to-the-point
Informed Consent
Episode 33

Considerations When Correcting Astigmatism

William Wiley, MD; Kourtney Houser, MD; and Blake Williamson, MD, join Marguerite McDonald, MD, FACS, to discuss the value of toric IOLs, when to use these lenses versus an incisional approach, and how to educate patients about astigmatic correction.

MARGUERITE: How do you educate your cataract patients on the value of toric IOLs to manage their astigmatism? How do you communicate your confidence in the technology? When do you go with toric lenses vs. LRIs?

I’m Marguerite McDonald of OCLI Vision in Oceanside, New York, and this is what we’ll be talking about in this episode of Informed Consent: Getting to Yes.

I have three distinguished guests. First, let me welcome back, Dr. Bill Wiley, Medical Director of Cleveland Eye Clinic in Cleveland, Ohio. Welcome, Bill.

BILL: Thanks, Marguerite. Thanks for having me. I really appreciate it.

MARGUERITE: Next is Kourtney Houser, a refractive surgeon at the Hamilton Eye Institute in Memphis, Tennessee, where she is also an assistant professor of ophthalmology in the Department of Ophthalmology at the University of Tennessee.

KOURTNEY: Thank you so much for having me.

MARGUERITE: And finally, I’m very pleased to have a key opinion-leader in this area, Blake Williamson, who is a refractive and cataract surgeon at the Williamson Eye Center in Baton Rouge, Louisiana.

BLAKE: Thanks for having me, Marguerite.

MARGUERITE: Before we get started, I’d like to ask each of you to describe your practice. Let’s go in reverse order. Blake…

BLAKE: Yeah, so we are multi-generational, family practice. We started about 75 years ago with my grandfather, who was an O.D., actually. He had four sons. All four of them went into ophthalmology and they're all practicing at Williamson Eye, or have for a while at least. Um, and then I'm a third generation. We have about 120 s- five or so employees. Uh, 10 optometrists, uh, four surgeons, seven locations and an in-house, uh, ASC. So, uh, a pretty, uh, pretty large vertically, uh, integrated practice down here at South Louisiana.

KOURTNEY: So, I work at, uh, a private practice with the university. So, I have residents and fellows with me, which I love having. And I also have two locations. I work at our downtown office in a satellite office. Um, most of my practice is cataract surgery, but I also have some refractive and cornea surgery mixed in, as well.

BILL: I practice in Cleveland Eye, uh, in Cleveland, Ohio at Cleveland Eye Clinic. And the majority of what I do is, is cataract refractive surgery. Initially we kind of had two separate practice entities, more of a refractive, you know, LASIK practice and then our traditional cataract practice, and then as we've all seen over the years, cataract surgery has transitioned to truly, an extension of refractive surgery. So, we try to look at every cataract patient as truly, a refractive surgery and make sure that patients understand what they're getting into and we try to meet those goals and meet the refractive goals.

We've got great technology now for basically almost any situation that may present itself, and I think it's a great time to be a provider in trying to reduce astigmatism and achieve those patient's refractive goals.

MARGUERITE: So, walk us through your thought process, Bill, if you will. When you see someone with just a small amount of astigmatism, do you do femto AKs or manual AKs? When do you say, "This is toric for me?"

BILL: I personally use a lot of interoperative aberrometry to help guide my astigmatism choice. So usually, I'm not making a final decision on which lens I'm going to choose until I'm in the operating room. So often, I'm walking into the operating room with both a monofocal or a toric lens, and depending on what interoperative route, interoperative aberrometry shows me, if it's more than a diopter of astigmatism, I'm going to use a toric lens. If it's less than a diopter of astigmatism, I'll do a manual LRI.

KOURTNEY: So, whenever my cataract evaluation patients come in, I make sure I evaluate the surface. I get typography, optical biometry, and also pay careful attention to their current refraction as well as their habitual glasses prescription. I review all of that information before I go in to talk with the patient, so I have some ideas of what I want to talk about. I bring all of the testing in with me to speak with the patient, as well, so I can show them the images.

But if I see someone that has about .4 diopters or more of against-the-rule astigmatism or about 1.7 of with-the rule, that's when my mind starts to think that I want to probably go with the toric, assuming it's regular and everything else looks normal on exam. If I have less astigmatism then that, then that's when I start thinking about doing a limbal relaxing incision. I prefer to do a femto LRI just because I feel like it's a little more accurate. And that is one thing, I think, with confidence the femto can do better than my hands with a manual LRI.

I do, however, do manual LRIs for some oblique astigmatisms that I have post-operatively. If it's consistent with the refraction in a post-op phaco, I will do a manual LRI in the clinic to touch up some of their residual astigmatism if needed.

BLAKE: Yeah, so, usually, with anybody with any reasonable amount of astigmatism, I'm actually talking to them about the light adjustable lens these days. But- but, uh, before that or if I didn't have access to that, usually the cutoff is about 1.5 for me. Uh, anything in that one, two, five to 1.5 range is when I'm going to kind of start talking about it, especially if it's against the rule.

Um, I find that with against the rules, uh, cylinder with my femto-AKs or my catalyst, you know, those very large incisions when you get up to over a diopter of Cyl against the rule, and that's right where my keratone's going to be, so I really don't like doing that. So, for against the rule cylinder, that one to one, two, five, I'm kind of talking to them about toric lenses. If it's- if it's with the rule however, right there around 90, I'll go up to about 1.5 before I convert them over to a toric lens.

MARGUERITE: And below that, do you like, uh, manual LRIs or do you like femto? Or do both?

BLAKE: Yeah, w- we use exclusively femto, uh, on- on the Catalyst. We stopped doing manual LRIs the day that they installed our Catalyst.

MARGUERITE: Same here. (laughs) So how do you approach the patient?

Could you pretend I'm Mrs. Smith and I have two and a half diopters of astigmatism, and you want me to have a toric? What would you say?

BLAKE: Yes. So, I'd say, "Listen Mrs. Smith, um, you have two issues. I want you to understand that you have two different problems that are affecting your vision. The first is your cataract. The second is something called astigmatism. Now, Mrs. Smith, you probably heard of astigmatism. What it means is that the shape of your eye is a little bit steeper than normal, and so it bends light rays a little differently and vision gets a little blurry. In order to fix your vision all the way and not just fix the cataract, we're going to have to address your astigmatism too.

Mrs. Smith, I want you to know something, you're going to have to make a choice. You have to fix your astigmatism one way or the other. Either we can do it after surgery with a new pair of glasses or bifocals or contacts or, if you'd like since you're already on the table anyway, we can just fix it right there with a toric lens implant. By doing this, this is going to provide you a lot of freedom from glasses after surgery at distance. I don't think you're going to have to wear bifocals."

KOURTNEY: Okay. So, Ms. Smith, I see here that you are having some trouble with your vision. You're interested in seeing better. I'm sure you've most likely heard that you have astigmatism whenever you've gotten your glasses filled. That means that there's nothing wrong with your eye, but you have a little bit of a funny shape to your cornea. And it means it's not quite like a baseball. If we decide to take your cataract out, you're going to be happy no matter what we do. But if we want to get you your absolute best vision without glasses then we will want to consider correcting your astigmatism. And if, uh, that is something that you would like to try to be out of glasses after your surgery, which you're probably used to wearing, then I think we can really improve the quality of your vision with the astigmatism correction.

BILL: What I would say, I'd say, "Mrs. Smith, you know, you have a fair amount if astigmatism. There's a number of ways we can correct that. You know, uh, thankfully, through cataract surgery, we have the ability to, uh, reduce or eliminate an astigmatism with functionally, a goal of getting you better vision without glasses. And if your goal is to see not only more clearly, but see more clearly without glasses, I strongly recommend that, uh, you choose, you know, astigmatism correction with your cataract surgery. We can do two different techniques when we do astigmatism correction. We can do, you know, a one-focus lens to give you great distance vision and then you'll wear reading glasses, or now we do have the ability to just treat both distance and near with it, with a multifocal lens, uh, and have astigmatism correction incorporated so that you could see clearly distance and near without glasses.

If you don't mind wearing glasses after surgery, what I'll recommend is just more or less a basic, you know, cataract surgery, but if your goal is to see better without glasses, I strongly recommend astigmatism correction.

MARGUERITE: How about, uh, multifocal toric implantation?

KOURTNEY: If we're going to put in multifocals, astigmatism correction is absolutely required. I think a multifocal can offer patients a lot of glasses independence and improvement in their life. But if you leave astigmatism, then the image quality just is significantly reduced. And so, it's, uh, imperative to correct it. And the reliability of a toric lens when possible is so much better than with a peripheral corneal relaxing incision. So, I think if at all possible, including your astigmatism correction with the multifocal, um, that's how you're going to increase your patient's satisfaction.

MARGUERITE: When you're approaching somebody for a multifocal toric, do you start off explaining the multifocality and then talk about the toricity? Or which do you approach first?

KOURTNEY: So, usually my discussion begins with the multifocality going in. I've looked at their, I usually get an OCT on these patients, as well, so I know in my mind if they're going to be a good candidate going on. And I start with asking them their value of glasses independence. If they're going into this hoping to have as much independence as possible, depending on their needs, then I will tell them, "Okay. Well, we have a few options. If you would like to just have some independence at near, we have options of multifocal, trifocal, bifocal, and some extended depth lenses." And if they say, "No, no, I definitely, um, want to just see distance and wear readers." Then I will say, "Okay. Well, we can do that, but we should also correct astigmatism."

KOURTNEY: If the patient does express some interest in getting independence from glasses for near, which often they do, then I'll go over the options. And then say, "In addition to correcting and giving you some near vision, it's also important that we correct your astigmatism. And lucky for you, we now have the technology to do so with one, one procedure."

BILL: It used to be if somebody had a lot of astigmatism, we, we had to kind of go through that with the patient and say, "Well, we can correct your distance, but we're probably not going to be able to correct distance and near." What's great now is we have presbyopic torics or monofocal torics and, uh, and then kind of an offshoot, a little bit of a side topic. We now have the adjustable, uh, lens that can treat astigmatism as well, which is, in a way, is a toric lens as well.

BLAKE: So, we- we just, we, uh, we just launched the uh, light adjustable lens here in Louisiana, uh, a few months ago. We have the only laser down here, so we've been getting patients from all over. A lot of post-RK, you know, post-refractive patients that, you know, that- that have heard about this and yeah, but- but even though you do, you hear about a lot to nail monovision or to nail that post-refractive patient, I keep telling people it's a great tool just for astigmatism itself.

Because if you think about it, Marguerite, I mean you know, how many times do you put in a- a- a toric lens for that patient who has two diopters of cyl, how many times do they have zero residual cylinder? Pretty rare. They may have like a quarter or a half diopter, right? And they're happy, no doubt about it. But it's the difference between 20 happy and 20 ecstatic is when you leave them with zero. And to me that's where the light adjustable lens comes in. There's a lot of, you know, there's a lot of extra chair time and a lot of extra visits, there's no doubt about it, but- but if you really are seeking that perfect, you know, 20 ecstatic outcome with zero residual cylinder, this is what I'm talking to patients about now.

MARGUERITE: It is so time intensive. Do you find that your practice has to, of course, charge more for that versus a standard toric?

BLAKE: So, it's a great question. We actually do charge more. It's about 50% more to get the light adjustable lens than it is a, uh, standard toric lens, which is combined with femto and all that. Um, and actually because of the amount of visits that patients have to go through to do that.

MARGUERITE: Now, over the years, toric IOLs have improved in design, of course. And the chance of a post-op rotation is really dropping. Um, I think there's some design features that have helped with that. Don't you agree?

KOURTNEY: I think across the board, we've made a lot of improvements in our astigmatism correcting lenses, so that's a lot less of a concern.

BILL: I agree. I think we've come a long way.

From what I can tell, any of the modern, uh, toric lenses available are gonna have a very low rate of rotation.

MARGUERITE: Do you find that you have to take your own incision into account? Is there any impact from your incision that you can predict and put in your formula?

BILL: Yeah. I, it's interesting. I, I've seen over the years, we've had differing thoughts on that and we, we initially we saw a fair amount of variability in surgical induced astigmatism, where we had a wide range from, uh, uh, as little as zero, you know, induction of, uh, astigmatism to as high as, you know, a diopter. And, uh, so we had some inconsistencies there. Now with intraoperative aberrometry, a lot of that's taken into account, where, you know, where we're, we're taking the reading afth- after the incision's been made and so we can use that into the calculation.

Also, I think a lot of the variability in the past was also a posterior corneal astigmatism, which we didn't have a great way, and we w- well, number one, I don't think we really understood that it was even there, and so we weren't measuring it or weren't considering it. And now with the Baylor nomogram, at least it goes into our consideration. Preoperatively, we also have the, you know, the newer biometry devices, can help estimate or measure posterior corneal astigmatism.

KOURTNEY: The, um, posterior cornea is really important in judging how much astigmatism to correct. If we base just on the anterior cornea, we're going to really underestimate the against-the-rule and overestimate the with-the-rule astigmatism. So, in order to take that into account, you have to divide them into two groups basically and treat them differently. So that's why your threshold for a toric is so much lower, um, for against-the-rule.

MARGUERITE: That’s an excellent point about taking the posterior cornea into account. And I’m afraid that’s where we’re going to have to leave it. Thank you all so much for participating.

KOURTNEY: Great. Thank you so much for having me.

BILL: Thanks so much, Marguerite. It's great to work with you. It's, uh, an honor to be on here with you. Thank you.

BLAKE: Thanks, Marguerite, I appreciate the opportunity.

MARGUERITE: You are all welcome. And to the audience, thanks for listening to Informed Consent: Getting to Yes. Stay well.

8/17/2020 | 15:53

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