Up Close with Presbyopia Solutions

Greg Parkhurst, MD, speaks with Gary Wörtz, MD, to share his experience with cornea-based treatments for presbyopia correction. Dr. Parkhurst highlights three key milestones in vision development and explains the ever-growing options available to surgeons to address the aging eye and achieve optimal refractive outcomes.

Gary Wörtz, MD: Open. Outspoken. It's Ophthalmology off the Grid—an honest look at controversial topics in the field. I'm Gary Wörtz.

A universal condition that results from aging, presbyopia, quite simply, is a fact of life, which can be quite unsettling. That 40-year-old patient with 20/20 vision and a chief complaint of sudden unexplained vision loss usually isn’t ready to hear what I’m about to tell them. And I’m steadily approaching that milestone myself. Like the sharp hearing, elastic skin, nimble joints, and overall resiliency that marked our golden days, our eyesight, too, eventually falls victim to Father Time.

Given that presbyopia will affect everyone eventually, this condition represents a major unmeet need in ophthalmology. In recent years, thankfully an increasing number of treatments and technologies have been developed to aid our presbyopia-correcting pursuits.

To learn more about options available to us, I spoke to Dr. Greg Parkhurst, a successful refractive surgeon, to learn more about his experience. Greg shares insights into his practice, including his approaches to various patient groups, and discusses the three milestones in vision development. We’ll also hear from Greg on finding those perfect “unicorn” patients in the quest to correct presbyopia.

Here’s Greg.

Speaker: Ophthalmology off the Grid is an independent podcast supported with advertising by Alcon.

Gary Wörtz, MD: Thank you all for joining us today for another episode of Ophthalmology off the Grid. This is Gary Wörtz, and today we have Dr. Greg Parkhurst with us. Greg is from San Antonio, Texas, and practices at Parkhurst New Vision. Greg and I have had some great conversations over the past year or so, and always enjoy getting his perspectives on sort of the new latest and greatest techniques. And so, Greg, thank you for joining us today.

Today we are going to talk about the Raindrop. But, before we get into that, give us a little bit of an overview of your experience as a young ophthalmologist, who is, sort of, out there, doing lots of good things. Tells us a little bit about your practice, and then we'll get into talking a little bit more about the Raindrop.

Greg Parkhurst, MD: Yeah, absolutely Gary. Well, thanks so much for inviting me to join you on this. You know, as far as my practice, primarily I'm a refractive surgeon, so, you know, I address almost, or approach almost every patient I see with kind of my refractive surgery hat on. So, that includes all patients. You know, if they are kids, I think about them in terms of where they are on their ocular maturity growth, and when they are going to become eligible for a procedure. When they are old folks, and have cataracts already, I approach their cataract treatment plan from a perspective on how to give them the best quality of vision, and less need for glasses. And then, certainly, for all the patients in kind of LASIK and presbyopic demographic. We're always looking at solutions to give them the best quality vision, at the same time, hopefully not have to be dependent on glasses and contact lenses.

So, the practice in San Antonio, it's a lot of refractive surgery. I would say the practice is about 50% cataract, but almost all of those are refractive in nature. And then the other 50% of the practice is devoted to laser refractive surgery, phakic IOLs, inlays, refractive lensectomy, and so forth. Also, we do a lot of work with optometry, so my practice is actually physically connected to the Optometry College in San Antonio, it's called the University of Incarnate Word. It's a newer OD school. It's only been around about ... I think this is their 7th year now. And we have four optometry students, 4th years, rotate through our practice full time. They spend about a month, and it's now a mandatory in-house rotation for every graduating student to spend a month in the refractive surgery practice. They get to see all the pre- and post-op care. They see the procedures done, so a lot of teaching going on in the optometric perspective.

And then, also, a lot of our patients are coming via optometric referral. So, I would say a good, large majority of the patients that are sent for cataract treatment are comanaged with optometrists in the community, and a good portion of refractive surgery as well. So, that's kind of a quick overview of the practice.

Gary Wörtz, MD: Well, that's great. And you're in a very enviable position with lots of refractive cataract and lots of corneal refractive surgery and opportunities. And also, I think opportunities to teach. I think that's really great.

But, obviously with this type of a practice there's a huge unmet need that's being, I guess, attempted to be met in multiple ways, and that's the unmet need of presbyopia, which we know is really the largest disease, if you want to call it a disease, in the world. With every patient who reaches 40 to 50, getting it in both of their eyes. So we know that presbyopia is a huge unmet need. I think as ophthalmologists, maybe in the past, we've sort of downplayed this as a disease. We've downplayed this as an unmet need. We've just sort of put it in the corner of, you know, go get reading glasses; that's not that big of a deal. And, at least, that's the way some of our profession approaches presbyopia.

But it seems like others are really willing to push the envelope. Whether that's with multifocal lenses, extended-depth-of-focus lenses, monovision, surgical options. And now we found ourselves even with a new category of solution, which is the inlays. And, we know the Kamra has launched, and a lot of surgeons are doing that, experiencing good results with Kamra. We also know there's lots of multifocal and other lenses that are coming out.

But I want to talk a little bit about Raindrop. Which seems to be another type of inlay, not like the Kamra; different mechanism of action. And maybe it has some distinct advantages, and perhaps disadvantages.

So, Greg, I's really like to approach this, if you would let me, as a skeptic. And not to be cruel or unusual, but I want to kind of really get to the meat of why you like Raindrop, or what your experience has been with Raindrop. And who are those patients, and how do you make that decision between maybe doing a different procedure or different technology, and where does Raindrop fit into your practice?

So, with all of that preamble, let's just start by saying: give me the ideal patient for a Raindrop. You probably have lots of patients who, maybe, could go either way with different technologies, but when you see ... Or, who's the patient that walks into your office and you say "all right, this is going to be a great patient for Raindrop" no question about it.

Greg Parkhurst, MD: Yeah, absolutely. And there's an immediate picture that comes to mind when you ask me that question, and it's actually a unicorn. We actually joke in the office about "All right, we found one! It's the Raindrop unicorn!"

Gary Wörtz, MD: Tell me about the Raindrop Unicorn.

Greg Parkhurst, MD: So, there's Kamra unicorns, too. But the Raindrop unicorn is an early presbyope. So, they are probably mid 40s, and they are a little bit hyperopic, and they've never had refractive surgery before.

Gary Wörtz, MD: Okay.

Greg Parkhurst, MD: So, what we found with Raindrop is that these patients do best when they have a little bit of preexisting hyperopia, so in fact, the ideal existing refraction in my practice is about +1 sphere.

Gary Wörtz, MD: Really? Okay.

Greg Parkhurst, MD: In my experience, the Kamra unicorns, I meant to say, also never had surgery before. But their existing refraction is slight myopia. And what I mean by kind of unicorn, means we can just do one procedure. We are not combining with anything else. All they need is this inlay. And that preexisting refraction needs to apply.

The other thing is that these patients can't be too far into dysfunctional lens syndrome. So whether they are Kamra patients or Raindrop patients, we're doing HD Analyzer scans. And Ideally we like to see the optical scatter index score less than 1.0. We see plenty of patients that come in with just presbyopia, maybe they're 60 or up. Usually their OSI score is going to be greater that 1, and we consider those patients to be better refractive lens exchange patients.

Gary Wörtz, MD: It sounds like the HD Analyzer is really decision-gate for you all, in terms of go/no-go inlay vs. a lens-based procedure. Fair?

Greg Parkhurst, MD: It is, absolutely. So we're really glad we have the HD Analyzer. We got it primarily when we started doing Kamra, but no so much as a centration. I mean, its used for centration, the Kamra. But, as you mentioned, even more importantly it's a screener. And I've actually been surprised, getting used to using that technology, how many patients out there have preclinical cataracts. Meaning, look at the slit lamp and you're like "Oh, man, this lens doesn't really impress me in terms of it's cataract nature.” But then you put them in the HD Analyzer and you see all this light scatter and you kind of hear from them what it is they are talking about. Their night vision is not as good, they need more light to read. You know, they are visual acuity when they are looking at a, you know, sometimes a slide presentation if they are in a business that requires, you know, PowerPoint.

And then you can kind of understand from the patient's perspective why they are talking about their vision not being as good, but yet we don't really see an obvious cataract yet. So, yeah, we are using HD Analyzer a lot. It's not a tool that says "you are a candidate for surgery, or not", but it's a tool that says which procedure fits your eye the best.

Gary Wörtz, MD: Right.

Greg Parkhurst, MD: Because we look at every patient from the perspective of what we've been calling in the Refractive Surgery Alliance, we're calling the Three Milestones of Vision Development.

The first milestone is ocular maturity. That means it's a full grown adult. Their vision or myopia is no longer increasing. Their prescription is stable. Along with full grown adults there is a set of procedures most applicable to fixing at ocular maturity.

Second one, presbyopia. And now it's great that we have a couple of inlays, and another one coming down the pipeline soon, to add to our toolbox to address that second milestone in vision development.

And then the third one, of course, is cataracts. So, the beauty of it is we have procedures, a total of seven now, so there are seven procedures now to address the three milestones of vision development. And the Raindrop as well as the Kamra Inlay are very important parts of that treatment plan.

Gary Wörtz, MD: Okay. So tell me a little bit about your experience with, you said there is a Kamra unicorn, those ideal patients tend to be more biopic. The Raindrop ideal patient, more the hyperopic side. Will you use those inlays in that way if you just find someone who is more myopic, you may switch over to using a Kamra, where as if they are a little more on the hyperopic side. Is that decision tree for you as well, kind of where their baseline refraction is or would you just go ahead and touch them up with the laser and use the inlay that you prefer?

Greg Parkhurst, MD: So, I do use preexisting refraction to help direct me towards which end I'm going to use. If they're low hyperope, they are great Raindrop patients.

Now, it turns out there's a lot more hyperopic unicorns out there, feeling the pain of presbyopia, just by definition.

Gary Wörtz, MD: Sure, sure.

Greg Parkhurst, MD: So, a young, low hyperope is going to manifest their presbyopia in a more significant way, at a younger age. So, you know, pre-stage to dysfunctional lens syndrome. The low myope are kind of functioning a little better, so they tend to present a little older if they have myopia. But, yeah, we do use that as a tool to help guide us. And, you know, another thing that's different about the two inlays right now is that Kamra is widely used in combination with laser vision correction. So, you can do a LASIK to treat astigmatism, or whatever the refractive area is, and then go ahead and add a Kamra to that.

I predict that in the future that will likely be the mainstream way of using the Raindrop as well, but that Raindrop is a little bit further back in time and development, in terms of working out the details of combining it with laser vision correction. So, so far we are not combining the Raindrop with laser vision correction. They need to be, just according to FDA Approvals, they need to be ideally an ametropic low hyperope, haven't had prior surgery, or otherwise a great corneal laser vision correction candidate.

Gary Wörtz, MD: So, one other question is, what is your depth of your pocket that you're using? I know with the Kamra, there was some that kind of evolved. So, what depth are you using for your pocket?

Greg Parkhurst, MD: So, for pockets, with Kamras, we want to leave, we want to go two thirds deep in the cornea, at least. With Raindrop, we're actually still doing it under a flap, which is also with the FDA Approval. So, you know, I've been involved in what is currently the pseudophakic clinical trial for Raindrop. And with those pseudophakic patients, we are investigating using a pocket. But that's another one that hasn't completely worked out yet, in terms of using Raindrop for the pocket. So, it's primarily done in a flap. And the most common flap thickness I'm using with Raindrop is 180 microns. It's a pretty thick flap.

Gary Wörtz, MD: Okay. So it's a thicker flap than we would typically use. I'm using like a 110 flap right now with my LASIK patients. So the thicker flap, but it's not a pocket.

Greg Parkhurst, MD: Correct. Now in the pseudophakic clinical trial that I alluded to, we're targeting two thirds depth in the cornea, and we're still seeing that the Raindrop has good effect, up to about between 200 and 220 microns deep. But, you know, I think you mentioned early on in the conversation, Kamra has, obviously, different mechanism of action, with kind of that pin hole depth of focus versus the Raindrop is creating a pro-focal cornea by making that little central bump. So the deeper you go with Raindrop, there is a depth where you don't get the same effect. So, you know, you want to get deep enough to get as below as many keratinocytesas you can to limit a risk of haze, but you cannot go so deep that you start to lose the effect of the inlay.

Gary Wörtz, MD: I got you. As I was kind of doing a little bit of research on this, this is interesting, because this is not a refractive lens as we would typically think about that. Am I correct in saying that there's really no refractive power? It's basically a hydrogel, that's basically like a soft contact lens, almost 80% water. And it's the same index of refraction as the cornea, or at least similar. So it's almost like we're adding tissue to the cornea to make a little pro-focal or multifocal bump. It almost reminds me, in some way, of the old Crystalens HD, where they kind of had that bump on the surface. Is that a ... Tell me, is that a correct assessment?

Greg Parkhurst, MD: Yeah, that's right. The other thing is it's similar to some of the old, like if you were ever using LADARWave in the past, they had that issue doing LASIK with leaving central islands. It's almost like that, where it's actually increasing spherical aberration to increase depth of focus by creating this hyperprolate cornea, centrally.

But the bump is only 2 mm in diameter, so that the peripheral cornea is still focused at distance, and then there is kind of a transition on in between, for intermediate vision.

That's kind of how it works. It does work extremely well. One of the things that we've been excited about is that, even on postop day 1, the patients are reading J1J1+. So, I don't think we often saw that with Crystalens, where the distance vision can be excellent, and the very close near vision can be J1+. There is a little more to it than that, but it works great.

Gary Wörtz, MD: So, would you consider this a multifocal cornea that you are creating? And if so, I know there is at least some question out there about glare and halos and the other time of multifocal symptoms. Tell me about your experience with that, with your postops.

Greg Parkhurst, MD: So, surprisingly, glare and halos have been minimal to none. And, you know, when I started using it, I kind of thought of it as multifocal optics. In fact, I even used to show patients a model of a multifocal eye well that I had. A big model I could show them the rings and say "Basically, what we are doing is taking this idea and putting it on your cornea". And surely even with the most recent multifocal lenses, which are really good now, we still hear about glares and halos, especially early on, the first 2 or 3 months.

You really see very, very little of that with Raindrop. And I think there is a couple of reasons.

1. There's only 1 ring to it, right? I mean, there's not like these concentric rings going on in diameter, it's only one.

Second thing is it's only done in the nondominant eye. So, the dominant eye is left untouched. The distance and quality vision in that eye is the same as it always was.

And then, finally, it actually is a different mechanism of action from what you think of with a multifocal. And a term that's been coined for this is a Raindrop term is "Pro focal". So, it's just kind of creating this hyperprolate cornea that's inducing circle aberration to get a bigger range of focus. And it's not exactly the same kind of mechanism we think of in terms of putting multifocal optics in the eye or even in the cornea, like you think it with intracorneal.

Gary Wörtz, MD: Okay. Well, I will be interested to learn more as time goes on. With that, I kind of understand what you are saying, and it will be interesting to kind of see how patients do, and whether or not we have those issues. But I'm glad to hear, in your practice, sounds like it hasn't been much of an issue.

You know, one of the things that I have in my mind, just as a question mark, because, again, I have not been one who's been diving in to this technology. I have not done Kamra and I have not done Raindrop yet. I am kind of considering it, but I'm still in that questioning phase. Why not just use your laser? Why not just use your excimer laser to create a monovision effect?

We all know that monovision, or creating a steeper cornea with your excimer laser is prone to, not quite as much accuracy and long term effect as, obviously, flattening the cornea with a myopic treatment. But, nevertheless, you have a great tool that can reshape the cornea. What is in your mind, what do you, maybe, default, or why would you go with Raindrop over just using your excimer to create a monovision effect in the non dominant eye?

Greg Parkhurst, MD: Well, there are a lot of people out there that don't like monovision. So, it's not necessarily a default, we still offer monovision for those patients who know they love monovision, and for example, they've been wearing monovision contacts for years and they just don't want the hassle anymore ... Those are great monovision LASIK patients. But for those patients that never really did like monovision or don't like the idea of the trade off, or they're giving up there distance to back their near. This is a technology that's reversible, can also be done on the cornea. And you get back the near without having to give up distance.

Gary Wörtz, MD: And I guess that's the real, the key to it then. So, do you feel like your patients are ... How much distance vision are patients giving up, if any, with Raindrop? Are hey losing a line or two or is it like they are not giving up any distance vision, and just gaining the near?

Greg Parkhurst, MD: So, binocularly they give up zero lines of distance. In the eye treated, on average, they give up one. But they gain five lines of near, so there is a huge benefit in terms of what they got versus what they gave up.

If you look at monovision, it's more like a one-to-one line. You basically trade one line of distance to gain one line of near. Here you get five, and only give up one in the treated eye. But both eyes open, you haven't given up anything. So patients are able to fuse that, their nondominant eye or, excuse me, their dominant eye, they still see as they always did. Their nondominant eye, they gave up almost nothing in the distance but they got back all this near. What patients tell me when we've trialed, you know, we do demonstrations of monovision before we do that with LASIK. We've been doing that for years. And what we heard back from patients when we were doing this kind of monovision or blended vision demos, a lot of them would say "You know what, this is fine for my near, but I don't really like that I have to give up my distance vision to get there. I still feel a little bit on the whack with this".

So for those patients that don't like that about monovision, this can be a great option.

Gary Wörtz, MD: So, this is something you say that patients really adapt to quickly, they give up, maybe a line in their nondominant eye, gain five lines, and fairly well accepted in your practice?

Greg Parkhurst, MD: Extremely well.

Gary Wörtz, MD: Okay.

Greg Parkhurst, MD: In fact, just even the message that something out there exists for presbyopia has driven a lot of people in our doors. You know there are so many myths out there about refractive surgery. Basically, the whole market thinks that refractive surgery is just LASIK. The market does not know that there's even other things, you know, there is actually seven procedures that we do, but our community only knows about the one.

So, this technology breaks down some of those myths. One of the myths is that "oh, I had LASIK and now I'm presbyopic and my LASIK wore off and it gave out on me. So I need to get LASIK repeated.” Or the other thing that they think is if they get LASIK they are going to trade their distance for their near, and they are going to still have to be wearing glasses.

One of the nice things about adding the Raindrop to our technology, is just the message to the community that says "hey, guess what guys, we've got a technology where you don't have to wear reading glasses, you can see both near and far, works great for both.” And they are like "Man, I want to know more about that.” So, what it's done is it's drawn a lot of people into the practice. Some of them end up sticking with the monovision they have been wearing, after they hear what the options are.

Gary Wörtz, MD: Sure.

Greg Parkhurst, MD: Some of them we do an HD Analyzer, and we see they've got cataracts, and we're like "Hey, guess what, we have a solution for that. In this case it's not going to be Raindrop, but we've got an option for you to get what you are after.”

So, it's been ... And then, for those Raindrop unicorns that come in, they are super happy. Because they get their near vision almost immediately. I mean, even a couple of hours postop, they are already reading up close. It really didn't take long at all.

Gary Wörtz, MD: Well, that's awesome.

Greg Parkhurst, MD: That's spreading word of mouth for the whole practice.

Gary Wörtz, MD: Oh yeah. When you have a patient who's experienced a great result early on with a new technology, they really become your cheerleaders for practice, and they are invaluable.

So one final question, as we kind of wrap up here, is what do your optometrists think about this? How have they taken to either comanaging these patients or seeing them postoperatively? Have you had experience with optometrists in the community receiving these patients back? What is their feedback then, if any?

Greg Parkhurst, MD: So, what I've found is that, especially the optometry students that we work with, you know there is four with us all the time; they are just super hungry to know about this technology. It's really amazing to see kind of what they know coming in to the rotation, and ask questions like "Are we doing bilateral LASIK these days or is it still one eye at a time?" And then, to see them just a month later, now they are talking about "Well, okay, this patient's perfect for Kamra and that one is perfect for an RLE, and that one is perfect for Raindrop. And they know the postop protocols, and they know what to watch for, and they know how to manage dry eye.

So, it's just a really exciting time in refractive surgery to see, you know, buy in by the ODs that are excited to offer the latest and greatest to their patients, to be a trusted resource where they can hear about everything that might benefit them and their vision. So, to our experience with the optometrists is that they are hungry to learn more about all these techniques. So it's been great.

Gary Wörtz, MD: Well, at the end of the day, if it's good for patients, that's what we all desire. And it doesn't matter the initials after the end of your name. If you are providing good patient care, that's a huge win, and that's why we all decided to go into this wonderful field.

So, Greg, thank you so much for coming on and giving us your early experience. I know this is going to be very beneficial for me personally, but I'm sure for a lot of others that are kind of figuring out "Is it time to jump in to the corneal Inlay field.” So, once again, thanks a lot, Greg. Really appreciate it.

Greg Parkhurst, MD: Thanks so much, Gary.

Gary Wörtz, MD: Take care.

Presbyopia is a growing area of focus for many patients and their doctors. As evidenced by Greg’s up-close experience, our solutions for managing presbyopia are growing, as is our understanding of their best uses. Thankfully we have yet another tool in our belt to help these patients ward off the trappings of Father Time. This has been Ophthalmology off the Grid with Dr. Gary Wörtz. To hear more, visit eyetube.net/podcasts. Be sure to rate, review, and subscribe, and stay tuned for more discussions on hot topic in ophthalmology. Thanks for listening.

Speaker: Ophthalmology off the Grid is an independent podcast supported with advertising by Alcon.