 Okay, we're going to get started, hopefully right on time, and as you know, thank you for being here early. We'll probably have some people roll in a little later because of the habitual eight o'clock grand rounds, but this is our update, which is quarterly-ish, but this is a refractive surgery update, but really it has very little to do with refractive surgery, but has a lot to do with probably more applicable anterior segment surgery, and what you'll see in clinic and very common problems that people will come in with, obviously, cataracts are super common, and Dr. Hughes-Pak will, hopefully this can be a discussion, and I know with trainees here, please ask all of your questions. We'll have time. We can discuss some of these things, and there's no such thing as a stupid question when it comes to this stuff, and then Dr. Kirshenbaum, our other fellow, wonderful fellow who's now working with me, will talk about a case, and then also a discussion about Presbyopia. Well, I guess you're not talking about Presbyopia today. She's going to give you an update on the EVO-ICL, which is the ICL is an implantable lens for myopia, and there's a new version of that, and she'll start that off interesting case. So I'd now like to introduce the wonderful Dr. Who, and she's going to talk about refractive surgery implications in cataract surgery measurements. All right. Hi, everyone. Yes. Hi, everyone. Thanks. Can everybody hear me okay? I'm projecting off my laptop because I used too fancy of a font, so it's going through me to Zoom now back to you. So thanks, everyone, for coming in bright and early, at least bright and early for me, Dr. Rithwin, and today I'm going to be presenting a, what can be a source of challenge and frustration for some cataract surgeons, which is the topic of post-refractive cataract surgery, or in other words, a day in the life of Dr. Rithwin's OR, and we'll be looking at some cases today. So I just remember last year as a chief resident, one of the dreaded things that I would experience on my VA rotation is getting some patient charts, maybe only a couple days before surgery, doing a chart review, and then realizing that the patient not only had LASIC, maybe even worse, had hyperopically LASIC in the past, and the correct IOL preparations hadn't been made, or even worse, I was supposed to be doing the calculations and I didn't know how, and I didn't really have a good grasp on how to evaluate these patients and to see whether they had LASIC or PRK or maybe even RK in the past, and to be honest, looking back, I don't think that these patients were really counseled properly in a way that I like to review with you today. So not unlike this screen-faced emoji, I felt pretty apprehensive taking these cases on, so we'll go through some of those concepts together. So the number of patients who are now getting refractive surgery is on the rise, and of course, now we are increasingly facing management of post-refractive patients, especially in our cervical practices, and incisional and laser refractive surgery both affects IOL calculations, and determining the K values or the keratometry values and the power of post-refractive. The post-refractive surgery cornea is especially challenging and problematic for reasons that we will go over in just a bit. So for those who aren't familiar, there is an ASERS calculator. They're actually a set of calculators where you can actually input data for prior myopic LASIC or PRK, hyperopically LASIC or PRK or prior RK, and this is what it looks like. Again, if you're not familiar with it, usually somebody will put in, there's three devices that you technically need to input the data for these calculators. Some of them come from topography, such as our Zeiss Atlas. Yes, Chiefs, you do need the Zeiss Atlas topography, so you have to go into the other room at the VA and make them turn on, and then for the pentacam as well, as well as IOL biometrics, such as the IOL master. Actually, one of the founders and one of the founders of many formulas and calculations, Warren Hill, he has said that for experienced surgeons, the accuracy of target within half a diopter of LASIC and PRK patients after cataract surgery is between 65 and 75 percent. Yes, so yes, thank you, Dr. Mifflin. So we're doing pretty good overall, but today we will go over some pitfalls and some challenges to look for. And then again, for those not as familiar, after you input the data, it will actually spit out a couple, a few numbers actually just based on various calculations and various different formulas. And we'll look at some examples, but pretty much as a surgeon, by the time you see this sheet, you're kind of looking more towards the bottom of the sheet where the numeric values first suggest the target are. All right, so again, how can you tell if someone has had prior refractive surgery? So of course, a slit lamp can help with RK incisions and also LASIC, if you can maybe hallucinate that there's a LASIC flap there. But if somebody has had PRK, it's very difficult or near impossible to discern if they've had any prior surgery. So topography is definitely very, very helpful in seeing any ablation patterns and not only helping you tell or not only can you, can it help you tell what type of surgery they have, but what actually type of correction they've had, meaning either myopic or hyperopic. So for example, this one is a myopic pattern. So for those who aren't familiar with topography, the warmer colors are steeper and the cooler colors are flatter. And you can also look at the numbers as well. You can see this is a myopic pattern where it's flatter in the center and then previously steeper or steeper in the periphery. And then for a higher paropic pattern, it is the warmer colors are in the center. So it's steeper in the center and then flatter in the periphery as denoted by these cooler colors. Of course, other challenges can arise. People can have abnormal scarring or de-centration of their inflation or irregular stigmatism. And so these aren't always clear cut examples. It can be a lot more subtle in findings. But this one over here, you can see that this is a very gorgeously centered ablation, very uniform. And I know that because it's actually my eye after I got PRK. So from Dr. Colin, one of our one of our corny fellows last year, and of course, Dr. Mifflin. And then over here, the hyper-op pattern. This is a pretty dramatic, dramatic example for more for teaching purposes, but usually or typically hyper-opic ablations and corrections are lower power corrections. So the findings can be more subtle. Again, so why are these, why are these targets so unpredictable and seemingly so elusive or they can be? And why is there such a lack of precision when trying to achieve a target for these patients? So as I mentioned before, there are numerous formulas that have been developed to calculate IOL power for eyes that have undergone refractive surgery. However, each and every one of these is an estimate and not an exact calculation. So if you think about, for example, a patient with RK after getting refractive surgery, the axial length is not is not affected by refractive surgery. However, determining the keratometric power in the post refractive cornea, that is the biggest challenge. And this is because if you imagine that there's now a smaller effective central optical zone after cataract surgery, especially after RK, this can lead to inaccurate measurements because keratometers and placidodisk based imaging devices will take rings of measurements and sometimes not go quite as close to the center of the cornea and therefore underestimate the power of the central cornea. So you can imagine in this example for a for a post for a myopic correction, it is underestimating the steepness of the central cornea because it is now more flat than would be in a typical cornea. So most generally most formulas in the traditional sense without any reflective considerations will tend to overestimate the power for overcorrection. And believe it or not, this is actually one of a big topic and actually one that was very heavily emphasized on my art hour, most recent written boards, unless I'm just biased from remembering that. But so so hence somebody, you know, it's very, very understandable that people would be very apprehensive to maybe take on these cases. So we'll just go over some cases. So this is a history of a woman who came in, she had 16 RK in both eyes, done 35 years ago, shadow also had a history of mono vision contact lenses. And she also developed two plus cataracts. And this is her. This is her topography. So you can see here again, myopic ablation or myopic correction from RK. So excuse me, not ablation because she had RK center is cooler. So flatter in the center and then super in the periphery in both eyes, you can see it's pretty uniform in terms of the in terms of the pattern and then also also quite center in terms of the optical zone. So for this patient, we ended up aiming distance in both eyes. And some surgeons will elect to to get IOL calculations and measurements in the morning and afternoon, just to see if there's any sign of diurnal fluctuations. So up to 60% of patients will have a diurnal fluctuation where overnight the cornea swells and then and then becomes flatter just because it's swelling of their incisions. So they can have a hyperopic shift in the morning and then become more myopic during the day. In this case, just again, if you're not familiar with IOL calculations, her caretometry values weren't significantly different from either AM or PM. And you can just kind of take a look at the, we usually look at K1, K2, and then also the Delta K as well. But for her, it was not as significant. And then again, this is that, this is that sheet where the ACRS calculator, where we've inputted all these numbers and it's spit out based on these different formulas, a estimation or suggestion for target. And so a lot of surgeons will look at the minimum, the maximum, look if there's any clusters, look if there's any outliers. And then sometimes others will be swayed by certain formulas based on their past experience. Some of our biometrists will put in the Holiday 2, Holiday 2, True K, and then also Barrett True K as well. But for this patient, we elected to choose 24 diapter lens in both eyes for a Plano target. And then this was also something that that we had explained and counseled the patient as well. But so this is her pre-op manifest refraction at week one in her left eye. She was seeing okay, but you can see that she was pretty hyperopic. This is also a known, a known, very short term or known short term phenomenon after cataract surgery for patients who have an RK with the swelling of the incisions and again also the same concept as diurnal fluctuations. More swollen cornea and a more flat cornea with a hyperopic shift. So some of these hyperopic shifts can last weeks to months. So just a lot of pre-counseling to the patient and a lot of, and a lot of counseling during their post-operative period as well. And also a lot of reassurance. So for post-op week one in the left eye, she had a hyperopic shift as you can see. And then for her right eye the first week, she was also hyperopic, a little bit less hyperopic in the left eye and then trending downwards furthermore at her post-op month or final post-op visit for the right eye and then six weeks out in the left eye. She was pretty much pretty close to Plano, pretty ematropic. And she was overall very, very happy with her surgery. She said that again endorsing diurnal fluctuations that we provided reassurances normal. She said that she had blurry vision in the morning with clearing throughout the day, but her vision was very, very good around 2 p.m. So then just some pearls for RK patients. Cataric surgery like I said after RK induces short-term corneal swelling with flattening and hyperopic shift for weeks to months. This is actually a cool kind of graph that I found from a study in 1994 where they studied some, they studied a biological simulation where they actually hydrated a radial curatotomy incisions with BSS and induced a 10-diopter change in the power of the cornea after 45 minutes and then they dehydrated the cornea and it actually went back to its baseline. But overall cataric surgery in eyes of previous RK, they generally do have good outcomes. So a study of one of the most recent studies done in China for post-RK cataract patients in 2016 show that there was a significantly, there's a statistically significant improvement in their in their best visual, best visual acuity. As well as the study also showed, the study actually also looked at 30 eyes with RK ranging from 8 cut to 16 cut and didn't find any significant difference between these. Yes. Yeah, of course. That's one of the challenges. I mean even as a Chinese study showed, typically the acuity is improved with surgery if it's well done, partly because of putting in a more pro-late IOL, we probably won't get into that, but maybe you will. But anyway, paying attention to the aberrations is super important. Yeah, exactly. So for those of you who have a question on new questions for RK patients, typically if it's less RK incisions, you can go between the RK incisions and not have too much worry. I actually think for this patient with 16 cut RK, we did do a clear corneal incision because the incisions weren't so deep on the cornea. You can get into a lot of trouble if you have splayed or gaived incisions or leaky incisions. So many surgeons will also consider a slurral tunnel or at least a grove temporal incision. I'll just comment also. Yeah, Catherine, we've done a couple of these recently and depending on the cornea, these my hopes tend to have big corneas, so sometimes there is enough room to squeeze in between with a two millimeter incision. But as she mentioned, the RK incisions are uniform depth and they tend to shallow peripherally, so many times you can still make a short incision, put a suture in it. I can't remember the last time I did a scleral tunnel on a RK patient. I just do the clear corneal incision and then suture it if I need to. But it is true that sometimes you'll split an incision peripherally and have to be prepared to suture it. And Dr. Lin has a comment too. I tend to be a little more conservative and I do do scleral tunnel incisions. The most recent one I did was two months ago. I think I believe it was a 16-cut RK. There wasn't quite enough room and I actually made ended up making not a scleral tunnel but a limbo groove. So like almost like what we do for a desicc incision. So like a limbo groove and then kind of grooved in with the keratome and that worked out really well. All right. And then case two, this is a gentleman with hyperopically sick many, many years ago. I believe by Dr. Mifflin and then also he had LRIs or limbo relaxing incisions to correct astigmatism. And then he also had a consecutive hyperopia or hyperopia, more regression from his lexic. And so he also underwent conductive keratococlasty or CK in 2014. So for those who aren't familiar, CK is where you actually take some radio high radio frequency and it creates heat and you literally shrink the collagen around the peripheral cornea. Thereby flattening the peripheral cornea and then relatively seepening the central cornea. So it is FDA approved for mostly it's for before for presbyopia, but for low for low power corrections of hyperopia. And of course he also developed cataracts. So this is his, these are his, this is his topography. As you can see, not as beautifully perfectly uniform, but still very centered in terms of the ablation and prior treatment. And you can tell that it's hyperopic again because it's steeper in the center and then cooler or flatter in the periphery. All right, and then these were his calculations. So again we chose just based on what we had previously talked about, looked at all the numbers, see if there's any outliers, see if there's any trends, averages, and we chose a 21 power, 21 diopter power in both eyes. So he's currently, yes, yes, go ahead. Any comment on your choice of IOL of being, it looks like is it an SA-6080? Yes. As opposed to some of the other IOLs we do? Yeah, exactly. So that was I think what Dr. Barlow was kind of maybe alluding to, but the SA-6080 has a negative sphericity. So it counteracts basically the sphericity. Yeah, so with a negative spherical aberration, you typically, especially in hyperopic patients or post-hyperopic correction patients, you would want to put in a lens with a positive, positive spherical aberration, whereas for typically our other cataracts, our other cataract patients, when they have a positive spherical aberration, people put in a negative spherical, a aspheric or negative spherical lens. Yeah, and then currently, he has post-op week two in the right eye, and then this was actually his post-op day one visit. So he's doing pretty well. He's really, really happy seeing that patients are, sorry, he's seeing that colors are amazing, but as you can see from his HPI, he was still wondering about a touch-up for the left eye, kind of being his first day. So again, just we counsel our patients, we counsel our patients with Dr. Mifflin. He teaches them in clinic and we also either he or the fellows or some of our technicians who actually call patients, you know, leading up to their surgery and answer more questions, set expectations, set boundaries of what is possible. You can see that still patients are always maybe expecting more, despite what you've told them. And so actually, as we had talked about this patient's ablation, I'm just going to go back, this patient's ablation was pretty well centered, not as uniform as RK, but relatively uniform, but compare that with this patient. So this patient has a history of monovision, lacy correction with a very decentered ablation. Currently, this patient, he underwent cataract surgery in both eyes. This is him actually a few months out. He's doing okay. He's not doing great. You can see that his refraction is close to the target we wanted in terms of Plano in the right eye and then monovision in the left eye, but he's struggling. He can see pretty well at intermediate distance, but he's still struggling without glasses, with up close and some distance, some distance vision. So as you can see, the more decentered, the more the more unpredictable the outcome can be. And so the more counseling, of course, and setting expectations for patients. There's also another kind of interesting topography of another patient who's had PRK in both eyes. This, I believe this is an eye that has, that still has a charigium, as you can see, very, very irregular. And then also this is another, his other eye actually has had a charigium removal and also PRK. So again, lots of counseling for this patient that a lot of the calculations that we do are estimates, but there's no guarantee in terms of glasses and spectacle independence. All right. And then case number three. This is a patient with monovision lacyc. She has really good near vision currently, but she is developing cataracts and has glares at night. And then we couldn't really tell, she was thinking it was myopic lacyc, but looking at her, looking at her topography. So if you look at the left eye, it does look more consistent with myopic lacyc. Again, cooler colors in the middle, meaning it's more flat in the middle compared to seep in the periphery. But looking at her right eye, it's a little bit funny. It's a little bit more tricky. So it looks, there are some features of myopic ablation, but it looks almost more consistent with a hyperopic correction. As you can see, it's more steep in the center, flat in the periphery, or maybe even more of a mixed astigmatism picture where they're myopic in one meridian and then hyperopic in another meridian. So what did we do for this patient? We actually just got a ton of calculations, as you can see. So we got many, many sets of calculations for both myopic and hyperopic lacyc treatment. And then clustered and saw, again, with all the lens choices, what the cluster was around. So for myopic lacyc, I believe, or myopic lacyc, or PRK, I believe she clustered around 18.5 diopters. And for hyperopic lacyc correction, she clustered around 17.5. So we split the difference and chose an 18.0 diopter lens. And we did choose an SA60-AT lens for assuming that she had more of a hyperopic correction in the past. And we did aim for kind of a more near-intermediate target for her. And we did tell her, and remember distinctly that when Dr. Mifflin went to see her in the PACU or in the pre-op area, he said, you know, it's kind of a fuzzy target. We're just going to aim for the best we can. But as we've talked about numerous times before, this may not be perfect. And so this is post-op week one so far. She's actually, she's doing okay. She says she's adjusting to new vision because, as you remember, she did have a history of mono-vision lacyc and had very good J1 plus or 20-20 near vision in that eye. So she's adjusting to her new vision. She's more close to plano than our minus 1.75 target. And she is not so happy that she's not able to read up close. So again, just kind of the variability and unpredictability of these types of ablations and these targets. All right. And then the last case, this one actually is a little bit of a, a little bit of a jump off topic from pure refractive surgery. But we'll start actually backwards. So this is a patient who came in last week in January, post-op week one, doing really, really well, very happy with his vision. We had a mono-vision target for him for his right eye as near and then his left eye as distance. And as you can see, he's doing really well pretty much right on target. And so if we look at his topography currently, does anyone want to make any comments about it? Any, any residents want to make any comments about it? Any patterns you see? So some, a regular ischic sigmatism overall pretty, actually a pretty good, pretty reasonable topography profile as in contrast to three months ago. This is what his same eye and the left eye looked like. Does anyone want to take a guess about what is going on here? So this is January, this is January, and this is three months ago or four months ago. Yeah, very good. Abigail, so good. So yes, he had a turigium. So you can see, oh, so sorry, you can actually see here that there is some profound flattening and then very irregular ischic sigmatism, of course. You can also see that in the placidodisc images. But yes, this corresponds to a turigium that he had. So he actually presented in September with a three millimeter turigium in the left eye. And so he came in initially for cataract evaluation. So topography was obtained, but we did counsel him that we may need to remove the turigium if it was causing any induced ischic sigmatism or regular ischic sigmatism. So we underwent turigium excision in October 2022, 2022. Then three months later we repeated biometry and also his topography. You can see that that there is a huge difference just removing that turigium from his eye. So also wanted to just take a look at his initial biometry. So this is our IOL master. Again, just attention drawn to a very large amount of ischic sigmatism as measured by the automated keratometer in the IOL master. Contrasting that with January 2023, you can see that he has almost no ischic sigmatism. So just the importance of removing turigium and sending your patient up for success and optimizing their cornea prior to cataract surgery. I know Cole and I had kind of run into a similar situation where we had an outreach patient and it was actually at fourth street and Dr. Lin was staffing us. This patient had a pretty large turigium, very, very dense cataract. And as you know with our outreach patients, it can kind of be difficult to schedule them consecutively for surgery and find our time. And so the question was whether we should remove the turigium or just do the cataract. And of course Dr. Lin correctly had advised that we should definitely remove the cataract sorry definitely remove the turigium first and same situation where he had almost 11 or I think almost or 13 diopters of of a sigmatism and then after we removed it he was closer to closer to Plano or closer to no a sigmatism. All right and then again this is also highlighted in his pentakam as you can see this is prior with his turigium and then also after turigium excited. All right so some key points are council, council, council your patient. As Dr. Lin said you should teach, measure and then teach again and then also be prepared to deal with the patient's unrealistic unrealistic expectations. In terms of measurements of course topography IOL biometry and then also considering a pentakam as well to look for posterior float changes or posterior cornea changes. When Dr. Rifflin counsels patients I really like when he uses the words or very specifically like there's a lack of precision in this process since you've had a prior refractive surgery and there's a lack of lack of predictability with our resources and formulas currently available. Be wary of variables and pitfalls and limitations and also recognize that the two eyes do not always act the same. And Dr. Rifflin do you have a comment? Is it on? One thing too I think is really helpful that I've started doing is just print out a color map and take that to the bedside or the chair side and just show the patient hey this is the shape of your eye we're going to do the best we can and I think that really has helped me teach people that hey it's you know and then you have to explain while the lenses only come in a half a die after and this is your stigma you know it's really helpful I think that visual is helpful you might want to look at the chats while we're waiting I just want to introduce and welcome Terry Spencer who's been back in town for year and a half two years he was one of our residents and came back here from South Dakota welcome Terry. Another thing that I think when Dr. Rifflin says that I think is very valuable is just do no harm and also speak the truth not what the patient wants to hear even though sometimes they will hear what they want to hear again just I think the big takeaway from today is that a lot of these formulas because you're plugging in many different variables from measurements that are inaccurate those then can turn other formulations and calculations and ratios to be a little bit skewed so anything on the cornea that is not perfectly you know symmetric especially from a post refractive surgery can just compound itself and that's why we have such large ranges in a lot of these formulas when we do these calculations so again council council council that's kind of the biggest takeaway from today. In terms of novel in terms of novel technologies there is see here there is a intraoperative wavefront aberrometry device I think we might have had it at the Moran maybe a few years ago and these systems have been shown to decrease residual refractive error in patients who have had refractive surgery basically it's intraoperative real time AFAKIC IOL calculations and they can also be used to refine as a sigmatism with toric lenses however there is debate about their utility with the use of newer generation IOL calculations and formulas but again kind of a cool thing to think about so again hopefully in conclusion you're not as intimidated or have a better understanding about how to approach these patients but you should not feel 100 percent confident because that does not exist there's no guarantee but hopefully maybe you're feeling more like this emoji this melting face emoji you know it's more of a fuzzy target but hopefully with you know proper counseling and discussions with your patient you and them can come to a melting kind of glob of satisfaction with the discussion that you're having so thank you again to of course Dr. Mifflin and the entire cornea team as well as a shout out to our amazing biometrists here in the building they make a huge difference in terms of counseling patients and they're a huge resource for our patients and they do a lot in terms of helping us prepare our cases but also again teach and and counsel patients so with that these are my references and any questions after these post-lazing patients this may be just bias psychological bias post-lazing patients are more likely to see a shift anybody else's observe better seeing that I recall the literature of anybody actually looking at that subject as opposed to very wise but I think it's true and these are formerly myopic eyes so you know I think if you looked at myopes or high myopes you'd probably see the same thing but yeah it's messy data and there are a lot of comorbidities and things like that so it's hard to know but I I think that's true Bill especially for formerly myopic eyes just a comment Dr. Barlow and I were talking before about aura which is the interoperative aborometry and measurement and I think most people kind of decided that it wasn't really that helpful because if it didn't correlate with your biometry in clinic then you didn't usually trust it so kind of one of those things but we need to move on to Dr. Kirshenbaum and we'll try to answer the chats on Dr. Who's Computer while Devina is talking there's a comment from Dr. La Rochelle and we can just go ahead and switch to the to the screen she says I started with patients with multiple enhancements and how to interpret their case yeah okay perfect never mind we weren't yet as we can see he has inferior steepening here in the right eye and then of his left eye even more a little bit he has inferior steepening in both eyes so now looking at this abnormal tomography OU so what are our options and this is not an exhaustive list there are case reports of people doing many different combinations and different types of refractive surgeries but these are the ones that we basically considered when deciding how to make this approach and so I'm just going to go through them one by one so first one you know saying this is too risky let's not do anything for this patient the things that worked against this for this patient was that this is a highly motivated patient he really wanted refractive surgery and he's been seeing multiple people to look at this the next one is LASIC so we're here to say don't choose LASIC in this patient so there actually is the study that I cited on the bottom by buzzard that basically looked at doing LASIC even in stable mild care to conus patients and three out of 16 patients needed to proceed to PK so that's about 18% so these patients you know this is the any abnormal topography is the number one risk factor for post LASIC ectasia so we do not want to do that then PRK so interestingly PRK another corneal ablation procedure but actually these patients can do pretty well after PRK you're still you know removing cornea but and have an increased risk of corneal ectasia but these two other studies by so the first one by Chalala he had a five year follow-up of PRK and 119 patients with mild to moderate care to conus and they actually found that near 70% of the patients had an uncorrected visual acuity of 2020 and only two eyes which was 1.6% had progression of disease at their five year follow-up so they did pretty well similar results also for the study by Gwedge who also looked at a large number of patients with mild to moderate stable care to conus and ended up having very good visual results the other things to consider is now we do cross-linking so it doesn't have to be PRK alone it can be PRK combined with cross-linking and I'll kind of go into a little more detail about what that involves this is of course an off-label use of PRK and also ICL and that can also be with or without cross-linking and this is another off-label use and studies have actually they have looked at using ICL in these care to conus patients and also have found good results so briefly just talk about there's an option to do simultaneous cross-linking in PRK this was popularized as the name Athens protocol but the main thing to really I wanted to point out here so basically they did multiple like a four steps to do cross-linking in PRK in a single session and for a little bit there was a lot of hype that improved top topography but the problem with this study was that they really didn't have a control group they just looked at how these patients did and even in this study they really didn't show much improvement in the visual acuity for these patients and a follow-up study by Iqbal done in 2019 basically showed that when they compared standard cross-linking with this like simultaneous with this simultaneously cross-linking in PRK the patients really had equivalent results into their visual acuity and their topography outcomes so really it was most likely the cross-linking result that they were seeing this study the other option is to do sequential cross-linking with topography guided PRK and this when there was actually study the study by Barton cited below actually compared this to PRK alone and even the simultaneous cross-linking in PRK that we discussed and showed that this has improved visual acuity and improves spherical clovint something very important is that there's increased predictability when you wait between the two you can actually get a more predictable refractive outcome when you wait to do the PRK there is decreased corneal astigmatism decreased in the max K the mean K and the posterior astigmatism and something that was really interesting in the study that compared the three is there is actually no progression seen at all in the group that had the cross-linking followed by the topo guided PRK there's also a decrease in the total higher order aberrations and very high safety and efficacy indices and of note these safety and efficacy indices were highest when the cross-linked was performed the cross-linking was performed before the eczema laser with the period of waiting and the least high with PRK alone as to be expected there is there were seen to be an increased amount of corneal haze we get some of that after cross-linking and after PRK so it's not surprising by combining the two there would be an increase in that and then also as an aside like a totally different thought process is again knowing we have cross-linking you kind of have a safety mechanism or a rescue so you can do the PRK and say listen if we do if we do this PRK and then see that you do have some progression we do have this option of turning to cross-linking so switching gears I just wanted to talk a little bit about the history of fake IOLs and kind of what brought us to this new update so first beginning with anterior chamber fake IOLs in the 50s to 80s this is pictured in this top picture over here so these lenses had angle support and did have complications associated with them such as endothelial failure or corneal edema ovalization of the pupil and disruption of the riddo-corneal angle so because of this basically in the 80s they came out with a few other options the first one being the lenses with iris and clavation which is seen here in the bottom picture commonly known as the varus size was a big one and that that got FDA approval in 2004 to treat like minus five diopters minus 20 diopters of myopia and then similarly the posterior chamber fake IOL so this was really well liked because this basically increased the distance from the endothelium and the angle so more safety looking at all those complications that we discussed for the anterior chamber fake IOLs and basically the progression you know the IOL was first the ICL was first approved followed by the Toric ICL and now we basically all the waiting waiting until 2022 the FDA finally approved the EVO here in the U.S. that was being being used way before this outside the U.S. so the big the big thing and why everyone makes the big deal about the EVO is that there's this central poor seen in the middle that basically facilitates the physiologic flow of aqueous humor so that no pi is needed anymore and what so there's actually five basic pores in the EVO so we have the one in the center then the two other paracentral ones and then two actually one in the leading haptic here and one in the trailing haptic and what's cool about the poor is that of course it reduces the rates of pupillary block because you have that central hole but what it also does is it makes this having the aqueous flow behind the ICL actually causes this like cushion of aqueous to be between the ICL and the crystalline lens and what that's found is that that actually helps prevent cataract formation which was another thing that we thought about with these ICLs and but something to think about having a central poor in the center of any lens there could be or there has been seen to be increased aberrations with this so this lens just to review this actually starts for minus three diopters a spherical equivalent all the way to minus 20 so this could even be thought of as an option for patients with less myopia and for one to four diopters of a stigmatism the interior chamber depth of course has to be greater than or equal to three millimeters and something important to note is this is actually when it's measured from the corneal endothelium to the anterior surface of the crystalline crystalline lens so you have to subtract the corneal thickness from the typical anterior chamber depth that you get from the biometries and of course we want to see the stable refractive history so within half a diopter for one year prior to the implementation so sizing sizing becomes the really important thing with all this and when we spend a lot of time looking at to pick the right lens for the patient so there's four different sizes and what these are are they vary in the overall diameter and was what determines the vault which is the distance between the eye I see on the crystalline lens though there are four sizes we typically use just the middle two and how we do this is there's actually an online system that uses the corneal white to white as well as the anterior chamber depth to calculate the appropriate vault but we also use our own measurements as you know refractive surgery we want all the measurements to kind of compare everything and choose the right option so we use the uvm that measures the diameter of the ciliary sulcus as well some people use the OCT to look at the crystalline lens rise and the angle to angle distance and just looking at a picture here of the uvm so we know what we're looking at so this top photo is basically like the ideal posterior chamber position after the ideal vault after implantation here in the red circles is where the haptics are sitting and they're appropriately seated in the photo B in the middle this is patient with like barely any vault and then C is a photo of excessive vault when the ICL was in normal position so even with the evo of course any procedure we do there are complications first being the refractive outcomes so undercorrection overcorrection these patients will typically develop presbyopia a little bit earlier night times halos and starbursts are a big one as with other refractive surgeries that have to be discussed in advance increased IOP so this is interesting they did a study of 196 eyes and they had one eye that had increased IOP in the evo group even with the central pore and that was because a patient had excess inflammatory debris built up at the central pore and then cataract again we said there's a lot less cataract with the evo but it was seen in about 0.5 percent incidence in 619 eyes but actually even that small amount to cataract they were not visually significant in the studies and then as with any intraoperative procedure infection and inflammation so basically after reviewing all of these different things with the patient and what the best obviously going through the risks and benefits and choosing what the best option was for him he chose to go ahead with the ICL and so just kind of showing a little bit more about like what we used here to decide the correct fault so we have like a caliper also pictured on the left that we used to measure the white to white in the office so we took his measurements here we got the UBMs as you can see here he actually has a very large anterior chamber depth which is great for the ICL but something we want to consider as this patient was using Toric ICL so we just want to make sure that there's not too much rotation which is something we're able to discuss with him um biometry really just pointing this out to show that luckily in this patient which was nice is the white to white was fairly consistent with the other measurements that just go ahead and hand and making us feel more confident in choosing our vault size okay so his surgery went well luckily and no complications just looking at his post operative visit so we first looked at his like one week results for his right eye he ended up 2015 his refraction was planosphere and then looking at his left eye similarly at his one week visit and his right eye in the second week visit he remained 2015 know you with prescriptions being a planosphere so kind of just to summarize the main points that I wanted to bring to all of you to think about when we were like even you know again Catherine made the scary face emoji so just kind of saying like we're approaching these patients when they're asking us questions sometimes we you know the initial response would be like oh no this patient has an irregular cornea this you know it should be an immediate no but of course depending on the patient refractive surgery can still be an option as long as they understand their risks but in in saying so Lasik should never be the option because these patients will their ectasias and their keratoconus can progress PRK can actually be a safe option alone but it's it's nice that we even have cross linking here and again we can even use the cross linking as a rescue if need be and as can be seen ICL is another safe and effective option that we can use for these patients that actually doesn't interfere with the cornea at all any questions thank you yeah I have a comment so I think so the topic of our Grand Rounds today is like updates in refractive surgery so I think with all the new technology doesn't really matter what it is whether it's an IOL calculation formula instrument to measure aberrometry or a device like the EVO ICL I still want to just go back to you know inform consent elective surgery and counteract surgery has become more and more kind of like elective surgery and refractive surgery so it's really really important to just teach our patients and make sure that you truly don't fall into the trap of routine surgery becoming routine because it's only routine until it isn't and about six weeks ago I had my first complication from an ICL patient and went through our redundant and over the top measurements like we always do for this minus 10 person and despite all of our predictions and calculators and everything her lens was just extremely over vaulted and to the to the extent that neither the patient nor I was confident in simply exchanging the lens we just took it out a week later and you know no complication so again I mean she's been a very good sport and she's back in her contacts and but you may get an outlier and when it's elective surgery you know you just need to really make sure that people understand pros and cons you know we've had a rare rare infection from basic or prk we have all probably seen or had complications in our IOL patients at this this point so I guess just one final messages don't let routine surgery become routine in terms of teaching the patient going over the pros and cons of the surgery before you do the surgery when when patients come in and I'm thinking we're going to do an ICL probably the biggest part of my consent process is their visual aberrations after surgery and so I tell them that 100% of them will have glare around lights at night I tell them to 100% expect it the glare that you get with the Evo ICL seems to be a little bit different from the standard ICLs when I think of the glare from a standard ICL their pupil essentially kind of dilates a little bit beyond the optic and so they get kind of a peripheral area of their vision at night where it's not corrected and so they're going to get kind of glare that is sort of like a broader light beam people with the Evo ICL are actually describing a central glare or a central aberration meaning like in the center of their vision they're actually getting a little bit of a weirdness when they look at a light and and some people are thinking that's due to that central hole what I found after I started in planning the Evo ICL is it's actually pretty hard to center these lenses they're really gummy and they just kind of sit where they want to and so it can be kind of challenging to get that hole right in the center of their pupil especially if you've got a torrid component that you're trying to get lined up as well and so it takes a little extra manipulation you have to be super careful with how you manipulate these lenses to try to center it but that's a distinct difference between this Evo ICL and the previous version of the ICL you can no longer order the previous version of the ICL so if you want to do ICL surgery you essentially have to use the Evo so you don't have another option and while it gets rid of the need in quotes for peripheral iridotomies there still are patients that get a little bit of a pupil block and still require a PI so I still tell patients that we may have to rescue them with the a little opening in their iris after surgery so I usually clue in on that with an elevation in the pressure sometimes you'll you'll figure out that they're getting a little bit of pupil block based on sort of vision complaints and and weird glare issues and sometimes I'll repeat the penicam and kind of see what their anterior chamber depth is doing and sometimes you'll see a narrowing of that anterior chamber depth and they might need a peripheral iridotomy so yeah the ICL if you see these Evo patients and you'll be able to see that the central hole really easily and at the slit lamp and it's almost always temporal the lens for most of them in a lot of these if you don't know the lens is put in with the haptics at the three and nine orientation and the Toric lenses are designed to be used that way and they pretty much always sit temporal I don't know but one point I just wanted to make the more broken somebody is the more willing they're are to put up with side effects and you take your minus 15 patient and they have a little nighttime halo-ish thing and they're pretty happy typically but again just goes back to the whole informed consent thing and patient selection and preparing the patient for the expected outcome which I agree with Brian it's like pretty much a hundred percent of those people are going to have some aberrations in dim light or night in my experience yeah I agree I haven't had any pupillary block issues but I definitely have seen a little bit of shallowing of the the enter chamber but I've run into more issues with glare from the prior version of the ICO with the PIs patients having kind of horrible glare just from the PI itself so it's nice to have to kind of trade that for maybe a less severe form of dysphotopsy