Multifocality Versus Monovision
Speaker 1: Ophthalmology off the Grid is supported by Imprimis Pharmaceuticals Inc, bringing dropless therapy to cataract surgery and LessDrops for post LASIK and other ocular surgeries. For more information, visit the websites godropless.com and lessdrops.com.
Gary Wörtz: Open, outspoken, it's Ophthalmology off the Grid. An honest look at controversial topics in the field. I'm Gary Wörtz. Multifocal versus monovision: It's a debate full of opinions and options. Dr. Daniel Chang and Dr. Jay McDonald each give us insight into what they consider the best option and why. They also share pearls for patient selection, monovision sweet spots, and groundbreaking research in optogenetics. Listen in, it's going to be a great episode.
This is Dr. Gary Wörtz with Ophthalmology off the Grid, and today I have with me a good friend, Dr. Daniel Chang. Daniel, how are you doing today?
Daniel Chang: Doing good, thanks for having me.
Gary Wörtz: Absolutely, it's our pleasure.
Daniel, one thing we don't agree on all the time other than our basketball teams is presbyopia, but I do always enjoy learning from you. I enjoy the way you think about things, so I'm sure everyone who is out there wants to hear your perspectives on presbyopia, including me, and I would like to have a little bit of dialogue on the ways you treat presbyopia and maybe the ways that other people think about it and some common pearls that we might all be able to take forward with us. With that, why don't you give us your perspective, and we'll have a little bit of a dialogue.
Daniel Chang: Great, fantastic. Happy to talk about presbyopia. I turned 42 this year, so I can start noticing the effects of presbyopia, so it becomes a personal issue. I think one thing to remember is we're used to treating presbyopia and thinking about it when a patient comes in is just a pair of reading glasses, get them out the door, and move on to the next patient. But for someone like myself who doesn't wear glasses, it's going to be a major hindrance to my life and an inconvenience to deal with it as it progresses. When it comes to presbyopia, we always have to treat it. It's either that or we're going to have basically visual loss at near. If we think about presbyopia as a $0.99 pair of glasses, we're going to be reluctant to do anything surgically for it.
Daniel Chang: If we think of it as an accommodating visual loss, a progressive disease that affects 100% of the population, leaves us unable to see up close, and there's no medical treatment for it, then we could have a little bit of a different perspective. We do have surgical treatments right now, there may be medical treatments coming in the future, but basically it's something that we have to deal with. Again, a pair of glasses works, but it also has its compromises: You can't find your reading glasses, you have bifocals. It's definitely been demonstrated the increase in difficulties with steps and curves, and when I talk to my patients, they all acknowledge that. If somebody has a pair of bifocals and trips because they miss a step and they fall and break a hip or something, compare that to maybe having some halos at night from multifocal lenses, then that becomes a bigger issue. It always has to be treated, and every treatment you have has some sort of side effects.
Do you think that because our patients and even we as doctors know there is a $1 solution to presbyopia, it somehow has cheapened the value of near vision in a disparate way?
Gary Wörtz: That's a great way of thinking about it. Glasses are an accepted part of society and sometimes even a valued part of society, and I think it's similar to the discussion and the argument when LASIK first became popular is, “Hey, if glasses work, then why should we do something different?” There's always the option. I think the important thing is not to force the patient down any particular pathway. As our surgical options improve, we should offer them, perhaps even encourage them, because the patient doesn't even know that's an option. But we shouldn't choose for the patient; we should let them decide. “Hey, there's multiple ways of approaching this, and these are the compromises with each. Which one would you like to have?”
Daniel Chang: Sure, and I think that when you realize how special it is, what time, what era we live in, in all of human history, it's only the last few decades that we've had the ability to change someone's natural vision. Glasses were a huge, important invention when they came out centuries ago. But now, it's the first time in human history where if someone has a problem with their refraction or now even with presbyopia, we have legitimate options where we can change how they see, typically for the rest of their life. It's interesting how even though we have those advantages at our disposal, sometimes we just fall into the same pattern of wanting to do what we've always done because that's the status quo.
Gary Wörtz: One thing I love about you and some of my other colleagues is just challenging the status quo and making a new level, a new horizon. Tell me some of the of your most favorite ways of treating presbyopia, whether that is some of the new technologies that are coming out, maybe some of the older technologies. Give me your perspective, when you meet a patient and they tell you that their goal is to be free of glasses both up close or maybe intermediate and in the distance, what are your go-to solutions for presbyopia?
Basically, I assess the patient and see what they're dealing with. Someone who is 40 or 41 and just starting to see a little bit of presbyopia and they’re plano or maybe they’re myopic, I would be concerned about doing a surgical procedure versus someone who is significantly inhibited or limited by their presbyopia or maybe has some incipient cataracts, that's going in terms of what I want to do. Basically, I'm looking at the amount of hindrance and the lifestyle and at least weighing the options in my mind in terms of what the risks and the benefits of what potential solutions I might have and just discuss it with them.
Daniel Chang: Currently, we don't have any medical approaches or eye drop approaches to the treatment of presbyopia. There are some that are being studied. Corneal inlays, at least the AcuFocus, the Kamra inlay, just got approved, so that does have a new option. I don't have any experience with that, but I would be interested in looking into that. Certainly from a cataract surgery or lensectomy standpoint is the option of using multifocal lenses, monovision perhaps, and different approaches from a surgical standpoint to treat presbyopia.
Tell me about your cataract population. It becomes almost an easier conversation when someone has lost or demonstrated loss of corrected acuity when they are complaining of glare and halos, they've got a legitimate cataract, and they are also having those same goals of wanting to maybe get a little bit more youthful vision, having more independence from spectacles. Tell me about your conversations with your cataract patients who want to have more independence from glasses at all distances.
Gary Wörtz: It's definitely a risk-benefit assessment, and I think that changes with time as technology improves with the lens extraction procedure, as technology improves with the intraocular lens options, and the potential even exchangeability in the future is that it would change our layout and that risk-benefit profile, and the options I would weigh them differently. Basically, I look at what their lifestyle is, what kind of things they like to do, and I also look at their physical [stature]—how tall they are, how long their arms are—in terms of what options I want to offer them from a treatment standpoint.
Daniel Chang: That's a great point you've brought up. The patient's physical stature, not just their eyes, not just how much coma they may have, or other features of their cornea, but their physical stature, also their hobbies, if they have long arms or short arms. You know, in the past, we had basically one multifocal or maybe a couple that had very similar properties in terms of where the near point was. Now we have new options in the Tecnis lines that come out, the AcrySof ReStor now has some different add powers as well. Tell me about where the sweet spot is for you and your practice and what the pros and cons are for how you choose one of the multifocals versus another.
Gary Wörtz: Again, I start with a questionnaire. Steve Dell introduced that concept, but I modified for my own practice. Basically, I get a feel for what the patient does on a day-to-day basis, how much they do certain activities, and again I look at how tall they are sitting in my chair and kind of where they're holding things when they're reading. A lot of times, basically they like what they are used to, not necessarily what you think would be best for them. I use exclusively the Tecnis multifocal line or family of IOLs for my surgical treatment of presbyopia because I like the optical quality that it gives both in spherical and chromatic aberration improvement and reduction. I think that's why I get really good results after surgery.
Daniel Chang: Basically, the three different models provide a near focal point at 13, 17, and 20 inches. I basically hold my hand in front of the patient or I have them hold something and I figure out how far away that is from them, and I say, “Hey, I can put your best focal point here.” All three of the lenses give excellent vision through a full range. Eighty percent of patients were glasses-free at distance, intermediate, and near for all three lenses—at least 80%—so they do get a full range of vision, but there are certain points where it's optimal.
Yeah, absolutely. My experience with multifocals has been a mixed bag, and I think that a lot of ophthalmologist who are out there may have tried some of the earlier multifocals, whether it was the Array, whether it was the first- or second-generation ReStor, and you know my experience was mixed. I definitely had some patients who loved their vision. They really were appreciative of the fact that we could give them back some near vision and distance. I had a fair number of patients who were just underwhelmed and were maybe a little bit, they felt like they paid more than the value I provided for them. Then I clearly had some patients who were incredibly unhappy, and so it's those patients who are vocal and who need a lot of chair time and a lot of hand-holding that you start assessing whether or not it's worth your time and effort and are you doing the right thing for the patients.
Gary Wörtz: I've had patients where I put a multifocal in one eye and a standard lens in the other eye, and they quite prefer the quality of vision in the monofocal eye, and again this was with an Alcon platform, that's just what I was using at the time, and I sort of said to myself, “Am I doing the right thing?” So after that patient was quite unhappy, I really just felt like for me and my practice, I was going to try to find a solution to presbyopia that maybe was a little bit more forgiving. I kind of use a runway analogy. I like landing the plane on a wide, long runway, and so I kind of have taken a more of an older approach, where I will take a patient who wants to have more independence from glasses and I will tend to recommend monovision for them. The reason for that is if the patient ... and I tend to be in this intermediate range, where I try to correct the nondominant eye for about a -1.50 and the dominant eye clearly for plano, and they can still fuse. They don’t lose their ability to fuse. And I have had a lot of success with that.
For me to consider dipping my toe back into the water with multifocals, and I'm clearly intrigued, I think your point is well taken that the Tecnis platform of lenses has some different optical qualities than some of the other lenses that we have used in the past, and that transfers over to their multifocal that they are using, but I'm still just a little bit nervous. Give me some pearls for patient selection in terms of patients who maybe not an absolute disqualifier but some relative red flags or yellow flags. If you're talking to another doctor like myself who is maybe thinking about getting back into the game, what's that low-hanging fruit out there where you're going to be more likely to get a happy patient than a problem patient?
Typically, the low-hanging fruit are the hyperopes, people who are used to wearing glasses all the time, people who aren't used to taking them off to read, people with worse cataracts, people who are coming from a worse situation, obviously otherwise-healthy eyes, ideally kind of laid-back personalities. Although I have no problems doing these in engineers, I enjoy the discussion with them beforehand, and they tend to understand it if you spend the time with them beforehand. A lot of surgeons out there have been burned by the previous multifocal experience, and unfortunately I think it's given the category of lenses a bad reputation.
Daniel Chang: Again, one thing I want to emphasize is not everything, not all multifocal lenses are created equally, even though some of the terms we use are very similar and the numbers on the box seem the same. It's kind of like the megahertz myth that we went through with computers, where it was as long as the megahertz or the megapixel myth on cameras, the bigger number, the better the camera. There's a lot more to optics than the numbers on the box. What I'm doing is encouraging manufacturers to talk about issues like refractive index, spherical aberration, and chromatic aberration because you really have to start with correcting the aberrations to start with good quality of vision. In a monofocal, the patient may or may not notice, but if you're going to do diffractive optics and create multifocality, if you don't start with great aberrations or minimal aberrations, you're just going to really suffer afterwards.
I think your point is well taken. You know, when you talk about diffractive optics, I think there is sort of this myth that diffractive optics are associated with poor visual quality. People don't realize this, but there are telescopes that are made with diffractive optics, and diffractive optics do not in any way, shape, or form necessarily have to correlate with waxy vision or decrease in visual acuity. Clearly, splitting light, you're going to be having some light focusing in near and some at distance, but diffractive optics in and of themselves do not have to be correlated with degradation in visual quality.
Gary Wörtz: Absolutely. Diffractive multifocal, and if you look at the FDA chart results for the new low add lenses from AMO, is that you do good improvement halos with smaller amounts of add, and it is possible to make a diffractive monofocal, which would have essentially zero halos or the same as your baseline control. We kind of associated diffraction, that word, with halos.
Daniel Chang: Right. We see the rings on the lens, and we think it's the rings we see as the halos.
Gary Wörtz: You're right. Canon does offer a line of diffractive lenses as an intermediate-expense solution to chromatic aberration issues as a way of not charging as much as their high-end lenses but using diffractive optics to improve the quality of the vision. Certainly, you don't see halos or circles on your pictures because of that. I think we have a lot to learn from an optics standpoint, not just assume they're all created equally.
Daniel Chang: Yeah, absolutely. Daniel, any other pearls, any other disqualifiers, people that may not be a good choice for those new surgeon starting out?
Gary Wörtz: I think just like we talked about before in terms of screening the patient both from a physical standpoint in terms of their eye in the exam and also from a personality standpoint and lifestyle standpoint. I was an investigator on the 3.25 and the 2.75 Tecnis multifocals, and one thing that I realized is a lot of my staff members were having their family members or themselves being enrolled in the study. You can convince yourself or you can convince a patient or influence them to like what they have, but you can't convince your staff because they get to hear the patients unfiltered. I had a staff member and then a nurse and the nurse’s mother-in-law, she did so well her father-in-law got in. So, it was a lot of people who were related to the process who wanted to get these lenses into their eyes, and they've all been very happy with it.
Daniel Chang: Really, I think it makes a difference what product you use. I don't want this to be a sales or promotional piece here, but I think there really is optically a difference and if you go look into it, it does make a difference in terms of your outcomes, in terms of the amount of patients you can make happy with your surgery.
I actually had the good fortune of meeting one of your staff members the other day who has a multifocal lens in her eye. I was actually kind of blown away because your staff is not going to give you ... they will tell you the absolute truth, and if they don't like something, if they like it, if patients like it or don't like it. Staff, actually I don't know how your staff is, but if patients are kind of grumbling about something, they kind of steer ... they can pretty quickly and they will come tell me. It's actually really important for us to listen to our staff about those things.
Gary Wörtz: When you tell me that your staff is actually excited about this, they're seeing happy patients, that’s actually—not to say that I don't believe you—but, when I meet your staff and talk to them and they tell me and I'm asking them what they can see, it's pretty incredible. As someone who kind of swore off multifocality years ago, I thought it was impossible, but Daniel you actually got me intrigued into dipping my toe back into the water. I thought it was impossible, and I think a lot of other surgeons around the country are maybe reevaluating the new generation of multifocal lenses, and we all want to find that solution for our patients that are going to make them happy. At the end of the day, if they're happy, we're happy.
It was neat that you mentioned the staff member that you met. We brought our staff down to Universal City Walk, and we were out at night looking at all the neon signs, so I stood next to her and pointed to different light sources and asked her what she saw, because I think that was a very educational experience for me because live description is different from a patient's recollection. You have a little less filtering there. For those thinking about dipping their toe back in the water, I say jump on in, the water's warm.
Daniel Chang: One more thing I want to add is: We haven't talked anything about pricing and reimbursement with anything. We started with the medical needs of the patient, and we talked about side effects because we're all going to deal with some sort of tradeoffs and side effects with our choices. But the financial aspect is an important one as well. I think it's important not to lead our thinking and discussion of presbyopia with the monetary discussion. That should go at the end because, as surgeons, our job is to really help our patients and to think about their needs first and then make sure it works financially for us.
Absolutely. I always think that if you keep the patient at the top of the pyramid and are always trying to take care of them, the rest works itself out. Daniel, I really enjoyed our conversation. I know that a lot of other surgeons are going to enjoy hearing this as well. Thank you for taking some time out of your day to make this happen. We look forward to many more conversations in the future.
Gary Wörtz: Thanks for having me.
Daniel Chang: Dr. Chang offered some valuable pearls for patient selection and their use of multifocals in their practice, but I wanted to hear from someone who truly feels that monovision trumps multifocality. Dr. Jay McDonald is a mentor of mine who has done a great deal of research in monovision and is one of the key opinion leaders on the subject. I caught up with him on Skype to discuss.
Gary Wörtz: Today I have with me Dr. Jay McDonald. Jay, it's just so good to have you here, and I'm just curious how you been doing lately since you've had a little more free time on your hands.
Yeah, Gary, I must say I certainly enjoy having time to pursue some things that I wasn't able to pursue while in active clinical practice. I can highly recommend it.
Jay McDonald: What's interesting is, just as a little background, I met Dr. McDonald, I think it was back in 2008; it was at the ACES meeting in Puerto Rico. I was a resident at that time, and I remember that you and Dr. Doug Katsev took me and my wife out to dinner, and I really never forget that. We had a great time. It was nice getting to meet some surgeons who were really prominent in their careers. Just that mentoring and willingness to share ideas was really special. I never forgot that, and really beyond that, it was the next day or two that I heard really one of the best lectures I've ever heard in all of ophthalmology. It was really your talk about how monovision trumps multifocality. All I have to say is, of all of the talks that I've heard, that probably is the one that made the biggest impacts in terms of the way I think about optics, the way I think about clinical practice, and really the way I think about presbyopia correction.
Gary Wörtz: I've always wanted to have a chance to pick your brain about your thoughts on monovision, and that's what this podcast is really about. They've given me an opportunity to interview people that I think have great ideas, great minds, and I've wanted to take advantage of that opportunity to unpack this whole concept a little bit, to learn a little bit more from you, and also for you to share your knowledge with other folks who might be listening.
With that being said, give us a little bit of background in terms of your understanding and your development of understanding the visual system and your opinions and the reason why you feel that monovision is such a great way to treat patients desiring continuous vision.
Okay, Gary. I was probably like you in 2008, several years before, when I began using some multifocal lenses. Multifocal lenses came out in the early 2000s and were strongly hyped as a way that seemed to make sense to see far off and up close and to become spectacle independent. However, I had a family that I had operated on. The dad was a chemistry professor at the university, and I had done monovision on him. When his wife came in to have her surgery, she loved what her husband was doing, but she had heard about multifocal lenses, so she thought she wanted to trump him and get the newest and latest and greatest. From all the standards, she was a good candidate. I told her, I said, “What your husband is doing and loving, I feel real comfortable about.” Anyway, she pushed me into doing a multifocal. I said, “Well, this is great. Here is a motivated patient.” Anyway, I did a multifocal lens on her and began a real struggle. She had a perfect refraction, but she really had a tough time adjusting to it and started having the typical complaints of patients who are having some problems with multifocality.
Jay McDonald: What that did for me, she was kind of the tripwire, because her husband was a very, very picky person, and I was somewhat tentative even to move him to monovision, even though he was extremely happy. Anyway, I thought, you know, what we're doing, I don't understand it, I couldn't understand, I couldn't explain in my own mind her complaints versus his complaints, etc. I thought, it's probably my obligation to try to understand what's really going on. So, I decided to, sometimes I do this, just jump headfirst into this, and I read some books on how we see and visual cognition and sort of located who in the literature of neurocognitive vision, the guru was a guy, a wonderful person, over at Vanderbilt, Randolph Blake. I cold-called Dr. Blake one night and started talking to him about how I wanted to understand what was going on with multifocality, monofocality, and monovision, and we just hit it off, which was wonderful.
I asked him if he would come ... the guy obviously knew exactly how everything works in the brain and in the eyes, and I said, “Would you come to Fayetteville and spend a few days? I bought you a plane ticket, spend a few days with me. Let's look at some patients, and I'll try to educate you about multifocal lenses and what we're doing, see the patients, and let's figure out so you can tell me what's going on?” That was kind of the beginning, and in fact Dr. Blake came, we had a wonderful experience interviewing patients, and he was taking notes and everything. Then we sat down for the next day or two and really wrestled through what was going on, and he and I later collaborated on some papers and textbook chapters and David Chang's book on mastering refractive IOLs, the couple of chapters in there I wrote about the neurocognitive vision, monovision versus multifocality. So, that's my history. I haven't told you the knowledge base that I acquired, I’ll share that with you, but you asked how I got started.
Sure, well that's so interesting. I find that our patients can be our best teachers after residency, but you have to spend enough time with them and you have to listen. You have to really care about what's going on, and you have to want to not to repeat your mistakes. I had a patient like that with EBMD who ended up being really a huge, she had a really big refractive surprise, and it changed the way I practice cataract surgery in patients with EBMD just because I went to the process of reevaluating how I take care of that group of patients. It's wonderful that that's the case because I think it's something that we as physicians—whether it's multifocals or LASIK and even beyond the anterior segment—in all of medicine, if you want to do better, listen to your patients when they have a problem and don't blow it off; take it to the next level, and come up with a solution. That's where this has been so enlightening for me because I don't have to go through that process with every patient because I can learn from you, and I can learn what patients are going to be good candidates or maybe a better approach.
Gary Wörtz: As I recall, and you can tell me if my recollection is correct, as I recall if we are talking about monovision, there really seems to be a sweet spot and I've used that in my own practice, really trying to correct the nondominant eye for that -1.50 result and trying to nail the dominant eye with as close to a plano result as possible. It seems like that you're really getting the best of both worlds. It's not really monovision with one eye on and one eye off; it's really more of a continuous vision, where the brain can summate the data from both eyes simultaneously. Can you tell me a little bit about how you came to that conclusion and why -1.50 is really the sweet spot for monovision?
Let me start first a little bit, and you rush me along if I'm dragging this out a little bit, I want to just refresh everybody that the human visual system is a contrast edged-based visual system. In other words, we see, the whole system is designed to see edges. The finer the edges are, we see those in the high frequency range, the mid frequency range, and then of course the large, gross movement, the large edges, which are seen in low frequency. What happens the farther away you get the two eyes, the more the signal-noise ratio comes in from the one eye that is out of focus, and it degrades a little bit more the signal that reaches the visual cortex when it puts it together. Of course, the closer they are in refracting terms, the closer especially the high-frequency wavelength, the high-frequency seeing, are matched, so you have a better discriminating of edges, which gives us the discrimination. Of course the smaller the edges, the finer the discrimination.
Jay McDonald: To try to explain in a short period of time, refer everybody those chapters for a little more bit lengthy and probably a little more cogent explanation. But I'm going to try to do this real quickly. We start off with the analog. Once light hits the opposite disc and the retinal pigment, we go from analog to digital. Everything after that is basically an electrical signal. Jack Holladay has pointed out that and other people, when you use multifocality, the first degradation you get is in just the analog part because of the diffractive lens and the structure of a multifocal lens, you lose about a 17% degradation signal. The next thing that happens that I think we need to pay attention to is in the ganglion areas of the retina, there are a million neurons and a million synapses, and after that, when we get to the visual cortex, there's actually over a billion neurons and synapses.
If we can just picture the relativeness of that computing power, you think of the ganglion cells and the retina as an EPROM chip, say of a million synapses and in the computing power of the visual cortex in the billions. There is over 1,000 full-power differential in a computing power. What happens when you have a multifocal image that falls on the retina? In the retina, the signal-noise ratio gets broken down. In other words, you get more static because you have those two images that are not congruent falling and being processed by the retinal ganglion cells. By the time those happen, you have a loss in your signal-to-noise ratio in that visual signal that you can never recover.
Now, once that multifocal image gets to the brain, you have this amazing visual computing power that is just out of sight but still starts working on a degraded signal when you're using a multifocal lens or an image. Contrast that with monofocality, where the signal is pure all the way through the retinal ganglion. So, that distance that you're looking at, if it's in focus and you have the refraction right, but when it comes from the left or the right eye to the visual system, it hasn't lost any power of the signal; there is no degradation of the signal. So, even though when you have a right eye, say, that's plano and a left eye that is +1.50, when those signals are not congruent but when they get to the brain, the brain has a pure signal-to-noise ratio, a pure signal to work on. Then it can use its tremendous computing power and put together these images that are separated by 1.50 D.
Whereas in a multifocal, yes it does have both the near and far, but in each eye, that signal has been degraded. What happens is you can never get the power of that broken signal in a multifocal lens ever recovered. Where that comes into play significantly is that luckily we have a lot of redundancy built into our visual system, and when we are 25, or 30, or 40, or 50 and we have a fairly complete well-functioning macula, that degradation fall off of 10 decibels or so doesn't start bothering us. But if you take, on top of that, a small amount of macular function or any other diseases that would cause that signal to be degraded, it really adds on top of that 10 decibels that you've lost with multifocality.
The patient then will certainly experience a loss of acuity, and that's the thing that I am most concerned about. If you can get the same amount or the same effect using monovision and preserve that integrity of the retina and the processing on each side, then you're going to always have the very best vision that patient can have in each eye, whether they lose one eye, whether be it macular degeneration in the other eye. That's probably the biggest concern personally that I have, although certainly I'm not saying you can't have satisfactory multifocal, spectacle-free patients. That certainly happens, and you see that every day in your patients. I'm just saying in the long run and for what for my own self, maintaining the integrity of the processing power of each eye with monovision just makes more sense to me in the long run. That's probably more story than you wanted to hear, but I hope that kind of explains where I'm coming from.
Absolutely. Let's look at that. I've got a few questions. I'll give you a little bit of my perspective. I have found that monovision is really like landing a plane on a really long runway. It's wide, it's a really forgiving procedure. What I mean by that if I'm going to do monovision to someone in my practice, I'm not always going through the hassle, especially in cataract patients who may or may not have worn contacts lenses in the past, I've not always had them go through the contact lens trial process because I feel like they're not really getting a good preview because they're looking through their cataract. I also know it's a really safe place to land because really if they don't like it, they can always revert back to spectacles as a last resort. And they don't have so much anisometropia at 1.50 D that they're not going to be able to tolerate bifocals.
Gary Wörtz: So, first of all, if I feel like if you're going to go with mini monovision or continuous vision at 1.50 D offset, you're really landing in a safe place. You haven't disqualified the patient from really any other option. The second thing is doing your refractive touchup is pretty easy because you can do laser vision correction on one or both eyes, should they not like their focal points. That's another fail-safe, really. The third thing is really the fact that patients with astigmatism are still candidates, as you can use toric lenses or perhaps astigmatic cuts to correct astigmatism. With that, you can give a really nice monovision result. It's really a tool that I have liked to use, I enjoy using it, it's highly effective, and it's really a safe way to have really happy patients.
My story is somewhat similar. I came out of residency in 2008. I started using the ReStor lenses, and I really didn't get a great wow factor. Actually, really as a matter of fact, I had a number of patients who were just really unhappy. It was a situation where I just scratched my head and thought, I feel like I'm doing the right thing, I feel like I'm getting a good refractive result, the phoropter, they're not really accepting much correction, they're measuring pretty good, actually. But there Snellen acuity is 20/20 and J 1 or J 1 plus, but they're just really dissatisfied with their quality of vision. Now, a lot of patience can adapt to that, and over time we know with neuroadaptation, it does help with that a little bit. But I just, really, I wasn't satisfied that this platform was going to be a good workhorse for me in the long term.
For a long time, I really just said, “Multifocals aren't for me.” Recently, I've decided to dip my toe back into the water, and I've been using the AMO ZKBOO, which has about a 2.00 D add. What's really interesting about this, and really all of these AMO lenses, is the defocus curve. The defocus curve really keeps a 20/20 to 20/25 level of vision from 0.00 D through about 3.00 D. That's with the ZK, the ZL, and the ZM. I've been pretty cautious with my patient selection. We want to make sure that they don't have a lot of coma, that they don't have a high angle kappa, and obviously that they have some reasonable expectations. But, Jay, I have to be honest with you: I've actually been blown away with how many happy patients we’ve had. These are patients who are not complaining about waxy vision, they're not taking a long time to adapt. These patients, many of which I'm frankly scared to have them do a video testimonial because I feel like they may raise expectations for other patients.
I don't know that I'm ready to double down on multifocality. I'm still processing what is the best approach, but I have to be honest, I think these lower add multifocals are really hitting that sweet spot, and maybe it's because of exactly what your research has said about monovision. But really, sort of applying it to multifocality, where you’re flattening the defocus curve, and you're keeping both images within a fairly close range, and you're providing a high signal-to-noise ratio to the brain. Would there, acrylic being a lower index of refraction acrylic, you don't have a lot of chromatic aberrations spreading the blue to red light on the retina. It just seems like this lens and these group of lenses have really provided a nice multifocal that is giving a high quality of vision. That's actually what I'm seeing, and frankly I'm surprised at how good they're seeing. With that, what would you say to that? I just want to hear your feedback on what I've said and maybe the newer generation of lower add multifocals, what would you say about that?
Well, I think, Gary, that's laudible, and I think over time these things that you can fix, in other words just like you talked about getting rid of that aberration, anything that lowers the signal-to-noise ratio, moving the focus curves closer together so that you don't have near the spread. There is a lot of redundancy in the visual system of the person with good retinas and good functioning visual cortex. I think there's no doubt, I agree that certainly your patient satisfaction has gotten better as multifocality and modality of multifocality has improved. I think you still have the basic issues of the loss of signal-to-noise ratio that maybe in the long haul will catch up with the patient.
Jay McDonald: Sure, you can't change. The technology is what it is; there's definitely give and take. I actually am happy to have another tool in my belt to help patients who maybe are interested in having that full range of vision. Maybe just to switch gears a little bit, what other things are you researching? I know that you have an active mind. You're never one to really take a break in terms of your thinking and your learning and your contributing. So, what are some things that you have been interested in, new things that you've learned, things that you feel like are advances that maybe the rest of us who are putting our nose to the grindstone maybe haven't heard of yet? I would just love to hear you speak on that.
Gary Wörtz: Gary, as you alluded to, my pastime reading is scientific journals, and not necessarily ophthalmology, but I have a very continued interest in the brain and how it functions, especially neurocognitive vision in the brain and how it functions. In 2014, a man named Karl Deisseroth—and I hope he's not listening because I probably mispronounced his last name—at Stanford, won the Nobel Prize for developing a technique called optogenetics. I don't want to go into great detail about it, but I actually got so excited by it. It is a way that we can identify and stimulate individual neurons in the brain, and I think it will be, it will take us beyond functional MRI and understanding and treating multiple neural disorders. Also, understanding how I think we have some big questions about what makes me feel, how do I conceptualize things, where is my soul? I call it, my lecture, Optogenetics Pathway to the Soul.
Jay McDonald: It's an amazing convergence of four or five amazing technologies from genetics to viral manipulation to opsin control that gives us the ability by a light mediated through laser stimulation and a record of individual neuron firings. That's just had me on fire the last year, I guess. I've been reading and putting that all together. Then the other thing from a clinical standpoint I might share: Be on the lookout, I will just say, be on the lookout for optogenetic research because it's going to be, the papers that will be coming out in the next 5 years that are going to tell us a lot more about the visual system and how we think and how the brain works.
As many of you know, photography has always been my secondary issue in life, and I spent a month in India last year photographing India but also visiting a colleague and friend that I had collaborated on several projects for, Daljit Singh. In 1995, I started getting e-mails and photographs from Daljit. He kept saying, “I think I’ve found the conjunctival lymphatics. I think I’ve found the corneal lymphatics. I found how they’ve communicated,” and on and on. Now after, he just last year has published a chapter in a book about the corneal conjunctival lymphatics and their connection, their relationship to the lucid interval, which is a circuit at the periphery of the cornea, a common lymphatic-like track, and canal of Schlemm, and their interconnections. I think it's going to help us understand and it's going to open a whole new light of looking at the cornea and fluid in the cornea and fluid transfer in the cornea, conjunctiva, and canal of Schlemm. I could go on about that. I think that's probably one of the most exciting things I've seen in ophthalmology.
It's amazing: As soon as you think you know everything about the eye, an advance like that comes along, and you think, “Wow, there's still so much to learn.” And that's why I think this field is so exciting. We get to help people in such a tangible way, but we're always learning new things, and for that, Jay, I just want to say thank you so much for your contributions to our field. You're truly a giant in our field, and you've made my clinical practice better and so many other doctors better surgeons and better thinkers. That being said, I just want to say thanks for coming on and giving us some things to chew on today.
Gary Wörtz: Gary, it's been my pleasure, and I well remember that dinner we had in Puerto Rico and maybe while you were thinking what I was thinking, I was observing one of the bright upcoming minds in ophthalmology and I knew it at the time. I loved your inquisitiveness, and I loved your way of fighting through and trying to understand the things that were going on, and it was obvious to me that you were going to be one of the coming leading thinkers in ophthalmology, and you certainly have done that. It's been a joy for me to have some time to talk about things that I love and think about all the time and keep me busy and reflect on my time in ophthalmology. Thanks for the opportunity.
Jay McDonald: Absolutely, and I want to hear from you maybe next year an update on this optogenetics. It sounds pretty incredible. Jay, thanks again for that, and for all of you out there that are listening, this is Dr. Gary Wörtz with Ophthalmology off the Grid. Thanks a lot.
Gary Wörtz: Ophthalmology off the Grid is supported by Imprimis Pharmaceuticals Inc, bringing dropless therapy to cataract surgery and LessDrops for post LASIK and other ocular surgeries. For more information, visit the websites godropless.com and lessdrops.com.