Lecture: Personalized Treatment for Keratoconus

DR GORDILLO: Good morning to everyone. I’m Dr. Carlos Gordillo, and I’m gonna share with you this presentation. Thank you to everyone for being here. And thank you to Orbis for the opportunity to give this presentation. I’m from Mendoza, Argentina, working in the cornea department of Zaldivar Institute, and the point of this presentation is to share with you all the knowledge that we have been learning through the years. So in the past, the only chance we had to propose for the patients with advanced keratoconus was contact lens until they don’t tolerate anymore, and after that, the corneal keratoplasty, the penetrating keratoplasty. So this has been changing through the years. And the advance of ophthalmology. So right now, we like to call these treatments of the keratoconus as “personalized”. It should be personalized, because every case has to be studied as an individual case. But we need to know which is the classification to understand which one is the best treatment for each patient. We have a lot of classifications, actually. Right now, they’re still changing. But the classic ones were proposed by Amsler, with stages, then we have some morphological classification with phenotypes, the ABCD grading, and the Oviedo classification is also morphological. The ideas of all of these classifications is to understand the stage of the keratoconus and how advanced it is. We need just a quick review of the classification with the Rabinowitz classification, which is classified according to cone morphology and topographic patterns. In the Amsler classification, it describes the different stages of keratoconus using the placid disc, and with the biomicroscopic findings. Belin proposes keratoconus staging, incorporating the anterior and posterior curvature of the cornea, the finest pachymetry, the corrected visual acuity, and they propose five different stages. It’s pretty complete. And then we have Fernandez Vega, et al., classification from Oviedo, using pachymetric maps, the thinnest point of the cornea, and distance from the center of the pupil to the thinnest point, and they classify the keratoconus as central, paracentral, or pericentral. So once we have identified the stage of our patient, we can propose different alternatives to solve the situation. So these alternatives will depend on our possibilities, but of course, the earlier we treat the patient, the best results we’re gonna have. As you know, keratoconus is bilateral, asymmetrical, and progressive. So we always need to take a look to both eyes. And as you can see in this publication, you can use all kinds of surgical techniques to halt the progression and to solve the irregularity of the corneal surface. I put this topography map of the world, where you can see the different mountains and the highest mountains, worldwide. I remember when I was trying to understand, when I was studying topography, it was very helpful for me to understand which was the hot part of the topography and the highest. We have people from worldwide here, so you can check how high is your country or your region. And remember that is the cone. Once you identify the cone, you need to understand that the different keratometric values will be according to the evolution. So what to do with the patient? What we can do — first of all, when we suspect the keratoconus, we need to do a corneal follow-up with topography. We need to do surface treatment. It’s very important at the beginning. Because we know that if you don’t treat the patient accurately, you’re gonna have evolution, progression of the keratoconus. If you have progression, you need to indicate the crosslinking. We have been performing crosslinking in young people, and our youngest patient is a 10-year-old. Because the progression was really, like, increasing very bad. And we need to halt the progression to avoid the asymmetry. If you have progression and asymmetry with keratometric values under 57, you can do a combined technique with crosslinking to halt the progression, and with intracorneal rings to improve the corneal surface. And finally, if you have a progression with a keratometric value more than 57, and low visual acuity, you’ll have to do DALK. It’s deep anterior lamellar keratoplasty. The idea of this webinar is to make a quick review of each stage and alternatives. So what I was saying before — the corneal surface is really important. It’s been described differently, the inflammatory process. Because of the eye rubbing. And there are videos that you can see on YouTube also. About how the eye rub can affect the cornea and the whole globe. So it’s very important to understand that all stages need to do the corneal surface. You can halt the progression in the early beginning. So you need to do this to all patients. The alternatives — you don’t need to do much. But you can just use cyclosporine, or artificial tears, and also you can add a punctal plug, to improve the tear film. So here is a topography of a patient before the corneal surface treatment. And after. You can see it’s been followed up for many years after the treatment. And you can see it’s still there. The ectatic area. But it’s better. So what to do? I’m gonna show you the different alternatives. Here you can see as the first step we can use the crosslinking. At the second step, as I was telling you before, the intracorneal rings and crosslinking. If it’s bigger, you can use the graft. But also, you need to understand that after the graft, you’ll have to perform crosslinking again. To the peripheral ring. I’m gonna talk about that. And how to solve the residual refractive error. You can use ICL or different IOLs. So as I was saying at the beginning, you need to consider that it’s a bilateral disease, it’s progressive, and asymmetrical. Asymmetrical means that it’s more in one eye than the other one. Usually it’s like that. We need to get used to ask our patients about the family history. We need to consider the age. We need to look for the evidence of progression. The corneal thinning. And the pachymetry, of course. So how we identify the progression? What and when? We have the objective progression that we can see in the topography maps. Then we have the manifest refraction that is changing, more than 1 diopter or more than 0.5 diopters of equivalent spheric, and when there is a difference between one eye and another, more than one, when the axis is not co-incident in the refraction with the manifest refraction, when there is a reduction in the pachymetry, and of course, when the patient tells us that the vision is changing. Sometimes we don’t see the progression at the beginning, because we don’t do topography to our patients. But if they are changing, the glasses, and they tell us they have changes in the vision, we need to pay attention on that. Then another case of progression — I was looking for very big cases. With a lot of evidence. So you can see these patients. We saw them in 2005. With this small cone. The pachymetry was low. But we indicated crosslinking at that moment. The patient never did it, and they came back in 2009. Four years after. With this huge cone. And the progression was like very… Big. And the necessity of a graft was there. So this is a very good case to show you how the progression can appear, if you don’t treat it. So I’m gonna tell you a few things about the crosslinking. What is it? It’s an association process of one or more molecules through the covalent unions. And some history. This doctor was Theo Seiler. He was a professor at the Dresden Technical University in Germany. And he described the process of crosslinking between 1987 and 1990s. He described the collagen polymerization after he was at the dentist. They were doing, like, a treatment at the dentist. With a photopolymer, to fix his teeth. And that’s when he started thinking about the idea of performing crosslinking. So they started an investigation. That was carried out in 1997. And the first publication with the result was made in 2003. 23 eyes with progressive keratoconus that were treated, and with reproducible results. Right now, we have a lot of different alternatives of crosslinking. The conventional is the one described by Dresden protocol. The accelerated is the one I’m gonna show you today. And then we have some other types. The transepithelial, and the iontophoresis crosslinking. But I’m gonna tell you about the accelerated one. So here you can see all the process to understand how it works. So when you do the crosslinking, you’ll have to mix the riboflavin. It’s a B2 vitamin. With dextran. The dextran is good, because it’s gonna maintain the osmolarity of the cornea. To avoid the edema. Then you have the photoactivation of the vitamin with the radiation. UV. It’s performed with a laser machine. I’m gonna show you. And it begins the collagen reticulation with the production of free oxygen radicals. So the link formation is stable, intra and intercellular. And you have a very hard cornea and you’re gonna avoid the progression of the conus. So how do you make the riboflavin to go inside the corneal stroma? You have different techniques. Epi off, when you take off the epithelium, and instil the riboflavin, that’s the traditional way, and that’s the way we choose to do it. Epi on. It’s another technique. And iontophoresis. It’s the same. It can be on or off, but the time is less. So we turn to the properties of the riboflavin absorption and concentration of the UV radiation. It’s in the corneal stroma, and it protects the endothelium. So as I was telling you before, we need to make a combination of dextran with riboflavin, because the dextran is gonna maintain the osmolarity of the cornea. You can see here the values, the normal value of the osmolarity. What you can do with the dextran. If you have a very thin cornea, you can use this without dextran. Osmolarity is gonna increase, and the corneal pachymetry is gonna increase also. Remember that you need to have 400 microns at least to do the radiation. Otherwise, you’ll have problems, like corneal edema, and you’ll damage the endothelial cells. So that’s why we need to describe the different kinds of radiation. So the more power you have, the less time you need. Be careful with the power. But the good thing is that this reciprocity law, described by Bunsen, with the technology — and the machine is gonna help us to save some time. For accelerated crosslinking, we have this. 9 millivolts, in 10 minutes, or 18 millivolts in 5 minutes. So preoperative, this is one of the questions that someone was writing. You need to consider every patient in ophthalmology that you’re gonna perform a surgery — the undercorrected visual acuity, the pinhole is very important, because if you’re gonna propose a surgery to the patient, you need to understand how good is the potential of the retina? If you don’t perform the pinhole, you’re never gonna know about it. The corrected visual acuity. Their refraction. They’re keratometric values. Their pachymetry, the topography, and the endothelial cells. Of course, a fundoscopy is necessary always. What about the Dresden protocol? I was telling you before — they proposed this. Because in 2003, we only had this 30 minutes machine. But the idea is to take out epithelium. You can see here in the graphic the epithelium — they used to remove — was in the center. Just in the ectatic area. And there are some different proposals right now, to do crosslinking in the ectatic area. We proposed to do a big crosslinking in the complete cornea. Because our experience show us that the evolution can appears in different places of the cornea. So we use, as I was telling you before, the accelerated crosslinking. I’m gonna show you a video. After we are doing the removal of the epithelium. This should be always performed in the surgery room, under a sterile situation. So after you take out the epithelium, you’ll have 20 minutes doing the riboflavin instillation. You’ll have to do the pachymetry after you remove the epithelium. And you’ll need to be sure that you have 400 microns. Otherwise, as I was telling you before, you can damage the cornea. So we need this machine. It’s really good and safe. Because you can use the three different alternatives of time. The crosslink is gonna act in the 300 anterior microns. So that’s very important, because you need to look for this line. It’s called the demarcation line. It’s like the signature that the crosslinking was performed. But be careful, because if you perform 9 minutes, you’re gonna see the demarcation line. For example, if you have a patient that has been crosslinked by some other doctor, you can look in the anterior stroma, and this line should be there. But if you do five minutes, maybe you don’t find it. We described this difference between 5 and 10 minutes in some Congresses in the past. Some complications you have to consider. It’s a surgery with a high level of security, if you follow all the protocols. In the immediate postoperative, you need to be careful with the epithelial ulcers, the corneal edema, the infections, and the corneal melting. Someone was asking this about the corneal melting. The combination of the crosslinking with mitomycin. We don’t use it. We only use riboflavin. And the late postoperative complication that has been described is the corneal haze. Again, if you treat correctly the patient with the good protocols, you’re not gonna have this complication, for sure. What is the correct treatment? Use steroids for the first month. Don’t take it out after 7 days. Because the haze is gonna be there. Remember that the crosslinking is gonna be working for the first month, and then you’ll have — for more than one year, it’s gonna still be having changes in the patient. So be careful, and don’t take out the steroids after one month. And then you need to control it until the third month. Because after three months, they usually can have this corneal haze complication. Contradictions of the crosslinking. Pachymetry less than 400 microns, severe dry eye, because you will have problems with the epithelialization. Limbal cell deficiency. For the same reason. And low endothelial cell count, because you might have some damage and you can have corneal edema. So let’s continue with the conclusion. It’s a conservative surgical treatment in keratoconus. It has shown safety and effectiveness in multiple reports. And it’s indicated in the time to halt the corneal thinning. Reducing more complex procedures in the future. And preventing the corneal graft. So just a quick question for you all. So the corneal crosslinking can be used for — and you have five options. I don’t know if you are able to answer this. Halt the progression of the keratoconus, increase the tolerance to the use of contact lens, improve the corneal surface, improve the refraction of the patient, all the answers are correct. So let’s see which one you choose. Okay. No. Not all the answers are not correct. Why? This is the correct answer, the first one. Halt the progression of the keratoconus, please. Now we’ll give the second step, where I will show you the effects of the intracorneal ring and the surgery, and you’re gonna understand why it’s not gonna improve the refraction, and it’s not gonna increase the tolerance to the use of contact lens. So intracorneal rings. The difference between these and the crosslinking is that the crosslinking is gonna halt the progression, and the intracorneal ring is gonna improve the corneal surface. So the intracorneal rings were first described by Barraquer in 1949, with the thickness law. They were using the rings to reduce high myopia. Again, the corneal map — it’s very interesting. And it’s very important for you to understand the topography. And to recognize the parameter and the topography morphology, to understand where and which kind of ring you need to use. So how we can choose the patient? The inclusion criteria? Which parameters to consider? What kind of — or types of rings we have? And the surgery tips. I’m gonna show you all of these. So inclusion criteria. For patients with keratometric values less than 57, and good pachymetry values, we can choose the intracorneal rings. Of course, we need to be sure that the patient has no scars or comas in the center, because otherwise, no matter that we have a regular corneal surface, if we don’t have transparency in the cornea, the results are not gonna be good. So what to consider before the surgery? Again, the visual acuity, the manifest refraction, the values of the autorefractometer, the corneal topographies necessary to do the calculation, the keratometric values, and the aberrometric values. Some doctors use the asphericity to make the corrections, and some don’t. But it’s been helpful. And then the corneal pachymetry, as I was telling you before. So the surgical plans are usually proposed considering all or some of these parameters. Giving — the doctor can give more or less relevance, depending on the case, to the keratometric values, to the corrected visual acuity, or to the pachymetry. Here you have a timeline, as I was telling you before. Dr. Barraquer described it first in 1949. And until 2000, we have been changing different theories, and incorporating different technologies. And the last thing you need to know is that right now the treatment of keratoconus is trying to be more customized as you can. I’m gonna show you this classification. It’s been described during these few months. We have two different kinds of rings. This material is PMMA. And then we have the CAIRS, allogenic intracorneal ring segments. It’s been described by Dr. Soosan Jacob, giving you this picture to show you. And this is a patient with an asymmetrical base intracorneal ring performed here at the Institute. So you can see the different rings and the different materials. So what about the PMMA? I’m gonna show you about Ferrara rings. The model. It’s a flat profile segment, and it’s compression of the internal edge of the cornea that determines the effect. Originally it was designed by Paulo Ferrara from Brazil, and it’s been marketed by Keraring, Corneal Ring, AJL, Intraseg, and different brands. Hopefully, I think, they are worldwide. I like always to share the faces of the doctors that have been working on different developments, because I think it’s easier to remember. I’m gonna show you these. It’s the symmetrical base. Intracorneal ring. You can see the difference between the asymmetrical base intracorneal ring, and the asymmetrical height intracorneal ring. So this was what I was telling you before, about how to customize the case. Once you identify the topography, you’ll be able to choose the ring and customize. Some important details. The less diameter you have, more effect. And the more thickness you have, more effect. So here you can see how deep we can go with the intracorneal ring. We usually propose 8% of the pachymetry of the patient. To put the — so you’ll avoid the extrusion. It’s one of the complications. And you can see here it’s a patient with a previous corneal graft. So how to choose? What to do? One or two rings? In which positions? We have a lot of nomograms around, that are gonna help us as a guide. But your own experience is the only guide we need to follow. It’s very important to understand that the nomograms can tell us what to do or how to put the ring, to put one or two, but the personal experience is gonna be the best nomogram. So what about the surgical technique? I’m gonna show you this combination procedure. We do the combination between corneal crosslinking and intracorneal ring in the same surgical procedure. If you have femtosecond laser, it’s great, because it’s easier, but you can also do a manual technique, and it’s very — the results are the same. So you can see here the description of the topography before the surgery, where you can see the correct visual acuity, the refraction, the axis, the incision, the deepness, and the selection of the intracorneal ring. This is the surgery. Used in the femtosecond laser. Here you can see the parameters that we have been choosing for the internal tunnel and the external tunnel. And after a few seconds, once you have chosen the intracorneal ring, you will introduce it through the incision you have done before. And you need to go deep and then turn the ring through the tunnel. Until you have the ring in the correct position. To correct the corneal ectasia. So you can see here that it’s already changing the shape. What to expect from the intracorneal rings? We need to know that they are gonna improve the corneal surface. Probably they will improve the visual acuity. Corrected or undercorrected. We’re gonna reduce the astigmatism. And we’re gonna reduce the optic aberration. Something important for me to share with you is that it’s not a refractive surgery. So we’re gonna — we’re trying to improve the corneal surface. After we have a regular cornea, we can make the arrangement for the refractive surgery. So it’s very important to understand the corneal topography, to understand the patterns, to know that the nomograms are a guide, and the cases are customized. I’m gonna show you this case, with the visual acuity in the preoperative. This is the topography and the refraction. And this is the 24 hours. We use one ring. A symmetrical base. So you can see the picture. In the postoperative, you need to take care that the incision is closed. And the deepness of the ring is as you said before. And here you have the results, with the really clear reduction of the astigmatism, and a regularization of the cornea. Here is another case. And I’m just showing you the topography, with the really clear reduction in this case. We use only one regular base ring. In this case, it’s really nice to show you, because this case is a patient that — during the pandemic quarantine, couldn’t come to our visit, our consultation, so we did the telemedicine consultation. And we asked him to take a picture of the eye. And as you can see, the ring is perfectly in position. And the cornea is clear. So it’s a clearly nice surgery also to control by telemedicine, in this pandemic situation. And there is another patient with the same surgery, in a different position. And just to show you how we ask the patient to take the picture, with no flash, with 10 or 15 centimeters from the eye, they can take a picture. So again, the intracorneal ring is gonna regularize the cornea. And the crosslinking is gonna improve the biomechanical properties. They are complementary. They are synergistic techniques, not competitive. So this is a presentation we did in Lisbon, and then in Cornea Journal, you can see it also. Where we can show the efficiency and the safety of doing the bilateral procedure in combination. And it’s the patient, when we perform crosslinking in one eye, and the combined surgery in the other. So it’s very important as a conclusion to identify the keratoconic type and the classification. It’s mandatory, before doing the surgery. The topographic image is required to identify the pattern, for achieving the correct selection of intracorneal rings, as well as the number and position of intracorneal rings, for each ectatic cornea. And implantation of the asymmetrical base is customized to control the treatment. So it’s always useful? No. And you can see here a picture of an OCT. This is from a patient that came to the hospital, and they performed crosslinking and intracorneal rings with this ectatic cornea. So of course, it’s not gonna help the patient to improve the vision. Sometimes we propose the rings in patients, thinking that it’s gonna make it better to improve the contact lens. But it’s not always useful. So be careful before doing these decisions. What to do in these kinds of patients? The corneal graft. So another question for you all… (cell phone ringing) I’m sorry. I don’t know what happened there. Again… So… Inclusion criteria proposed for intracorneal ring implantation. K values over 57. Pachymetry more than 400 microns. Absence of corneal opacities. Presence of strong striae. Let’s see your answer. No. If we have Vogt striae, we’re not gonna be able to do the intracorneal ring implantation. We’re gonna have to do a corneal craft. It’s very important to know that you need less than 57 keratometric values. So finally, let’s talk about the corneal graft. The DALK is the gold standard for keratoconus treatment with corneal graft. It’s a deep anterior lamellar keratoplasty. The peeling off was described by Dr. Malbran in 1964. And this is a typical cornea for corneal graft selection. With keratometric values over 57, you can see a 61 here. It’s good pachymetry. But the keratometric values are very high. Be careful, because sometimes here you have some values. But you need to take care of these ones. And if you see here, there is a corneal scar also. So if you use corneal rings, it’s not gonna be useful. Here’s a picture of a 24-hour DALK performed by Dr. Lotfi and Dr. Grandin. It’s beautiful and you can see there’s no inflammation. It’s a safe technique. And here you have the results after one year. And after the stitches’ removal. Almost with no change and no astigmatism in the residual refraction. So which are the benefits of the DALK? You avoid immune rejection of the corneal endothelium. The procedure is extraocular and not intraocular. The topical corticosteroids can usually be discontinued before — than the PK. There’s minor endothelial cell loss. Comparing PK with the DALK, you may have superior resistance to rupture of the globe after trauma. And the sutures can be removed earlier with DALK. Always try to do this. So at the beginning, it can be more difficult. But once you learn the technique, it’s easier. What to do after you perform the corneal graft? It’s not over. So it seems to be over, but no. We need to consider the corneal crosslinking in the peripheral area. After the corneal graft also. So as I was showing you before this picture, we have a trepanation area in the center. This is a patient, a 29-year-old, with a diagnosis of keratoconus, and the DALK was performed in 2011. This was the final refraction. It was very good. And very low astigmatism. So the patient left. And when they came to the consultation again, we have evidence of histopathological variation in keratoconus, after the graft. We know that you can have recurrence of the keratoconus in the corneal graft. But mostly in the union between the donor and the recipient. So Dr. Malbran again — he described the corneal ectasia in the peripheral ring. He also described a surgical technique to make a reconstruction of the cornea. So the idea to show you is that we need to halt the progression, after you have performed the corneal graft, because it’s really important to avoid the progression, again, for these patients. You can see here a case. That case I was showing you before. He came after six years with this corneal ectasia. The corneal ectasia was because the thinning in the peripheral ring, in the superior area. So what we propose for these cases is to do intracorneal rings. To reduce the astigmatism. But the most important thing is to do the crosslinking, with epithelial debridation in the peripheral ring, with the same technique. I’m gonna show you a short video of a patient with a corneal graft. That we have — we performed this surgery. Doing the tunnel. And the implantation of the intracorneal rings. And after we did the instillation of the riboflavin, we did the irradiation. As you can see there, we were covering the center of the graft. Because we don’t want to irradiate healthy cornea. Here is the postoperative picture, and you can see the ring. The scar of the graft and the transparency of the cornea. It’s very safe. What’s gonna happen if these patients have some refractive error after this? We can propose different techniques to resolve the refractive error. So if the patient don’t want to use contact lens, or glasses, you can use phakic ICL. I’m gonna show you this case of a patient with a high myopia in both eyes. In the right eye, we did DALK. In the left eye, we did a combined procedure of crosslinking and intracorneal rings. Here are the topographies. After the graft. You can see here… This was the refraction. And after the intracorneal rings, the topography was much better. Here’s the refraction. So Dr. Zaldivar performed a surgery with a phakic ICL. And you can see here the image of the phakic ICL in the intracorneal rings and in the DALK. And these are the results. After one year and a half of the surgery. And this is the final refraction. So this patient is a pilot. You can see — you can have excellent results. So as a conclusion, IOL are good options to treat residual refractive errors in keratoconic patients. And before ICL implantation, you need to be sure to regularize the corneal surface, to halt the progression of the ectasia. Well, it’s been long, but we’re going to finish in this presentation. So final conclusions: The early diagnosis and adequate treatment of the keratoconus allows us to halt the evolution and to have a prompt visual rehabilitation of the patient. Promotion and prevention are important tools for our patients. Remember that most of the them are young patients. With an active life. And we need to help them to go back to their regular life. Thank you very much to my mentors, Dr. Grandin and Dr. Lotfi, and just a picture to finish of Mendoza, the city where I live. So we have a few minutes left for some questions. I’m gonna check. Lawrence, I don’t know if you have any questions for me.

>> Yep. So you can go ahead and stop sharing your screen. We have quite a few questions, if you have some time, in the Q and A box.

DR GORDILLO: Okay, thank you. Is it safe to combine — I think I already answered this one. Greetings. My opinion in hypoosmolar? I already did that. Hypoosmolar crosslinking — we try not to do that, but we can use it to make a safe crosslinking. Idiopathic… We don’t have that after the keratoconus. What happens if you don’t treat it? You’ll have evolution, probably. You’ll have progression. If you don’t treat it. You’ll need to do corneal graft. The good thing to tell the patients with keratoconus that I always tell them is not to be afraid, because if they have a safe and healthy retina, they are never gonna get blind. The patients are always afraid of that. Sometimes I tell the patient that — imagine that they are fixing a car. If you have a good motor, you can only change the glasses of the car, and everything is gonna work properly. So if they have a good retina and you fix the cornea, they’re gonna be able to see. Some more questions I’ve been answering, I guess. Most of them. The intracorneal rings are not changing the endothelial pump mechanism. Not at all. Because it’s only in the stroma. It’s not changing at all. Yeah. Combined surgery for crosslinking and intracorneal rings reduce the rehabilitation time for young patients. Which one has more success? All the surgeries are good, but the important thing is to know that as early you do the surgery, the best refractive result you will have. For IOL calculation after corneal graft, you do the same as a typical calculation. My opinion for scleral contact lens. So it’s good for rehabilitation, but it’s transitory. I mean, if you can’t do, for example, right now, with the pandemic situation, we’re not able to do — to perform corneal graft, so the scleral lens are good, but you need to tell the patient that it’s gonna be changing. Usually we propose crosslinking and scleral lens until they do or perform the corneal graft. Remember that in the future, that patient is gonna have a cataract. And if you do the cataract surgery, you need to have a regular cornea. Well, again, about the crosslinking and the intracorneal ring, which one is earlier? We perform them together. At the same moment, usually. You can do it all together. We don’t need to wait. There are many questions that are the same. IOL, toric — yes. We do toric implantation. Dr. Zaldivar performed the surgery. The crosslinking usually is not gonna improve the vision. It’s gonna make just a small change in the topography. And in the final refraction. Okay. We don’t have experience with this contact lens crosslinking. My friend Dr. Soosan Jacob performed that for corneas below 400 microns. We don’t. Why not using a full ring? Because usually the full rings are for very big corneal ectasia, and usually the visual acuity is not gonna be that well corrected. So if you recognize the topography, and the corneal pattern, you’ll able to correct with one ring. Or maybe two, but… Not with a big one. Okay. Yeah. The demarcation line is a good indication for effective crosslinking? Yes. It means that the crosslinking — it’s there. It’s like a scar. You know? But if you don’t have the demarcation line, maybe you did a five minute surgery. So don’t worry about that. Why is DALK inevitable if crosslinking can give us corneal stability in terms of progression? No, like what I was telling before is that if you do a crosslinking, probably you’re not gonna have to make a DALK. But after DALK, you need to be careful with the progression, and to try to perform the crosslinking. If you see progression in the peripheral ring. How often we repeat the crosslinking? Never. We have never had the necessity in any patient to repeat it. How can keratoconus be diagnosed early, without topography? So this is a very good question. I did a protocol that I didn’t share it today. For those doctors or clinics that don’t have topography. So we did good — you’ll be able to diagnose the keratoconus with keratometric values over 46, you need to suspect. With corrected visual acuity that is not good at all, when you have different axes between the refractometer and the visual acuity, and if you have of course some of the biomic microscopical signs, like the nerves, the scars. What is the target area in crosslinking after DALK? We do in all the peripheral cornea. Complete. If you receive a patient with crosslinking already done, and you just indicate for intracorneal ring, you can do it immediately, or you wait for some time? Usually we can make it immediately. We don’t wait. Can one perform a crosslinking in 40 plus? Of course. We have been doing crosslinking until 60, 70, 80-year-old. It’s a really important concept. That the age is not related with the progression. Corneal implantation and corneal graft? It’s the same. I’m sorry there was a confusion with that. It’s the same. Different terminology, but it’s the same. It’s very good question of Dr. Manda. If it’s a must to crosslink all patient after DALK, it’s also a must for PK? It’s not a must, but you need to consider — usually we know with the evolution of our follow-up patients that the patient with DALK or PK indication with very thin corneas in the preoperative, probably you will have evolution, so you tell the patient about this before the graft. And they don’t want to go back there. So if you have a good follow-up, you’ll be able to know if it’s necessary or not. For both DALK or PK. Yes. Can you combine crosslinking and ICL implantation? Or ICL implantation with intracorneal rings? Okay. I think this question was already answered during the presentation. Yes. You can do ICL after crosslinking. We wait one year. And you can do also after intracorneal rings, after one year. Because you need to have a stabilized cornea. If it’s possible to repeat crosslinking, if it keeps progressing, yes, you can do it. But we don’t have this experience. Because we never had the progression. What to do if a DALK fails? Depending on the cause. But usually you don’t have rejection. On anterior lamellar keratoplasty. Results between crosslinking and crosslinking with intracorneal rings are comparable? Or one is superior? They are not competitive, as I was telling you before. They are complementary. Okay. I think we are done with the time. There are a lot of questions. I’ll be saving these questions, if you want me to answer them after I finish the webinar. I’ll be in contact with everyone. You have my contact here. Thank you, everyone, for sharing this hour of keratoconus. I think it’s gonna be useful. Please feel free to make any questions or contact me. If I can help you, I’ll be happy to do that.