 Please come in have a seat it is time to get things going again now as many of you are aware in selecting speakers for residence day in the past we invited people from outside and then someone had the bright idea that we have a lot of talent among our alumni and so we select an alumnus of the year and for 2022 honored at the Academy meeting last fall our own Majid Moshefar Dr. Moshefar was a medical student at Georgetown a resident at the University of Illinois he did two fellowships here he was a corny and refractive surgery fellow then he stayed around for more as an anterior segment and uveitis fellow finishing that in 1998 I was thrilled when he joined our faculty to take over corny and refractive surgery it was absolutely you know a good move for our patients and he worked with us until 2014 he left the professor at the Proctor Foundation in San Francisco he came back and since returning to Salt Lake he has had a corny and refractive surgery anterior segment practice at Hoops Vision he also has gone to the administrative side he's the medical executive director at Lone Peak hospital and it is my pleasure to welcome Dr. Moshefar to talk to us about some issues related to refractive surgery this afternoon Dr. Moshefar. Thank you for the introduction and I think the reason I did two years was because after I finished the first year they just said you know this guy's just not ready and so we have to really keep him here and then when I finished that they still said Dr. Olson said this guy's not ready we have to keep him here longer so we can teach him how to do things and I'm so happy to be back with my family Moran is my family another day goes that I talk about Moran and the history and all the great people here and I'm humbled and honored to be here when Dr. Mifflin called me last summer and told me that hey Majid we were wondering if you could be the distinguished alumni and I said are you sure you know because I always think of myself as a substandard talent and I said Mark why me and then he said well you know I guess we couldn't find anyone better I said well okay because you know we have so many smart neurologists we have smart retina specialist glaucoma specialist cataract surgeons you know refractive surgery kind of goes way down there and you will see that when I start to talk you see that it's pretty easy even a kindergarten kid can understand what I'm talking about but I'm humbled I'm really humbled and it's an honor to be here with great minds and I will try to talk and it's wonderful it's after lunch so you can take a nap as I talk because it's not it's not that hard to understand what I'm going to say I was going to go and talk about my area of interest and my area of interest by primarily femtosecond assisted lenticule implantation basically the reverse of smile that people talk about but then when I talk with my students they all said oh come on let's talk about something that we are doing and I actually felt better so what I'm going to talk about this next 45 minutes or so is primarily the stuff that my great students have done just in the last five weeks and three of them already submitted for publication and after this I'm going to meet the students and work on three more manuscripts before 6 p.m. and send them out so I'm not kidding you and I was telling Dr. Petty that my wife and my kids are the highlights of my life but the students are truly the second highlight of my life I never thought that I could find the passion and I'm lucky because I learned so much from them on that note I wanted to tell you something when I found out that Elaine and Kelly they put this picture up there I called Lynn and I said Lynn why did they choose this picture why didn't you give them this other picture of mine and then she said well Dr. Moshe that picture belongs to 30 years ago and I said yeah but I look better in that one and kind of looked at me and said yeah so on that note I kind of knew that I'm getting old and I am old but at the same time I'm honored to be here to share my little knowledge what I know which is not much with great minds here. I have no financial interest but yes there are a couple of FDA instruments that I am part of them that I'm doing right now for eligibility and feasibility that I will talk about but I'm not getting any money personally or any personal check from these companies including Johnson and Alcon. I'd like to mention Carter Payne, Devin Harvey, Michael Herron, David Cha, Jack Wang and also David West these are the people who right now currently are working in our office little office in Draper and I'm going afterwards to meet David Cha so I want to thank them because they are the ones who share their data with me so I said and I said to them that let's present your data here to our other research residents and Dr. Payne is our wonderful fellow who is finishing and going to George Washington and he's just a wonderful person and I can't thank him enough for all the projects that we've done so far. The primary objective of this paper is to simply briefly talk about a little overview of lenticule extraction, talk about the distribution of the refractive error and pupil in the refractive population and primarily in Draper population because that's what we see and what is the corneal curvature changes after refractive surgery whether it's lacy or PRK and compare them and look at the optical zone is it really 6.5 or is it not really 6.5 and what sort of aberration it's created by these different surgery whether it's lacy whether it's smile and lastly briefly talk about the relevance of this if any. We all know about PRK, we know about lacy and lenticule extraction or what people call relax is basically a femtosecond platform and this relax or femtosecond platform that some people call smile basically uses a device a femtosecond platform to create two dissections in the cornea anteriorly and little bit deeper posteriorly and these two dissections meet and then they create a disc and then you have this small incision 4, 3, 5 depending on who you're talking about and then through that small incision you remove this the femtosecond assisted dissected lenticule and depending on the power can be for hyperopia can be for myopia can even be for mix of stigmatism and it is called relax unfortunately over time this relax terminology was coined smile and the reason it was coined smile is because the platform was introduced in 2016 and that's what we have been using in the United States since 2017 and people call it small incision lenticule extraction and that's because the company was a Zeiss company otherwise this is really a relax and we are actually have another laser platform that I am working with FDA right now and we are in the feasibility stage we've already done 30 some eyes with it and it's called smooth incision lenticule keratoma looses that's also relax it's just another name for it and that is what companies nowadays are doing they're trying to confuse the scientific literature and everyone else by using different terminology and then guess what there's another one Zimmer wonderful company fantastic company I really like them they also have platform called Zimmer that called CLEAR or clear corneal lenticule extraction for advanced refractive correction these three procedures are identical by principle they all use basically femtosecond platform and they all do the same thing this is one of the first cases that I did in 2017 the patient is actually fixating on the light on on their own and then you create a posterior dissection with a femtosecond bunch of bubbles and then you're doing the anterior dissection which is usually at the depth of 120 in United States but it can be as deep as 160 and as shallow as 100 and then that's the anterior dissection and then eventually you do a incision it can be superior it can be inferior it can be whichever direction you want to put it and originally it was five millimeter and this is actually one of the older videos of mine shows you the five millimeter incision now we're doing this through a three millimeter incision it was easier to do it that way and the dissection requires some manual labor that's where I do my workout my wife says you need to do more work out I say honey this is my workout this is the manual dissection that I do here and then you do the posterior dissection and eventually you take this lenticule out and these lenticules are removed and we right now doing not nothing anything special with them but I sure we did something with them and just to show you this is the lenticule we always look at it and we say it's pretty and many times we just toss them out unfortunately so and then this is the other platform that we are working with Johnson and Johnson and again it's going through two sites in the United States and it's called silk again it's the same thing it's relaxed and we are basically docking on the eye the only difference with this relax or this a platform is that you actually create the suction on the eye the patient cannot fixate on the green light anymore you are creating a suction the same way we do for LASIK the vision gets dim once the vision is dim you try to basically center the and you can see the ablation is different you can see that the posterior dissection just done then that then the anterior dissection is done and then you do the little tiny incision up there and that's it and what is the advantage of this well there is no advantage this is just a patent that they developed for themselves they can talk about the advantage of this versus the other one and I don't want to get into that that's beyond this talk but this is another platform and then once it's done you basically go ahead and you let me see if I can show this to you guys here I am marking the cyclotortion of the eye before I put the suction on the eye in this one you actually mark the pupil because the suction makes the vision dark and as you all know once you create a suction the pupil becomes somewhat dilated and it goes through kind of a movement that's why we mark them and then this is afterwards once the dissection is done and again similar concept you really can't tell the difference between the smile from silk they're both the same procedure and you basically do the dissection and then you remove the lenticule and again we look at the lenticule and we're hoping that one day we would be able to do some work with this perhaps with Dr. Mamal this is laboratory and Dr. Werner's laboratory because you can actually see that this entity is really about six or six point five depending on what platform and what size you decided and sometimes they can be very thin and and they are extremely thin this this thing here right now is about 70 micron and you can actually see the imperfection of the lenticule and those semi circular pattern on this one for example and this is another platform again clear platform and in the clear platform again you creating the suction on the surface and again you do the same thing over and again you take the lenticule out and again it's the same sort of a thing so we have these three platforms that we use now I wish and I think I want to also thank Dr. Bajokli who is one of the pathology fellows here with Dr. Mamalis who's working with Dr. Payne on an editorial that we are writing right now for one of the journals that really this is confusing to use different abbreviation for some some procedure that is identical and the angle we're taking that this is femtosecond assisted and this is a keratomalusus procedure and why don't we just call this a small incision lasik because it's still this keratomalusus or why don't we just stick with the relics and that's what we're trying to do right now and instead of letting companies use their own trade names such as clear and silk and confuse the scientific literature when the procedure is really the same now before I go any further to the optical part of our study here I just wanted to ask and see if our residents kind of understand the importance of when we say we're doing a minus six smile or a minus six lasik if we take that lenticule out and let's say we freeze it and then we put it underneath a lensometer theoretically what is the power of that lenticule so I have a patient who's a minus six I create that lenticule which I just showed you and I take that lenticule if I put that lenticule theoretically underneath a lensometer what is the power of this lenticule what is it guys very good it's plus six and that's why when you are evaporating the cornea we're doing a minus six exomer laser and you can smell it in your nostrils that is about plus six amount of stromal tissue as well and here I'm showing you another one it's a minus six minus 150 axis 30 yes we can talk about that afterwards yes I'll talk with you about that when it comes to curvature changes so when you do a minus six minus 150 axis 30 and if you do that on lensometer what is the power of this one you think Jordan do you know it is going to be plus six plus 150 axis 30 plus six plus 150 axis 30 you just have to sit down and jive that in your head and you'll see why and then it becomes in a minus cylinder plus 750 minus 150 axis 120 now I can also show you a mixed astigmat and make things even more difficult but this is the concept and the reason I just chose to do the minus and myopic astigmatism is because the talk is primarily about myopia and myopic astigmatism and not hyperopic relax or mixed astigmatic relax now when we're talking about the pupil size we decided to look at bunch of student patients in the last six seven weeks in Draper and we said let's go back and look and see if we can find all the data on our patients in an OPD scan machine and see if you can look at the distribution of the refractive error anyone who walks into the office conjunctivitis, lasik, transplants, glaucoma, whatever and we looked at all these patients who had specifically OPD scan because with the OPD scan you can look at mesopic and photopic pupil you can also look at the refractive error you can also look at the change in the size of the pupil over time because it's more dynamic so basically based on that we looked at about 1400 hours and yes it was almost 50-50 male and we noticed that there were about almost 8% high myopes over the six diopters and less than 5% of the patients were mixed astigmats that means these were patients who were almost planosperical equivalent and about 15% were hyper over now remember these are not only refractive screening patients these are patients who just come to us to see us and this is really reflective of what's in the literature to if you look at the literature from Germany or other places that have done some big demographic on that now what's interesting we also noticed that there were 2.8% character conics and I remember there was a point that we thought that character conics was 1 in 10,000 then they changed it to 1 in 2,000 then they start saying that no no no character conics can be sometimes 0.3% and now there are some papers that even say it could be 1% I said the incidence of character conics is 1.162 sometime in the past and I was kind of attacked by that but I truly truly think that the incidence of character conics if you include subclinical character conics it is a lot more than what people think and so many times you do cataract surgery the cataract surgeons in the group here that you look at that topography on a nine-year-old and you see that steep corny and a thin corny and you say oh this lady did have character conics it's just that the diagnosis is a lot less noted than it really is so I truly think that there is almost three out of hundred people walking the streets of Draper who have just subtle character cones we looked at the pupil size this is nothing all of you guys know that that as the age increases per decade the size of your pupil gets smaller whether it's mesopic or photopic nothing extraordinary about that but then if you look at the normal distribution looking at the young blue bars here versus the older patients like myself the maroon color you can see that there is this shift from the left to the right on the diagram here that shows you that the pupil sizes actually get smaller as you get older whether it's mesopic or photopic linear regression nothing into it it simply shows you that as you get older closer to 100 we had bunch of patients who were in their 90s and we had a couple of patients who were there six and seven years old and look at this data and out of these patients we noticed that yeah definitely the pupil gets smaller as you get older again I love this because I think this is a hard work of one student and he deserves to have his data shown here same thing here refractive error the more hyperopic you become plus nine versus minus 21 the pupil sizes also get smaller too now we can sit here and talk about accommodation and all that stuff but overall the g stuff it is in that this big cohort the size of the pupil definitely became smaller as the refractive error became more hyperopic we looked at the control group and we wanted to know okay if you look at just refractive error can we really say age match if the pupil sizes are larger for myopes always more than the hyperopes yes the pupil sizes are statistically larger for the myopes versus the hyperopes and mixtastic match but there is no difference between the mixtastic match and the hyperopes same thing with the angle kappa for the pediatric ophthalmologist here they know angle kappa is a big deal and we know that the angle kappa is always associated with hyperopia but when it comes to higher the myopia is the level of angle kappa gets less and less and less and that's what you see on the pentacamp the higher the myopia is the less the angle kappa is and the closer the vertex of the cornea is going to be with respect to the center of the pupil and here we're simply showing that again that there is definitely a correlation in terms of the photopic mosaic pupil size and the level of sphere i love this one because this is what we need for topography guided lasik when we do topography guided lasik the fact is topography is always going to be on the vertex or the line of sight or the vertex of the cornea the contour is not going to be theoretically on this pupil and what we are showing you is that there is still a dynamic phenomena is happening the misopic pupil versus a photopic pupil it always moves more toward the nose and also slightly superior so that means when you pupil constricts you actually have a centroid shift in the dynamics of your pupil and this is nicely demonstrated here that it becomes more nasal and slightly superior now what's interesting is that this was a big deal when we were doing rk i did mini rk and when i was here a fellow with dr clinch and we actually went to dr k spear for two weeks to get a workshop with that too and we did rk mini rk and we always made a big deal about putting pilot carpet in the eye to make the pupil smaller and every time we put that pilot carpet in the pupil always would move toward the nose more this is a real thing so there is a centroid shift that happens and the higher elaboration for those of you who are interested in cataract surgery not a cataract surgeon but in the cataract surgery you can see that prior to the cataract surgery these patients haven't had cataract surgery yet you can see that the patients who undergo cataract intraocular lens the level of h o a whether it's internal whether it's external or whether it's total it's slightly more than the younger people who are undergoing your common lasik prk and smile and then look at the keratoconic eyes of course they have a high amount of higher order aberration but what i like about this slide is that the higher order aberration in keratoconic patient is not just in the cornea guys you can see that the patients with a higher order aberration externally that have keratoconus they also have higher amount of higher order aberration internally and you know why because it neutralizes their vertical coma their lens accommodates with a very nice zonular form not in a very regular form so you can have a keratoconic patient that has a significant inferior cone but can use his lens to neutralize the higher order aberrations of the cornea so you can have an internal higher order aberration to neutralize your external higher order aberration as shown here lastly i just wanted to show you this is something that we all have seen the older you get the more against the rule stigmatism you become and this is shown nicely here when you're not young almost 70 percent of your patients have with the rule stigmatism and when we become old like me it's almost 51 percent have against the rule stigmatism now we looked at this group and i didn't want to get too much into it because we have other stuff to talk about but when we looked we wanted to see if these against the rule stigmatisms are always lenticular because we thought oh older people get against the rule stigmatism because it's mainly lenticular no these patients still had many of them against rule stigmatism under cornea as well as the against the rule stigmatism in their lens corneal curvature we all know about the total corneal curvature in a normal person it's about what 42 43 45 diopters what about the radius of curvature we all know it's about 7.8 and those people who do contact lenses are quite familiar with this radius of curvature that's how you you know what what sort of a lens you should pop on the patient's cornea but what about posterior curvature that's the nebulous area that when i was a fellow nobody even told me about posterior corneal curvature you guys know about posterior corneal curvature much more than when i was an attending and the posterior corneal curvature that what is the usual radius of curvature of a posterior cornea so a 6.4 now many people don't talk about posterior ratio to the anterior ratio but the pa is extremely important for the cataract surgeons who want to do cataract surgery on patients and nobody talks about the pa ratio but that's the ratio of 6.4 over 7.8 that i will get to in a second and what is the diopter of the posterior curvature you know that a lot because you do a lot of toric iols what is the posterior curvature of the cornea and diopters guys it's about minus 6 point that's the posterior corneal curvature all right so this is very important later on when we talk about changes in the corneal curvature especially anteriorly and also posteriorly after latex surgery or smile so what we what happens when you shape off the cornea what happens when you basically take that cornea and burn it down with 40 600 micron you flatten the cornea what do you mean by that you increase the radius of the curvature you take that curvature from 7.8 millimeter to 8.6 8.2 millimeter and that's why their power of the cornea goes from 45 diopters all of a sudden to 39 diopters so you actually reduce the power of the cornea by changing that radius of curvature but that radius of the curvature change you all know is not one to one when you do six diopters of correction on somebody's cornea you are not going to make that cornea six diopters flatter that ratio is not one to one i wish it was but it's not and that's because you're only looking at anterior corneal curvature you're not looking at a posterior corneal curvature and you also don't think of other factors that are involved which is right now beyond the scope of this talk but we will talk a little bit about this ratio because this ratio is something that we all take for granted but it is extremely important because if you are doing a patient who's minus 10 versus a patient who's minus one the delta change of your corneal curvature per diopter of a change of that cornea when you burn it or you cut it or you do whatever with it that ratio is not the same this was a paper that we wrote in 2012 at morana ice center on almost 3000 patients and we showed that this ratio for lasik patient was about 0.7 to 0.8 it's a known fact now in the world that the cornea changes but about 0.7 0.8 diopters and we also showed that that changes based on the micro keratone versus femtosecond if you do contura if you don't do wavefront if you do wavefront optimize and we showed all that and this was a slide that people use all over the country and everywhere else this was one of the first one that showed that as the spherical equivalent correction increases if you're doing somebody who's minus seven or eight versus somebody who's about minus one or two the ratio goes down and it goes down almost toward 0.7 0.8 and this ratio when it comes to minus one and minus two and even less it even more noisy so we looked at this ratio and we wanted to know if this ratio was any different between the patients whether you get lasik or prk so what did we do we decided to choose patients who were happy they were happy with their correction you wanted them to be minus five they were minus five you wanted to reduce the cylinder from minus one to minus one you did that so these patients did not undergo enhancement these patients had one year follow-up not three months and we looked at these patients tomographies and looked at their keratometries and looked at the achieved correction which was basically ametropization and we wanted to know these patients had the same ratio and looking at them based on one year data to preoperative data we showed that the ratio for these patients based on this number of eyes and this demographic here what is that ratio one thing we identified when we looked at these patients we noticed that well first of all the higher order aberration was higher in the prk group second of all the prk groups had a steeper cornea and the smile group had a higher level of myopia well these groups are not the same but at the same time we realized that there is always a selection bias patients who are prk usually thinner that's why the pachymetry is thinner patients who usually get prk usually have inferior steepening patients who get smile usually are higher myopes so this inherent selection bias was controlled later on in the study to analyze further stuff for us but in terms of the common ground you know typical 2020-2030 safety efficacy this is the nine standard graph that every journal asks us to do when we looked at the nine standard graph predictability line of correction best line of correction everything was very similar except the stigmatism which was noisier for the smile otherwise in terms of safety and efficacy index and everything else all three platforms were very similar but it wasn't the course of the study to look at that standard treatment because people have done that we wanted to look at the delta k change per spherical equivalent for lasik versus prk versus smile and what we noticed that yeah lasik still is somewhere around point eightish but we noticed that the smile was lower than lasik and this even if you normalized the group which we did still revealed that for some odd reason when you're trying to do a minus eight on a smile you cannot make that cornea the same flatness that you can in a lasik and we think that has to do with the fact that this ratio is lower because maybe the cornea is not being dissected as i think dr stag was asking maybe because the cornea inferiorly is not intruded maybe because the bowman is intact and by having the bowman intact and not damaging that anterior 120 micron of the cornea and not making 11 hour of cut maybe these corneas are inferiorly stronger and maybe that's why the ratio was different we did correlation studies age we tried to see if there was a factor of age yes there was some correlation between age and the change in the ratio we did notice that and that is not something new but we noticed that that ratio was present not only for lasik but also for smile and we noticed that this ratio gets less as you get older and what does that mean what does that mean if the patient gets older and the ratio gets smaller that means if you want to correct somebody for two diopters you don't need to do two diopters on an old person you do 1.6 on the other hand if you want to do two diopter on a young person you need to do 2.1 that's what this tells you that's all what about looking at pachymetry really no real correlation that we could find that was statistically important or different between the groups preoperative pachymetry didn't show anything we also looked at keratometry yes there was some correlation between the preop k and the ratio and this correlation that we identified was more obvious in lasik but not in prk and not in smile and again that means if you have a steeper cornea and you do lasik on them versus prk and smile they may behave differently and we did look at the total correction and this is granted the higher the correction the lower the ratio the lower the correction the bigger the ratio so when you are doing only minus one or two the ratio should be closer to one and when you're doing minus eight the ratio should be minus 0.79 so it should be less which also indicates that because the ratio goes lower when you're doing a minus eight you can reduce your nomogram and do maybe minus 7.25 that's what this shows you regardless of age and this is the importance of delta k delta sq not just for cataract surgeon this is important for refractive surgeons to have a nomogram every surgeon should have their own nomogram and we also looked at the cylinder and the cylinder that we only found was that there is some correlation between smile and cylinder and we think this has to do with the fact that smile still cannot correct cylinder as good as lasik and prk because of lack of nomogram and because of the limitation of strange so when it comes to cylinder our correlation shows that there is undercorrection so in summary what we found yes there is about lasik has a highest higher rate of ratio smile has the lowest ratio and the flatter the cornea is the higher the ratio and the older you are the higher the ratio and the higher the correction that you're doing you need the lower ratio so you need to ablate the cornea less and has this been published not exactly in this form for smile we also wanted to look at posterior corneal curvature for those cataract surgeons in the group how much change do you see in the posterior corneal curvature we talked about the posterior corneal radius we talked about anterior corneal radius we said the anterior corneal radius is about 7.8 7.6 posterior corneal radius we talked about was about 6.5 6.3 if you do that ratio what is the ratio of the eye this is something that I hoping that today the residents take with them home if you start doing for average joe young person pa ratio who doesn't have care to conus whether you're my oak whether you're hyperope whether you are mixtastic max what is the ratio I want you guys to remember this because pa ratio is very important not for me but for you guys eventually when do you do cataract surgery so we looked at it so we looked at this ratio and we wanted to know okay we go we burn this we shave this we dissect this and we make this flatter so we increase the radius of curvature so by increasing the radius of the curvature the pa ratio which is the posterior anterior ratio of course goes down and then we said well let's look at it and we look at this very crowded graph here and we showed that all these ratios which were like 0.8 0.8 boom they all go down they go to 0.7 0.8 boom goes down to 0.7 same thing for smile all three of them all three platform behave the same way when it comes to change in the ratio after surgery for myopic myopic astigmatic correction and they were not any different from one another so the change in the ratio after you zap cut whatever is very similar now this is not the case for rk we're not going to talk about that that's under the talk by itself now what about the curvature of the back remember we talked about the posterior curvature being minus 6.5 6.4 6.3 okay now you take this cornea you make it up late you make it look like a frog cornea okay what happens to the posterior cornea curvature the posterior cornea curvature becomes less myopic the minus 6.2 becomes minus 6.15 the minus 6.1 becomes minus 6.0 there is a decline so becomes less myopic but the change is not impressive but there is still a change in the curvature so the back of the cornea becomes slightly flatter but nothing like the anterior curvature and many of you say oh come on 6.15 minus from minus 6.2 is that a big deal you're absolutely right is not a big deal but for some patients that you are doing the calculation for an axial length of 25 millimeter and now their case anteriorly is 39 this can impact the calculation by 3 to 4 percent you can actually have the power of the lens change by half a diopter so posterior corneal curvature change even though it becomes less myopic meaning that still becomes more flat and oblate shape still has a very subtle impact on some patients what about q value a sphericity well you guys do cataract surgery all the time and you guys put all those you know lenses that have a sphericity in them and the q value oh i like techniques i like this lens i don't know because you know i always talk about that right and you always say what's the q value of that lens what's the q value of this one this one has this q value that one has that q value that q value is important because of this and i'm going to show you that in a second what is the q value of a normal person who has a normal cornea and doesn't have a flat frog cornea this is a flat frog cornea this is an eagle cornea which is beautifully prolative well this cornea of course if it gets too bad then it's a keratoconic cornea this cornea is more minus and this cornea is more plus and that is based on this ab ratio that people use that's why it's a ratio guys and the more a cornea is prolate the negative it is and the more cornea frog and oblated is is more positive and what you are seeing here again is the posterior q value the posterior q value of the cornea is minus 0.31 but what is the anterior one it's very similar it's about minus 0.26 so the q value anteriorly and posteriorly is minus what happens when we do lasik or prk on these patients what happens to this q value jordan so here you are pre post pre post pre post pre post pre post pre post anteriorly you go from minus 0.3 ish to almost plus 0.5 something 0.3 to plus 0.5 so you see this change that is why when you see these patients 20 years later they had their lasik thanks to me now they come to you they have to have their cataract surgery done and you are saying oh i'm going to put a lens i'm going to use johnson and johnson lens or that other lens because the q value is minus 0.2 something you are trying to bring this q value down that is the reason and these are the patients that had surgery a year ago so you can see that the q value definitely goes up the a sphericity becomes more plus but nobody talks that much about the q value of the posterior cornea and there is a change even in the q value of the posterior aspect of the cornea and i'm just simply showing it here in this is in this thing in this with the magnitudes and i'm showing that there is a change so the posterior a sphericity definitely increases both in lasik and smile compared to the preoperative q value we try to do a multivariable analysis to see if we can come up with a model can we really guess what the pa ratio is going to be if everything goes nice and dandy if the patient doesn't go blind and they don't get a flap dislocation or in growth and you do a minus five can we really predict the pa ratio afterwards well you know i have to tell you something about multi-linear regression you can use a multi-linear regression and the students do it all the time you can correlate the change in the refractive error after my lasik surgery to my neighbor's golf course scores and all that so i just want you to know you need to look at multivariable regression with some some skepticism but definitely the pa ratio depends on the total amount of correction and also the pre-op and age and the posterior cornea so the posterior cornea definitely has a factor here and then if you look at the prk again correction age and pre-op value has a factor there and lastly smile again the level of correction pre-op pre-value posterior q-value and age so you cannot ignore the posterior q-value and the pre-op pa value but age and the level of correction has a major impact on it as well now remember i told you that if you look at the anterior curvature and put the patient on the or good old Bosch and Lohm keratometer or just look at the sagittal curvature the ratio is not one to one we talked about it we said that if you do 44 diopter patient and you do four diopter they're not going to become 40 they're going to still be like 42. something why is that well we wanted to come up with a better predictor what if there is a better way to make sure that it's really one to one prediction if somebody's really getting a six diopter correction is there a map on that pentakam machine that i can look that really tells me it's minus six is there a map that i can find that's not tangential that's not posterior can i use a map that tells me that if i'm doing a minus eight diopter correction i can see that minus eight almost on the surface of the cornea before and after surgery well we looked at difference maps we looked at difference maps with pentakam we looked at the difference map of anterior sagittal curvature this is what we do all the time we looked at the difference map of refractive power we looked at the difference map of trunet power we looked at the difference map of t-c-r-p now many of you have done cataract surgery on post-lastic patients and you go to the ascrs iol calculator remember that t-n-p you see there and it says 4.0 millimeter optical apex zone or pupil zone well people have looked into that for many years so we looked at that and we wanted to find the best predictor for that which one of them is the best one well i tell you this right now for high corrections mainly these two but i'm going to show it to you so we wanted to look and see if diopter for diopter of correction which one of these different maps before surgery and one year after surgery really predicted almost to the t the correction and we use this machine you are all familiar with these difference maps that you can get this is a very useful tool if you use this you can actually get different display with different type of maps so we used it for those four that i just showed you and we looked at them we looked at the sagittal curvature pre and post we looked at refractive power pre and post we looked at trunet pre and post and we also looked at total corneal power pre and post and what we came up with was that indeed for lacy kampirkin smile when you compare these and stratify them based on the level of myopia that they had before surgery which one can give you almost 99 percent or 95 percent great prediction and we came up with this very crowded graph here for you so i'm going to go through that blue ones just look at the blue and the green here the blue and the greens are the t crps and the tnps and what you see here is that they are a lot closer to the zero which means that we were really right on in terms of predicting the correction for lacy prk and smile across the board compared to the sagittal one and compared to the refractive power one so that's why you can never use your sagittal from your lens star or from your iol master to predict for you because those are really not going to give you what the trunet power and tc rp is going to give you because the those two are including the posterior curvature those are looking at your you know collective power change we looked at the high myopes again they do a lot better than these two other ones so tc rp and tnp were better we did the same thing for moderate myope which were between minus three and six we see the same thing but then when it comes to low myopes remember that old graph i showed you from 2012 paper of mine it becomes all over the place and that's where if you're dealing with a low myope we should still go back to the good old sagittal because we think the sagittal is better for lacy crp what about smile we don't have enough data to give you most of our patients were harder high myopes and moderate myope so we don't know anything about the smile right now to tell you but nobody is doing the minus one and a minus half with smile most of them are three and four but for low myopes prk and lacy still sagittal and refractive power which is mainly based on the anterior curvature we'll get you by so in summary we noted that lacy tnp at five millimeter prk tnp at five millimeter was the best but not for smile it was tcrp at four millimeter not pupil apex which now takes me to another talk so this apex business is very important when you do rk versus prk versus lacy if you ever want to do calculation you have to look at these factors and for lacy can prk it's five millimeter pupil zone but for smile for some reason it's apex not the center of the pupil and i'll get to that in a second for you guys and this is simply showing you the correlation was very tight for these lacy can smile and for lacy can prk and for smile is actually good it's just that we have less number of patients now let's talk about effective optical zone because that's we're talking about the vertex versus the apex versus the pupil size a pupil measurement when when you use i think you guys use the great platform here ex 500 laser which is usually programmed for 6.5 millimeter but you blend to nine millimeter well if you do that you think you're getting 6.5 millimeter but you're not we're not none of us are and the fact is that the actual zone that you get is a lot less and why is that important that's because some of your patients may have large pupil and what happens if you do a too much of a correction one of my friend was asking me what's wrong with trying to do a eight millimeter ablation zone or eight millimeter lenticule for a smile and i said that's because you have to remove a lot of tissue it's tissue hungry and then what if you do too much too small like we used to do here i remember at moran we used to do with the summit apex plus when i was a fellow 4.5 millimeter optical zone with no transition 4.5 millimeter optical zone with no transition and now we're doing 6.5 with nine millimeter transition so what happens if you do too small decentralization glare halo coma trayfoil everything and what about if it's not centered that even causes more irregular stigmatism and obelisk stigmatism so we wanted to look and what we did we looked at those difference maps and we tried to see if you could estimate the actual size of the ablation and you know vertically and horizontally and we did that and we tried to use both tangential and the tc rp map in order to guess the ovality and the size of this 6.5 millimeter optical zone and we found out that no it's not 6.5 but also it's not to my surprise 4 or 5 it was still better than that and i'm showing it to you here that for lasik and prk when we are doing a 6.5 millimeter zone in reality you're getting somewhere between 6.2 and 5.9 because sometimes they're oval and for prk it's about 6.1 to 5.7 but for smile it was a lot better and that's because you're actually creating a lenticule and you're exercising it and you're taking it out you're not chafing just in the corners and for smile the optical zone was actually bigger you can see that that the actual optical zone here was this red one and if you compare that to the program one this was the program optical zone and this is the actual optical zone and for lasik was the blue one which was the program one and this is the actual optical zone this is showing us that smile gives you a better optical zone yes the effective optical zone which i like to call it true optical zone in smile is larger than lasik and prk but for between lasik and prk there is no difference this is the next finding concerning the smile and lasik remember i showed you that when we do the smile relax procedure smile specifically patient is fixating and if you look here the red is the smile and it always looks more nasal and superior more nasal and superior whereas the prk and lasik they're very centered overall with respect to the center now this is showing you that when you are doing a smile everything is with respect to the line of sight we think the line of sight is closer to the vertex of the cornea that's not really true but that's the best demonstration here that is why in smile everything is always more nasal and a little bit more superior remember that centroid shift i showed you when the patient is sitting on maybe that laser and they're nervous and they're looking at that green light and it's blinking and you're docking that thing on their eyes and you're telling them to look at the light they're always a little bit more nasal and up because they are centered with respect to the vertex whereas in prk and lasik they are they can be looking a little bit off but you are tracking the pupil and by tracking the pupil you are always on the pupil center therefore it looks more like that and where is the real problem thing is that maybe it's somewhere between these two that's where the line of sight is that's why it looks more de-centered with respect to one versus the other so in another word smile is de-centered superiorly and nasally and lasik is de-centered inferiorly and temporally the biggest higher order aberrations that we need to know about is coma truffle and spherical aberration but i still think it's only spherical aberration and coma i do not think truffle is a big deal and i'll explain that to you in a second too crowded but all i'm trying to show you is that this is the paper that we just submitted on higher order aberration and we showed that the higher order aberration change is a statistically significant the larger the smaller the area is meaning that the correlation is negative if the area of your treatment is bigger your higher order aberration is smaller of that of course the case if you have a nine millimeter optical zone you're not going to have any spherical aberration if you can put a lens inside somebody who has cataract surgery and it's nine millimeter optical zone i wish we could the spherical aberration most likely would be less and that's because the larger the area is the less the higher order aberration and this is nicely shown for all of them in in this diagram and what i'm showing here is that if your area of treatment is smaller your aberrations are a lot more and if your area is bigger your aberration is a lot less and that's correlated primarily with spherical aberration which is primarily the q value which is why you always want to in cataract surgery change that it was not correlated with these values to a great extent and that's what we show that the smaller the optical zone the larger the higher order aberration was and this induction can cause mainly by your what we call the z4 on the aberration system we wanted to look at these and everyone talks about smile causing more aberration or lacy is causing more aberration and we really wanted to look at that too in our own little center so we did and we see that yes total aberration goes up goes up goes up now i remember when i used to do summit apex plus we didn't have these devices but because our optical zone was only 4.5 and we thought the patients seeing 2030 should be grateful i don't know why they're complaining because we increased the total higher order aberration by 11 folds that's 1100 percent we increased it for them from going from remember we talked about aberration being 0.3 for young people 0.4 we would take that to 1.8 2.8 sometimes that's because our ablations were only 4.5 but look here with our new platforms and i think that this platform is the ex 500 which is exactly like the one you have up there your aberration increases maybe by 80 90 percent maybe doubles but it's not more than that but it is not less because they are trying to claim to you that your higher order aberration is diminished after contour or after lacy or after prk and that is not the case but the induction is a lot less than ever before what about smile smile also increased the higher order aberration despite the fact that the effective optical zone was bigger spherical aberration same thing almost goes up i'm not going to say exactly doubles but it goes up by about somewhere 50 to 80 percent and the coma lastly here shown that there is increase in the coma for prk and lacy but not for a smile the horizontal coma goes down in smile you know why because the patient is actually looking and you're closer to the vertex that is why there is an advantage sometimes because there is a decline in the vertical coma in the horizontal coma what about the vertical coma vertical coma doesn't increase actually becomes in a magnitude different in a different direction but the coma there is an increase for lacy there is some decrease but you have to understand this does not mean it's a bad thing but for prk did not change so is there a big deal that vertical coma or horizontal coma changes so differently yes it is it is indeed a concern but you have to also understand that vertical coma can be in a different direction and the horizontal coma can be in a different direction so the magnitude can change and it can be advantageous trayfoil it's very difficult to say trayfoil by itself has any clinical value why because when you look at the coma or spherical aberration you were talking about 0.3 micron 0.25 micron difference but when you're talking about trayfoil whether it's oblique or horizontal we're talking 0.03 0.02 0.01 changes that is clinically may not be so tangible to us at this point so we really can't say much about it why am i showing this crowded bar graph to you because i want to show you that if you look in this side horizontal coma oblique trayfoil horizontal trayfoil are really clinically not that relevant but if you look here spherical aberration and vertical coma is quite relevant in terms of the magnitude of microns so you can see that the spherical aberration goes and the coma also changes but the rest is not as important simply showing you that the higher the myopia higher the higher aberration showing you that if your asphericity is in sync with your higher aberration spherical aberration yes it is completely linearly coordinated that's why the bigger the plus q value is the bigger the sa is going to be so in summary we can say that the change in the q value and the spherical aberration are really correlated and we can also say that the ratio of the spherical change the higher aberration is very nicely correlated that's why higher myopes have higher aberration in conclusion yes pupil size and age have correlation we talked about the spherical error we talked about angle kappa we talked about the fact that the refractive error has an impact on them we talked about the fact that keratometry but age and cylinder and attempted correction can affect the sphere the ratio of change in keratometry we also talked about the fact that having a nomogram would make a difference because of that ratio and we also talked about different map differences that can have better predictability especially tcrp and tnp and with the fact that the effect of optical zone it is definitely more in sync with what the reality is and the best way is to look at the not the tcrp map but the tangential map and remember that smile truly gives you a larger effective optical zone but the prk and lasik are very similar despite the fact that there is epithelial remodeling the induction of the vertical coma and the higher order aberration in smile is a little bit more than lasik and prk and this could be due to the fact that we are looking at the center of the vertex of the cornea not the center of the pupil and that may be the reason the numbers look different because most of the aberrometers are with respect to the pupil if the aberrometers were with respect to the center of the site or the vertex maybe the numbers would have looked totally the other way the take-home message is this that i want the residents to respect posterior corneal curvature i hope that they know what the pa ratio is in normal people and i hope that they know that this ratio changes with time and also with refractive surgery and yes it is important to remember that it's not about just the effective lens position that everyone talks about in cataract surgery but also the pa ratio after refractive surgery and that's how sometimes people can that can get hyperropic surprise and i want to thank you all for listening to me and i'm sorry it was not a very interesting talk but i think it's important to have a good refresher on these things sometimes thank you yes amy all right well i want to applaud you for your you and your students analysis of a lot of numbers but i think earlier in your talk you mentioned that you see less flattening of the keratometry values in smile compared to lasik and prk so do you see more myopic regression with smile no i do not see myopic regression with smile and that is the amazing thing if you look at the patients who have had their treatment done so the question was is there more regression with smile than with lasik no there is no regression with smile compared to the others the reason people are undercorrected is because of me because i don't have a good nomogram if i had a better nomogram as a surgeon then i would have known how to compensate for that you have to understand that the anterior corneal 120 micron or more is untouched with lasik and if anything the posterior corneal curvature even though changes just like lasik and prk it changes less and the epithelial hyperplasia is a lot less than prk so you can't say the regression that we see patient comes back six months after lasik after smile for a minus seven and their minus one that's regression no it's because most of i didn't have a good nomogram that is the reality in my opinion ooh maybe there it comes thank you so much that was awesome i might have missed this in all your data and you may have looked at this but one thing i've always wondered about smile is do the stromal layers truly collapse down and create zero space after you take that lenticule out did you see pacometric changes that you felt you should have seen with the level of ablation pattern as well um as you look at your data this is a this is a very very good question is there a collapse in that potential space there's a potential space there that potential space is not going to go anywhere you know until i die most likely so that potential space there is forever right and the way we have to think about it is that if you have a pita bread and you go in there and you take the dough out and you let the anterior lamella and the posterior lamella collapse on one another is there first of all some remodeling there i assure you there is remodeling especially in the periphery especially where that annulus of cut is and yes i'm sure people are going to look at this with confocal and everything else to show what's happening there and people have already done that by the way some of them has been done on rabbit models and all that there is a collapse that's why there is even some strie but the problem is those collapse are more tangible in those double digits and high corrections that surgeons like me do without having any respect for the cornea meaning that if you're doing a minus 13 diopters of course you're going to cause a major gap and sometimes you actually can see it in the periphery but if you're doing a minus two or three with these platforms and by the way there's a subtle difference between these companies you may not see that so my answer to you is that yes there is a potential space yes there is remodeling and as i think it was dr stack would said something about that dissection is there some cutting in that periphery and i also think we shouldn't be so happy go with creating larger flaps because larger caps because some of these platforms you can make a nine millimeter cap and you have a lot more wiggle room in there to do your business i think when you are dissecting the cornea way out like that you are also affecting the risk of ectagia and i still don't think we can say that there is no ectagia with small absolutely disagree with that and i still think that we are seeing some posterior cornea curvature sometimes on those corrections that moshifa shouldn't have done a minus 12 and i did a minus 12 because i wasn't thinking right so the answer to your question is yes there is a collapse of tissue yes there is a potential yes there is remodeling but i think those are more tangible in higher level of corrections just one more question i first i'll smile i think it was the 2018 or 2019 at a meeting in india and i left there thinking what what unique attributes this has that would you know make a refractive surgeon the u.s want to adopt this and so if you're projecting forward five to ten years you know what percentage of refractive surgeons do you think will be offering this on the whole across the country do you think it will just be something at you know major larger centers still trying to really understand what what the unique niches for this in the market i'm sure you all heard the question is smile ever going to capture the lion of refractive surgery which is still lacy i have to tell you this because i remember lacy in its infancy and i saw the trajectory and right now i am doing a study one eye contour one eye smile and i'm also doing another study one eye silk one eye conventional good old lacy and every day carter sees these patients 2015 2012 in the contour eye or the regular conventional lacy guy the other eye 2025 2020 sometimes 2030 the first day week one later a little bit better week four a little bit better month three he just showed me a patient 2012 2012 now think about it four years into smile and we're already seeing 20 over 12 and 20 were 15 and that is not fair we are comparing a toddler a four-year-old five-year-old toddler to a 20-year-old mature kid who has all the whistles on it lacy has everything a lacy can suck the torsion iris registration beautiful femtosecond bubble integrity we still dilly-dallying with the energy on smile we still dilly dallying with the energy on silk and clear so the answer to your question is right now hands down lacy is the pretty thing in the market but smile with time or i should say relax with time is going to take over but internationally i truly think that having one machine and not an excited dimer laser and a femtosecond but one machine to do everything it's so much better and also from a mechanical point of view when patients go home with smile i don't have to worry about them as much but with lacy you still have to worry about once in a bloom on somebody having flaps to this location but the answer to your question is when is that i think some people would adopt to it 100% with time but in my hand i still think that they're a person that i will still do lacy can never do smile on them mixtastic mats and things like that hyperropic smile is not i should say hyperropic relax is not great that's why augmentation procedures would be the way to go so long answer to your question is it will catch but in united state five years from now ask me i would still say we're still making we still paying for our mortgages with lacy then smile okay i've got a basically first comment was very interesting observations microphone here for a second about these important physical and optical characteristics of eyes and their implications for clinical optics and especially surgical interventions that was point one point two a little longer uh dodging most of far's work illustrates the importance of measuring and understanding the smaller less obvious optical factors and interactions measuring and tracking outcomes and satisfaction leads to improvement of techniques and patient satisfaction if you weren't motivated to teach your patients or to teach your refractive or cataract patient well with regard to imprecision or variability in outcomes you should be now are there other questions comments it was thank you so much and i also want to thank mark nifflin for listening to my talk