens and had to have that after the DSEC. Then in five eyes the IOL was just not removed and the DSEC was done. So this is a video of a recent case that I did with Dr. Mifflin and it kind of just shows that our technique here as well. So we use a four and a half limbal incision and this is showing the stripping of the decimates. In this case you can kind of make out there is an ACIOL here and we're now removing the decimates membrane and this is just injecting healon. And then in all our cases we do vending incisions. So we do four paracentral vending incisions. This cornea was very, very tough so it was kind of hard to make them in this patient. And then we remove the healon and enlarge the wounds. And here we're loading our tissue onto the boost and glide. And so right now the endothelial cells are up. We're putting a little healon on it. And so this part of the surgery everything goes pretty well. We're just now slowly inserting the tissue, taking care to make sure the ACIOL doesn't come up. We have an anterior chamber maintainer that really helps. And here we're injecting air and also taking care to make sure it's going in front of the lens and under the graft and putting a suture. And so here I'll just pause it. You can kind of see this nice ring around the tissue so you know that the tissue is where it should be and the air is underneath it. But it's a little de-centered so we're actually going to use the roller to kind of re-center it here. So this was interesting. We were almost done. And then you'll see one more pass. And if you watch carefully, that pass might have been a little too harsh because the bubble just completely goes away. And we're not really sure where the bubble is at this point. So we kind of have to take air out, put more BSS in. And the venting incisions are kind of handy to see if air is in between the graft. And we're trying one more time here but again the air isn't exactly where it should be. And then on this last time we get it exactly where we want it. Except for now the graft is still in fairly display. So here we're going actually, we can go through the venting incisions and help move the graft into position. And we're just kind of sliding on top of the graft and putting it, centering it there. And then these venting incisions are very useful because we can remove any interface fluid. And this patient did really well. So in these outcomes, our routine desex, we had the visual outcomes of those patients without any ocular comorbidities like AMD or glaucoma. 94% of them were greater than 2040, 30% were greater than 2020. But those are, they all had really pretty minimal complications. The complicated desex, all of them except for maybe one or two had really snake pink comorbidities. So it's hard to judge their outcomes. But in all cases they all had improvement of vision except for three cases that I'll talk, or six cases that we'll go through. Other complications, so this is our non-complicated standard desex. One had a graft failure that required a repeat desex. But it was only because the graft had persistent folds. It was donor tissue from a previous, that might not have been cut properly. It was from a lasik tissue, a donor tissue with previous lasik. And then five patients had rejection episodes that all resolved with steroids. One had elevated pressure and one had pupillary block. But no dislocation, no infection, no epithelial ingrowth. Whereas the complicated desex had a few more complications. So detachment, five of the 30 complicated had detachments. And in two of them it required a subsequent PK. So one was an 86-year-old woman who underwent an ACI removal with desex. And in one of her eyes the graft just never attached and she had to have a PK. The other one it was partially detached and then repositioned and she did pretty good. So both of her eyes were 2200 before surgery and then she ended up 2070 in both eyes. The one with the desex and the PK. The three other detachments, one was kind of earlier on in the learning curve. And this one was just a complicated surgery. Also there was vitreous notably in the wound. The graft after two re-bubbling attempts never attached and had to have a PK as well. And the other one were detachments that were salvaged with the re-bubbling. So of all these 30 cases, three of them had graft failure. Two of them were the ones I talked about who needed PK. And then another one actually did really well. She had a complicated eye with a shallow chamber, two tubes, PAS. She was improved from counting fingers to 2060 and then at six months she developed endothelial failure. Four patients had pre-existing glaucoma and then they developed elevated pressures and needed further surgery. And then five patients had IOL dislocation. And then during three of these IOL, secondary IOL placement or repairs, there was one patient who had a hyphema that required an almond valve and anterior chamber washout. So in reviewing these cases, one thing that was interesting is to consider the role of the air bubble in patients with dislocated IOLs. Possibly that could be pushing on zonules and causing IOL dislocation. Two of our pseudo-exfoliation patients had to have a subsequent IOL exchange later. And then when is the best time to do a DSEC with these cases before so you don't risk doing further damage to endothelial cells just with the surgery or waiting until the view improves and doing it later. And then when do you need to remove an ACIOL? You know, a lot of our, five of our cases, five of the ones we didn't remove, all four of them did really well. Only one had complications. And then the challenge is in they fake you and maintain an air bubble. And then finally, you know, which cases should you just do a primary PK instead of doing another DSEC? But I think with our technique and our success rate, it's worthwhile in most patients to do a DSEC. And so this is just one other surgical case. This is one of the patients who had a previous failed DSEC and now we're doing her PK. So here we've refined the cornea and her DSEC, she has an almond valve here. It's kind of hard to see. But we're going to remove the first the PK here. We're kind of looking for the DSEC graph, but we don't really see it there. And then it's kind of interesting, it didn't really separate and we have to cut it out again here. And now we remove that part of the graph. And this is just kind of maybe a poor prognosis eye. She's just very complicated. She has all this PAS that likely contribute to her DSEC graph failure. That is to be cleaned out and there's her almond valve. And this is when she had her DSEC, there was an ACI well that was removed and there's an iris sutured IOL as well here that we have to be cautious of. And we're looking for any vitreous and there's her tube that's in good position as well. And so we just did her surgery about a week ago, but she's doing very well. So the last section, this was at Canyonlands, which is nice. We're almost done with this presentation. So we want to we in considering how to treat patients with a failed penetrating character, Plasti DSEC has shown to be very effective. The debate is whether you should strip the decimates or just can you leave decimates membrane and just put the graft in. And so we wrote a letter in response to one of Mark Terry's cases case series. And, you know, he wasn't very the nicest person in his reply where he kind of said, you know, he's done 1300 cases or 11 years and he has the lowest dislocations in the world. And, you know, he kind of questioned our techniques. So we went back and a little bit more follow up and we've had 26 consecutive eyes for patients who have failed penetrating care to Plasti. And in all our series, none of the decimates membrane was stripped and we use vending incisions in all of them. And we use the boost and glide for graft insertion. So we looked at our outcomes and a lot of people have reported on this, but detachment rates range up to almost 30%. And there's only been two series where they did not strip the decimates membrane. So our outcomes were endothelial cell loss was about 30%, which is in line with most studies. In our dislocation, only one of them was noted to have a fluid clap. It wasn't a complete detachment. It was peripherally attached. And so our dislocation weight, one out of 26 was 3.8%. Whereas Terry's, he had 17 pks and, you know, it was 5.8%. Other complications, one case resulted in failure due to rejection. And then one desec was doing very good and then had to have a Trab. And then the endothelial failed after the Trab about two or three months later. Of the 13 eyes that did not have ocular comorbidities or graft failure, 92.3% had better than 20, 30 vision. And 30% were better than 25. So Terry also advocates doing a graph, a desec graph that's smaller than the PK, whereas we just same size ours estimating it with calipers during surgery. And here's one of our anterior segment OCTs. You can see the previous PK and then our desec graph, which did really well. And here's another one. So we're hoping to publish this in AJO pretty soon. Okay. And then last thing I have, I thought this was a really cool picture. This is kind of the complete opposite of desec. This is the DALC. So in DALC, we've maintained the entire patient's own decimate. And we've only transplanted the anterior cornea after we've removed the decimates from the donor tissue. So he did great. He had a little bit of a posterior tear in the decimates, but it was very small. And after surgery and post-up day one, he did really good. And then one week later, he said his vision's really blurry, and he came in with this decimates attachment. So we were going to bring him back the next week, maybe in the Maya's room, put an air bubble, see what we could do to save that. But one week later, he had spontaneous reattachment, and he actually did really, really good. So in conclusions, desec is really one of these landmark innovations in ophthalmology. Future advancements, improving DMEC techniques, looking at outcomes, improved desec techniques, and ultimately cultivated endothelial cell transplantations is probably not too far off the horizon. Desec, our technique with boosts and glide and bending incisions, really showed really good outcomes with low complications, non-stripping endothelial caroplasties, effective and failed PKs. And then in these more complicated cases, we have to be mindful of how to manage them in that they do have higher rates of graft attachment glaucoma in Iowa this location. So I'd like to thank, of course, Dr. Michelin, Dr. Mosifar, and then several medical students and Wally and Chris McGriff who have helped me a lot with the femtosecond laser studies. Yes. There was one other report, a case in the literature, that someone had an open PC after a yag, and then the patient had to be re-bubbled, and then the lens went back to the vitreous. So, yeah, I think maybe the air would be pretty cautious or see what else, how, what it can do the lens. Yes. You know, we didn't, we couldn't go near her. So I think maybe if we did, I looked at her other eye with anterior segmental CT, and she had not closed their angles, but they were narrow, so possibly doing an LPI or even, yeah, we do. Exactly. Yes. Mm-hmm. Yeah. Yeah, that would be great. Yes, talk to my mouse. Yes. Yeah. Yes. Oh, that's a great question. So the FACO D6 and the ones we did with just the non-stripping for the PK, most of those we do topical, but the dialogue exchange or something we think it's going to be longer, we do retroball bar. Thank you.