Jason J. Nichols, OD, MPH, PhD: The Merriam-Webster Dictionary defines disease as “a condition of a living animal or plant body or one of its parts that impairs normal functioning and is typically manifested by distinguishing signs and symptoms.” Does myopia fit the definition of a disease?
Thomas Aller, OD: Classically, we haven’t thought of myopia as a disease, but, based on the latest science, we should. Myopia has been shown to be an independent risk factor for glaucoma, cataract, and retinal detachment, and the higher the myopia — the higher the risk.1 Myopic macular degeneration is a relatively newly accepted designation and it’s causing widespread blindness around the world.
David A. Berntsen, OD, PhD: I agree. In addition, studies are showing that even lower levels of myopia increase the risk for serious consequences.
Kate Gifford, BAppSc(Optom)Hons, GCOT: Yes. A relationship exists between each part-millimeter increase in axial length and the risk of pathology, particularly pathology such as myopic macular degeneration. If myopia at lower levels was benign, there would be no additional risk compared with that of an emmetrope, but that’s simply not the case. Even one diopter of myopia carries a higher risk. We’re very good at explaining to patients how, for example, uncontrolled glaucoma presents a lifetime risk of vision loss. However, as a community, we’re not as good at explaining that myopia, even at -3.00D, and particularly when we reach -5.00D to -6.00D, poses very real risks.1,2
Dr. Nichols: Regarding increasing risk, is there a “safe” level of myopia?
Brett O’Connor, OD: No, clinical evidence tells us that any amount of myopia is a risk factor for ocular diseases. It is true that high myopes are more likely to develop complications, but, in reality, complications are occurring in low and moderate myopes, too. One researcher made a comparison between myopia as a risk factor for ocular diseases and smoking and high blood pressure as risk factors for cardiovascular disease.1 Obviously, a patient who presents to his primary care physician smoking three packs of cigarettes per day and in hypertensive crisis is going to demand attention, as would a high myope in one of our practices. But what about the patients who have moderately elevated blood pressure and smoke a half pack per day? The primary care physician certainly still has a responsibility to talk about the patient’s risk factors and would likely begin some type of treatment. Why should optometrists treat low levels of myopia differently in our practices?
Another reason there is no “safe” level of myopia is that it’s an unpredictable disease. We know genetics and some lifestyle factors play a role, and that can guide our thinking to a certain extent, but we really don’t know with certainty which patients will progress and to what level. We also don’t fully understand the differential effects myopia can have among patients; for example, why a -10.00D eye in one patient can have a pristine macula and peripheral retina, while a -3.00D eye in another patient might develop retinal detachment or other complications.
Flitcroft has made quite a powerful argument that there is no safe level of myopia.1
Dr. Nichols: What is the prevalence of myopia throughout the world, particularly high myopia?
Dr. Berntsen: The most recent data indicate the prevalence in the United States is at least 33%.3 Prevalence has been increasing here,4 and even more so in other parts of the world. Among young adults in East Asia, the prevalence has reached 80% to 90%.5 High myopia, too, is on the rise globally.1
Genetics vs. Environment in Myopia and Myopia Progression
Dr. Nichols: What is currently known about the role of genetics and environment in myopia?
Dr. Aller: Conventional thinking had been that myopia is largely genetically predetermined and that progression stops at a certain age, but we’re moving away from that theory. We’re realizing that although genetics may be responsible for the development of myopia, it’s possible to modify progression. A study7 Prof. Wildsoet and I conducted illustrates this point beautifully. We randomly assigned a pair of identical twin girls to wear either single-vision or bifocal contact lenses in a double-masked prospective trial design. Each started the study at around -1.25D. At 1 year, the level of myopia doubled in the twin who wore single-vision contact lenses and it decreased in her sister, who wore the bifocal contact lenses. Although this particular study involved just a single pair of twins, it reflects the increasing body of evidence, including our subsequent randomized clinical trial,8 indicating that both genetics and environment are at work in myopia.
Dr. Berntsen: It certainly appears that both are involved. Also, we’re learning in myopia, as we have in other disease states, that there’s no single, “magic” causative gene. The genetics are complex and multifactorial. I’m of the mindset that genetics may predispose one to myopia, but environment also plays a role.
Dr. Nichols: What do we know about near work as a potential contributor to myopia?
Dr. Gifford: Associations between myopia and near work are definitely emerging. Investigators are in the process of teasing out the exact associations. The duration of near work and working distance may be factors. New research indicates that high accommodative demands due to close working distance, even of a short duration, may promote axial elongation, and spending more than 30 to 45 minutes on a single task seems to be associated independently with myopia progression in children.9
Dr. Nichols: Speaking of potentially modifiable risk factors, what do we know about time spent outdoors and its relationship to myopia?
Dr. O’Connor: We know there’s a negative correlation between increased outdoor time and the incidence of myopia.10,11 However, research is ongoing, and questions remain about the precise nature of the correlation. For example, one question is whether physical activity while outside is necessary to achieve a myopia-inhibition effect. Initial research has suggested this may not be the case.12
I think it’s important to note that while we should be researching and trying to understand the various potential lifestyle and environmental contributors, we must also recognize that we can’t rely on modification of these contributors alone for optimal myopia management.
Treatment Options for Controlling Myopia
Dr. Nichols: We’re all watching with great interest the emerging data pertaining to lifestyle and environmental variables that impact myopia, but we also have treatment options we can offer to help control myopia progression. Dr. Berntsen, tell us about the rationale behind optical interventions.
Dr. Berntsen: Most of the optical designs currently being evaluated aim to reduce myopia progression by eliminating hyperopic retinal defocus in the periphery of the eye. When we measure refractive error in the periphery of an emmetropic eye, we find relative peripheral myopic defocus; refractive error in the periphery is more myopic than at the fovea. However, according to longitudinal data collected in children, approximately a year or two before an eye becomes myopic, hyperopic defocus develops in the periphery of the eye along the horizontal meridian.13 Many of the optical treatments currently being evaluated come into play from that point forward. Evidence from basic science research shows that myopic peripheral defocus, light focused in front of the retina, is a very strong stop signal for eye growth, while hyperopic peripheral defocus, light focusing behind the retina, is a growth signal.14 Most of the optical designs aimed at slowing myopia progression are believed to work by either eliminating peripheral hyperopic defocus or causing myopic defocus while providing clear central vision.
The easiest way to accomplish this is with contact lenses because they move with the eye. In contrast, with spectacles, the optical center is fixed. When the eyes move around, the desired effect isn’t achieved on the back of the eye.
Dr. Nichols: Just last year, Huang and colleagues15 performed a meta-analysis to determine the effectiveness of various interventions for myopia control in children. They found atropine, peripheral defocus modifying contact lenses, and orthokeratology (ortho-K) to be effective, with regard to either refraction or axial length.
Dr. Berntsen: Yes. Our understanding continues to evolve as more studies are published, which sometimes validate previous work and sometimes contradict it, but evidence is building in all three of these areas. We have solid evidence from both non-randomized studies and randomized clinical trials that orthokeratology slows eye growth.16-18 Optical interventions, in general, are producing treatment effects.19 For soft multifocal contact lenses, all published studies have used a center-distance design, and there is variability in the size of the treatment effect.8,20-23 Children who were compliant with wearing the lenses often have a better treatment effect.23 There are no published trials evaluating center-near multifocal contact lens designs for myopia control.
Low-dose atropine, i.e., 0.01%, the third intervention you mentioned from the Huang study, has been shown to have an effect on refractive error. In my opinion, its effect on axial growth is less clear. In the Atropine in the Treatment of Myopia (ATOM) studies, ATOM124 and ATOM2,25 there was, unfortunately, not a randomized comparison between 0.01% atropine and a placebo control. Comparing across the two studies, eyes in ATOM2 that received 0.01% atropine had slower refractive myopia progression than eyes in the original ATOM study that received a placebo control; however, the axial growth rate of these two groups are essentially the same.26 On the other hand, a recent ARVO abstract reported axial effects with 0.01% atropine.27 We need more research in this area, and I believe a few groups are planning to initiate a fully randomized clinical trial comparing 0.01% atropine to a concurrent control group.
Dr. Aller: I agree. Based on the available evidence, I don’t think we can say 0.01% atropine accomplishes axial length control, so I usually start with 0.02% or I use two drops of 0.01%.
Dr. Nichols: What are the pros and cons associated with the myopia treatments we have available to us?
Dr. O’Connor: I’m lucky to be a young practitioner at a time when we’re approaching a sort of golden age of myopia control. A great deal of research has emerged and more is coming all the time. We’ve reached a good understanding of several options that are effective, and we’re expecting reports from comparative research soon. We also have a fairly good grasp of what doesn’t work; the recent Huang meta-analysis we discussed really helped to clarify which interventions aren’t worth pursuing and which are effective. And, as we discussed, the three that are effective are orthokeratology, low-dose atropine, and center-distance multifocal contact lenses.
Taking ortho-K first, most optometrists are well-versed in the benefits it offers patients. Not having to wear correction during the day is something that is very desirable to many patients due to the convenience. Another benefit to ortho-K specifically is that the parents are invested. Parents who have decided to pursue this option are often the ones who have done some research, and due to the larger initial time commitment and associated cost, compliance is rarely an issue. One important risk with orthokeratology is microbial keratitis (MK). Any time contact lenses are worn overnight, we need to be conscious about the potential for infection. With proper care and compliance, we can minimize this risk, but it’s something about which patients and parents must be aware. Another risk with ortho-K is the chance that, even though we achieve what we believe is a successful fit, the lens centering nicely, good vision, and so on, the patient may not be happy. Maybe he doesn’t like the way it feels, or the way he sees, or maybe glare is an issue. In that scenario, you may not accomplish what you set out to do. Also, later in the course of treatment, as young patients age, schedules change, and so on, it can become more difficult to get a full night of treatment. Finally, the cost of ortho-K can be prohibitive for some patients.
Center distance multifocal contact lenses have some distinct advantages. In my mind, this is the most intuitive option for parents. They understand that many kids wear soft contact lenses, but the design of this particular lens enables it to slow the progression of the child’s worsening vision. In contrast, it can be difficult for a parent to understand why a child who doesn’t have an eye infection or some kind of discomfort would use an eye drop. As far as ortho-K, some parents have simply never heard of it. Considering all of those factors, multifocal contact lenses seem to be the most palatable option for many parents, and the risks with daily wear soft lenses are minimal, especially the newer single-use lenses, as long as everyone is aware of the risk for infection with improper use.
Lastly, as we mentioned previously, we’re awaiting further evaluation of low-dose atropine. However, it does bring several advantages to the table. In some respects, it requires the least amount of effort by the patient and parent. No special contact lenses must be worn and there is no training period. Provided they can obtain the medication easily, they have nothing additional to do except use the drop. One downside of atropine is the likely rebound effect that must be managed. Other downsides include the difficulty of obtaining the medication, tracking patient compliance, and possible sterility concerns if the medication is used improperly.
Dr. Gifford: We also don’t have the caliber of evidence that we need to fully understand the long-term implications of atropine, which is a systemically active medication.
Dr. Aller: I tend to use atropine only for patients who can’t wear contact lenses, who have high myopia at a young age, or who aren’t hitting our treatment goals. And I use it cautiously, at a low dose.
Myopia Management in Practice
Dr. Nichols: Contact Lens Spectrum surveys practitioners every year, and one of the questions we ask is whether they’re actively practicing myopia control with optical interventions. The results have been interesting. In 2015, approximately a quarter of practitioners reported active myopia management with optical interventions.28 In 2016, the percentage increased to a third, with nearly 60% reporting that they use soft center distance multifocal contact lenses and about 40% reporting that they use ortho-K.29
Do you foresee combination treatments for myopia control at some point in the future?
Dr. Berntsen: It’s a possibility. Studies are being done to evaluate, for example, combining soft multifocal contact lenses and atropine.
Dr. Nichols: When treatments have different mechanisms of action, it’s reasonable to expect they might have synergistic effects.
What Constitutes an Effective Treatment?
Dr. Nichols: Do you have in mind a threshold that an intervention should cross to be considered effective?
Dr. Berntsen: Looking across all of the studies of ortho-K and center-distance multifocal contact lenses, a 40% reduction in myopia per year is the outcome that’s consistently achieved. Of course, the percentage is higher or lower in some studies, but 40% plus is what we can expect. It would be great to have more than that, but I’m not a big advocate of a magical threshold that dictates clinical meaningfulness. We wouldn’t want to say that a 48% reduction isn’t good enough because we set a 50% finish line. In my opinion, a better approach is to use the best treatments available at any given time.
Dr. Gifford: Glaucoma is a good analogy. We want to reduce IOP by one-third in general, but we may have a patient whose pressures persistently hover near 20 mmHg and that might be acceptable in that individual case. Similarly, we may be treating a myopic patient who’s progressing a little each year, which may not be what we’re aiming for, but we can accept it. It’s important that we set realistic expectations for patients and parents. We can’t expect any product to be perfect. We don’t expect any glaucoma product to be perfect. But we know glaucoma patients face a lifelong risk of blindness if we don’t intervene, and it’s the same with myopia.
Dr. Berntsen: And, as in glaucoma, no single solution or device will work for every patient. Every patient is different.
Dr. Nichols: Do you find that parents tend to have a percentage in mind for extent of myopia reduction for their children?
Dr. Gifford: I think it’s guided by the practitioner. If we were to say it should be 50% percent, and as we’ve talked about we caution against giving an absolute number, the parents will look for that number. If we say we’re looking for a certain amount per year, some parents are concerned about any progression and think we’ve failed them. But if we explain that children who are their child’s age are likely to have progressed by three-quarters of a diopter this year and he or she has progressed by one-quarter of a diopter, that’s a good result. Parents are very much guided by the information we give them, and we have a responsibility to do that correctly.
Engaging and Educating Patients, Parents, and Practitioners about Myopia Control
Dr. Nichols: What exactly do we mean by myopia management? What should the practitioner be thinking about relative to myopia management?
Dr. Gifford: “Management,” rather than “treatment,” is how we should think about it. Bringing in the glaucoma analogy again, we’re managing myopia over a period of time. Management starts with assessing the patient’s risks for either development or progression. This includes the pre-myope, the child who’s at risk of becoming myopic, whether that’s due to family history or individual characteristics. Then we need to prescribe the appropriate correction. To digress briefly, I’ve noticed that parents can have the misconception that once their child starts atropine, their myopia will be fixed. So we really need to explain and ensure they understand that we still need an optical correction. In my practice, I consider contact lenses to be the key optical correction, and we have other options if we need them. That brings me to a third aspect of myopia management, which is to educate. We need to educate the patient and the parents about the whole picture, the risks, how there’s more to the problem than measuring and correcting refractive error — that we need environmental and lifestyle interventions as well. We should look at the whole patient in terms of individual characteristics and binocular vision, and then prescribe the appropriate corrections and lifestyle changes.
Dr. Nichols: How do you approach the patients and parents? For example, how do you start the discussion about treatment options?
Dr. Berntsen: At the University of Houston Myopia Control Clinic, several doctors offer myopia control. We stress that all of us should ensure that we clearly present to parents the evidence to support our treatment recommendations. We introduce multifocal contact lenses or orthokeratology first, depending on the level of myopia. Our interpretation of the evidence is that ortho-K doesn’t produce the same kind of effect as can be achieved with a soft center-distance multifocal contact lens for very low amounts of myopia. Orthokeratology at very low amounts of myopia doesn’t give the same type of optical effect that you can get by putting on a soft multifocal. When parents ask specifically about atropine, we explain what we know and don’t know about it. Very often, I think parents appreciate that. They become engaged in understanding why we’re making the recommendations that we’re making.
We let parents know what we can expect to happen as far as results, on average, while making it clear that we can’t predict exactly what their child’s outcome will be. We stress, too, that no treatment option will completely stop the progression of the myopia. In addition, it’s important to let them know up front that the prescription will change. Otherwise, when there is a change in their child’s prescription, they think you don’t know what you’re doing. It’s much easier to educate about this at the outset than to try to explain it later.
Regarding children and contact lenses, some parents have no issue whatsoever and others have the concern “Can my kid wear contact lenses?” We’re able to tell them yes, she can; we have 7-year-olds who have no problem independently inserting, removing, and caring for their contact lenses. From there, we make our recommendation. Overall, it’s important that the patient is motivated and the parent is involved, and that the treatment recommendations are individualized.
Dr. Gifford: Speaking of kids and contact lenses, as we’ve been discussing, the scientific data increasingly point to contact lenses as our best option for myopia control. Therefore, embracing myopia management in clinical practice means embracing pediatric contact lens fitting. Colleagues have questioned whether pediatric contact lens wear is more dangerous than those lifelong pathology risks which come with progressing myopia. A few years ago, I conducted an analysis of the risks of contact lens wear compared to the risks of complications from myopia. Based on several references, as well as a few assumptions about lifetime risks, I compiled the annual incidence and lifetime risk of retinal detachment, glaucoma, myopic maculopathy, microbial keratitis (MK), MK resulting in loss of best-corrected visual acuity, and infiltrative keratitis.30 What the numbers reveal is quite sobering. For example:
- The pediatric daily disposable contact lenswearer who doesn’t progress past -3.00D is still three times more likely to have a retinal detachment in his/her lifetime than MK from daily disposable lenses.
- The pediatric myope who progresses into the 3.00D-6.00D range of myopia is equally likely to have a retinal detachment than to have a case of MK with orthokeratology in a lifetime, and minimal likelihood of vision loss with the latter.
- The myope over -5.00D is nearly four times more likely to develop myopic maculopathy in a lifetime than MK from a lifetime of orthokeratology or daily wear silicon hydrogel contact lenses.
- Glaucoma in a myope -1.00D or more is about as likely as MK over a lifetime of ortho-K wear.
- The annual risk of retinal detachment in the 3.00D-6.00D myope is five times higher than his or her annual risk of MK from daily disposable contact lenses and on par with the risk of MK from pediatric ortho-K.
It’s easy to see that if a pediatric myope is actively managed, and doesn’t progress past -3.00D, the ocular health risks are dramatically reduced. Lower myopia makes contact lens wear for myopia control riskier by comparison, but these numbers show us that the contact lens risks are much lower than many doctors think. It’s important for us to look beyond the immediate risks of contact lens wear to the lifetime management of our patients.
Dr. Nichols: As we know, regulatory agencies aren’t moving as fast as we’d like in response to the growing body of evidence in myopia control. The interventions that have been shown to work remain off label. But, in your minds, is there any doubt that managing myopia as we’ve been discussing shouldn’t be standard of care?
Dr. Aller: While it’s definitely my standard of care, until it’s being done by a majority of practitioners, or perhaps for some practitioners until it has official approval from the FDA, we can’t really call it standard of care. However, and this is a point Dr. Berntsen often makes, even if it isn’t your intent to manipulate defocus on the retina, you’re doing it one way or another with everything you prescribe.
Dr. Nichols: Dr. Gifford, how did you get started with myopia control as a segment of your practice?
Dr. Gifford: Once I started talking about myopia management with parents, I found we’d be having long, involved conversations about research papers, treatment options, and so on. So I developed a communication tool to streamline that process. The more I talked with colleagues at clinical conferences, the more they were requesting copies of it. That led me to develop MyopiaProfile.com , a resource for optometrists. Practitioners can download the communication tool and adapt it for their own use. The site includes a blog and other information. Also, my optometrist husband, Paul Gifford, PhD, and I developed MyKidsVision.org , which aims to tell the story of myopia to parents. After all, what’s the point of practitioners getting involved with myopia control if parents don’t know or understand why this is an issue. We find that doctors are using this information in the exam room as they’re explaining the whole myopia story to parents, including genetic and environmental risks, and potential solutions to the problem.
Other useful resources are available as well, including MyopiaPrevention.org and MyopiaControl.com . Contact Lens Spectrum devoted an issue to myopia last year that contains very informative papers, including one by Langis Michaud, OD, that provides guidelines for choosing treatments. The resources for understanding the scientific basis for myopia control are available, and they’re crucial to practitioners’ understanding and ability to field the questions they’ll be asked.
Dr. Nichols: Do you make recommendations related to the modifiable risk factors in your practice?
Dr. O’Connor: Yes, by the time we’ve finished the exam and the decision has been made to pursue myopia control, we’ve already walked through the information at MyKidsVision.org and delved deeper into whichever areas we need to flesh out depending on the individual case. We talk about the two main modifiable risk factors: first, the amount and duration of near work as well as the working distance, and second, time spent outdoors. We point out that we’re not saying kids should study less, but that we want them to manage these factors in whatever ways they can. We say a great place to start is to move the working distance out somewhat, in other words, don’t hold that tablet or cell phone right at the nose. I stress the 20-20-20 rule and even take it a step further by suggesting that for every 20 minutes spent looking at a screen or book, 20 minutes should be spent outdoors.
Dr. Gifford: Convincing people to make lifestyle changes is one of the most difficult things to do in medicine. However, we have evidence behind the recommendations we’re making and that evidence should be part of our message.
Dr. Nichols: How do parents react when they learn you can provide treatment that can help?
Dr. O’Connor: Some are relieved; some are even excited, particularly those who are nearsighted themselves. Often, parents will tell me they’ve always worried their child’s vision would get as bad as their own.
Challenges and Opportunities
Dr. Nichols: What do you think are the biggest challenges and the biggest opportunities in managing myopia?
Dr. Gifford: We can sum up the challenges and the opportunities with one statement: just do something. Even though more awareness now surrounds myopia control, it’s discussed at conferences more frequently, and treatment options are available, there’s still a reticence on the part of some doctors to “put the wheels in motion.” That’s the biggest challenge as I see it, but it’s also the biggest opportunity. Do something, start somewhere, whether that means atropine for the spectacle-wearing child or center-distance multifocal contact lenses. We have solutions we can offer, we just have to do something for these patients. Start by having these conversations.
Also, as a community of eyecare providers, if we understand that myopia is a disease with lifelong ramifications as opposed to something that simply requires correction, then we send a very different message to the public. One key message, which has been picked up in the popular media where I practice in Australia, is screen time vs. green time. As Dr. O’Connor said previously, parents don’t want us to tell children to study less, but they don’t mind if we tell them to get off the iPad or get away from the screen, so the screen time vs. green time message has gained some traction and momentum in Australia.
Dr. Aller: I agree that where disinterest in providing this care exists it needs to be overcome. Sadly, most of the disinterest is amongst our colleagues and while the optical industry is making progress, it is much too timid in my opinion and much too slow to meet this challenge. Optometrists have the unique challenge and the tremendous opportunity to take responsibility for managing the pending myopia epidemic. Because axial elongation is irreversible, pathologies associated with excess elongation are likely also irreversible, so the challenge for optometry is to get ahead of these changes and start now to lessen excess myopia progression. Perhaps as in no other field and with no other conditions or diseases, optometry actually has a chance to dramatically lessen the prevalence of blindness and vision impairment associated with excessive myopia progression thirty or more years into the future. I would encourage practitioners, as Dr. Gifford said, to get started now.
Dr. Berntsen: What we’re talking about is a paradigm shift, and right now, we’re in the midst of it. We’ll get to the point where we, as a community, are routinely discussing this with our patients. Until then, these conversations may be the first time a parent hears about myopia management, so it’s a foreign topic to them. They’re of the mindset that when myopia increases, we just provide a new pair of glasses and that’s it. They’re not yet hearing the message about the risk factors for serious ocular diseases and conditions. So doctors need to start talking about it consistently, and, I agree, that is both the biggest challenge and the biggest opportunity.
Dr. O’Connor: Once a practitioner decides to incorporate myopia management into his or her practice, one of the biggest challenges is learning how to get a patient’s entire team on board. Of course, the patient has to be willing, but you also need to get at least one parent on board. Sometimes you need buy-in from both parents — or even grandma. I had a situation in my practice in which a patient and her mother decided to pursue myopia management, and after 6 months of successful control with multifocal contact lenses, the father called and informed me he was no longer willing to pay for the lenses.
I hope this won’t be the case for long, but right now, I think the biggest opportunity for practitioners of myopia management is practice differentiation because so few eyecare providers have embraced the importance of this field. It’s an opportunity to make patients and families happy and generate referrals at the same time.
Dr. Nichols: Certainly, management of myopia presents a growth opportunity for individual practices and optometry as a whole. It’s not only an opportunity to take good care of the patients in our exam chairs but also to contribute to reducing vision loss on a global scale. As Noel Brennan has informed us, if the rate of myopia progression could be reduced by just 33%, the frequency of high myopia, which puts eyes at significant risk for sight-threatening complications, would be reduced by 73%.31 And, if the rate of myopia progression could be reduced by 50%, the frequency of high myopia would be reduced by 90%. That would erase quite a bit of blindness from the world. •
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